研究者詳細 - 黒島　義人

口頭発表・ポスター発表等 - 黒島　義人

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鋼の逆磁歪効果を用いた微小き裂長さの推定について ~磁歪出力に及ぼすひずみ履歴の影響~

野中維生, 黒島義人

日本機械学会九州支部第77期総会・講演会 2024年03月日本機械学会

繰返し面内純せん断負荷下における炭素鋼薄膜のすべりとき裂の発生挙動

今村隼斗, 黒島義人

M&M材料力学カンファレンス 2023年09月日本機械学会

開催期間： 2023年09月27日 - 2023年09月29日記述言語：日本語開催地：筑波国名：日本国

Fatigue behaviors differ between thin film and bulk materials, even if they are the same material. Reports show that the incidence of grain slip saturates at 0.1 when loading is applied in the shear direction. The purpose of this study is to clarify the behavior of slip and crack initiation in carbon steel thin films subjected to cyclic shear loading. We investigated the effects of carbon content and film thickness on slip and cracks. Pure iron, S10C and S45C are selected as specimens to investigate the effect of carbon content. Then, to investigate the effect of film thickness, tests are conducted with film thickness/grain size ratio t/D less than 0.8 and greater than 1.67. A torsion bending tester (Shimadzu TB-10) is used. As a result, in-plane slips and cracks are more likely to occur with higher carbon content, while out-plane slips are more likely to occur with lower it. Increasing the t/D increased out-plane slips, but not increasing in-plane slips and cracks. The following three points are considered from this study. In-plane slips occur more frequently when the volume fraction of pearlite is large, and is considered to be caused by the concentration of strain. Out-plane slips occur more frequently when t/D exceeds 1.67, suggesting that it is caused by the deformation of crystal grains in the film thickness direction. The larger the amount of in-plane slip, the more cracks are observed, suggesting that the cracks are caused by in-plane slip.

鋼のねじり低サイクル疲労におけるManson-Coffin則の結晶粒径依存性－微小き裂伝ぱ速度とき裂長さの関係

伊賀寛人, 黒島義人

M&M材料力学カンファレンス 2023年09月日本機械学会

開催期間： 2023年09月27日 - 2023年09月29日記述言語：日本語開催地：筑波国名：日本国

Many actual structures, such as piping and turbine shafts, are subjected to torsional low-cycle fatigue. However, there have been many studies on high-cycle fatigue due to torsion, but few studies on low-cycle fatigue due to torsion alone, and there are many unknown points. Fatigue tests were conducted in a torsion testing machine (490 Nm capacity) at room temperature in air, with both swings and controlled torsion angles over a specified total strain range. Cracks were observed using the replica method, in which replicas of the specimen surface were taken at regular intervals in each total strain range and observed with an optical microscope. In this study, it is shown that there is a grain size dependence of the Manson-Coffin law in torsional low-cycle fatigue and that the microcrack propagation rate is independent of crack length in torsional low-cycle fatigue.

高真空環境における高強度鋼の微小き裂伝ぱ特性と応力拡大係数範囲の関係

藤井海都, 黒島義人

M&M材料力学カンファレンス 2023年09月日本機械学会

開催期間： 2023年09月27日 - 2023年09月29日記述言語：日本語開催地：筑波国名：日本国

In general, high-strength steel is known to occur an internally initiated fatigue fracture called "Fish-eye failure" in the very long life region. In addition, the fatigue life of a fish-eye failure is dominated by the ODA (Optically Dark Area) that forms around the fracture origin. Therefore, it is necessary to elucidate the formative mechanism of ODA in order to predict the fatigue life of fish eye failure. Besides, it has been reported that small surface cracks propagate at extremely low speeds below the lattice spacing in a vacuum simulating the interior of high-strength steel. However, it has not been confirmed that the growth of these small cracks forms ODA. In this study, fatigue tests were conducted from a very short crack to a long crack, which corresponds to internal failure in the very long life region, instead of the fatigue tests with a relatively long crack of around 150 μm that have been conducted so far. The results of intermittent observation of the growth behavior and the relationship between the crack growth rate, stress intensity factor, and maximum stress suggest that small cracks grow and form ODAs.

小型十字試験片を用いた純せん断疲労試験法の開発

前迫恒希, 黒島義人

日本機械学会九州支部第76期総会・講演会 2023年03月日本機械学会

鋼の逆磁歪効果を利用した微小疲労き裂情報の測定

田中洸成, 黒島義人

日本機械学会九州支部第76期総会・講演会 2023年03月日本機械学会

繰返し面内純せん断負荷における炭素鋼薄膜の疲労挙動

森本裕, 黒島義人

M&M材料力学カンファレンス 2022年09月日本機械学会

開催期間： 2022年09月26日 - 2022年09月28日記述言語：日本語開催地：弘前

In the same materials, film and bulk materials show different mechanical properties. In fatigue testing of metallic thin film, several studies have been reported for axial and bending directions, however, there are few studies for shear direction. In addition, multiple parallel slips in the same grain are considered out-plane direction, a single linear slip in a grain is considered in-plane direction. Therefore, in this study we conducted fatigue tests under cyclic in-plane pure shear loading to S10C and S45C.We focused on the effect of pearlite volume fraction on slip generation and the relationship between cracks and slips. As a result, about 90% of the slip that occurred in S10C was out-plane direction. About 70% of the slip that occurred in S45C was in-plane slip. This is considered to be caused by the concentration of strain due to pearlite. In addition, more cracks were observed in S45C than in S10C, Consequently, cracks in the carbon steel film are considered to have grown from in-plane slip.

高強度鋼の真空下における超長寿命域でのき裂伝ぱ特性について

黒島義人, 入井涼介, 藤井海南斗

M&M材料力学カンファレンス 2022年09月日本機械学会

開催期間： 2022年09月26日 - 2022年09月28日記述言語：日本語開催地：弘前

In general, high-strength steel is known to occur an internally initiated fatigue fracture called "Fish-eye failure" in the very long life region. In addition, the fatigue life of a fish-eye failure is dominated by the ODA (Optically Dark Area) that forms around the fracture origin. Therefore, it is necessary to elucidate the formative mechanism of ODA in order to predict the fatigue life of fish eye failure. Besides, it has been reported that small surface cracks propagate at extremely low speeds below the lattice spacing in a vacuum simulating the interior of high-strength steel. However, it has not been confirmed that the growth of these small cracks forms ODA. In this study, fatigue tests were conducted from a very short crack to a long crack, which corresponds to internal failure in the very long life region, instead of the fatigue tests with a relatively long crack of around 150 µm that have been conducted so far. The results of intermittent observation of the growth behavior and the relationship between the crack growth rate, stress intensity factor, and maximum stress suggest that small cracks grow and form ODAs.

ΔK＜４の真空中における高強度鋼の微小き裂伝ぱ特性

中山詠治朗, 黒島義人

M&M材料力学カンファレンス 2021年09月日本機械学会

開催期間： 2021年09月15日 - 2021年09月16日記述言語：日本語開催地：名古屋

High Strength Steel shows internal origin type fatigue failure as called Fish eye failure in low stress and high cycle region. In this failure, ODA is formed on the fracture surface. Although the explication of the mechanism of ODA formation is needed for the explication of the Fish eye failure mechanism, the explication is not yet accomplished. It’s reported that internal fatigue crack in high strength steel is propagating extremely slowly by recent investigations. And crack propagation rate was suggested that series of the low alloy steel depend on the maximum stress and ΔK. In this study, fatigue test of the same material was in vacuum environment. As a result, ΔK≤4 MPa√m as for crack propagation rate, it suggested that the test on condition of long initial crack was faster than the test on condition of short initial crack. Therefore crack progress speed depend on the test conditions as well as the maximum stress..

鋼の磁歪効果による微小き裂長さの測定

藤井秀行, 黒島義人

M&M材料力学カンファレンス 2021年09月日本機械学会

開催期間： 2021年09月15日 - 2021年09月16日記述言語：日本語開催地：名古屋

Small fatigue crack closure is observed as a thing with a possibility that the influence of change of the stress level and a stress ratio, etc. to the crack growth behavior can be explained, and until now various researches have been done. Although there is a method using the strain gage as the dynamic measurement method required for the elucidation of a minute fatigue crack, in respect of generating of minute fatigue cracks being directly contacted to a measuring object thing, and there is a problem in durability or measurement of the crack growth behavior, it may not necessarily be effective. Then, its attention was paid to the magnetostriction effect which is one of the magnetic actions of a ferromagnetic substance. Measurement of micro fatigue crack information under dynamic load without requiring a simple device and contact with the object was carried out and the change in the magnetic field around the test piece due to the magnetostrictive effect was measured using a coil. We investigated micro fatigue crack length from the information.

低サイクルねじり疲労を受ける中空試験片に及ぼす結晶粒径の影響

冨安剛, 黒島義人

M&M材料力学カンファレンス 2021年09月日本機械学会

開催期間： 2021年09月15日 - 2021年09月16日記述言語：日本語開催地：名古屋

Many actual structures suffer from low cycle torsional fatigue, such as pipes and turbine shafts. However, there have been many studies on high cycle fatigue due to torsion, but there are few studies on low cycle fatigue using torsion alone, an there are many unclear points.It is widely known that in low-cycle fatigue, the Manson-Coffin rule that allows the fatigue life to be organized by the plastic strain width is established. The relationship is not clear. In recent years, there has been a report on the specific fatigue crack initiation behavior in studies of pure shear low cycle fatigue of thin film materials.Therefore, in this study, repeated low-cycle torsional fatigue tests were performed using S10C hollow specimens, and focusing on the main crack that caused the fracture, was the Manson-Coffin rule equivalent to the microcrack propagation law? It was investigated.

繰返し面内純せん断負荷下における炭素鋼薄膜のすべり発生挙動

森田隼斗, 黒島義人

第74期日本機械学会九州支部総会・講演会日本機械学会

鋼の磁歪特性を利用した微小疲労き裂の測定

跡部亮輔, 黒島義人

第74期日本機械学会九州支部総会・講演会日本機械学会

高強度鋼の超高サイクル域における極低速き裂進展について

飯田啓太, 黒島義人

第74期日本機械学会九州支部総会・講演会日本機械学会

低サイクルねじり疲労におけるManson-Coffin型寿命線図に与える結晶粒径の影響

古長友哉, 黒島義人

第74期日本機械学会九州支部総会・講演会日本機械学会

面内純せん断負荷下での炭素鋼薄膜のき裂発生におよぼす金属学的因子の影響

野村拓哉, 黒島義人

M&M材料力学カンファレンス日本機械学会

開催期間： 2019年11月02日 - 2019年11月04日記述言語：日本語開催地：九州大学

At the same materials, mechanical properties of a film different from those of a bulk and we consider that fatigue property
of a film is different from that of a bulk. In this study, According to a report by Ueda et al., It was reported that when a thin
film experiment was conducted, the occurrence of slips and cracks was small. It has been reported that crystals also differ
from in-plane and out-of-plane shear components．Therefore, in this study, we investigated the difference in the location and
concentration of slip due to the pearlite volume fraction of carbon steel thin films, and the mode of occurrence of slip using
EBSD and metallurgical factors.As for the form of slip, pure iron is near the grain boundary, and in S10C, several slips occur
in parallel within the same grain. What was occurring was confirmed.S10C slips are considered to occur only in crystals that
satisfy certain conditions, such as having multiple crystals in the film thickness direction and pearlite on both sides. Other
non-slip crystals are considered to be plastically deformed due to the high pure shear applied, so slips are occurring but are
considered to have been restored.

低サイクルねじり疲労における微小き裂伝播特性と Manson-coffin 則の関係

氷室天, 黒島義人

M&M材料力学カンファレンス日本機械学会

開催期間： 2019年11月02日 - 2019年11月04日記述言語：日本語開催地：九州大学

A low cycle torsional fatigue test of carbon steel S10C for machine structural use was performed with strain
control. Using a mechanism that applied Martens's mirror device, the scale was read, and the torsional torque was
increased or decreased to achieve a predetermined torsional angle, and experiments were performed with total strain
widths γ = 1.0%, 1.5%, and 2.0%. As a result, the propagation behavior of cracks in low cycle torsional fatigue was
connected and propagated by innumerable microcracks. The fatigue life calculated by the small crack propagation law,
focusing on the main crack that caused the fracture, was equivalent to the fatigue life of the Manson-Coffin’s law.

高強度鋼のΔKが4MPa√m以下の極低速き裂進展挙動について

堀貴雄, 黒島義人

M&M材料力学カンファレンス

開催期間： 2018年01月記述言語：日本語

High Strength Steel shows internal origin type fatigue failure as called Fish eye failure in low stress and high cycle region. In this failure, ODA is formed on the fracture surface. Although the explication of the mechanism of ODA formation is needed for the explication of the Fish eye failure mechanism, the explication is not yet accomplished. It's reported that internal fatigue crack in high strength steel is propagating extremely slowly by recent investigations. And crack propagation rate was suggested that series of the low alloy steel depend on the maximum stress and ΔK. In this study, fatigue test of the same material was in vacuum environment. As a result, ΔK≤4 MPa√m as for crack propagation rate, it suggested that the test on condition of long initial crack was faster than the test on condition of short initial crack. Therefore crack progress speed depend on the test conditions as well as the maximum stress.

CiNii Article

磁歪特性を利用した周辺磁場計測による微小き裂情報の測定

小松昭文, 黒島義人

M&M材料力学カンファレンス

開催期間： 2018年01月記述言語：日本語

Small fatigue crack closure is observed as a thing with a possibility that the influence of change of the stress level and a stress ratio, etc. to the crack growth behavior can be explained, and until now various researches have been done. Although there is a method using the strain gage as the dynamic measurement method required for the elucidation of a minute fatigue crack, in respect of generating of minute fatigue cracks being directly contacted to a measuring object thing, and there is a problem in durability or measurement of the crack growth behavior, it may not necessarily be effective. Then, its attention was paid to the magnetostriction effect which is one of the magnetic actions of a ferromagnetic substance. Measurement of micro fatigue crack information under dynamic load without requiring a simple device and contact with the object was carried out and the change in the magnetic field around the test piece due to the magnetostrictive effect was measured using a coil. We investigated micro fatigue crack information from the information.

CiNii Article

繰返し純せん断負荷下における炭素鋼薄膜の微小き裂の進展挙動

山田純平, 黒島義人

M&M材料力学カンファレンス

開催期間： 2017年01月記述言語：日本語

Even if metal thin film is the same material, it does not know that different mechanical characteristics form a bulk material are shown, and general fatigue behavior showing a bulk material does not necessarily appear. The present condition is that research of the fatigue behavior in the repetition shear load of a metal thin film is not made compared with the thing of load direction axis and bending. From studies of thin films in the cyclic loading to date, a crack with a locally slip in S10C occurs. The cause such crack occurs, the strain in the ferrite by applying the cyclic shear loading occurs, pearlite is considered to crack been concentrated deformed part that is sandwiched between the pearlite harder than ferrite because no deformation occurs. In addition, with respect to micro fatigue crack propagation in the repeated shear load of the bulk material, it was confirmed that the stiff cracks were inhibited by hard pearlite crystal grains, but the propagating cracks also progressed into the pearlite grains. Therefore, in this study, fatigue cracks are generated and developed by applying a repeated shearing load to the thin film material of S10C, and the influence of the observation / microstructure of its progress process was examined. As a result, it was confirmed that the pearlite crystal grains of the thin film material prevented the crack growth as well as the bulk material, and the propagating cracks also progressed into the pearlite crystal grains.

CiNii Article

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