担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

The flapping wings of insects undergo large deformations caused by aerodynamic forces, resulting in cambering. Insect-mimetic micro wings for flapping-wing nano air vehicles mimic these characteristic deformations. In this study, a 2.5-dimensional insect-mimetic micro wing model for flapping-wing nano air vehicles is proposed to realize this type of wing. The proposed model includes a wing membrane, a leading edge, a center vein, and a root vein, all of which are modeled as shell elements. The proposed wing is a 2.5-dimensional structure and can thus be fabricated using polymer micromachining. We conducted a design window search to demonstrate the capabilities of the wing. The design windows, which are areas of desirable design solutions in the design parameter space, are iteratively searched using nonlinear finite-element analysis under quasi-steady aerodynamic modeling. Here, thickness is selected as a design parameter. The properties of real insects, polymer materials, and fabrication conditions are used to determine the other parameters. A fabricable design solution that generates sufficient camber is found from the design windows.

DOI： 10.3390/biomimetics9030133

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper presents a novel fabricable design and demonstration of a polymer micromachined wing for flapping wing pico air vehicles, which is capable of producing camber deformations similar to those of real insects. The proposed wing is a 2.5-dimensional structure comprised of the leading edge, center, and root veins, and the wing membrane such that it can be fabricated using polymer micromachining. The design window that refers to the area of satisfactory design solutions is iteratively searched using a nonlinear finite element structural analysis. In the design problem, the mean camber is the design characteristic, the thickness of each vein is the design parameter, and the design constraint is the fabricability. A final design solution with sufficient camber is selected from the design window, and the fabricability is demonstrated using polymer micromachining.

DOI： 10.1109/NEMS60219.2024.10639876

Scopus

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

The inverse and direct piezoelectric and circuit coupling are widely observed in advanced electro-mechanical systems such as piezoelectric energy harvesters. Existing strongly coupled analysis methods based on direct numerical modeling for this phenomenon can be classified into partitioned or monolithic formulations. Each formulation has its advantages and disadvantages, and the choice depends on the characteristics of each coupled problem. This study proposes a new option: a coupled analysis strategy that combines the best features of the existing formulations, namely, the hybrid partitioned-monolithic method. The analysis of inverse piezoelectricity and the monolithic analysis of direct piezoelectric and circuit interaction are strongly coupled using a partitioned iterative hierarchical algorithm. In a typical benchmark problem of a piezoelectric energy harvester, this research compares the results from the proposed method to those from the conventional strongly coupled partitioned iterative method, discussing the accuracy, stability, and computational cost. The proposed hybrid concept is effective for coupled multi-physics problems, including various coupling conditions.

DOI： 10.32604/cmes.2024.049694

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>In this study, we propose a new feedback control model for insect flight maneuverability, and conduct the numerical analysis using the proposed model. In the proposed model, the feedback control based on the observation for actual insects is introduced to the partitioned analysis model for the wing-body interaction, where the flapping wings and the surrounding air flow coupling is monolithically formulated using a finite element method such that the wing’s characteristic motions are simulated stably, while the one-way coupling from the wings to the body is used assuming a perturbation from the quasi-steady flight state. The roll control, on which we focus here, in our numerical result shows the good agreement with the body’s attitude control of an actual insect observed in the previous experiment. In our future work, we will elucidate a maneuverability mechanism of controlling body’s attitudes in insect flapping flight using the proposed model.</p>

DOI： 10.15748/jasse.11.201

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jasse/11/1/11_201/_pdf

担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

It is still unclear how elastic deformation of flapping insect wings caused by the aerodynamic pressure results in their significant cambering. In this study, we present that a vein–membrane interaction (VMI) can clarify this mechanical process. In order to investigate the VMI, we propose a numerical method that consists of (a) a shape simplification model wing that consists of a few beams and a rectangular shell structure as the structural essence of flapping insect wings for the VMI, and (b) a monolithic solution procedure for strongly coupled beam and shell structures with large deformation and large rotation to analyze the shape simplification model wing. We incorporate data from actual insects into the proposed numerical method for the VMI. In the numerical analysis, we demonstrate that the model wing can generate a camber equivalent to that of the actual insects. Hence, the VMI will be a mechanical basis of the cambering of flapping insect wings. Furthermore, we present the mechanical roles of the veins in cambering. The intermediate veins increase the out-of-plane deflection of the wing membrane due to the aerodynamic pressure in the central area of the wing, while they decrease it in the vicinity of the trailing edge. As a result, these veins create the significant camber. The torsional flexibility of the leading-edge veins increases the magnitude of cambering.

DOI： 10.3390/biomimetics8080571

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In flapping insect wings, veins support flexible wing membranes such that the wings form feathering and cambering motions passively from large elastic deformations. These motions are essentially important in unsteady aerodynamics of insect flapping flight. Hence, the underlying mechanism of this phenomenon is an important issue in studies on insect flight. Systematic parametric studies on strong coupling between a model wing describing these elastic deformations and the surrounding fluid, which is a direct formulation of this phenomenon, will be effective for solving this issue. The purpose of this study is to develop a robust numerical framework for these systematic parametric studies. The proposed framework consists of two novel numerical methods: (1) A fully parallelized solution method using both algebraic splitting and semi-implicit scheme for monolithic fluid–structure interaction (FSI) equation systems, which is numerically stable for a wide range of properties such as solid-to-fluid mass ratios and large body motions, and large elastic deformations. (2) A structural mechanics model for insect flapping wings using pixel modeling (pixel model wing), which is combined with explicit node-positioning to reduce computational costs significantly in controlling fluid meshes. The validity of the proposed framework is demonstrated for some benchmark problems and a dynamically scaled model incorporating actual insect data. Finally, from a parametric study for the pixel model wing flapped in fluid with a wide range of solid-to-fluid mass ratios, we find a FSI mechanism of feathering and cambering motions in flapping insect wings.

DOI： 10.1002/fld.5251

Scopus

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記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

The novelty of this study includes the development of an insect-inspired flapping wing nano air vehicle (FWNAV) using polymer micromachining or MEMS flyer and its computational flight performance using a fluid-structure interaction (FSI) analysis. The present FWNAV consists of a micro transmission with a support frame, a micro wing, and a piezoelectric bimorph actuator. This FWNAV can be easily fabricated using polymer micromachining and its flight performance can be accurately predicted using the FSI analysis. Hence, this study will lead toward the development of tethered and flyable FWNAVs with the size of the smallest flying natural insects.

DOI： 10.1109/MEMS49605.2023.10052580

Kyutacar

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper demonstrates the importance of three-dimensional (3-D) piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator. It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects (i.e., piezoelectric coupling effect). In addition, there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end (i.e., 3-D effect). Hence, modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices, which contributes to the accurate prediction of their behavior.

DOI： 10.32604/cmes.2023.024614

Scopus

CiNii Research

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study, an iterative design window (DW) search using nonlinear dynamic simulation was proposed for polymer micromachined flapping-wing nano air vehicles (FWNAVs) that can satisfy both nonlinear and unsteady design requirements, which are contradictory to each other. The DW is defined as an existing area of satisfactory solutions in the design parameter space. The present FWNAVs have a complete 2.5-dimensional structure such that they can be fabricated using polymer micromachining. The micro-wing of our FWNAVs has been designed using morphological and kinematic parameters of an actual dipteran insect. Finally, using our method, we found the DW that allowed miniaturization of the design down to 10 mm while satisfying all the design requirements. Our findings demonstrate the possibility of further miniaturizing FWNAVs down to the size of small flying insects.

DOI： 10.1007/s10999-022-09635-4

Scopus

CiNii Research

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Piezoelectric-structure interaction (PSI) and fluid-structure interaction (FSI) are multi-physics coupled systems. These interactions affect the vibration characteristics of coupled systems and thus such complex coupled systems must be controlled. This paper proposes computational control based on the finite element method for strongly coupled multi-physics analysis of the PSI of a thin flexible piezoelectric bimorph actuator. The vibration characteristics and the effect of direct velocity and displacement feedback (DVDFB) control in coupled systems are investigated. The displacement and velocity feedback gains are used together as well as separately. DVDFB control is extended to the FSI of stiff and soft structures to study vibration characteristics using active control and compare the stability of the two types of structure. The results of PSI show a reduction in actuator displacement amplitude and a shift in the resonance frequency due to DVDFB control. For FSI, the results for a stiff material show a reduction in displacement. The velocity feedback gain has no effect for a stiff material and leads to instability due to a large control force. The results for a soft material show a reduction in displacement and amplitude and more stability compared to the case for the stiff material.

DOI： 10.1080/15502287.2022.2066032

Kyutacar

Scopus

CiNii Research

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This study endeavours to introduce an inventive hierarchical coupling methodology for evaluating the flight capabilities of polymer micromachined flapping-wing nano air vehicles (FWNAVs) using advanced computational tools. Furthermore, our objective is to provide a practical demonstration of FWNAVs in both tethered and airborne scenarios. These dual objectives represent the distinctive and pioneering aspects of this research. Such FWNAVs, which are insect-inspired robots, have a 2.5-dimensional structure. An FWNAV comprises a micro piezoelectric drive system and a pair of micro thin flexible wings. The drive system includes a micro transmission and a piezoelectric bimorph actuator. The flight performance of the designed FWNAV is evaluated using a hierarchical coupling approach, where the whole system is decomposed into a micro wing and a micro piezoelectric drive system. The coupling between these parts is modelled as one-way coupling and that between the micro wings and the surrounding air is modelled as strong coupling. In the one-way coupling analysis, nonlinear structural dynamic analysis is conducted for the micro piezoelectric drive system, where the dynamic response is transmitted to the micro wings via the Dirichlet boundary condition. In the strong coupling analysis, strongly coupled fluid-structure interaction analysis is conducted for the micro wings and the surrounding air to consider their strong coupling. The optimisation of flight performance is conducted using fluid-structure interaction analysis to achieve sufficient lift force to support the weight of an FWNAV. The design of a tethered and flyable FWNAV with a size of 10 mm or smaller is demonstrated. This FWNAV can be easily fabricated using polymer micromachining.

DOI： 10.1080/19942060.2023.2271053

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Multilayered flexible piezoelectric energy harvesting devices (FPEDs) are a new future harvesting technology which are highly flexible and lightweight than familiar cantilever piezoelectric energy harvesters. This mechanical vibration driven FPED is a strongly coupled multiphysics phenomena that involve complex natural three-way interaction among the composite piezoelectric structure, the electric charge accumulated in the piezoelectric material, and a controlling electrical circuit attached to it. Efficient and accurate computational solution approaches are essential for analyzing these mechanical vibration-driven FPEDs to capture the main physical aspect of the coupled phenomena and to accurately predict the output voltage. While there are some numerical models for simple familiar cantilever type piezoelectric energy harvester reported in the literature, a fully three-dimensional strongly coupled model for complex material distributed, complex geometry, and multilayered FPED involving strong coupling of structure, piezoelectricity, and circuit phenomena has not yet been developed. A partitioned iterative algorithm is developed using a hierarchical decomposition approach wherein the coupled three fields are solved separately and coupled through loop union integration techniques that provide an efficient and accurate simulation of FPEDs. The simulation results matched the experiment results very well. This study provides a basis for the natural extension of partitioned iterative finite element coupled algorithm to simulate the future piezoelectric energy harvesting technologies involving a strong coupling of structure, piezoelectricity, and circuit phenomenon.

DOI： 10.1080/15502287.2023.2291013

Kyutacar

Scopus

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担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>In a micro piezoelectric drive system for insect-mimetic flapping wing nano air vehicles, a small translational displacement of the piezoelectric bimorph is converted to a large angular displacement using a transmission based on the geometric nonlinearity of large bending of the elastic hinges. The piezoelectric bimorph and the transmission strongly interact with each other due to the scale effect. Furthermore, in the piezoelectric bimorph, the direct and inverse piezoelectric effects are coupled with each other. Hence, in the micro piezoelectric drive system, the direct-piezoelectric, inverse-piezoelectric, and structural coupling occurs. In this study, a finite element analysis method based on the block successive under-relaxation method is proposed for the dynamic analysis of this triply coupled phenomena, and the dependency of the convergence property on the relaxation coefficient is investigated.</p>

DOI： 10.1299/jsmecmd.2023.36.os-0202

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2023.36/0/2023.36_OS-0202/_pdf

担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmebiofro.2023.34.1f10

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmebiofro/2023.34/0/2023.34_1F10/_pdf

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：最終著者   記述言語：日本語   掲載種別：記事・総説・解説・論説等（その他）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Insect flapping wings undergo large deformations such as feathering and cambering for creating large thrust forces. Hence, insect-mimetic wings for flapping wing nano air vehicles (FWNAVs) will replicate these characteristic deformations. For the purpose of realizing this type of wings, in this study, a 2.5-dimensional (2.5-D) insect-mimetic wing model for FWNAVs is proposed. The proposed wing model consists of the leading-edge, the central vein, the root vein, and the membrane, all of which are described by shell elements. The feathering and cambering of the proposed wing model can be caused by the aerodynamic pressure. Furthermore, the proposed wing can be fabricated using polymer micromachining because of the complete 2.5-D structure. In order to demonstrate these capabilities, we perform the design window (DW) search. The DW is defined as the existing area of satisfactory design solutions in the design parameter space, where each solution can produce a sufficient camber. The DWs for the leading-edge, the central and root veins are searched continuously using the geometrically nonlinear finite element analysis under quasi-steady aerodynamic modeling. The thickness is chosen as the design parameter, while the other parameters are set following actual insects and polymer materials. Finally, we determine the final solutions from the DWs for a specific polymer micromachining technique. In our future work, the proposed solutions will be manufactured for the future miniaturization of FWNAVs.

DOI： 10.1109/NEMS54180.2022.9791094

Kyutacar

Scopus

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担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>This study proposed a partitioned method with a feedback control to analyzed maneuvering of insects during flapping flight. This method decomposed the insect flapping flight into wing and body subsystems and then coupled them using feedback control. In the wing subsystem, the strong coupling of the flexible wings and surrounding fluid was accurately analyzed using the finite element method to obtain the thrust forces acting on the insect’s body. The resulting thrust forces were passed from the wing subsystem to the body subsystem, and then rigid body motion was analyzed in the body subsystem. The controlling of wing subsystem is done by the feedback control using the body angular displacement and velocity. The fundamental performance of the proposed method is demonstrated from the comparison between the present results and the actual observation of maneuver.</p>

DOI： 10.1299/jsmecmd.2022.35.12-07

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2022.35/0/2022.35_12-07/_pdf

担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

A flight device for insect-inspired flapping wing nano air vehicles (FWNAVs), which consists of the micro wings, the actuator, and the transmission, can use the fluid-structure interaction (FSI) to create the characteristic motions of the flapping wings. This design will be essential for further miniaturization of FWNAVs, since it will reduce the mechanical and electrical complexities of the flight device. Computational approaches will be necessary for this biomimetic concept because of the complexity of the FSI. Hence, in this study, a computational approach for the FSI design of insect-inspired micro flapping wings is proposed. This approach consists of a direct numerical modeling of the strongly coupled FSI, the dynamic similarity framework, and the design window (DW) search. The present numerical examples demonstrated that the dynamic similarity framework works well to make different two FSI systems with the strong coupling dynamically similar to each other, and this framework works as the guideline for the systematic investigation of the effect of characteristic parameters on the FSI system. Finally, an insect-inspired micro flapping wing with the 2.5-dimensional structure was designed using the proposed approach such that it can create the lift sufficient to support the weight of small insects. The existing area of satisfactory design solutions or the DW increases the fabricability of this wing using micromachining techniques based on the photolithography in the micro-electro-mechanical systems (MEMS) technology. Hence, the proposed approach will contribute to the further miniaturization of FWNAVs.

DOI： 10.3390/fluids7010026

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents a feasibility step in the development of an insect-inspired flapping wing nano air vehicle using advanced engineering technologies such as microelectromechanical systems (MEMS) technologies. To develop an insect-inspired flapping wing nano air vehicle, a one-wing polymer micromachined transmission is proposed in this paper. The novelty of this study includes (1) the use of the geometrically nonlinear bending deformation of a set of two parallel elastic hinges as the basis for the transmission mechanism, which produces a large rotational displacement from a small translational displacement, and (2) a complete 2.5-dimensional structure that can be fabricated using standard microfabrication techniques, including etching, photolithography, deposition, and curing, without any post-assembly. This design is also an improved version of our previous design, a two-wing polymer micromachined transmission. The transmission proposed here has a great advantage over other types of transmission mechanisms, including its low energy loss because no post-assembly is required (reduced friction loss); its low total weight; its capacity to be further miniaturized without difficulty; and its performance, i.e., ability to produce the necessary stroke angle of approximately 30° without resonance assistance.

DOI： 10.1088/2631-8695/ac2bf0

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

The key to the design of advanced micro electro–mechanical devices is an accurate evaluation of the circuit-integrated piezoelectric oscillator that accounts for its complicated configuration. Here, the direct numerical modeling of this oscillator leads to a general formulation as a structure–piezoelectric–circuit interaction. Hence, this study developed a strongly coupled partitioned iterative method for the structure–piezoelectric–circuit interaction. The proposed method was constructed using hierarchical decomposition, the partitioned iterative method for two coupled fields, and loop union. That is, the whole system of the coupled multiphysics is hierarchically decomposed into coupled two-field subsystems, partitioned iterative algorithms for two coupled fields are applied to these subsystems, and the coupling algorithms for these subsystems are reduced to a single coupling algorithm. In the proposed method, three distinct direct piezoelectric, inverse piezoelectric, and circuit solvers are strongly coupled with each other. The inverse piezoelectric solver uses shell finite elements to analyze the response of the thin oscillator efficiently, while the direct piezoelectric solver uses solid finite elements to accurately describe the three-dimensional distribution of the electric potential in the piezoelectric continuum. The proposed method can accurately analyze coupling phenomena in the RC circuit, piezoelectric shunt damping, and piezoelectric energy harvesting.

DOI： 10.1016/j.compstruc.2021.106572

Scopus

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   北九州市   2021年05月26日  -  2021年05月28日

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   北九州市   2021年05月26日  -  2021年05月28日

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   北九州市   2021年05月26日  -  2021年05月28日

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   北九州市   2021年05月26日  -  2021年05月28日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

This paper presents an improved design of polymer micromachined transmission for flapping-wing Nano Air Vehicles (FWNAVs) in comparison with our last design. Design Improvement includes (1) reduction of the crack and fracture during microfabrication, and (2) performance improvement of the transmission. The novelty of our polymer micromachined transmission includes (1) the transmission mechanism based on the geometrical nonlinear bending deformation, and (2) the complete 2.5-dimensional structure that can be fabricated using standard microfabrication techniques including the etching, the photolithography, the deposition, and the curing process. The complete 2.5-dimensional structure requires no post-assembly and leads to further miniaturization without so much difficulty. Each wing of FWNAVs will be driven by the proposed transmission and actuator separately. The present transmission can produce around 40° stroke angle, which is about 50% higher than that of our previous work without considering the mass effect.

DOI： 10.1109/NEMS51815.2021.9451440

Kyutacar

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

The piezoelectric energy harvesting devices for the conversion of mechanical vibration into electric energy via a flexible piezoelectric energy harvesting (FPED) structure have gained greater attention. Here, the large deformation of the FPED structure causes a strong interaction with the electric field (direct-piezoelectric effect) and structural field (inverse-piezoelectric effect), and vice-versa. Also an electrical circuit is attached to the electrodes covering the piezoelectric layers. This becomes a three-way coupling of the structure, the electromechanical effect of the piezoelectric material, and the electrical circuit. A mathematical and numerical model of the complex physical system of the involved multiphysics coupling characteristics in order to predict the operational properties and to increase the performance is very important. The presentation will discuss a partitioned coupling algorithm based hierarchical decomposition using finite element method for piezoelectric energy harvesting from structure-piezoelectric-circuit interaction. Results obtained with the finite element analysis are compared with the experimental results of PEHDs with base excitation reported in the literature.

DOI： 10.23967/wccm-eccomas.2020.163

Scopus

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this study, the coupled solid piezoelectric and shell inverse-piezoelectric analysis method for a thin piezoelectric bimorph with metal layers is proposed. The piezoelectric bimorph is usually thin and includes the metal layers such as the electrode and the shim plate. In the proposed method, the solid and shell elements are used for the piezoelectric and inverse-piezoelectric analyses, respectively, since the solid elements can describe the various types of the distributions of the electric potential along the thickness, and the shell elements are suitable for analyzing the thin structure. The block Gauss-Seidel method is used to couple the solid piezoelectric and shell inverse-piezoelectric analyses. In the iterative passing of the solution variables, the transformation method is used between the solid and shell elements. The rules of mixture for the bending rigidity and the mass are used for modeling the single shell structure in the inverse-piezoelectric analysis. A pseudo-piezoelectric modeling for the conductor is proposed to consider the metal layers in the piezoelectric analysis. This modeling allows us to reuse existing programs of the piezoelectric analysis without any modification.

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

A partitioned iterative method based on hierarchical decomposition is proposed for providing numerical modeling and analysis of the piezoelectric energy harvester which is involved in coupled fluid-structure interaction, coupled electro-mechanical, and a controlling electrical circuit for piezoelectric structural applications in energy harvesting. This circuitintegrated piezoelectric structural application in energy harvesting surrounded by fluid media takes the form of natural four-way coupling of fluid flow, the structure, the electromechanical effect of the piezoelectric material, and the electrical circuit. This can be formulated exactly as a fluid-structure-piezoelectric-circuit interaction. These coupled four fields are hierarchically decomposed into the fluid-structure interaction, structure-piezoelectric interaction, and piezoelectric-circuit interaction interactions. Then these subsystems are decomposed into each field. The proposed finite element method enables to reuse of existing techniques because of its modularity. Furthermore, scalability to multiphysics and multisystem couplings is expected. There are some numerical approaches in particular monolithic coupling methods are studied which are computationally expensive and leads to an ill-conditioned coefficient matrix. Nevertheless, accurate modeling for predicting the characteristics of this four-way coupling using partitioned methods has not yet been developed. This method enables an investigation of piezoelectric structures in fluid with complex geometry, material composition, and attached electrical circuits to the harvester. A flexible piezoelectric bimorph harvester in the converging channel is analyzed to demonstrate the efficiency of the proposed method. The results indicate that the method captures the coupled effect accurately.

DOI： 10.23967/coupled.2021.031

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

The novelty of this study is the proposition of a design window (DW) search using the nonlinear dynamic simulation, and the finding of the DWs of the polymer micro transmission that satisfies the nonlinear and unsteady design requirements conflicting with each other simultaneously. Here, the DW is defined as an existing area of satisfactory solutions in a design parameter space, which is defined as the flapping frequency equivalent to small flies and the mass of the micro wing supported by the transmission design. Since this micro transmission is the key component of the flapping wing nano air vehicle (FWNAVs) which has a 2.5-D structure and is fabricated using polymer micromachining so proposed DWs will contribute to further miniaturizing FWNAVs.

DOI： 10.1109/ICRAE53653.2021.9657802

Kyutacar

Scopus

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担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>Any shape change of insect’s wings during their flapping motion will be passively caused by external forces such as the inertial and aerodynamic forces because the wings have no interior muscle. The camber deformation, which is the focus of this study, plays an important role in the aerodynamic performance of the insect’s flapping flight. In this study, the effect of passive cambering is investigated using a fluid-structure interaction analysis and a pixel wing model using only structured shell elements, which adequately simulates the camber deformation in actual insects.</p>

DOI： 10.1299/jsmecmd.2021.34.176

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2021.34/0/2021.34_176/_pdf

記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>Bonding and forming of carbon fiber reinforced plastic by induction heating are required for medium-sized aircraft manufacturing. In this paper, electromagnetic and thermal conduction coupled finite element analysis method is described for induction heating of carbon fiber dry cloth. Experiments of induction heating are also performed to discuss the validity of analysis method and experimental method. Comparing the temperature of test pieces between analysis and experimental results, validity of both methods is confirmed for both aluminum sheet and carbon fiber dry cloth.</p>

DOI： 10.1299/jsmecmd.2021.34.130

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2021.34/0/2021.34_130/_pdf

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>In micro-electro-mechanical systems using piezoelectric bimorph actuators such as FWNAV, small displacements given by the actuators can be magnified using a transmission using the flexible structure. Hence, in these systems, coupling among the direct and inverse piezoelectric effects, and the flexible structure occurs. In this study, a partitioned iterative method is proposed based on the block SUR algorithm for this strongly coupled problem, and the basic performances are demonstrated in numerical examples.</p>

DOI： 10.1299/jsmecmd.2021.34.249

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2021.34/0/2021.34_249/_pdf

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>In recent years, energy harvesting from environment has attracted much attention. In particular, piezoelectric bimorph energy harvesters, which are effective as an energy source for MEMS, have been widely studied. In piezoelectric energy harvesters, structure, piezoelectricity, and circuit are strongly coupled in a complicated and hierarchical manner. For the three-field coupling phenomena, unlike two-field coupling phenomena, various partitioned algorithms are possible. Hence, in this study, we develop three partitioned algorithms using hierarchical decomposition: In the first algorithm, all fields are solved implicitly or strongly coupled using the block Gauss-Seidel (BGS) method (fully strong coupling algorithm). In the second algorithm, the structure-piezoelectric interaction is solved implicitly or strongly coupled using the BGS method, and the circuit is solved explicitly or weakly coupled (partially strong coupling algorithm). In the third algorithm, all fields are solved explicitly or weakly coupled (fully weak coupling algorithm). These methods are applied to a typical piezoelectric harvester, namely a cantilevered piezoelectric bimorph, and their performances such as the accuracy and the computational cost are discussed.</p>

DOI： 10.1299/jsmecmd.2021.34.210

CiNii Research

その他リンク： https://www.jstage.jst.go.jp/article/jsmecmd/2021.34/0/2021.34_210/_pdf

記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>　Heating analysis of CFRP and carbon fiber dry cloth for aircraft structures, which is expected for a medium-sized aircraft, is performed. Comparing the temperature of test pieces between numerical and experimental results, validity of both experimental and analytical methods is confirmed for both aluminum and carbon dry cloth sheet. Analysis is made for the layers of carbon dry cloth sheet and CFRTP plate.</p>

DOI： 10.14243/jsaem.29.576

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130008142891

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>In insect flapping wings, the camber deformation is caused by the aerodynamic forces. Since the camber will improve the aerodynamic performance of Flapping Wing Nano Air Vehicles (FWNAVs), it is important to elucidate the passive mechanism of the cambering. The pixel wing model consisting of a structured mesh using shell elements that can simulate the camber deformation caused by the fluid–structure interaction has been proposed for the purpose of computational efficiency. In this study, the performance of the pixel wing model is evaluated as the pixel model resolution is changed. The minimum pixel model resolution is determined such that it can keep enough magnitude of camber compared to actual insects. Furthermore, it is found that the cambering of the pixel wing model can be effectively changed using the wing's chord-wise flexural stiffness given by the root vein pixels and the thickness of the wing membrane pixels.</p>

DOI： 10.15748/jasse.8.163

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130008062974

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Piezoelectric-structure-fluid interaction is a complex multiphysics coupled phenomena appears wherein piezoelectric devices are in contact or surrounded by the fluid media. The piezoelectric energy harvesting using ocean waves, wind flow, and mechanical vibrations are some of the popular energy savaging methods wherein thin piezoelectric bimorphs surrounded by the fluid is used for power harvesting. With recent advances on micro air vehicles actuated by piezoelectric bimorph actuators in the fluid (surrounding media) as attracted the of piezoelectric-structure-fluid interaction. Generally, in these applications, the piezoelectric bimorph is thin, flexible, and surrounded by the fluid. The large deformation of the thin flexible piezoelectric bimorph causes strong interaction with the electric field (piezoelectric effect) and the surrounding fluid, and inversely, these two fields significantly affect the structure. The piezoelectric field-structure-fluid interaction analysis is very significant. In this work, we propose a hierarchal decomposition method to solve piezoelectric-structure-fluid interaction of a piezoelectric bimorph in the fluid. The proposed method is applied to a flexible restrictor flap in converging channel, where the rubber flap is replaced by the piezoelectric bimorphs made of PVDF or PZT-5H. The resonance frequency of the piezoelectric bimorph in the fluid agrees well with the theoretical and numerical pure FSI cases. These results show a good agreement with the previous studies.

Scopus

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this study, a computational fluid-structure interaction (FSI) framework for characteristic deformations in insect's wings is proposed. The proposed framework consists of a pixel wing model using a structured shell finite element mesh, a projection method for the monolithic FSI monolithic equations using an algebraic splitting, and the FSI dynamic similarity law to measure dynamic similarity between model's and actual insect's flights. It is shown that the proposed framework can directly simulate passive feathering and cambering in insect's wings caused by the FSI, whose magnitudes are very close to those of actual insects.

DOI： 10.23967/coupled.2021.012

Scopus

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記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（研究会，シンポジウム資料等）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2020 IEEE. This paper presents a polymer micromachined transmission from small translational displacement to large rotational displacement, which has the potential for further miniaturizing a variety of micro robot applications such as insect-inspired flapping wing nano air vehicles (FWNAVs). Innovative claims include (1) the transmission mechanism using a geometrically nonlinear bending, (2) the microfabrication process consisting of only the standard steps such as the deposition, the photolithography, the curing, and the release without any post-assembling, and (3) the stroke angle of about 40° without any dynamic effect.

DOI： 10.1109/NEMS50311.2020.9265594

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2020 Elsevier Ltd A thin triple-layer piezoelectric bender, also known as a piezoelectric bimorph with a metal shim, consists of an elastic layer (metal shim) sandwiched between two piezoelectric layers. It is one of the most commonly used piezoelectric composite structures in both sensing and actuation applications. Therefore, this study deals with the coupled piezoelectric-structure interaction analysis of a thin piezoelectric bimorph with a metal shim. In this work, the best features of the solid and shell elements were combined to analyze the piezoelectric and structural fields, respectively, in a thin piezoelectric bimorph with a metal shim. This approach addresses the shortcomings of using a single finite element mesh for both the piezoelectric and structural fields. A transformation method using the block Gauss-Seidel algorithm is employed to exchange the variables between solid direct-piezoelectric and shell inverse-piezoelectric analyses. The metal layer can be analyzed as an elastic body with electrical boundary conditions. A pseudo direct-piezoelectric evaluation method for the metal shim in the piezoelectric analysis is proposed. This method allows us to reuse the existing piezoelectric analysis program, where the metal shim is analyzed as the pseudo direct-piezoelectric material in a single analysis procedure. The homogenization method for the evaluation of bending rigidity and mass is used for modeling the single shell structure in the inverse-piezoelectric analysis of a thin piezoelectric bimorph with a metal layer. Numerical results are given for various electrical configurations of actuators and sensors to validate the present method. Comparison with an exact solution illustrates the accuracy, efficiency, and capability of the developed solid direct and shell inverse-piezoelectric analysis coupled with a pseudo direct-piezoelectric evaluation method to capture the sensor and actuator response of a thin piezoelectric bimorph with a metal shim.

DOI： 10.1016/j.compstruct.2020.112284

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2020 Elsevier B.V. This paper proposes a numerical method for analyzing a thin piezoelectric bimorph in fluid. A hierarchically decomposed finite element method (FEM) is proposed for modeling the triply coupled piezoelectric-structure–fluid interaction. The electromechanical coupling (piezoelectric-structure interaction) behavior in a thin piezoelectric bimorph is described by the classical constitutive equation, the incompressible fluid flows by the Navier–Stokes equation and the structure by the Cauchy equation of motion. The piezoelectric-structure–fluid interaction system is decomposed into subsystems of fluid–structure interaction (FSI) and piezoelectric field, then the piezoelectric field and the FSI are coupled using the block Gauss–Seidel method, the fluid–structure interaction is split into the fluid–structure velocity field and the pressure field using an algebraic splitting and the fluid–structure velocity field is partitioned into fluid velocity field and structure velocity field. Using the proposed method, the resonance characteristics of a piezoelectric bimorph cantilever made of PVDF and PZT-5H material in fluid are investigated for actuation and sensor configurations.

DOI： 10.1016/j.cma.2020.113006

Kyutacar

Scopus

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2020 World Scientific Publishing Company. In this study, element-quality-based stiffening (EQBS) was developed as a method of maintaining mesh quality in the pseudoelastic mesh-moving technique. The proposed EQBS technique increases the stiffness of the element based on two element quality parameters, the element area and shape; this differs from techniques used in previous studies. Importantly, EQBS includes the previously proposed Jacobian-based stiffening (JBS) and minimum height-based stiffening (MHBS) techniques as a specific case. Therefore, it is quite general scenario of the selective stiffening of the mesh. The proposed EQBS technique was applied to the mesh-moving of a rectangular domain including a structure consisting of a square and a fin that undergo large translations and rotations. The proposed EQBS technique showed better performance than JBS on test problems with large translations and rotations applied to the structure. This is because EQBS considers the shear deformation of the element in addition to the tensile and compressive deformations.

DOI： 10.1142/S0219876218501463

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Copyright © Crown copyright (2018).All right reserved. Electric and Fluid-Structure interaction (EFSI) is a complex coupled multi-physics phenomenon appears in microelectromechanical system (MEMS) when these microdevices are operated in a fluid media. In this study, the EFSI phenomena refer to a combination of electromechanical (electric-structure interaction) coupling and fluid-structure interaction coupling. Both the electromechanical coupling and the fluid-structure interaction can be simulated in a monolithic way or in a partitioned iteration way. In the proposed method the electromechanical coupling is simulated in a partitioned iterative way with separate solvers for the electrical and mechanical equations using block Gauss-Seidel (BGS) iteration method, while the fluid-structure interaction is simulated in a monolithic way by solving the fluid and structure equations simultaneously using a projection method. The proposed algorithm combines these two methods to analyze the strongly coupled EFSI in MEMS. The proposed method is applied to a flexible flap made of piezoelectric bimorph actuator in a converging channel. The EFSI analysis results show a good agreement with FSI results when a very low input bias voltage is applied to the actuator.

Kyutacar

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>Cambering in the flapping wings of insects plays an important role in the aerodynamic performance of their flight. In a previous study, the authors proposed a wing model using shell finite elements to elucidate the mechanism of cambering. However, the analysis of a strongly coupled fluid–structure system using this model would be quite computationally expensive because of the necessity of robust mesh-moving techniques. Therefore, in this study, a new wing model using rectangular shell finite elements is proposed. In the proposed model, the veins and membranes are described as pseudo-elastic materials. The cambering of the proposed model is investigated by comparison with the previous model.</p>

DOI： 10.15748/jasse.7.181

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007855464

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

<p>アクチュエータやセンサに用いられる圧電バイモルフは，通常，電気回路に接続される．この場合，圧電バイモルフの機械的挙動は回路からの電荷の影響を受け，また圧電バイモルフは回路内でコンデンサのように振る舞う．ゆえに，圧電バイモルフを用いる電気機械システムの設計プロセスにおいて，逆圧電‐圧電連成に加えて，圧電バイモルフと回路との連成を考慮する必要がある．本研究では，この逆圧電‐圧電‐回路連成問題に対する新しい有限要素解析手法を提案する．薄い複合材圧電バイモルフを考慮するために，逆圧電解析にはシェル要素，圧電解析にはソリッド要素を用いる．従って，ソリッドとシェルの間における変数変換方法を用いる．回路解析は1自由度で記述する．また，圧電‐回路連成において，電位と電荷の連続性に基づく連成条件式を提案する．連成アルゴリズムは，ブロックガウスザイデル法に基づいている．逆圧電解析において，曲げ剛性および質量に対する材料の複合則を用い，圧電解析において，導体の疑似圧電体評価法を用いる．最後に，本解法によって，RC回路およびシャントダンピングにおける連成現象を正確に解析できることを示す．</p>

DOI： 10.11421/jsces.2020.20200015

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007885624

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 World Scientific Publishing Company. This work presents multiphysics numerical analysis of piezoelectric actuators realized using the finite element method (FEM) and their performances to analyze the structure-electric interaction in three-dimensional (3D) piezoelectric continua. Here, we choose the piezoelectric bimorph actuator without the metal shim and with the metal shim as low-frequency problems and a surface acoustic wave device as a high-frequency problem. More attention is given to low-frequency problems because in our application micro air vehicle's wings are actuated by piezoelectric bimorph actuators at low frequency. We employed the Newmark's time integration and the central difference time integration to study the dynamic response of piezoelectric actuators. Monolithic coupling, noniterative partitioned coupling and partitioned iterative coupling schemes are presented. In partitioned iterative coupling schemes, the block Jacobi and the block Gauss-Seidel methods are employed. Resonance characteristics are very important in micro-electro-mechanical system (MEMS) applications. Therefore, using our proposed coupled algorithms, the resonance characteristics of bimorph actuator is analyzed. Comparison of the accuracy and computational efficiency of the proposed numerical finite element coupled algorithms have been carried out for 3D structure-electric interaction problems of a piezoelectric actuator. The numerical results obtained by the proposed algorithms are in good agreement with the theoretical solutions.

DOI： 10.1142/S0219876218501062

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Miyazaki-shi   2019年11月05日  -  2019年11月07日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Miyazaki-shi   2019年11月05日  -  2019年11月07日

担当区分：筆頭著者   記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 Elsevier B.V. Thin piezoelectric bimorph cantilever is increasingly employed throughout the field of actuator and sensor applications in the microelectromechanical system (MEMS). Generally for finite element analysis of piezoelectric bimorph cantilever, three–dimensional (3D)solid element can accurately takes into account a linear or quadratic distribution of electric potential over the thickness for various electric configurations of the actuator and sensor applications. As the MEMS structures usually are quite thin and undergo large deformations, shell elements are very well suited for the structural discretization. This paper is focused on the development of a novel coupled algorithm to analyze the electromechanical coupling in a piezoelectric bimorph actuator and sensor using the shell and solid elements to simulate the structural and electric fields, respectively. The electric force induced by the inverse piezoelectric effect is transformed from the solid elements to the shell elements as an equivalent external force and moment, and the resultant displacements are transformed from the shell elements to the solid elements to evaluate the direct piezoelectric effect. Two different approaches were developed to analyze the electric field–structure interaction. In the first approach, for each block Gauss–Seidel (BGS)iteration, multiple full Newton–Raphson (N–R)iterations are executed until the tolerance criteria are satisfied. In the second approach, the BGS and N–R loops are unified into a single loop. A piezoelectric bimorph actuator and sensor were analyzed for various electrical configurations to demonstrate the accuracy of the proposed method.

DOI： 10.1016/j.finel.2019.02.001

Kyutacar

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   札幌市   2019年06月28日  -  2019年06月30日

記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019, International Institute of Welding. The characteristics of the cycles of coupled phenomena that occur among elastic-plastic contact deformation, current distribution, heat generation, and thermal conduction during resistance spot welding are examined using coupled finite element analyses. The current density peak that appears at the center of the interface moves outward along the interface to the high-contact resistance region, then the peaks in the current density, contact resistance, Joule heat generation, and temperature migrate outward with the contact edge followed by the melting zone during the welding process. The influence of welding parameters on the cycles of coupled phenomena is also examined. When the weld current is increased, the current density within the contact surface does not increase but enlarges the high-temperature region instead of heating the central part of the interface. When a small electrode force is applied, the nugget formation is initially enhanced not due to the increased contact resistance but rather because of the increase in the current density through the interface with a reduced contact area.

DOI： 10.1007/s40194-018-00699-5

Scopus

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   さいたま市   2019年05月29日  -  2019年05月31日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

DOI： 10.32604/icces.2019.05888

Kyutacar

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

日本   さいたま市   2019年05月29日  -  2019年05月31日

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>A piezoelectric bimorph for actuators and sensors is usually connected to a circuit. The piezoelectric bimorph is affected by charge from the circuit in its mechanical behavior, and it also plays a role of a capacitor in the circuit. Therefore, the coupling of the piezoelectric bimorph and circuit as well as the structure - piezoelectric coupling should be taken into account in the design process of the actuators and sensors using the piezoelectric bimorph. Here, the novel finite element analysis method is proposed for this structure – piezoelectric – circuit coupled problem. Structural and piezoelectric analyses are performed using the finite element method with the shell and solid elements, respectively. Circuit analysis is a single degree of freedom. The coupled equations for the piezoelectric – circuit coupling is proposed from the continuous conditions for the electric potential and charge. The coupled algorithm is based on the block Gauss-Seidel method and a novel transformation method between the solid and shell variables. In the structural analysis, the rule of mixtures about the bending rigidity and the mass is used. In the piezoelectric analysis, the pseudo-piezoelectric evaluation method is used.</p>

DOI： 10.1299/jsmecmd.2019.32.276

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007817403

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>The selective mesh stiffening in this study changes the stiffness of the element based on both the element area and shape. It includes the stiffening in the previous studies as a specific case, and leads to a general scenario in the pseudoelastic mesh–moving. This scenario gives better mesh quality in the mesh-moving of a rectangular domain with a structure consisting of a square and a fin undergoes large rotations. This is because the shear deformation of the element is adaptively considered.</p>

DOI： 10.15748/jasse.6.67

Kyutacar

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007611945

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>Piezoelectric energy harvesting from the mechanical vibrations has attracted considerable research interest in the last decade. This work presents a finite element modeling of forced vibration of flexible piezoelectric devices (FPED). The successful design of the FPED depends on the identification of the optimal geometry, material configurations, and loading conditions to achieve maximum power efficiency at a specific band of excitation frequencies. A piezoelectric energy harvesting (PEH) process from the mechanical vibration takes the form of two-way coupling between piezoelectric and inverse piezoelectric effect, while the piezoelectric energy harvesting from the ocean waves takes the form of three-way coupling between fluid, piezoelectric, and inverse piezoelectric effects. There are some experimental and theoretical studies about piezoelectric energy harvesting from the mechanical vibrations as-well as ocean waves in literature. Meantime, performing design optimization via experimental studies is very expensive. An accurate FE modeling of the coupling effects between the fluid, piezoelectric, and inverse piezoelectric effect will reduce the cost-effective design optimization and increase the energy efficiency of the PEH. In the present study, the FE analysis of FEPD is presented. The result obtained with the FE model is compared with the experimental model reported in the literature.</p>

DOI： 10.1299/jsmecmd.2019.32.279

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007817401

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>昆虫羽ばたき翼におけるキャンバーは，空力性能の向上に重要な役割を果たす．ゆえにその生成メカニズムを解明する事は，昆虫はばたき飛行を理解するために重要である．昆虫はばたき翼のキャンバー生成における翅脈の力学的役割を解明するために，はりとシェルの有限要素を用いた形状簡略化モデルが提案されている．このモデルでは，必然的に不均一な要素分割を用いているため，流体構造連成解析の場合，ロバストなメッシュ制御方法が必要となり，計算コストがかなり高くなることが予想される．そこで本研究では，メッシュ制御を簡易化できるように，均一な要素分割を用いるピクセルモデルを提案する．本モデルでは，メッシュを均一なシェル要素により構成し，その剛性の違いにより，翅脈と翼膜の役割りを与える．先行研究のモデルとの比較を通じて，提案モデルの基本的妥当性について検討する．</p>

DOI： 10.11345/japannctam.65.0_331

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130008100946

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 Tech Science Press. All rights reserved. This study proposed a partitioned method to analyze maneuvering of insects during flapping flight. This method decomposed the insect flapping flight into wing and body subsystems and then coupled them via boundary conditions imposed on the wing’s base using one-way coupling. In the wing subsystem, the strong coupling of the flexible wings and surrounding fluid was accurately analyzed using the finite element method to obtain the thrust forces acting on the insect’s body. The resulting thrust forces were passed from the wing subsystem to the body subsystem, and then rigid body motion was analyzed in the body subsystem. The rolling, yawing, and pitching motions were simulated using the proposed method as follows: In the rolling simulation, the difference of the stroke angle between the right and left wings caused a roll torque. In the yawing simulation, the initial feathering angle in the right wing only caused a yaw torque. In the pitching simulation, the difference between the front- and back-stroke angles in both the right and left wings caused a pitch torque. All three torques generated maneuvering motion comparable with that obtained in actual observations of insect flight. These results demonstrate that the proposed method can adequately simulate the fundamental maneuvers of insect flapping flight. In the present simulations, the maneuvering mechanisms were investigated at the governing equation level, which might be difficult using other approaches. Therefore, the proposed method will contribute to revealing the underlying insect flight mechanisms.

DOI： 10.32604/cmes.2019.06781

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 by the Japan Society for Computational Engineering and Science. Piezoelectric bimorph for actuators and sensors is usually thin and includes conductor layers such as the electrode and the shim plate. Therefore, this study deals with the coupled piezoelectric and inverse-piezoelectric analysis of thin piezoelectric bimorph with the conductor layers. Solid elements can describe the various types of distributions of electric potential along the thickness, while shell elements are more appropriate to analyze the thin structures. Therefore, instead of using piezoelectric solid elements or piezoelectric shell elements for both the piezoelectric and inverse-piezoelectric analyses, the solid and shell elements are used to simulate the electrical and structural fields, respectively. The coupled algorithm is based on the block Gauss-Seidel method and the transformation method between the solid and shell variables. In the structural analysis, the rule of mixtures for the bending rigidity and the mass is used. A pseudo-piezoelectric evaluation method for the conductor is proposed in order to use the existing programs for the piezoelectric and inverse-piezoelectric analyses without any modification. Finally, it is demonstrated that the proposed method shows very accurate potential distributions in the actuator and sensor modes of the thin piezoelectric bimorph with the conductor layers.

DOI： 10.11421/jsces.2019.20190011

Kyutacar

Scopus

CiNii Article

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© Springer Nature Switzerland AG 2019. Coupled finite element analysis is expected in several fields of research and development, where necessity of coupled analysis of not only two phenomena but also three or more phenomena is increasing. The demand for multiscale and multiphysics analyses is also increasing. A coupled analysis approach that combines an in-house code and a general-purpose commercial finite element analysis code using a message passing interface is very promising for these analyses. To examine the practical usefulness and effectiveness, this approach was applied to the triply coupled and multiscale analyses of a resistance spot welding problem and to the dynamic coupled analysis of an ultra sonic piezoelectric motor. The approach is effective to perform various types of coupled finite element analyses of multiphysics and multiscale problems.

DOI： 10.1007/978-3-030-14883-6_7

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>Resistance spot welding is widely used in manufacturing industries such as automotive industry. In this paper, we propose electric current analysis and thermal conduction analysis with deformation effect for resistance spot welding analysis. Effect of deformation on bonding strength and triply coupled effect for contact deformation, electric current and thermal conduction are discussed.</p>

DOI： 10.1299/jsmecmd.2019.32.227

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007817379

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2018 American Physical Society. This study shows that characteristic modes, such as the figure-eight mode, can be created in the path of the wing tip, which is caused by the fluid-structure interaction, using a flapping model wing with two lumped flexibilities describing the elevation motion as well as the pitching motion. A direct numerical simulation based on the three-dimensional finite element method for fluid-structure interaction (FSI) analyzes the behaviors of the model wing, the surrounding air, and their interaction, where the dynamic similarity law for the FSI is used to incorporate actual insect data, and the parallel computation algorithm is used to perform the systematic parametric study. Characteristic modes, such as the figure-eight mode, are observed in the path of the wing tip from the elevation motion of the simulated wing. This motion is considered as the forced vibration caused by the interaction with the surrounding fluid excited by the flapping of the wing. Therefore, this motion can be modulated by the flexibility to change the natural frequency, which can be controlled by the muscles at the base of the wing in the actual insect. The present simulation shows that the selection between these modes in the path of the wing tip depends on the ratio between the natural frequency of the elevation motion and the flapping frequency. In the case of the figure eight, the upward elevation motion of the wing acts on the leading-edge vortex (LEV) so as to keep its momentum upon stroke reversal. Therefore, this LEV can remain in the wake of the wing after stroke reversal and enhance the next LEV. Because of this effect, the lift increases significantly as the mode of the wing tip path shifts to the figure-eight mode. This understanding will contribute to a developed field of bioinspired micro air vehicles; i.e., it will reduce the complexity of electromechanical devices that prescribe entire motions of their wings.

DOI： 10.1103/PhysRevE.98.032411

Kyutacar

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Muroran-shi  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>Insects have developed their high-performance maneuverability using flapping flight in the process of their evolution. In this study, a partitioned method based on our partition model for their flapping flight, which consists of the subsystems of the wings, the body and the control, is proposed to analyze their maneuverability. Here, the proposed method is applied for a maneuver, which is assumed as the perturbation from the static hovering state. In this case, a specific analysis procedure reduced from the proposed method is the one way coupling from the wing to body subsystems, i.e. the insect flapping wings are analyzed using a finite element method for the fluid-structure interaction, the resulted thrust force acts on the insect's body, and its motion is calculated using the equation of motion of a rigid body. The fundamental performance of the proposed method is demonstrated from the comparison between the present results and the actual observation with respect to the yaw, roll, and pitch as three basic modes of maneuver.</p>

DOI： 10.1299/jsmecmd.2018.31.225

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007653641

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>In general, piezoelectric bimorph for actuators and sensors is thin and includes electrodes and shim plates. Therefore, this study deals with the thin composite piezoelectric bimorph. Solid elements can describe the various type of distributions of electric potential over the thickness. However, shell elements are more appropriate for the thin structural analysis. Therefore, instead of using piezoelectric solid elements or piezoelectric shell elements, solid elements and shell elements are used to simulate the electrical field and the structural field, respectively. The coupled algorithm is based on the block Gauss-Seidel method and a novel transformation method between the solid and shell variables. In the structural analysis, the rule of mixtures about the bending rigidity and the mass is used. In the electrical analysis, the single piezoelectric solver is used to obtain the potential distribution in the composite piezoelectric bimorph using a pseudo-piezoelectric treatment for the conductor. Finally, this study illustrates the very accurate potential distributions in the actuator and sensor modes of the thin composite piezoelectric bimorph.</p>

DOI： 10.1299/jsmecmd.2018.31.236

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007653661

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmemecj.2018.J0270401

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007619310

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study, a shape simplification modeling of insect flapping wings is proposed in order to reveal the mechanical roles of the veins in their cambering, since it seems to be unclear how the elastic deformation of insect wings caused by the aerodynamic force results in their camber. In the proposed modeling, the veins are divided into the areas according to their functions, and the macroscopic constitutive relationship in each area is described using the corresponding beam. Furthermore, the wing membrane supported by the veins is described using a rectangular shell. The aerodynamic pressure dominant in the cambering is considered in the static deformation of the model wing. The finite element analysis taking into account the geometric nonlinearity is applied to the proposed model with the setup consistent with the actual insect. As the result, the mechanical roles of the veins in the cambering of insect flapping wings are revealed.

DOI： 10.11421/jsces.2018.20180018

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmebio.2018.30.1I12

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007410874

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>Electrical contact resistance plays important role in melting and bonding of steel sheets interface for resistance spot welding. Although many researchers have proposed theoretical models of electrical contact resistance, microscale structural and electrical coupled finite element analysis is required to evaluate electrical contact resistance because its characteristics depend on the real contact surface, elasto-plastic large deformation contact behavior, electric current and temperature. In this study, we discuss a microscale structural and electrical coupled finite element analysis for the electrical contact resistance. In this analysis, the structural analysis with elasto-plastic, large deformation and contact effect is performed using measured surface based finite element analysis model and temperature dependent material properties. Deformed shape obtained by the structural analysis is used for the electrical analysis considering temperature dependent electrical resistivity. The electrical contact resistance analyses are performed to discuss the SS–RVE (Statistically Similar Representative Volume Element) size and computational cost, and to confirm the validity of the proposed analysis method. The dependency of the electrical contact resistance on the contact pressure and the temperature are compared with those of Babu's model and experimental results from the viewpoint of these path dependencies.</p>

DOI： 10.1299/jsmecmd.2018.31.257

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007653677

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© The Institution of Engineering and Technology 2017. The authors have designed and microfabricated millimetre-scale wing-shaped hybrid microstructures composed of rigid structures of single crystal silicon (SCS) substrates and flexible polyimide (PI) membranes. The wing-shaped microstructures mimicking insect flapping flight have been newly designed using a fluid-structure interaction analysis, and the hybrid microstructures based on the design method have been successfully microfabricated using a simple process flow with SCS substrates coated with PI membranes. Shape of the SCS parts in the hybrid microstructures have been successfully fabricated using deep reactive ion etching of the SCS substrate with small etching rate, and the wing plates of PI membranes have been prepared with the photolithography and the curing processes. The flexibility of the PI membranes of the fabricated hybrid microstructures was also confirmed using the bending test of the PI membranes.

DOI： 10.1049/mnl.2017.0428

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2017 IEEE. We have designed and microfabricated millimeter-scale wing-shaped hybrid microstructures composed of rigid structures of single crystal silicon (SCS) and flexible polyimide (PI) membranes. The wing-shaped microstructures mimicking insect flapping flight have been designed using a fluid-structure interaction analysis, and have been microfabricated using microfabrication technologies with the SCS substrates coated with photosensitive polyimide membranes. The shape of the SCS parts of the hybrid microstructures have been fabricated using deep reactive ion etching (D-RIE) process. The flexible parts of PI membranes have been prepared using photolithography and the subsequent curing process of the micro-patterned photosensitive PI thin film. The wing-shaped hybrid microstructures fabricated have been observed, and the flexibility of the PI membrane part of the hybrid microstructures was also confirmed using the bending test of the PI membrane.

DOI： 10.1109/NEMS.2017.8017145

Kyutacar

Scopus

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Korea   Busan   2017年05月25日  -  2017年05月26日

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

倉敷   2017年05月18日  -  2017年05月19日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2016 IOP Publishing Ltd. The high torsional flexibility of insect wings allows for elastic recoil after the rotation of the wing during stroke reversal. However, the underlying mechanism of this recoil remains unclear because of the dynamic process of transitioning from the wing rotation during stroke reversal to the maintenance of a high angle of attack during the middle of each half-stroke, when the inertial, elastic, and aerodynamic effects all have a significant impact. Therefore, the interaction between the flapping wing and the surrounding air was directly simulated by simultaneously solving the incompressible Navier-Stokes equations, the equation of motion for an elastic body, and the fluid-structure interface conditions using the three-dimensional finite element method. This direct numerical simulation controlling the aerodynamic effect revealed that the recoil is the residual of the free pitch vibration induced by the flapping acceleration during stroke reversal in the transient response very close to critical damping due to the dynamic pressure resistance of the surrounding air. This understanding will enable the control of the leading-edge vortex and lift generation, the reduction of the work performed by flapping wings, and the interpretation of the underlying necessity for the kinematic characteristics of the flapping motion.

DOI： 10.1088/1748-3190/12/1/016008

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

愛知   2017年01月19日  -  2017年01月20日

記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2016 Elsevier LtdThe numerical stability of electromagnetic and structural coupled analysis methods is examined in terms of the spectral radius for various methods combined with a coupled algorithm, time integration methods for structural analysis and eddy current analysis, and coupled effect evaluation methods. The coupled analysis method with the conventional serial staggered algorithm, generalized–α method for structure, backward difference method for eddy current, and coupled effect evaluation using previous time step results is seen to be the most suitable from the viewpoints of stability and computing time. The stability of the conventional parallel staggered algorithm is found to be much improved if the generalized–α method is used for structural analysis.

DOI： 10.1016/j.compstruc.2016.09.003

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2018 Japan Welding Society. All Rights Reserved. Resistance spot welding of three steel sheets is used in automotive manufacturing. The determination of welding conditions for three steel sheets welding is more difficult than that for two steel sheets welding because in the former case, two interfaces are simultaneously welded. The welding condition to improve the weld strength of thin and thick sheets’ interface is required for thin, thick, and thick sheets welding. In addition, avoiding weld spatter is an important technical concern for the three sheets welding. This paper discusses the triply coupled effects of elasto–plastic large deformation contact, electric current, and thermal conduction for the three sheets welding via triply coupled finite element analyses. The triply coupled effects of thin and thick sheets’ interface and those of thick and thick sheets’ interface are compared to discuss the special characteristics of the triply coupled effects of three sheets welding. The nugget diameter of the thick and thick sheets’ interface is larger than that of the thin and thick sheets’ interface because the electrical contact resistance and the base electrical resistance of high-strength steels are higher than those of general-strength steels. Furthermore, the chain of the coupled effects of electrical resistances, Joule heat generation, temperatures, and electrical resistances is strong. As the effect of welding current on temperature by the coupling effect for the thick and thick sheets’ interface is stronger than that for the thin and thick sheets’ interface, the possibility of spatter increases. Increasing the nugget diameter solely for the thin and thick sheets’ interface using electrode force is difficult because the effect of the electrode force on the nugget diameter is approximately the same for both interfaces. On the contrary, material characteristics can affect the nugget diameter solely for either of the interfaces. The possibility of spatter increases for the welding condition with a sheet gap because the temperature of the contact edge for the sheets’ interface increases.

DOI： 10.2207/qjjws.35.63

Scopus

CiNii Article

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>In this study, a FSI design approach of an insect–inspired MEMS wing is proposed. Similar to actual insects, the proposed design actively uses the FSI to create the passive wing motion. Each design solution has a so-called 2.5–D structure for the MEMS technology. The 3–D unsteady monolithic FSI equation system is solved to find the satisfactory design solutions using a projection method. An area of satisfactory design solutions in a design parameter space is found. Each design solution in this area can generate the thrust sufficient to support the weight of the model insect.</p>

DOI： 10.11345/japannctam.64.0_OS8-02-01

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007510260

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2017 International Center for Numerical Methods in Engineering. All rights reserved. Electrical contact resistance is an important parameter for resistance spot welding. In this study, a microscale electrical contact resistance analysis method is proposed for resistance spot welding. The microscale electrical contact resistance analysis method is combination of an elasto–plastic large deformation contact analysis and an electric current analysis. The electric current analysis is performed for deformed shape of asperity. The tendency of the electrical contact resistance on contact pressure and temperature for the electrical contact resistance analysis agrees with that for Babu’s electrical contact resistance model. A multiscale coupled analysis method is also proposed for resistance spot welding. The multiscale analysis consists of macroscale elasto–plastic large deformation contact, electric current and thermal conduction triply coupled analysis and microscale electrical contact resistance analysis. It is confirmed that the resistance spot welding analysis without measurement of electrical contact resistance can be performed by using the microscale electrical contact resistance analysis.

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2017.30.284

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130006551242

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2017 International Center for Numerical Methods in Engineering. All rights reserved. In this analyze, a novel finite element coupled algorithm using numerical methods to analyze the interaction between fluid-structure-electric fileds has been presented for piezoelectric actuators. Piezoelectricity is fundamentally an interaction between structure and electric fields. In this paper, at first we analyze the piezoelectric interaction using 3D solid elements and MITC4 shell elements. Solid elements are used for electric analysis and MITC4 shell elements are used for geometric nonlinear structural analysis. The induced electric forces and moment of forces are translated from 3D solid elements to MITC4 shell elements using a novel translation method, and displacements from MITC4 shell elements are translated to 3D solid elements using shell element displacement interpolation functions. A projection method is employed in order to solve the interaction between MITC4 shell structure and fluid field.

Scopus

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmebio.2017.29.2F23

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007123468

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2017 International Center for Numerical Methods in Engineering. All rights reserved. In this study, a FSI design of an insect-like micro flapping wing is proposed. Similar to actual insects, the proposed design actively uses the FSI to create the passive wing motions. Each design solution has a 2.5-D structure for the MEMS technology. The 3-D unsteady monolithic FSI equation system is solved to find the satisfactory design solutions using a projection method in a parallel computation environment. An area of satisfactory design solutions in a design parameter space or Design Window (DW) is presented. Each design solution in the present DW can generate the thrust sufficient to support the weight of the model insect. Therefore, the insect-like MEMS-based MAVs are possible.

Kyutacar

Scopus

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2017.30.275

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130006551222

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

<p>A strongly coupled multiphysics analysis of the electric-structure-fluid interaction in micro electro mechanical system (MEMS) using the finite element method is presented. The strongly coupled electric-structure interaction is based on the block Gauss-Seidel (BGS) iteration scheme, while the strongly coupled structure-fluid interaction is based on the projection scheme. A novel translation algorithm for the electric force and the structural displacement accurately takes into account the electric-structure interaction in MEMS. Therefore, this algorithm combines these schemes to analyze the strongly coupled electric-structure-fluid interaction in MEMS. The proposed method is applied for a flexible piezoelectric bimorph actuator in a channel to demonstrate its performance.</p>

DOI： 10.11345/japannctam.64.0_OS8-02-02

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007510311

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

<p>Resistance spot welding is widely used in manufacturing industry. Analysis of resistance spot welding is required for examination of welding mechanism and determination of welding parameters such as weld current, electrode force and weld time because welding parameters are obtained empirically. In this paper, effect of structure–electric current–thermal conduction triply coupled model on resistance spot welding analysis results are examined to make analysis more efficient. Statistically similar representative volume element size and resolution of finite element analysis model are also discussed for microscale electrical contact resistance analysis of multiscale resistance spot welding analysis.</p>

DOI： 10.11345/japannctam.64.0_OS8-02-04

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007510177

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2017.30.295

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130006551250

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Korea   Seoul   2016年07月24日  -  2016年07月29日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Korea   Seoul   2016年07月24日  -  2016年07月29日

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2016.29.4_305

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007093965

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2016.29.4_154

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007094354

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

3枚重ね抵抗スポット溶接では，材質や板厚により接合強度を確保し，かつ，スパッタレスな溶接条件設定が難しいケースが多い．本報では，大変形弾塑性接触・電流・熱伝導3連成解析により3枚重ね抵抗スポット溶接特有の3連成現象および溶接条件が接合強度やスパッタにおよぼす影響を検討する．

DOI： 10.14920/jwstaikai.2016f.0_12

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005435757

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2016.29.4_271

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007093825

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

2015年10月28日  -  2015年10月30日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Tokyo   2015年10月26日  -  2015年10月26日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Hokkaido   2015年09月16日  -  2015年09月19日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

In this study, a hierarchal decomposition for the interaction of the structure, fluid and electrostatic field or the structure-fluid-electrostatic interaction, which is one of typical phenomena in micro-electro-mechanical system (MEMS), is proposed in order to solve it efficiently. The proposed decomposition partitions the structure-fluid-electrostatic interaction into the fluid-structure interaction (FSI) and the electrostatic field, and, moreover, splits the FSI into the velocity and fluid pressure fields. In this way, the whole interaction system is decomposed into the three fields in a hierarchal way. The proposed decomposition is implemented using a finite element method and is applied to a micro cantilever beam actuated by the electrostatic force in air. It follows from the comparison among the results for the structure-fluid-electrostatic interaction, the FSI and the experiment that the proposed method taking into account the full-interaction can predict the vibration characteristic of the MEMS accurately.

Kyutacar

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Interactions between elasto-plastic contact deformation, electric current and heat conduction produces complicated triply coupled effect in the resistant spot welding. Since the coupled effect affects weld strength, the coupled finite element analysis is required to determine welding parameters such as welding current, electrode force, welding time and electrode shape. This paper discusses in detail the elasto-plastic contact, electric current and thermal conduction triply coupled analysis method. The coupled analysis method uses modified electrical contact resistance model, modified thermal contact resistance model and iterative partitioned coupled algorithm suitable for strong coupled problem. The validity of the method are discussed under the different condition such as welding current, electrode force, welding time, material and number of the steel sheets. The analysis result of nugget growth curve agrees very well with experimental result for two sheet welding. The validity is confirmed by not only nugget growth curve but also surface temperature of steel sheet and electrode for three sheet welding with high tension steel. The solution convergence is discussed for the iterative partitioned coupled algorithm and the conventional coupled algorithm. Since the coupled effect is strong for between electric current and thermal conduction, the choice of the coupled algorithm is important for the resistance spot welding analysis. Effect of elasto-plastic contact deformation, change of electric current distribution and thermal conduction on resistance spot welding are discussed from the viewpoint of coupled effect. The coupled model with ability to simulate the chain of coupled effect is required to improve the analysis reliability. The importance of temperature dependency of material property, electrical contact resistance, thermal contact resistance and latent heat effect are also discussed.

DOI： 10.2207/qjjws.33.271

Scopus

CiNii Article

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Copyright © 2015 Tech Science Press. In this study, a hierarchal decomposition is proposed to solve the structure- fluid-electrostatic interaction in a microelectromechanical system (MEMS). In the proposed decomposition, the structure-fluid-electrostatic interaction is partitioned into the structure-fluid interaction and the electrostatic field using the iteratively staggered method, and the structure-fluid interaction is split into the structurefluid velocity field and the fluid pressure field using the projection method. The proposed decomposition is applied to a micro cantilever beam actuated by the electrostatic force in air. It follows from the comparisons among the numerical and experimental results that the proposed method can predict the MEMS vibration characteristics accurately.

Kyutacar

Scopus

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担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2015.28._258-1_

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110010044383

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

In recent years, Micro Air Vehicles (MAVs) mimicking insects have been developed for the purpose of observation in narrow and disaster areas. Micro Electro Mechanical Systems (MEMS) are typically manufactured using the semiconductor manufacturing technology, and have attracted much attention in various fields. In this study, in order to realize an insect-like MAV, its prototype millimeter wing is developed. The prototype wing is designed based on the mechanics of insect flapping wings and the data of an actual insect. The prototype wing made of a single crystal silicon and a polyimide membrane is fabricated, and its fundamental characteristics are evaluated.

DOI： 10.1299/jsmemnm.2015.7._30pm1-E-5

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110010046076

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

DOI： 10.1299/jsmeapbio.2015.8.66

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110010043721

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2014 IOP Publishing Ltd.The relative importance of the wing's inertial and aerodynamic forces is the key to revealing how the kinematical characteristics of the passive pitching motion of insect flapping wings are generated, which is still unclear irrespective of its importance in the design of insect-like micro air vehicles. Therefore, we investigate three species of flies in order to reveal this, using a novel fluid-structure interaction analysis that consists of a dynamically scaled experiment and a three-dimensional finite element analysis. In the experiment, the dynamic similarity between the lumped torsional flexibility model as a first approximation of the dipteran wing and the actual insect is measured by the Reynolds number Re, the Strouhal number St, the mass ratio M, and the Cauchy number Ch. In the computation, the three-dimension is important in order to simulate the stable leading edge vortex and lift force in the present Re regime over 254. The drawback of the present experiment is the difficulty in satisfying the condition of M due to the limitation of available solid materials. The novelty of the present analysis is to complement this drawback using the computation. We analyze the following two cases: (a) The equilibrium between the wing's elastic and fluid forces is dynamically similar to that of the actual insect, while the wing's inertial force can be ignored. (b) All forces are dynamically similar to those of the actual insect. From the comparison between the results of cases (a) and (b), we evaluate the contributions of the equilibrium between the aerodynamic and the wing's elastic forces and the wing's inertial force to the passive pitching motion as 80-90% and 10-20%, respectively. It follows from these results that the dipteran passive pitching motion will be based on the equilibrium between the wing's elastic and aerodynamic forces, while it will be enhanced by the wing's inertial force.

DOI： 10.1088/1748-3182/9/4/046009

Scopus

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担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

This study is concerned with aerodynamic effects in passive pitching dynamics of insect flapping wings, which would be based on the Fluid-Structure Interaction (FSI). Thus, we evaluated them using three-dimensional numerical analyses for the FSI based on the finite element method. In the numerical analyses, the FSI in insect flapping wing is broken down into its constituent components in order to find the aerodynamic effects in the passive pitching dynamics as follows: (a) The dipteran passive pitching dynamics is based on the interaction between the wing's elastic and aerodynamic forces, while it is enhanced by the wing's inertial effect. (b) The air damping leads the mode of wing's natural vibration from underdamping to overdamping so as to form the characteristic pitching motion, where the damped natural vibration of the wing appears so as to enhance the wing rotation.

DOI： 10.1299/transjsme.2014cm0106

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130003399154

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

流体と構造が強く連成する現象に対する信頼性の高い解析手法が求められている．相似模型実験は，鍵となる無次元数の増加に伴い，それらの条件を同時に満たすことが難しくなる．一方，計算は，近年，急速に発展しているが，現象の複雑化に伴い，一層，結果の妥当性を検討することが求められる．そこで本研究においては，計算と相似模型実験の相補完による流体構造連成シミュレーションを提案し，具体的な流体構造連成現象として，昆虫羽ばたき飛行を取り上げて，その有効性を検討する．

DOI： 10.11345/japannctam.63.0_83

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005478028

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

DOI： 10.1299/jsmecmd.2014.27.403

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110009940260

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

Copyright © 2014 Tech Science Press. In this study, a projection method for the monolithic interaction system of an incompressible fluid and a structure using a new algebraic splitting is proposed. The proposed method splits the monolithic equation system into the equilibrium equations and the pressure Poisson equation (PPE) algebraically using the intermediate velocity in the nonlinear iterations. Since the proposed equilibrium equation satisfies the interface condition, the proposed method is strongly coupled. Moreover, the proposed PPE enforces the incompressibility constraint. Different from previous studies, the proposed algebraic splitting never generates any Schur complement. The proposed method is applied to a channel with a flexible flap, which is one of typical test problems, where its superior computational efficiencies are demonstrated.

Kyutacar

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84919969728&origin=inward

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

This study is concerned with air damping effect in passive pitching motion of insect flapping wing, which will be based on the Fluid-Structure Interaction (FSI). Thus, we evaluated it using three-dimensional numerical analyses for the FSI based on the finite element method. From the numerical analysis, we found that the air damping leads the mode of wing's natural vibration from underdamping to overdamping so as to form the characteristic pitching motion.

DOI： 10.1299/jsmemecj.2014._J0220401-

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110009943479

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study, performances of a projection method for the interaction system of an incompressible fluid and a flexible elastic structure are evaluated. The proposed projection method splits the monolithic equation system into the equilibrium equations and the pressure Poisson equation (PPE) using the intermediate velocity in the nonlinear iterative procedure. The monolithic equation system has the drawbacks of the large degrees of freedoms and the ill-condition. The proposed formulation reduces these drawbacks. The performance of the proposed projection method is demonstrated using a channel with a flexible flap, which is one of typical test problems, and a flapping flexible wing in a closed tank with comparable fluid and structural mass densities. It follows from the results for these numerical examples that the proposed projection method is efficient for the cases, where some conventional monolithic and partitioned methods would suffer the numerical difficulties. © 2013 by the Japan Society for Computational Engineering and Science.

DOI： 10.11421/jsces.2013.20130017

Scopus

CiNii Article

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

スペイン   イビザ   2013年06月16日  -  2013年06月19日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study a finite element analysis using hierarchal decompositions for the interaction of structural, fluidic and electrostatic fields is applied for vibration analyses of a MEMS structural component. The interaction is partitioned into the electrostatic field and the fluid-structure interaction (FSI) using the block Gauss-Seidel method. The FSI is split into the pressure field and the other using a projection method, where the intermediate state variables are used for the splitting without generating computationally expensive Schur complement matrices. The developed finite element analysis is applied for a micro cantilever beam actuated by the step electrostatic force in vacuum and air. It was demonstrated from the comparisons among the numerical and experimental results that the proposed analyses provide the results consistent with the experimental results. It follows from the present results that the numerical analyses taking into account the interaction of the structural, fluidic and electrostatic fields are required for the accurate predictions of the vibration characteristics of the MEMS structural components. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaia.79.1291

Scopus

CiNii Article

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study a consistent projection method for the fluid-structure interaction (FSI) was proposed. The intermediate state variables were used to split the monolithic equation system into the equilibrium equations and the pressure Poisson equation (PPE). The incompressibility constraint is asymptotically satisfied by solving the proposed PPE in the iterative solution procedure under the asymptotic agreement of the intermediate velocity with the velocity. Therefore the proposed method is consistent with the monolithic method. The performance of the present method was demonstrated using a channel, which is one of typical test problems, and a flexible wing flapping in the closed fluid domain with the comparable fluid and structural densities. © 2013 The Japan Society of Mechanical Engineers.

DOI： 10.1299/kikaia.79.1161

Scopus

CiNii Article

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Japan   Kanazawa   2012年09月09日  -  2012年09月12日

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）

DOI： 10.1299/kikaib.78.300

Scopus

CiNii Article

担当区分：責任著者   記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Australia   Sydney   2010年07月19日  -  2010年07月23日

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

2010年05月28日  -  2010年05月28日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study, we evaluated the lift force generated by the crane-fly's flapping wing with the passive pitching using the dynamically scaled model. Since the wing and the surrounding fluid interact with each other, the dynamic similarity between the model and actual crane-fly flights was measured using not only the Reynolds and Strouhal numbers but also the mass and Cauchy numbers. Although there existed the difference between the mass number due to the constant acceleration of the gravity, but the lift coefficient simulated by our model indicated that the flapping wing with the passive pitching produces the enough lift force to support the crane-fly's weight.

DOI： 10.1299/kikaib.76.764_601

Scopus

CiNii Article

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Yokohama   2010年03月29日  -  2010年03月31日

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

We have studied the passive maintenance of high angle of attack and its lift generation during the crane fly's flapping translation using a dynamically scaled model. Since the wing and the surrounding fluid interact with each other, the dynamic similarity between the model flight and actual insect flight was measured using not only the non-dimensional numbers for the fluid (the Reynolds and Strouhal numbers) but also those for the fluid-structure interaction (the mass and Cauchy numbers). A difference was observed between the mass number of the model and that of the actual insect because of the limitation of available solid materials. However, the dynamic similarity during the flapping translation was not much affected by the mass number since the inertial force during the flapping translation is not dominant because of the small acceleration. In our model flight, a high angle of attack of the wing was maintained passively during the flapping translation and the wing generated sufficient lift force to support the insect weight The mechanism of the maintenance is the equilibrium between the elastic reaction force resulting from the wing torsion and the fluid dynamic pressure. Our model wing rotated quickly at the stroke reversal in spite of the reduced inertial effect of the wing mass compared with that of the actual insect This result could be explained by the added mass from the surrounding fluid. Our results suggest that the pitching motion can be passive in the crane fly's flapping flight.

DOI： 10.1242/jeb.030684

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this study, the passive pitching due to wing torsional flexibility and its lift generation in dipteran flight were investigated using (a) the non-linear finite element method for the fluid-structure interaction, which analyzes the precise motions of the passive pitching of the wing interacting with the surrounding fluid flow, (b) the fluid-structure interaction similarity law, which characterizes insect flight, (c) the lumped torsional flexibility model as a simplified dipteran wing, and (d) the analytical wing model, which explains the characteristics of the passive pitching motion in the simulation. Given sinusoidal flapping with a frequency below the natural frequency of the wing torsion, the resulting passive pitching in the steady state, under fluid damping, is approximately sinusoidal with the advanced phase shift. We demonstrate that the generated lift can support the weight of some Diptera.

DOI： 10.1242/jeb.020404

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this paper, an incremental formulation of pressure based method for fluid-rigid body interaction using intermediate variable is presented. The present method is based on the method proposed by Matsumoto and Kawahara in previous studies. In their method, the pressure Poisson equation equivalent to the incompressibility constraint is derived by using the intermediate fluid velocity and the approximation of enough small error between the intermediate fluid velocity and the fluid velocity. In the present method, all terms appear in the coupled equation system are evaluated in the same time instant, and unknown variables are solved incrementally by iterative solution procedure in each time step so as to satisfy the coupled equation system defined in the time instant. The present formulation is required when structural nonlinearity such as large deformation should be considered. The present method is applied for the free vibration of a rigid circular cylinder in a quiescent fluid to verify its performance.

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this paper, a strongly coupled method for interaction of rigid body, incompressible viscous fluid and electrostatic field is developed. The present method is composed of monolithic and partitioned methods. The former solves structure-fluid interaction and the later solves interaction of electrostatic field and the other fields. The difference between the present method and conventional method is the introduction of the iterative solution procedure in the partitioned method. To demonstrate the fundamental performances of the present method, it is applied to simulate a micro membrane actuated by electrostatic force situated in air. The present result agrees well with the theoretical solution when the displacement of the rigid body is small. We also comfirm that the iterative solution procedure makes the present method to be the strongly coupled method through the numerical example.

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）

主要雑誌 代表的研究業績

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this paper, a parallel monolithic method for shell-fluid interaction based on the consistent Pressure Poisson Equation (PFE) is developed and its parallel computational efficiency is demonstrated. The previous and present studies show that iterative solvers without preconditioning work well to solve the PPE, even though the coefficient matrix of the original linearized coupled equations becomes to be ill-conditioned. As a consequence, combining with the iterative solvers without preconditioning parallelized based on the mesh decomposition, the developed method can archive efficient parallel computation. To demonstrate the performances of the developed method, it is applied to simulate the vibration of an elastic plate situated in the wake of a rectangular cylinder and a flapping elastic wing in fluid.

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes an efficient monolithic method for shell-fluid interaction problems based on the fluid pressure Poisson equation (PPE). The PPE is derived so as to be consistent with the coupled equation system for the shell-fluid interaction. In the proposed method, the fluid pressure is derived implicitly so as to satisfy the incompressibility. constraint and all the other unknown variables except those for the shell are derived explicitly. The coefficient matrix of the PPE is well-conditioned even if the structure is very stiff or heavy compared to the fluid, and even if the ill-conditioned submatrix is generated due to the shell elements. These characteristics are successfully utilized to combine the proposed method with the standard conjugate gradient method. To demonstrate fundamental perfermances of the proposed method, it is applied to evaluate the vibration characteristics of a thin elastic cantilever plate in a quiescent fluid.

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

In this paper, a novel insect flight model based on fluid-structure interaction is proposed. Incorporating the high compliance of the wing base, which is observed in Diptera, the proposed model can express the automatic control of the wing rotation via fluid-structure interaction and can generate the adequate aerodynamic forces for the insect flight. The fluid-structure interaction is simulated by a monolithic method based on the finite element method. The result given by the proposed model is investigated by comparison with experimental results of the dynamically scaled model of the fruit fly given by Dickinson et al.

Scopus

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes a new monolithic approach based on the fluid pressure Poisson equation (PPE) to solve an interaction problem of incompressible viscous fluid and an elastic body. The PPE is derived so as to be consistent with the coupled equation system for the fluid-structure interaction (FSI). Based on this approach, we develop two kinds of efficient monolithic methods. In both methods, the fluid pressure is derived implicitly so as to satisfy the incompressibility constraint, and all other unknown variables are derived fully explicitly or partially explicitly. The coefficient matrix of the PPE for the FSI becomes symmetric and positive definite and its condition is insensitive to inhomogeneity of material properties. The arbitrary Lagrangian-Eulerian (ALE) method is employed for the fluid part in order to take into account the deformable fluid-structure interface, To demonstrate fundamental performances of the proposed approach, the developed two monolithic methods are applied to evaluate the added mass and the added damping of a circular cylinder as well as to simulate the vibration of a rectangular cylinder induced by vortex shedding. Copyright © 2005 John Wiley & Sons, Ltd.

DOI： 10.1002/nme.1348

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes a new monolithic approach based on the Pressure Poisson Equation (PPE) I to solve interaction problems of incompressible viscous fluid and an'elastic body. The PPE is derived I so as to be consistent with the coupled equation system for the fluid-structure interaction (FSI). Based on this approach, we develop two efficient monolithic methods. In both methods, the fluid pressure is derived implicitly so as to satisfy the incompressibility constraint and all the other unknown variables are derived fully explicitly or partially explicitly. The coefficient matrix of the PPE for the FSI has characteristics of (a) symmetric and positive definite feature, (b) reduction of degrees of freedoms to be solved, and (c) less dependence of the condition on material properties. The arbitrary Lagrangian-Eulerian method is employed for the fluid to take into account the deformable fluid-structure interface. To demonstrate fundamental performances of the proposed approach, the developed two monolithic methods are applied to simulate the vibration of a rectangular cylinder induced by vortex shedding.

DOI： 10.1299/kikaib.71.1565

Scopus

CiNii Article

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記述言語：英語   掲載種別：研究論文（その他学術会議資料等）

ギリシャ   Santorini   2005年05月  -  2005年05月

主要論文集（会議）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes a strong coupling method considering non-conforming mesh on fluid-structure interface. In the present method, a transformation matrix derived from the geometrical relations between non-conforming fluid and structural meshes on fluid-structure interface is directly combined with the formulation of the strong coupling method to satisfy the compatibility and equilibirium conditions on fluid-structure interface. The conjugate gradient method is applied to solve the derived coupled equation system by introducing the consistent pressure Poisson equation. To verify basic characteristics of the proposed method, it is applied for free vibration of a cylinder in quiescent fluid. The added mass and damping coefficients derived by the present method agree well with those by other researchers.

DOI： 10.1299/kikaib.71.1346

Scopus

CiNii Article

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes an efficient strong coupling method for fluid-structure interaction based on the explicit method for structure and the semi-implicit method for fluid. The solution process of fluid-structure interation system is divided into that of fluid and structure, which is independent to each other except data transfer of the fluid-structure interface. Some existing codes with small modification can be utilized to realize the above two solution processes. Note that the time increment is restricted by the Courant's and diffusive number conditions. The method is applied to solve a loaded cantilever in a flow channel under some conditions. Through the numerical results, characteristics of the method are compared to those of a strong coupling and a weak coupling method.

DOI： 10.1299/kikaib.70.3098

Scopus

CiNii Article

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

© 2003 Elsevier Science Ltd. All rights reserved. This paper describes a parallel strong coupling method for interaction of incompressible viscous fluid and an elastic body. The method is based on a multi-steps strong coupling method proposed by authors, which can employ a conjugate gradient (CG) method to solve the simultaneous equation system. Using the domain decomposition method with the element-by-element approach, the CG algorithm in the method is parallelized. To demonstrate the accuracy and parallel efficiency of the method, it is applied to the problem of vibrating behavior of an impacted cantilever beam in water. The method is implemented on PC-cluster system. The accuracy of the result and parallel efficiency are discussed.

DOI： 10.1016/B978-008044046-0.50336-5

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes a search method for multi-dimensional design window (DW), which is defined as an existing area of satisfactory solutions in a design parameter space. The method consists of the following two steps: (1) direct search for satisfactory design solutions using a continuous evolutionary algorithm (CEA) from a wide area of the design parameter space in a robust manner, and (2) identification of a precise structure of DW by clustering the detected satisfactory solutions with a modified K-means algorithm. The CEA is a kind of genetic algorithms modified to deal with continuous variables. The modified K-means clustering algorithm contains an explicit procedure to determine the optimum number of clusters. The proposed DW search method was implemented to an integrated computational aided engineering system for multi-disciplinary structural design developed by the authors, and then the method was applied to shape design of a microelectrostatic actuator for next generation high-density optical memory. A DW consisting of four clusters, i.e. four sub-DWs was obtained, and the features of the representative design solutions of the four sub-DWs were compared with each other in detail, and a final design solution was determined. © 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0045-7949(02)00293-6

Scopus

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes a multi-step strong coupling method to analyze an equation system of incompressible viscous fluid and an elastic body. The procedure is derived based on the following techniques; (a) sub-structuring, (b) velocity-pressure splitting, and (c) time integration of Newmark's family. Only simultaneous equations with well-defined symmetric matrices are solved in the method. To demonstrate fundamental performance of the method, it is applied to solve an impacted beam in fluid. The result shows good agreement with a previous work.

DOI： 10.1299/kikaib.68.2451

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Austria   Vienna   2002年07月07日  -  2002年07月12日

主要論文集（会議）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

For satisfactory design of micromachines, this paper describes a search method for a multi-dimensional design window (DW), which is defined as an area of satisfactory solutions in a feasible design parameter space. The method consists of the following two steps: (1) direct search for satisfactory design solutions using continuous evolutionary algorithm (CEA, a kind of E A), and (2) identification of DWs from the solutions using a modified K-means clustering algorithm. The obtained DWs are expected to give engineers useful information to understand a design problem, and, further, give them new ideas of design. To demonstrate practical performance of the proposed method, it was applied to a shape design of micro electrostatic actuator for optical memory.

Scopus

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記述言語：その他外国語   掲載種別：研究論文（学術雑誌）

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper proposes an automated search method for multidimensional design window (DW), which is defined as an area of satisfactory design solutions in a design parameter space, using both continuous evolutionary algorithms (CEA) and improved K-means clustering. This method consists of two phases: (a) CEA-based search for satisfactory design solutions in an ill-structured design space, and (b) clustering-based identification of DWs from the solutions. To demonstrate practical performance of the method, it is applied to an automated structural design of micro electrostatic actuator for optical memory. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

DOI： 10.1299/kikaic.67.460

Scopus

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）

Tokyo   2000年04月  -  2000年04月

開催期間： 2023年05月31日 - 2023年06月02日   記述言語：日本語   開催地：つくば市，日本   国名：日本国  

開催期間： 2023年04月25日 - 2023年04月28日   記述言語：英語   開催地：カンヌ   国名：フランス共和国  

Technical Programme consists of 3 Plenary Lectures, 12 Semi-Plenary Lectures, 62 keynote Lectures, 53 Minisymposia, 562 oral presentations, 4 tech talks, namely, 643 presentations overall.

開催期間： 2023年01月15日 - 2023年01月19日   記述言語：英語   開催地：ミュンヘン   国名：ドイツ連邦共和国  

開催期間： 2022年11月16日 - 2022年11月18日   記述言語：日本語   開催地：鹿児島（オンライン）   国名：日本国  

開催期間： 2022年11月16日 - 2022年11月18日   記述言語：日本語   開催地：鹿児島（オンライン）   国名：日本国  

開催期間： 2022年11月16日 - 2022年11月18日   記述言語：日本語   開催地：鹿児島（オンライン）   国名：日本国  

開催期間： 2022年11月14日 - 2022年11月16日   記述言語：日本語   開催地：徳島   国名：日本国  

開催期間： 2022年11月14日 - 2022年11月16日   記述言語：日本語   開催地：徳島   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年08月31日 - 2022年09月02日   記述言語：英語   開催地：Iizuka, Japan   国名：日本国  

開催期間： 2022年07月31日 - 2022年08月05日   記述言語：英語   開催地：横浜   国名：日本国  

Number of minisymposia: 287, Number of abstracts: 2,069 (Asian Pacific: 1,086, Americas: 370, Europe - Middle East - Africa: 613), Number of participants: 2,346 (Asian Pacific: 1,258, Americas: 408, Europe - Middle East - Africa: 680)

開催期間： 2022年07月31日 - 2022年08月05日   記述言語：英語   開催地：横浜   国名：日本国  

Number of minisymposia: 287, Number of abstracts: 2,069 (Asian Pacific: 1,086, Americas: 370, Europe - Middle East - Africa: 613), Number of participants: 2,346 (Asian Pacific: 1,258, Americas: 408, Europe - Middle East - Africa: 680)

開催期間： 2022年06月01日 - 2022年06月03日   記述言語：日本語   開催地：秋田市，日本   国名：日本国  

開催期間： 2021年09月21日 - 2021年09月23日   記述言語：日本語   開催地：札幌・オンライン  

開催期間： 2021年09月21日 - 2021年09月23日   記述言語：日本語   開催地：札幌・オンライン  

開催期間： 2021年09月21日 - 2021年09月23日   記述言語：日本語   開催地：札幌・オンライン  

開催期間： 2021年09月21日 - 2021年09月23日   記述言語：日本語   開催地：札幌・オンライン   国名：日本国  

開催期間： 2021年09月01日 - 2021年09月03日   記述言語：英語   開催地：Kyoto, Japan  

開催期間： 2021年09月01日 - 2021年09月03日   記述言語：英語   開催地：Kyoto, Japan  

開催期間： 2021年09月01日 - 2021年09月03日   記述言語：英語   開催地：Kyoto, Japan  

開催期間： 2021年09月01日 - 2021年09月03日   記述言語：英語   開催地：Kyoto, Japan  

開催期間： 2021年09月01日 - 2021年09月03日   記述言語：英語   開催地：Kyoto, Japan  

開催期間： 2021年05月26日 - 2021年05月28日   記述言語：英語   開催地：北九州市，日本  

開催期間： 2021年05月26日 - 2021年05月28日   記述言語：英語   開催地：北九州市，日本  

開催期間： 2021年05月26日 - 2021年05月28日   記述言語：英語   開催地：北九州市，日本  

開催期間： 2021年05月26日 - 2021年05月28日   記述言語：英語   開催地：北九州市，日本  

開催期間： 2021年04月25日 - 2021年04月29日   記述言語：英語   開催地：Xiamen, China  

開催期間： 2021年01月11日 - 2021年01月15日   記述言語：英語  

開催期間： 2020年09月27日 - 2020年09月30日   記述言語：英語  

開催期間： 2019年11月05日 - 2019年11月07日   記述言語：英語   開催地：Miyazaki, Japan  

開催期間： 2019年11月05日 - 2019年11月07日   記述言語：英語   開催地：Miyazaki, Japan  

開催期間： 2019年09月16日 - 2019年09月18日   記述言語：日本語  

開催期間： 2019年09月16日 - 2019年09月18日   記述言語：日本語  

開催期間： 2019年09月16日 - 2019年09月18日   記述言語：英語  

開催期間： 2019年06月28日 - 2019年06月30日   記述言語：日本語   開催地：北海道大学  

開催期間： 2019年06月03日 - 2019年06月05日   記述言語：英語   開催地：Sitges (Barcelona), Spain  

開催期間： 2019年06月03日 - 2019年06月05日   記述言語：英語   開催地：Sitges (Barcelona), Spain  

開催期間： 2019年05月29日 - 2019年05月31日   記述言語：日本語   開催地：ソニックシティ（大宮）  

開催期間： 2019年05月29日 - 2019年05月31日   記述言語：日本語   開催地：ソニックシティ（大宮）  

開催期間： 2019年03月25日 - 2019年03月28日   記述言語：英語  

開催期間： 2018年11月23日 - 2018年11月25日   記述言語：日本語  

開催期間： 2018年11月23日 - 2018年11月25日   記述言語：日本語  

開催期間： 2018年09月18日 - 2018年09月20日   記述言語：英語   開催地：Muroran, Japan  

開催期間： 2018年09月18日 - 2018年09月20日   記述言語：英語   開催地：Muroran, Japan  

開催期間： 2018年09月09日 - 2018年09月12日   記述言語：日本語  

開催期間： 2018年06月11日 - 2018年06月15日   記述言語：英語   開催地：Glasgow, UK  

開催期間： 2018年06月06日 - 2018年06月08日   記述言語：英語   開催地：ウインクあいち  

開催期間： 2018年05月23日 - 2018年05月25日   記述言語：日本語   開催地：長野市生涯学習センター， 長野市大字鶴賀問御所町1271-3　TOiGO WEST 4F  

開催期間： 2017年09月16日 - 2017年09月18日   記述言語：日本語   開催地：大阪  

開催期間： 2017年09月16日 - 2017年09月18日   記述言語：日本語   開催地：大阪  

開催期間： 2017年09月16日 - 2017年09月18日   記述言語：日本語   開催地：大阪  

開催期間： 2017年08月22日 - 2017年08月24日   記述言語：日本語   開催地：機械振興会館  

開催期間： 2017年08月22日 - 2017年08月24日   記述言語：日本語   開催地：機械振興会館  

開催期間： 2017年08月22日 - 2017年08月24日   記述言語：英語   開催地：機械振興会館  

開催期間： 2017年05月18日 - 2017年05月19日   記述言語：日本語   開催地：倉敷  

開催期間： 2017年01月19日 - 2017年01月20日   記述言語：日本語   開催地：ウィングあいち  

開催期間： 2016年09月22日 - 2016年09月24日   記述言語：日本語   開催地：名古屋  

開催期間： 2016年09月22日 - 2016年09月24日   記述言語：日本語   開催地：名古屋  

開催期間： 2016年09月22日 - 2016年09月24日   記述言語：日本語   開催地：名古屋  

開催期間： 2015年10月28日 - 2015年10月30日   記述言語：日本語   開催地：新潟コンベンションセンター  

開催期間： 2015年10月10日 - 2015年10月12日   記述言語：日本語   開催地：横浜  

開催期間： 2014年11月22日 - 2014年11月24日   記述言語：日本語   開催地：岩手盛岡  

開催期間： 2014年09月26日 - 2014年09月28日   記述言語：日本語   開催地：東京  

開催期間： 2014年09月07日 - 2014年09月10日   記述言語：日本語   開催地：東京  

開催期間： 2014年08月28日 - 2014年08月30日   記述言語：日本語   開催地：姫路  

開催期間： 2014年06月11日 - 2014年06月13日   記述言語：日本語   開催地：広島  

開催期間： 2014年05月21日 - 2014年05月23日   記述言語：日本語   開催地：盛岡  

開催期間： 2013年11月02日 - 2013年11月04日   記述言語：日本語   開催地：佐賀市  

開催期間： 2013年11月02日 - 2013年11月04日   記述言語：日本語   開催地：佐賀市  

開催期間： 2013年09月08日 - 2013年09月11日   記述言語：日本語   開催地：岡山  

開催期間： 2010年11月01日   記述言語：日本語   開催地：日本 大阪  

開催期間： 2010年09月05日 - 2010年09月08日   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2010年08月17日 - 2010年08月19日   記述言語：日本語   開催地：日本 長崎  

開催期間： 2010年05月26日 - 2010年05月28日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2010年05月26日 - 2010年05月28日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2009年09月13日 - 2009年09月16日   記述言語：日本語   開催地：日本 岩手  

開催期間： 2009年04月   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2009年04月   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2009年03月18日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2009年03月18日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2009年03月18日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2009年03月09日   記述言語：日本語   開催地：日本 飯塚市  

開催期間： 2009年03月09日   記述言語：日本語   開催地：日本 飯塚市  

開催期間： 2009年03月09日   記述言語：日本語   開催地：日本 飯塚市  

開催期間： 2008年11月01日 - 2008年11月03日   記述言語：日本語   開催地：日本 沖縄  

開催期間： 2008年11月01日 - 2008年11月03日   記述言語：日本語   開催地：日本 沖縄  

開催期間： 2007年11月26日 - 2007年11月28日   記述言語：日本語   開催地：日本 京都  

開催期間： 2007年09月09日 - 2007年09月12日   記述言語：日本語   開催地：日本 大阪府吹田市  

開催期間： 2006年11月03日 - 2006年11月05日   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2006年11月03日 - 2006年11月05日   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2006年08月22日 - 2006年08月23日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2006年07月16日 - 2006年07月22日   記述言語：英語   開催地： USA California  

開催期間： 2006年06月12日 - 2006年06月14日   記述言語：日本語   開催地：日本 大阪  

開催期間： 2006年06月12日 - 2006年06月14日   記述言語：日本語   開催地：日本 大阪  

開催期間： 2006年05月26日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2005年05月12日   記述言語：日本語   開催地： 福岡  

開催期間： 2005年05月   記述言語：日本語   開催地：日本 東京  

開催期間： 2005年05月   記述言語：日本語   開催地：日本 東京  

開催期間： 2005年04月   記述言語：日本語   開催地：日本 高知  

開催期間： 2005年04月   記述言語：日本語   開催地：日本 つくば  

開催期間： 2005年04月   記述言語：日本語   開催地：日本 東京  

開催期間： 2005年04月   記述言語：日本語   開催地：日本 つくば  

開催期間： 2005年03月11日   記述言語：日本語   開催地：日本 福岡  

開催期間： 2004年11月   記述言語：日本語   開催地：日本 仙台  

開催期間： 2004年11月   記述言語：日本語   開催地：日本 仙台  

開催期間： 2004年11月   記述言語：日本語  

開催期間： 2004年05月   記述言語：日本語   開催地：日本 東京  

開催期間： 2003年07月   記述言語：英語   開催地： USA Albuquerque  

開催期間： 2003年05月   記述言語：日本語   開催地：日本 東京  

開催期間： 2002年09月   記述言語：日本語   開催地：日本 東京  

開催期間： 2002年09月   記述言語：日本語   開催地：日本 鹿児島  

開催期間： 2002年05月   記述言語：日本語   開催地：日本 東京  

開催期間： 2002年01月   記述言語：日本語   開催地：日本 東京  

開催期間： 2001年11月   記述言語：日本語   開催地：日本 札幌  

開催期間： 2000年08月   記述言語：日本語   開催地：日本 名古屋  

開催期間： 2000年04月   記述言語：日本語   開催地：日本 東京  

開催期間： 1999年11月   記述言語：日本語   開催地：日本 東京  

開催期間： 1999年11月   記述言語：日本語   開催地：日本 東京  

開催期間： 1999年07月   記述言語：日本語   開催地：日本 大阪  

開催期間： 1999年06月   記述言語：日本語   開催地：日本 東京  

開催期間： 1999年01月   記述言語：日本語   開催地：日本 東京  

開催期間： 2013年03月06日 - 2013年03月08日   発表言語：日本語   講演種別：基調講演   開催地：東京  

講演種別：基調講演   開催地：東京工業大学大岡山キャンパス  

講演種別：招待講演   開催地：金沢大学  

講演種別：招待講演   開催地：大阪  

講演種別：招待講演  

講演種別：招待講演   開催地：PACIFICO Yokohama  

講演種別：招待講演   開催地：福岡  

講演種別：招待講演   開催地：福岡  

講演種別：招待講演   開催地：東京  

講演種別：招待講演   開催地：福岡  

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：日本国

受賞国：アメリカ合衆国