| 1. |
Virendra Kumar Verma, C.K. Gopalakrishnan, Shigeru Hamada, Tatsuo Yokoi, Hiroshi Noguchi, Effect of strain localization on fatigue properties of precipitation-hardened steel with an arbitrarily length crack, International Journal of Fatigue, 10.1016/j.ijfatigue.2020.106017, Vol.143, p.106017, 2021.02. |
| 2. |
Thanh Thuong Huynh, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi, Roles of Hydrogen and Plastic Strain Distribution on Delayed Crack Growth in Single-crystalline Fe–Si alloy, Materials Science and Engineering: A, 10.1016/j.msea.2020.140703, Vol.803, p.140703, 2021.01. |
| 3. |
Bryan Proaño, Hirofumi Miyahara, Toshiharu Matsumoto, Shigeru Hamada, Hitoshi Sakai, Kiyoshi Ogawa, Suyalatu, Hiroshi Noguchi, Plastic strain distribution throughout the microstructure duality during the fracture process of non-combustible Mg products fabricated by selective laser melting, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102805, Vol.110, p.102805, 2020.12. |
| 4. |
He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi, Shallow crack effect on evaluation of residual tensile strength: Harmless and stable cracks in finite-sized structure made of ductile metals, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102734, Vol.109, 2020.10, Residual tensile strength (hereinafter abbreviated as ‘residual strength’) is a critical fail-safe consideration but has rarely been reported in the case of shallow pre-cracked structures. When the pre-crack depth is shallower than a critical value, the residual strength of cylindrical specimens made of interstitial-free steel exhibits a plateau identical to the tensile strength of smooth specimens, and with a rupture occurred far away from the pre-cracked cross-section. According to the damage characteristics by microscopic observation and the plastic strain distribution by kernel average misorientation measurement, such a situation exists when the physical meaning of residual strength changes from fracture instability to plastic instability. The corresponding mechanism, with the assistance of finite element analysis, is ascribed to the following: 1. The plastic strain localization induced by shallow cracks preferentially hinders plastic instability in the pre-cracked cross-section rather than promotes fracture instability at the crack tip because the high fracture toughness makes shallow cracks remain non-propagating or stable-propagating at least until plastic instability occurs; 2. Whether a shallow crack strengthens or weakens the pre-cracked cross-section depends on the integrated factors of the effective area of cross-section for bearing load narrowed by the crack depth (negative effect), the strain hardening and damage initiation in near crack-tip region affected by gradient plasticity (positive or negative effect), and uniform plasticity in remote crack-tip region alleviated by plastic strain localized near the crack tip (positive effect). Then, the above features are defined as the ‘shallow crack effect’ in the residual strength issue. To incorporate this problem in design, a residual strength diagram considering physical meanings of residual strength and corresponding damage characteristics is suggested. It helps to estimate the trend of residual strength from the perspective of plastic strain localization. Finally, influential factors on the ‘shallow crack effect’ in the residual strength issue are discussed.. |
| 5. |
He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi, Distinguishing geometric and metallurgic hydrogen-embrittlement susceptibilities in pre-cracked structures made of interstitial-free steel under monotonic tension, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102574, Vol.108, 2020.08, Hydrogen embrittlement (HE) is widely believed to be harmful to engineering structures made of ferritic steel, particularly in the presence of pre-cracks. However, in this study, the ultimate tensile strength (UTS) of shallow pre-cracked cylinder specimens made of interstitial-free (IF) steel, which represents a standard microstructure of ferritic steel, does not always decrease in the hydrogen environment. Namely, the fracture characteristic is sensitive to hydrogen, but UTS is not under specific conditions. This influence of HE contrary to the common-sense understanding is attributed to the following: (1) the crack propagation assisted by hydrogen-enhanced localized plasticity (HELP) is stable before the onset of plastic instability because of exceedingly-high fracture instability toughness; and (2) the plastic strain localization at the pre-crack tip and secondary crack tips resisted the onset of plastic instability. Additionally, this effect calls into question the general applicability of conventional investigation of HE susceptibility that mainly focuses on the variation of fracture characteristic, which is often defaulted to cause changes in mechanical properties. Here, HE susceptibility is deduced to be depended mainly on geometric properties (geometric HE susceptibility) for shallow pre-cracked structures, while that for deep pre-cracked structures depends mainly on material properties (metallurgic HE susceptibility). Subdividing HE susceptibility helps identify conditions under which plastic strain localization caused by HE susceptibility is beneficial for UTS in fail-safe design.. |
| 6. |
He Liu, Shigeru Hamada, Motomichi Koyama, Hiroshi Noguchi, Equivalence between shallow notch and shallow crack in structural failure caused by plastic instability, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102577, Vol.108, 2020.08, Introducing crack-like notches is essential for investigating the mechanical properties of pre-cracked structures because fatigue pre-cracking occasionally fails to ensure some rigorous investigation conditions. However, the results obtained by previous studies related to crack-like notches under small-scale yielding are invalid for shallow notches with extensive plasticity, particularly when plastic instability instead of unstable crack propagation governs the structural strength. This study focused on the plastic instability occurring under the plane strain condition without the assistance of pre-crack propagation. The boundary condition, geometric configuration, and elastoplastic fields dominating the overall work hardening in notched and cracked cross-sections were considered in finite element analyses. From the perspective of asymptotic and phenomenological analysis, this study proposes that a shallow crack-like notch should satisfy the following requirements: (1) the structural strength should be independent of the notch geometry, except for the notch depth; (2) the elastoplastic fields in the notched cross-section should be broadly convergent to those in the pre-cracked cross-section; (3) the failure mode characterized by damage pattern should be similar. The underlying reason for crack-like notches existing in extensive plasticity is that different elastoplastic field gradients close to the notch root or crack tip may still result in the same overall work hardening in notched and pre-cracked cross-sections. This concept was experimentally verified using interstitial-free steel, which is a typical strain-hardening ferrite steel with excellent ductility and simple metallurgical microstructure. The generality of the identification method and the significance of influential factors for shallow crack-like notches are discussed in this study.. |
| 7. |
Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Influence of dynamic-strain aging due to excess Mg on fatigue crack growth rate scatter in Al6061-T6 alloy, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102617, Vol.108, 2020.08, Fatigue failure results in high industrial costs, and its mechanism requires close examination; however, current methods are costly and time-consuming due to the need for a large number of test specimens. The purposes of this study are to investigate the influence of dynamic strain aging on fatigue crack growth rate (FCGR) scatter in Al 6061-T6 alloys and to present a new approach to evaluate the scatter of FCGR using a limited number of the test specimen. Rotating bending fatigue tests of 6061-T6-based Al alloys with added Zr and excess Mg were performed under constant amplitude loading using smooth specimens. The scatter behavior of FCGR is investigated by examining the fatigue crack growth on the specimen surface and fractographic observation on the fracture surface. The accounting for the interaction effects of multiple surface cracks and fractographic examination on striation formation from previous findings revealed that excess Mg promoted small scatter in Mode I fatigue crack growth. This study showed that local plastic deformation affected the FCGR scatter of microstructurally-large fatigue cracks. These findings suggest that dynamic strain aging of Mg induces stable Mode I crack growth due to pinning of dislocation movement on slip planes during the crack growth process.. |
| 8. |
Yuto Wakita, Yuya Tachikawa, Hironori Nakajima, Shigeru Hamada, Kohei Ito, Visualization and mechanical strength of glass seal in planar type solid oxide fuel cells, International Journal of Hydrogen Energy, 10.1016/j.ijhydene.2020.05.153, Vol.45, No.41, pp.21754-21766, 2020.08. |
| 9. |
Virendra Kumar Verma, Motomichi Koyama, Shigeru Hamada, Eiji Akiyama, Effects of hydrogen content that alters damage evolution mechanisms in SUH 660 precipitation-strengthened Fe–Cr–Ni steel, Materials Science and Engineering A, 10.1016/j.msea.2020.139750, Vol.791, 2020.07, This study aims at understanding the change of the hydrogen embrittlement mechanism with respect to hydrogen content of a precipitation-strengthened Fe–Ni–Cr-based steel. Hydrogen was electrochemically introduced with different current densities. The hydrogen-charging deteriorated crack initiation and propagation resistances as well as the crack tip blunting capability. Further, with increasing hydrogen content, the primary cracking sites changed from coarse carbides to slip bands, and then to grain boundaries. Moreover, because the crack initiation probability increased and the resistance to trans-granular crack propagation decreased with hydrogen content, the crack coalescence associated with slip localization occurred more frequently.. |
| 10. |
Tingshu Chen, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Fundamental criterion Ktrans for failure analysis of hydrogen-assisted cracks in notched specimens of pure Ni, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102556, Vol.107, 2020.06, © 2020 Elsevier Ltd The effects of short notches on crack initiation and extension were studied under electrochemical hydrogen charging in pure nickel. In the hydrogen-charged smooth specimen, multiple cracks were initiated on grain boundaries after significant plastic deformation and were subsequently arrested by crack blunting in the interior of neighboring grains. With the assistance of sub-cracks on specimen surface, quasi-cleavage crack propagation occurred soon after, causing the final failure. The introduction of a notch did not change the crack initiation site (grain boundary). However, crack propagation exhibited significant initial notch-length dependence. A 2.5 mm notch caused quasi-cleavage crack propagation without sub-critical cracks (intergranular cracks) initiation and growth, because the notch root acted as a strongly preferential site for crack extension. However, with a smaller notch, sub-critical cracks initiation and growth were necessary to extend intergranular fracture depth and reach a critical crack length to supply adequate plasticity. This plasticity could not be met in the initial stage from the notch root with hydrogen charging. The relation between maximum remote stress and critical crack length among different notch lengths was shown to be a geometry-independent parameter of pure nickel, which can predict tensile strength under various notch configurations.. |
| 11. |
Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Simplified stress field determination for an inclined crack and interaction between two cracks under tension, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2020.102561, Vol.107, 2020.06, © 2020 Elsevier Ltd Multiple initiated cracks are frequently occurred on structural components, and they have significant effects on fatigue life due to interaction between several cracks. The objective of the present study was to investigate the inclination of a crack and the interaction effect between two cracks. By analyzing the stress distribution around a single crack and various results from the available literature on the stress intensity factors of the interaction between two cracks, an estimation method was introduced to evaluate the inclination effect and the crack interaction between two cracks in a variety of positions subjected to tension loads under Mode I loading conditions. The effect of cracks length and cracks distance on stress distribution was examined. The study results showed that crack interaction obtained by proposed method was in good agreement with previous findings from the stress intensity factor handbook. Finally, an approximate procedure for estimating the crack interaction in an arbitrary position for two- and three-dimensional cases was proposed.. |
| 12. |
Virendra Kumar Verma, Motomichi Koyama, Shigeru Hamada, Eiji Akiyama, Multiple damage mechanisms facilitated by planar dislocation glide in a commercial-grade precipitation-strengthened Fe–Ni–Cr-based steel, Materials Science and Engineering A, 10.1016/j.msea.2020.139250, Vol.782, p.139250, 2020.04. |
| 13. |
Kai Suzuki, Motomochi Koyama, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi, Planar slip-driven fatigue crack initiation and propagation in an equiatomic CrMnFeCoNi high-entropy alloy, International Journal of Fatigue, 10.1016/j.ijfatigue.2019.105418, Vol.133, 2020.04, © 2019 Elsevier Ltd High-cycle fatigue crack initiation and propagation in an equiatomic CrMnFeCoNi high-entropy alloy were investigated using smooth specimens. The microstructural deformation characteristics, i.e., planar dislocation slip, significantly affected the fatigue crack initiation and small fatigue crack propagation. The deformation localization associated with dislocation planarity led to multiple crack initiation on the slip planes. The crack propagation mechanism comprised crack formation on slip planes around the main crack tip and subsequent coalescence. The fatigue crack propagation mechanism shifted to Mode I type as the crack length increased.. |
| 14. |
Thanh Thuong Huynh, Motomichi Koyama, Yoshimasa Takahashi, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi, Plastic deformation sequence and strain gradient characteristics of hydrogen-induced delayed crack propagation in single-crystalline Fe–Si alloy, Scripta Materialia, 10.1016/j.scriptamat.2019.11.012, Vol.178, pp.99-103, 2020.03, © 2019 Acta Materialia Inc. Microscopic features of hydrogen-induced delayed crack propagation in a thin sheet of single-crystalline Fe-3wt%Si alloy were investigated. The crack tip plastic deformation associated with the effect of hydrogen during the crack propagation leaves three adjacent regions where different plastic strain gradients and dislocation densities are observed. These regions revealed the effects of plastic deformation and hydrogen-dislocations interaction around the crack tip on the rate-limiting process of hydrogen-induced delayed crack propagation in thin specimens.. |
| 15. |
Bochuan Li, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Effect analysis of stress-intensity-factor-range decreasing rate for obtaining threshold stress-intensity-factor-range, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2019.102377, Vol.104, 2019.12, © 2019 Elsevier Ltd The threshold stress intensity factor range ΔKth can be obtained using the ΔK decreasing method. Because ΔKth is dependent on the ΔK decreasing rate, the rate is regulated by the American Society of Testing Materials standard. However, the rate was derived under specific conditions, and its applicability to materials with physical properties different from ordinary steel has not been clarified. To address this issue, this study performed plasticity-induced-crack-closure analysis with the Dugdale model. The dependence of material properties on ΔKth of long crack was determined for steel, aluminum and magnesium. The results showed that the rate value proposed by the standard is valid for all materials with different yield strengths and different Young's moduli within 10% error.. |
| 16. |
Samsol Faizal Anis, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Mode I fatigue crack growth induced by strain-aging in precipitation-hardened aluminum alloys, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2019.102340, Vol.104, 2019.12, © 2019 Elsevier Ltd In this study, the effects of Mg on the fatigue crack growth (FCG) characteristics of precipitation-hardened Al6061 alloys containing Zr and excess Mg are examined. The growth behavior of microstructurally large cracks is investigated via rotating-bending fatigue tests conducted at room temperature. Analyses of the crack propagation and striation features show that excess Mg promotes the occurrence of Mode I fatigue cracks. These facts suggest that dynamic strain aging due to Mg restricts dislocations motion, resulting in greater work hardening, and generates a large number of active slip systems, leading to more non-localized slip and a large area of striation formation. Consequently, it is concluded that this phenomenon induces highly stable crack growth in Al alloys with excess Mg, which influences the fatigue crack growth rate (FCGR) scatter of microstructurally large cracks. A reasonable mechanism of strain-aging-induced Mode I FCG in Al alloys is proposed on the basis of the morphological aspects of fatigue striation formation.. |
| 17. |
Bryan Proaño, Hirofumi Miyahara, Toshiharu Matsumoto, Shigeru Hamada, Hitoshi Sakai, Kiyoshi Ogawa, Suyalatu, Hiroshi Noguchi, Weakest region analysis of non-combustible Mg products fabricated by selective laser melting, Theoretical and Applied Fracture Mechanics, 10.1016/j.tafmec.2019.102291, Vol.103, p.102291, 2019.10. |
| 18. |
Shigeru Hamada, Kejin Zhang, Jiwang Zhang, Motomichi Koyama, Tatsuo Yokoi, Hiroshi Noguchi, Effect of shear-affected zone on fatigue crack propagation mode, International Journal of Fatigue, 10.1016/j.ijfatigue.2018.06.003, Vol.116, pp.36-47, 2018.11, It is well known that the fatigue limits of some precipitation-hardened steels with a punched hole do not increase, even if the tensile strengths of base-metal increases. This study suggested that the dominant reason for this strange phenomenon is a transition from the Mode I type fatigue crack propagation due to the cyclic plastic deformation to Mode II type propagation due to the damage accumulation by a quantitative analysis of influential factors based on fracture mechanics. This result can open a probability that the fatigue limit of the punched hole with shear-affected zone can be actively quantified.. |
| 19. |
Shigeru Hamada, Taro Suemasu, Shuto Fukudome, Motomichi Koyama, Masaharu Ueda, Hiroshi Noguchi, Roughness-induced stress shielding effect in fatigue crack propagation under Mode II loading, International Journal of Fatigue, 10.1016/j.ijfatigue.2018.06.029, Vol.116, pp.245-256, 2018.11, Roughness-induced stress shielding effect under cyclic Mode II loading caused by fracture surface roughness, i.e., the effect of decreasing loading stress intensity factor K, is investigated. A fatigue crack propagation test by applying cyclic Mode II loading on a small textured material is performed. The decrease in K is a few percent quantitatively, and the decrease is sufficiently small to ignore. Using the failure surface observation results, we discuss the mechanism of the fatigue crack propagation during cyclic Mode II loading on the textured material and validate the repeated crack propagation mechanism of damage accumulation, void formation, and coalescence.. |
| 20. |
Shigeru Hamada, Jiwang Zhang, Kejin Zhang, Motomichi Koyama, Toshihiro Tsuchiyama, Tatsuo Yokoi, Hiroshi Noguchi, Ductile-to-brittle transition in tensile failure due to shear-affected zone with a stress-concentration source: a comparative study on punched-plate tensile-failure characteristics of precipitation-hardened and dual-phase steels, International Journal of Fracture, 10.1007/s10704-018-0304-9, 2018.08. |
| 21. |
Temma Sano, Daisuke Sasaki, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Proposal and ver ification of novel fatigue crack propagation simulation method by finite element method, 22nd European Conference on Fracture, 2018.08. |
| 22. |
Junji Sakamoto, Shigeru Hamada, Hiroshi Noguchi, Effects of the shape of small flaws and damage due to a focused ion beam on the fatigue strength characteristics of annealed medium‑carbon steel, Engineering Failure Analysis, 10.1016/j.engfailanal.2018.02.005, Vol.87, pp.49-68, 2018.05, © 2018 Elsevier Ltd Fatigue tests and hardness tests were conducted in order to clarify the effects of the shapes of small flaws and damage caused by a focused ion beam (FIB) on the fatigue strength characteristics of annealed medium‑carbon steel. The notch root radius of the flaw at the branch point dominates the type of the fatigue limit and was found to be approximately 50 μm, a value that was significantly smaller than the 500 μm of two-dimensional notches in steel. The effect of the FIB-damaged layer on fatigue crack initiation from the FIB-milled notch in the steel was negligible. Moreover, the present study indicated that the effect of the FIB-damaged layer on the fatigue crack initiation at the FIB-milled notch could be evaluated simply by using a hardness test for the other materials and FIB conditions.. |
| 23. |
Shigeru Hamada, Tsuyoshi Moriyama, Hiroshi Noguchi, Dependence of fatigue limit on step height for stepped 0.45% carbon steel with singular stress field, Engineering Fracture Mechanics, 10.1016/j.engfracmech.2017.07.010, Vol.188, pp.20-35, 2018.02, A method was proposed for evaluating the relationship between the fatigue limit and the step height for a stepped plate with a sharp corner. With reference to a small crack size dependence of fatigue limit, step heights were divided into three levels, and a new evaluation method was proposed for representing the singular stress field intensity around the corner tip. An intensity factor of the singular stress field of the corner was introduced and correlated with the step height. The fatigue limit for stepped plates was represented by the threshold value of the range of the intensity factor. Moreover, the fatigue limits for extra-low stepped plates and high stepped plates, which could not be directly measured, were estimated based on the fatigue phenomena at these conditions.. |
| 24. |
Kejin Zhang, Shigeru Hamada, Motomichi Koyama, Tatsuo Yokoi, Hiroshi Noguchi, Influence of shear-affected-zone due to punching on tensile characteristics of steel plate, Procedia Structural Integrity, 10.1016/j.prostr.2018.12.196, Vol.13, pp.1047-1052, 2018.01, © 2018 The Authors. In punched steel plate, "punched specimen" from here onwards, the region near the edge of the punched hole is called the shear-affected-zone (SAZ), where tensile characteristics are compromised due to the punching process. However, the specific characteristics and influence on the tensile characteristics of the SAZ are unknown. Therefore, it is difficult to predict the effects of punching on the specimen. Here, we evaluated two kinds of specimens: punched and "honed." The hole of the honed specimen is formed by drilling and polishing, thus there is no SAZ on the honed specimens. In these specimens, we focused on the initiation and propagation of cracks under tensile loading and set the following objectives: (1) Determine whether any special events occur in the fracture mechanism of the punched vs honed specimens under tensile loading. (2) Find the reasons for any special events that occur. In our investigation, a punched specimen showed brittle fracture even within the static range of the strain rate. By failure surface observation of the punched specimens, we found that under tensile loading, cracks caused by the shear stress aligned with the tensile direction initiate in the SAZ. These cracks are the origin of the final fracture of the punched specimen. We assumed that whether the break is a ductile failure or brittle fracture depends on whether the crack tip becomes blunt. The differences in the fracture behaviors are investigated via detailed fracture surface observation.. |
| 25. |
Shigeru Hamada, Taro Suemasu, Motomichi Koyama, Masaharu Ueda, Hiroshi Noguchi, Re-examination of fatigue crack propagation mechanism under cyclic Mode II loading, Procedia Structural Integrity, 10.1016/j.prostr.2018.12.191, Vol.13, pp.1026-1031, 2018.01, © 2018 The Authors. The essence of rolling contact fatigue is the so-called "Mode II fatigue crack propagation." However, its understanding has not progressed as much as that of Mode I. We think that this cause is the name: "Mode II fatigue crack propagation." Originally, Modes I and II represented the loading modes for still cracks in fracture mechanics, and not the fatigue crack propagation mechanism. There are many cases where the knowledge of fatigue crack propagation under Mode I loading is applied to that under Mode II loading without consideration. Moreover, in the rolling contact fatigue region where the fatigue crack propagates under Mode II loading, a large plastic deformation is caused by the rolling contact load. Therefore, it is necessary for the test method to reproduce the effects of an actual machine to test materials that exhibit large plastic deformation. Therefore, in this study, we aim to classify the fatigue crack propagation phenomena, regardless of Mode I and II loadings, and re-examine the mechanisms. To that end, we developed a novel test method that enables pure Mode II loading. We used a micro-thin film disc as a specimen, making it possible to cut out and test a part subjected to a large plastic deformation from the actual machine. By observations of the crystallographic structure before the fatigue test and the successive observation of fatigue crack propagation behavior, we propose a crack propagation mechanism, namely, damage accumulation type fatigue crack propagation under Mode II loading, which is different from the opening type fatigue crack propagation.. |
| 26. |
Bochuan Li, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Threshold stress intensity factor range of a mechanically-long and microstructually-short crack perpendicular to an interface with plastic mismatch, ENGINEERING FRACTURE MECHANICS, 10.1016/j.engfracmech.2017.07.023, Vol.182, pp.287-302, 2017.09, In this study, we investigated long fatigue crack growth perpendicular to a soft-hard material interface comprising the same Young's moduli but different yield strengths. We determined the degree of fatigue crack growth retardation attributable to the interface under the constant stress intensity factor range (Delta K) using the plasticity-induced crack closure analysis with the Dugdale model. We subsequently determined the threshold stress intensity factor range (Delta Kth) under a constant stress amplitude (sigma(a)). Under a constant Delta K, the retardation degree was primary dependent on the two materials' yield strength ratio. Under a constant sigma(a), Delta Kth was dependent on both the yield strength ratio and the distance between initial crack tip and interface. (C) 2017 Elsevier Ltd. All rights reserved.. |
| 27. |
Naoki Fukumura, Bochuan Li, Motomichi Koyama, Tomohiro Suzuki, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi, Material property controlling non-propagating fatigue crack length of mechanically and physically short-crack based on Dugdale-model analysis, THEORETICAL AND APPLIED FRACTURE MECHANICS, 10.1016/j.tafmec.2017.04.012, Vol.90, pp.193-202, 2017.08, Non-propagating fatigue crack lengths were analytically calculated under stress control conditions using plasticity-induced crack closure analysis with the Dugdale model. In addition, a non-dimensionalization method was applied in terms of the Burgers vector and a monotonic plastic zone size under small-scale yielding conditions, which was validated for various initial crack lengths and material properties. When the yield strength was increased, the non-propagating fatigue crack lengths were found to increase for a short crack and decrease for a long crack. The non-dimensionalization enabled the analytical derivation of a generalized non-propagating fatigue crack length, which can be utilized for fatigue designs. The material property controlling the threshold stress intensity factor range of mechanically and physically short-crack was discussed. (C) 2017 Elsevier Ltd. All rights reserved.. |
| 28. |
岡崎三郎, 中村眞実, 濱田繁, 松永久生, 松岡三郎, 高圧水素ガス曝露を施したオーステナイト系ステンレス鋼板突合せ溶接継手の疲労寿命特性, 材料とプロセス(CD-ROM), Vol.30, No.2, p.ROMBUNNO.421, 2017.08. |
| 29. |
S. Hamada, M. Nakanishi, T. Moriyama, H. Noguchi, Re-Examination of Correlation between Hardness and Tensile Properties by Numerical Analysis, EXPERIMENTAL MECHANICS, 10.1007/s11340-017-0272-4, Vol.57, No.5, pp.773-781, 2017.06, Contact, singular-field, and large-deformation numerical analyses were performed to re-examine the correlation between hardness and tensile properties. Materials have single hardness values, but continuous changes in stress-strain diagrams; it is impossible, in principle, to correlate the hardness to one stress-strain value. Therefore, there must exist an application limit, which is discussed in this study. Because discretization error is unavoidable in such analyses, a method for leveling the discretization error regardless of the analysis condition was introduced. Moreover, in order to generalize the analysis results, the stress-strain diagram used for this analysis was considered as a dimensionless expression in arranging the results. From the analytical results, the following conclusions were deduced. The range in which the empirical equation between hardness and tensile strength is applicable depends on only the value of the work hardening exponent. Moreover, for the 0.05-0.2 range of the work hardening exponent for general steel, the prediction of tensile strength from the hardness is possible with 10% error at indenter face angles between 110 degrees and 136 degrees in case of the wedge indentation.. |
| 30. |
Koki Tazoe, Shigeru Hamada, Hiroshi Noguchi, Fatigue crack growth behavior of RS SCM440 steel near fatigue threshold in 9-MPa hydrogen gas environment, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 10.1016/j.ijhydene.2017.03.223, Vol.42, No.18, pp.13158-13170, 2017.05, In this study, stress intensity factor range (Delta K) decreasing tests were conducted and the in situ observations were used to investigate the fatigue crack growth behavior of JIS SCM440 steel near the fatigue threshold in a 9-MPa hydrogen gas, environment. The fatigue crack growth rate reflected the threshold behavior of the material, although the crack propagation knee point immediately before the threshold stress intensity factor range (Delta K-th) could not be distinctly identified. The fatigue crack was also observed to exhibit uneven propagation immediately before Delta K-th. In contrast, the knee points in a helium gas environment and air were very distinct. Fractographic analysis further revealed the existence of inter granular facets, which were observed immediately before Delta K-th in the hydrogen gas environment. Conversely, no facet was observed immediately before Delta K-th in the helium gas environment and air. The formation of the facets was considered to be one of the causes of the uneven crack propagation immediately before Delta K-th in the hydrogen gas environment. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.. |
| 31. |
岡崎三郎, 中村眞実, 濱田繁, 松永久生, 松岡三郎, オーステナイト系ステンレス鋼板突合せ溶接継手の疲労寿命特性に及ぼす水素の影響, 材料とプロセス(CD-ROM), Vol.30, No.1, p.ROMBUNNO.202, 2017.03. |
| 32. |
Saburo Okazaki, Shigeru Hamada, Hisatake Itoga, Hisao Matsunaga, Masami Nakamura, Saburo Matsuoka, A case study of a cooling pipe for a pre-cooler used in a 70-MPa hydrogen station, American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 10.1115/PVP2017-65435, Vol.6B-2017, 2017.01, Copyright © 2017 ASME. A case study was conducted on the cooling pipe of a pre-cooler which had been used in a 70-MPa hydrogen station demonstration project. The cooling pipe consisted of a main pipe, a mechanical joint pipe and a mechanical joint. The main and mechanical joint pipes had been joined using TIG welding. Through chemical composition analysis, microstructure observation and Vickers hardness measurement, it was revealed that the main and mechanical joint pipes had been manufactured from SUS316L and that 316L was the filler metal used for TIG welding. Round-bar specimens were machined out of the main pipe in order to investigate the tensile properties of the base metal. On the other hand, both round-bar specimen without reinforcement and square-bar specimens with reinforcement were fabricated from the weld-joint. Using the three types of specimens, slow strain rate tensile tests were performed in 0.1 MPa nitrogen gas and in 115 MPa hydrogen gas at a temperature of -40 °C. Reduction of area (RA), φ, for the round base-metal specimen, the round weld-joint specimen and the square weldjoint specimen were respectively, 83.5 %, 71.3 % and 81.4 % in nitrogen gas, whereas the related values in hydrogen gas were 60.1 %, 61.3 % and 40.1 %. In other words, the RA for the three types of specimens was smaller in hydrogen gas than in nitrogen gas. Dimples were formed on the fracture surfaces of the three specimen types in nitrogen gas, whereas both dimples and quasi-cleavages were formed in hydrogen gas.. |
| 33. |
岡崎三郎, 濱田繁, 中村眞実, 松永久生, 松岡三郎, 井藤賀久岳, 水素ステーション実証試験で使用されたプレクーラー用冷却パイプの事例解析, 材料とプロセス(CD-ROM), Vol.29, No.2, p.ROMBUNNO.204, 2016.09. |
| 34. |
Shigeru Hamada, Shogo Kashiwa, Hiroshi Noguchi, Measurement of local mechanical properties using multiple indentations by a special conical indenter and error analysis, JOURNAL OF MATERIALS RESEARCH, 10.1557/jmr.2015.383, Vol.31, No.2, pp.259-273, 2016.01, This paper proposes a method for determining the mechanical properties (Young's modulus, Poisson's ratio, yield strength, and work hardening factor) of a material at a specific point using an indentation technique that utilizes a specially designed indenter in conjunction with an inverse problem and finite element analyses. The specially designed indenter combines the characteristics of spherical and conical indenters and can be used to produce multiple indentations at a single point. The feasibility of the proposed method for determining the local mechanical properties of a material was confirmed by detailed precision verifications in the ideal case and the worst case.. |
| 35. |
Daisuke Sasaki, Motomichi Koyama, Shigeru Hamada, Hiroshi Noguchi, Tensile properties of precracked tempered martensitic steel specimens tested at ultralow strain rates in high-pressure hydrogen atmosphere, PHILOSOPHICAL MAGAZINE LETTERS, 10.1080/09500839.2015.1049574, Vol.95, No.5, pp.260-268, 2015.05, Tensile tests were performed on precracked Cr-Mo martensitic steel (C: 0.38, Si: 0.22, Mn: 0.84, P: 0.024, S: 0.021, Ni: 0.08, Cr: 1.11, Mo: 0.15, Cu: 0.12, Fe: bal. (wt%)) specimens at various strain rates (ranging from 6.5x10(-8) s(-1) to 1.0x10(-4) s(-1)) in high-pressure (95MPa) hydrogen and helium atmospheres. Irrespective of the strain rate, the tensile strength in the helium atmosphere was 1400MPa. In the hydrogen atmosphere, the tensile strength decreased to less than 600MPa at a strain rate of 2.0x10(-5) s(-1). However, the tensile strength increased to 900MPa when the strain rate was decreased to 6.5x10(-8) s(-1). This recovery of the tensile strength was because of the decrease in the local stress in the vicinity of the precrack because of hydrogen.. |
| 36. |
Naoki Fukumura, Tomohiro Suzuki, Shigeru Hamada, Kaneaki Tsuzaki, Hiroshi Noguchi, Mechanical examination of crack length dependency and material dependency on threshold stress intensity factor range with Dugdale model, ENGINEERING FRACTURE MECHANICS, 10.1016/j.engfracmech.2015.01.003, Vol.135, pp.168-186, 2015.02, The threshold stress intensity factor range Delta K-th was analytically calculated under stress control conditions using the plasticity-induced crack closure analysis with the Dugdale model. Before obtaining Delta K-th, the accuracy of the method was verified. The characteristics of the crack closure behavior were discussed by specifying the small-scale yielding (SSY) and large-scale yielding (LSY). The analysis results of Delta K-th were discussed systematically by non-dimensionalizing them with the Dugdale model. Under the SSY condition, DKth was dependent on Young's modulus and Poisson's ratio. Under the LSY condition, Delta K-th increased when the initial crack length or yield strain increased. (C) 2015 Elsevier Ltd. All rights reserved.. |
| 37. |
Hao Wu, Shigeru Hamada, Yasuji Oda, Hiroshi Noguchi, Effect of internal hydrogen on very high cycle fatigue of precipitation-strengthened steel SUH660, INTERNATIONAL JOURNAL OF FATIGUE, 10.1016/j.ijfatigue.2014.07.006, Vol.70, pp.406-416, 2015.01, The fatigue life of SUH660 steel is dominated by crack initiation in the region of very high cycle fatigue owing to the new crack initiation behavior near the tip of temporarily arrested crack. The effect of internal hydrogen on very high cycle fatigue life is investigated focused on crack initiation life via fatigue and Vickers hardness tests. Hydrogen inhibits cracks initiation, and accelerates the increase in crack initiation lives with decreasing stress in low and medium hardness zones. Hydrogen increases the hardness in low and medium hardness zones. Hydrogen extends new crack initiation lives and causes longer very high cycle fatigue life. (C) 2014 Elsevier Ltd. All rights reserved.. |
| 38. |
Junichiro Yamabe, Hisao Matsunaga, Yoshiyuki Furuya, Shigeru Hamada, Hisatake Itoga, Michio Yoshikawa, Etsuo Takeuchi, Saburo Matsuoka, Qualification of chromium-molybdenum steel based on the safety factor multiplier method in CHMC1-2014, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 10.1016/j.ijhydene.2014.10.114, Vol.40, No.1, pp.719-728, 2015.01, To clarify the usefulness of the safety factor multiplier method for Cr-Mo steel in the CHMC1-2014 standard for hydrogen-service components, slow-strain-rate tests of smooth and notched specimens and fatigue tests of notched specimens were performed in air and in 115 MPa hydrogen gas. The series of tests determined a safety factor multiplier of approximate to 3.0, which allowed only quite small design stresses for Cr-Mo steel. Furthermore, the safety factor multiplier can be predicted by fatigue crack growth (FCG) analysis for a notched specimen, i.e., in this respect, the fatigue test of notched specimen is a kind of FCG test. On the basis of this idea, safety factor multipliers for types 304, 316, and 316L austenitic stainless steels were predicted from FCG data to be 2.0, 1.6, and 1.3, respectively. Because the results demonstrate that the safety factor multiplier method provides overly conservative safety factors for some steels, design methods for specific component applications by testing based on design by rule and design by analysis are newly proposed. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.. |
| 39. |
Shigeru Hamada, Tomoya Fujisawa, Motomichi Koyama, Norimitsu Koga, Nobuo Nakada, Toshihiro Tsuchiyama, Masaharu Ueda, Hiroshi Noguchi, Strain mapping with high spatial resolution across a wide observation range by digital image correlation on plastic replicas, MATERIALS CHARACTERIZATION, 10.1016/j.matchar.2014.10.010, Vol.98, pp.140-146, 2014.12, In this study, a one-step replica method was applied at 0, 3, and 7% plastic strains in pearlitic steel. A microstructural digital image correlation was then performed on acetyl cellulose plastic replica surface images to obtain high spatial resolution strain maps across a wide observation range. In order to validate the digital image correlation on the replica, digital image correlation was also conducted on the chemically etched sample surface. Although the digital image correlation results were affected by replica shrinkage, its effect could be corrected by a simple experimental equation relating the shrinkage ratio dependence on the solvent immersion time. Reproducible strain maps were obtained for the plastic replica for any macroscopic strain, strain components, or degree of microscopic strain localization. (C) 2014 Elsevier Inc. All rights reserved.. |
| 40. |
井藤賀 久岳, 濱田 繁, 松岡 三郎, G0310706 ASTM試験法による水素ガス中破壊じん性測定における問題点([G031-07]材料力学部門一般セッション:環境と材料,材料力学部門), 年次大会 : Mechanical Engineering Congress, Japan, Vol.2014, pp."G0310706-1"-"G0310706-5", 2014.09, The fracture toughness, J_, of SCM435 was investigated in 115 MPa hydrogen gas, 0.7 MPa hydrogen gas and air at room temperature. J_ig tests were conducted in accordance with the ASTM E1820. J_ig in 115 MPa hydrogen gas was much smaller than in 0.7 MPa hydrogen gas and air. In air, a stretched zone was formed at the tip of the fatigue pre-crack, followed by dimples. In hydrogen gas, quasi-cleavage instead of stretched zone and dimples were formed at the pre-crack tip. The fracture toughness test shown in 0.7 MPa hydrogen gas is the same as that shown in a fatigue crack growth test in 0.7 MPa hydrogen gas at a number of cycles of n = 1 and stress ratio of R = 0; and thus J_ig in hydrogen gas is not the real fracture toughness.. |
| 41. |
大西 洋輔, 西本 篤史, 佐々木 大輔, 小山 元道, 濱田 繁, 野口 博司, OS1004 水素環境での極低周波数域におけるS10Cの疲労き裂進展挙動, M&M材料力学カンファレンス, Vol.2014, pp."OS1004-1"-"OS1004-3", 2014.07, In order to clarify an influence of hydrogen on the fatigue crack propagation in ultra-low frequency region, we investigated the frequency dependence of the crack propagation rate of S10C in hydrogen and nitrogen atmosphere. In the hydrogen atmosphere, crack propagation rate decreased with decrease in frequency. In particular, the reduction in crack propagation rate was markedly low in the ultra-low frequency (0.001 Hz). However, crack propagation rate in the nitrogen atmosphere also decreased in the ultra-low frequency region. Hence, we concluded that the decrease in crack propagation rate was concluded to stem from carbon diffusion as well as hydrogen diffusion.. |
| 42. |
Hao Wu, Shigeru Hamada, Hiroshi Noguchi, Fatigue strength characteristics evaluation of SUH660 considering small fatigue crack propagation behavior and hardness distribution, INTERNATIONAL JOURNAL OF FATIGUE, 10.1016/j.ijfatigue.2013.12.011, Vol.63, pp.1-11, 2014.06, The fundamental characteristics of SUH660, which a precipitation-strengthened stainless steel, were investigated by tensile, fatigue, and Vickers hardness tests. Owing to the observed crack propagation mechanisms, the S-N diagram had two "fatigue limits": the fatigue strength at 10(7) cycles and the safe side of the fatigue limit based on the threshold of PSB crack propagation. There was significant variability between the Vickers hardness distributions of the test zones, which indicated the existence of high and low hardness zones in a single specimen. It was observed that more cracks were initiated and propagated in the low hardness zone than in the high hardness zone. Therefore, the fatigue strength of SUH660 steel is low compared to its high tensile strength. (C) 2014 Elsevier Ltd. All rights reserved.. |
| 43. |
Tomoya Fujisawa, Shigeru Hamada, Norimitsu Koga, Daisuke Sasaki, Toshihiro Tsuchiyama, Nobuo Nakada, Kazuki Takashima, Masaharu Ueda, Hiroshi Noguchi, Proposal for an engineering definition of a fatigue crack initiation unit for evaluating the fatigue limit on the basis of crystallographic analysis of pearlitic steel, INTERNATIONAL JOURNAL OF FRACTURE, 10.1007/s10704-013-9895-3, Vol.185, No.1-2, pp.17-29, 2014.01, In this study, in order to define a fatigue crack initiation unit, the relationship between the fatigue crack initiation process and the crystal structure in the pearlitic steel used for railroad rails was examined and fatigue tests, focusing on crack initiation, were performed. The fracture surfaces were analyzed using a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The crystal structure of the pearlitic steel is composed of "pearlitic colonies" that have the same lamellar structure direction and "pearlitic blocks" that have the same ferrite crystal direction. The SEM and EBSD results revealed that the crack initiation depends on the pearlitic colonies. Therefore, we defined the characteristic dimension for fatigue crack initiation as the pearlitic colony size. However, for safety purposes, the pearlitic block size should be considered the engineering definition of the fatigue crack initiation unit, since decreasing the pearlitic block size should cause an improvement in the fatigue limit of pearlitic steel.. |
| 44. |
Hisao Matsunaga, Michio Yoshikawa, Hisatake Itoga, Junichiro Yamabe, Shigeru Hamada, Saburo Matsuoka, Tensile-and fatigue-properties of low alloy steel JIS-SCM435 and carbon steel JIS-SM490B in 115 MPA hydrogen gas, American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 10.1115/PVP2014-28511, Vol.6B, 2014.01, Copyright © 2014 by ASME. Slow strain rate tests using smooth specimens of two types of steels, low alloy steel JIS-SCM435 and carbon steel JIS-SM490B, were carried out in nitrogen gas and hydrogen gas under a pressure of 115 MPa at three different temperatures: 233 K, room temperature and 393 K. In nitrogen gas, these steels exhibited the so-called cup-and-cone fracture at every temperature. On the other hand, in hydrogen gas, in both steels a number of cracks initiated on the specimen surface and coalesced with each other at every temperature, which led to a marked reduction in ductility. Nonetheless, even in hydrogen gas, JIS-SCM435 exhibited a certain reduction of area after the stress-displacement curve reached the tensile strength (TS), whereas JIS-SM490B exhibited little, if any, necking in hydrogen gas. In addition, tension-compression fatigue testing at room temperature revealed that in both steels there was no noticeable difference between the fatigue strengths in air and 115MPa hydrogen gas, especially in a relatively long life regime. Considering that there was little or no hydrogen-induced degradation in either TS or fatigue strength in JIS-SCM435, it is suggested that JIS-SCM435 is eligible for fatigue limit design on the basis of a safety factor (i.e. TS divided by the allowable design stress) for mechanical components used in hydrogen gas up to 115 MPa.. |
| 45. |
Shigeru Hamada, Takuya Kinoshita, Kazunori Morishige, Komei Hayashi, Toshiyuki Ishina, Hiroshi Noguchi, Engineering definitions of small crack and long crack at fatigue limit under tensile mean stress and a prediction method for determining the fatigue limit of a cracked Mg alloy, INTERNATIONAL JOURNAL OF FATIGUE, 10.1016/j.ijfatigue.2013.08.006, Vol.56, pp.86-94, 2013.11, A simple method was proposed for evaluating the influence of mean stress on the fatigue limit of a cracked specimen using engineering approximations. Three types of crack sizes were introduced for evaluation: an "extra small crack," a "small crack," and a "long crack". The threshold stress intensity factor range was shown for each size based on crack non-propagation behavior using physical foundations. The effect of mean stress on the fatigue limit of the cracked specimen was formulated, and fatigue tests were performed on a magnesium alloy to check the approximation errors, which were found to be almost within 10%. Furthermore, the small-long crack transition was characterized experimentally. (C) 2013 Elsevier Ltd. All rights reserved.. |
| 46. |
Hao Wu, Shigeru Hamada, Hiroshi Noguchi, Pre-strain effect on fatigue strength characteristics of SUH660 plain specimens, INTERNATIONAL JOURNAL OF FATIGUE, 10.1016/j.ijfatigue.2013.06.021, Vol.55, pp.291-298, 2013.10, Precipitation particles in precipitation-strengthened materials are considered to be cut by pre-strain treatment, which affects the fatigue strength. In this study, fatigue tests were performed on precipitation-strengthened stainless steel SUH660 to investigate the effect of pre-strain on fatigue crack initiation and propagation characteristics. Fatigue test results showed that pre-strained specimens have a shorter fatigue crack propagation life compared to non-strained specimens; this is the opposite of results observed in carbon steel. The accelerated fatigue crack growth observed in pre-strained specimens was first assumed to be caused by precipitate cutting. A dislocation accumulation model for the fatigue crack tip in the precipitation-strengthened material was then suggested. Buff-polished specimens were also used for the fatigue tests, and the results showed that the work-hardened layer had a significant impact on the fatigue strength and fatigue life. (C) 2013 Elsevier Ltd. All rights reserved.. |
| 47. |
Shigeru Hamada, Mitsuji Ueda, Komei Hayashi, Hiroshi Noguchi, Simple calculation method for stress concentration and stress intensity of T-shaped member, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 10.1016/j.ijmecsci.2013.05.015, Vol.75, pp.8-15, 2013.10, The objective of this study is to clarify the influence of shape parameters on the stress concentration in simple forms. In recent years, by the spread of general purpose Finite Element Method (FEM) analysis software, anyone can carry out FEM analysis now and can grasp the stress state of a structure. However, in order to grasp the influence on a stress state when some shape parameter has changed, FEM analyses for each shape are required, and it requires long time. As an example of this issue in fatigue strength design, the relation between the plate and rib in a T-shaped structure, containing a corner, is analyzed. The stress concentration factor or stress intensity factor between these two connected shapes are analyzed by the FEM, and a method of approximating the stress concentration factor and stress intensity factor in an actual shape is proposed. Then, the proposed FEM-based method was validated through a comparison of the results obtained using this method for shapes of finite dimensions with existing analytical solutions for shapes of infinite dimensions. (C) 2013 Elsevier Ltd. All rights reserved.. |
| 48. |
福村 直樹, 佐々木 大輔, 濱田 繁, 野口 博司, OS1003 Dugdaleモデルを用いた下限界応力拡大係数範囲の解析, M&M材料力学カンファレンス, Vol.2013, pp."OS1003-1"-"OS1003-3", 2013.10, An evaluatuation for threshold stress intensity factor range under a stress controlled condition, using effective threshold stress intensity factor range, was proposed. Threshold stress intensity factor range was evaluated by analyses of plasticity-induced crack closure for two types of crack size:a small crack and a long crack. Plasticity-induced crack closure was analyzed for two dimensional crack in plane stress. Besides, theoretical examinations were performed in order to explain the mechanism that the fatigue limit of high hardness steel decrease with a rise of hardness. Relationship between threshold stress intensity factor range and pre-crack length which was evaluated by analysis of plasticity-induced crack agreed with experimental results qualitatively. Dependency of yield stress was different between a small crack and a long crack. The threshold stress intensity factor range of a long crack decrease with a rise of yield stress. This result could be helpful to reveal the mechanism that the fatigue limit decrease with a rise of hardness in high hardness.. |
| 49. |
山田 康介, 横川 秀斗, 石名 敏之, 濱田 繁, 野口 博司, OS1521 任意の欠陥を持つ材料の疲労限度の予測と5056アルミニウム合金での検証, M&M材料力学カンファレンス, Vol.2013, pp."OS1521-1"-"OS1521-3", 2013.10, This paper is to propose a method to predict the fatigue limit of the material having a defect of any shape. The 5056 aluminum alloy with Mg added has a fatigue limit, but in the case of specimens with Micro-Hole or smooth specimens, the fatigue crack is not initiated in the fatigue limit. Under these circumstances, the fatigue limit is equal to the fatigue crack initiation limit. Therefore, the following two experiments were carried out to elucidate the material property of5056 aluminum alloy adding Mg: (1) Fatigue test of notched specimens for the prediction of the fatigue limit in the area where the fatigue limit is equal to the fatigue crack initiation limit. (2) Fatigue test of Pre-Cracked specimens when a defect has sufficient stress concentration to initiate the non-propagating crack. From (1) and (2), we propose a method of predicting the fatigue limit of materials having a defect of any shape with a minimum number of fatigue tests. Furthermore, to test this method, we examined whether theoretical values and test results are equal for some specimens with Micro-Hole.. |
| 50. |
付 依然, 金 鍾天, 大本 洋平, 濱田 繁, 野口 博司, OS1526 鋭い切欠きを有するエポキシ樹脂における疲労き裂進展挙動の実験的解析, M&M材料力学カンファレンス, Vol.2013, pp."OS1526-1"-"OS1526-3", 2013.10, Recently, polymer materials have increasingly used in many industries due to their unique properties, such as chemical corrosion resistance and its lightness. Despite the investigations which are being carried out on the fatigue phenomena of epoxy resin with various kinds of fibre, the epoxy does not seem to have been fully studied. Moreover, there is lack of understanding about the fatigue behavior and its mechanism. In cyclic bending fatigue tests, on the other hand, the resin are easily fractured even though the stresses are below the critical values. The objective of this study is to analyze the fatigue crack growth behavior of epoxy resin (bisphenol-A-epichlorohydrin type epoxy resin) during mechanical repeated loads. The rotating bending fatigue test was carried out in order to analyze the fatigue crack propagation. A notch was introduced on the specimen, therefore a crack propagates and cause the final fracture of the specimen. In this paper we tried to find the fatigue crack behavior.. |
| 51. |
濱野 泰明, 財前 賢吾, 松枝 剛広, 坂本 惇司, 濱田 繁, 野口 博司, OS1532 S45C焼入れ焼戻し材を用いた欠陥形状が疲労き裂の停留挙動に及ぼす影響の検討, M&M材料力学カンファレンス, Vol.2013, pp."OS1532-1"-"OS1532-3", 2013.10, A small artificial hole is regarded as a pre-crack and square root area parameter is considered as one of the most important parameter for the fatigue limit of materials which contain small defects. In this study, introducing a sharp notch by using focused ion beam (FIB) or a small artificial hole which have the same area on the quenched and tempered 0.45% carbon steel specimen, we carried out these specimens fatigue tests and we investigated the difference of the two defect shape in the hard material. From the fatigue tests, we obtained two important results. First, the fatigue limit of the specimen with the small artificial hole was higher than the specimen with the FIBed notch. Second, fatigue crack initiation and propagation behavior was different between the two types of the specimens. Usually, there are no differences for annealed steel in the two defect shapes. Therefore, the hardness may affect the fatigue crack behavior of the two defect shapes.. |
| 52. |
李 慧超, 車 仁清, 金 鍾天, 澤口 孝弘, 濱田 繁, 野口 博司, 津崎 兼彰, OS1538 TWIP鋼におけるひずみ制御低サイクル疲労挙動特性, M&M材料力学カンファレンス, Vol.2013, pp."OS1538-1"-"OS1538-3", 2013.10, A TWIP (Twinning Induced Plasticity) steel is an austenitic steel which contains about 30% Mn , 3% Si and 3% Al, and have attracted much attention for their excellent mechanical properties such as its strength and strain hardening. Fatigue life is an important property of the material. In the study, to find the relationship between the strain hardening and the fatigue life for the Fe-30Mn-3Si-3Al TWIP alloy, analyses of the strain hardening under different applied strain were performed. For this, tension and compression strain controlled low-cycle fatigue tests were carried out in order to obtain the relationship between the strain hardening and the fatigue life. From the test, the stress-strain curve and the stress which changes as increasing the number of cycles were obseved. Briefly, the results indicated the state of hardening rate under Δε = 2.0% was higher than Δε = 1.0% conditions. In this paper we tried to find the work-hardening effect under the low cycle fatigue loading.. |
| 53. |
佐々木 大輔, 東田 賢二, 金山 寛, 濱田 繁, 野口 博司, OS2108 水素環境下でのき裂先端における塑性変形領域局所化の再現を目的とした新たな構成方程式の提案と水素脆化メカニズムへの応用, M&M材料力学カンファレンス, Vol.2013, pp."OS2108-1"-"OS2108-3", 2013.10, The effect of hydrogen on the strength of metals is known as hydrogen embrittlement, which affects the structural integrity of a hydrogen energy system. The effect of hydrogen at a specimen with a crack is stronger than a smooth specimen. With our simulation's result, it is generally recognized that hydrogen atoms near a crack tip play an important role in the hydrogen embrittlement. This research purpose is the reproduction of the localized plastic zone at the tip of a crack. Due to the purpose, we proposed a novel nonlinear constitutive equation. In this equation, we used a hypothesis that the hydrogen absorbed in the metal affects the yield stress of the metal. A simulation with the proposed equation was performed and from the result, we observed increasing of dislocation at the tip of a crack but we could not observe the localized plastic zone at the tip. From these simulation results, we proposed a hydrogen embrittlement mechanism .. |
| 54. |
石名 敏之, 濱田 繁, 野口 博司, G031054 有限要素法解析による小規模降伏条件の提案([G031-05]材料力学部門,一般セッション : 破壊力学,転位), 年次大会 : Mechanical Engineering Congress, Japan, Vol.2013, pp."G031054-1"-"G031054-5", 2013.09, In order to clarify the transition of the coefficient in ASTM standard equation by the degree of work hardening, elastic-plastic finite element method analysis in which stress-strain curve was approximated by two straight line of Young's modulus E and tangential modulus E_twas carried out. By dividing stress by yield stress and strain by yield strain, various stress-strain curves could be expressed only by using the value of E_t/E. Based on the non-linear crack mechanics, the loading stress when equivalent plastic strain at node point of a crack tip became a constant value was obtained as an analysis solution. Imitating the normalized arrangement manner of numerical solution in Dugdale model in which similarity rule is effective under continuum mechanics, dimensionless quantities relevant to stress intensity factor and crack size were defined. Element size dependency in analytical solution was eliminated and transition in coefficient of small scale yielding condition equation against the value of E_t/E. was proposed. When normalized crack size a/l_0=200 and ratio of tangential modulus to Young's modulus (E_t/E) is 0.2, the coefficient of small scale yielding was 2.5 which is equal to ASTM standard condition equation.. |
| 55. |
Hao Wu, Shigeru Hamada, Hiroshi Noguchi, Fatigue strength prediction for inhomogeneous face-centered cubic metal based on Vickers hardness, INTERNATIONAL JOURNAL OF FATIGUE, 10.1016/j.ijfatigue.2012.09.021, Vol.48, pp.48-54, 2013.03, To find the Vickers hardness (HV) value for predicting the fatigue strength of inhomogeneous face-centered cubic (FCC) metals, HV tests were performed on SUH660 stainless steel. The results indicate that the intrinsic hardness distribution can be obtained from the HV distribution in test zones according to the Vickers hardness definition. The soft zone greatly affects the fatigue strength of an inhomogeneous FCC metal. Therefore, for another inhomogeneous FCC metal in which fatigue cracks initiate and propagate easily in the softest zone, the fatigue limit can be predicted using the mean HV value of the softest zone. (C) 2012 Elsevier Ltd. All rights reserved.. |
| 56. |
石名 敏之, 濱田 繁, 野口 博司, OS2141 R-curveのFEM解析によるマグネシウム合金の小規模降伏条件の提案, M&M材料力学カンファレンス, Vol.2012, pp."OS2141-1"-"OS2141-2", 2012.09, In order to clarify the small scale yielding condition in magnesium alloy, FEM analysis of the R-curve whose shape is considered to be the material characteristic shape was carried out. As an object material, magnesium alloy AZX312 was used. From the FEM analysis results, the shape of the R-curve of its first step when an initial crack size α= 200 μm is obviously different from those of α= 900μm and α= 2000μm. It is considered that the transition crack size from the small scale yielding to the large scale yielding may be between 200 μm and 900 μm. However, the threshold crack size given by the ASTM standard E399 is much larger than 900μm. The ASTM standard is based on experimental results of many materials, however, the standard does not consider the difference of Young's modulus of each materials. So, in magnesium alloy whose Young's modulus is low, the ASTM standard is considered to be not effective.. |
| 57. |
Hamada S, Wu H, Noguchi H, Microscopic fatigue crack behavior in precipitation strengthening stainless steel A286, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 10.1299/kikaia.77.223, Vol.77, No.773, pp.223-227, 2011.12, In order to clarify the fundamental fatigue strength characteristic of precipitation strengthening type stainless steel: A286, fatigue tests were performed. In the fatigue test, the authors paid attention to the behavior of microscopic fatigue cracks in order to make clear fatigue strength properties more than those with usual fatigue tests. As a result of the fatigue test, the fatigue strength characteristic of A286 became clear as shown below. The crack of a size according to a crystal grain diameter is easy to initiate and propagate by Mode II. Many cracks initiate and propagate even if the stress is around the fatigue limit and the fatigue crack cannot stop, then the cracks coalesce and it becomes longer, and finally results in a failure. This is the reason why the fatigue failures occur even after 10 7 cycles. © 2011 The Japan Society of Mechanical Engineers.. |
| 58. |
Shigeru Hamada, Yuu Sakoda, Daisuke Sasaki, Masaharu Ueda, Hiroshi Noguchi, Evaluation of fatigue limit characteristics of lamellar pearlitic steel in consideration of microstructure, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.60.790, Vol.60, No.9, pp.790-795, 2011.09, In this study, tensile and fatigue tests were performed to evaluate the fatigue limit of lamellar pearlitic steel used for manufacturing railroad rail. The fatigue ratio of lamellar pearlitic steel was lower than that of general steels, the reason for which is unknown. Fatigue cracks initiated in pearlitic steel at a very early stage of the fatigue test. Then, it was speculated that the steel should be treated as that with initial defects. In order to determine the initial defect size in the ultra-low cycle fatigue test, tensile tests were performed. The tensile test results clarified that the crack initiation size depends on the crystal structure. In order to predict the fatigue limit of the pearlitic steel, the prediction method proposed by Murakami was applied to the steel. The measured defect sizes were applied to the prediction method, and fatigue tests were performed. The predicted fatigue limit and the test results were in good agreement. In addition, in order to evaluate the crystal structure at the location of the fatigue crack initiation, electron backscatter diffraction pattern (EBSD) analyses were performed. The analysis results revealed that the crack initiation depends on the pearlite block. Then, we concluded that the fatigue limit of pearlitic steel can be predicted by Murakami's method and the defect size is pearlite block size. Then, decreasing the pearlite block size would cause an improvement in the fatigue limit of the pearlitic steel. © 2011 The Society of Materials Science, Japan.. |
| 59. |
K. Hayashi, S. Hamada, T. Matsumoto, M. Sakamoto, H. Noguchi, METHOD OF EVALUATION OF DISTRIBUTION CHARACTERISTICS OF FLAKY INCLUSIONS, STRENGTH OF MATERIALS, 10.1007/s11223-011-9310-0, Vol.43, No.4, pp.411-416, 2011.07, In order to evaluate the maximum size of the flaky inclusions in a Si-added noncombustible Mg casting alloy, we propose a method for evaluation of distribution characteristics of flaky inclusions. The validity of this method is verified through simulations with arbitrary inclusion distributions. The proposed method enables prediction of the maximum size of the flaky inclusions in an arbitrary volume of material.. |
| 60. |
劉 敏健, 濱田 繁, OS0508 モードII疲労き裂進展の有効応力拡大係数幅の測定(OS5-2 き裂進展・計測,OS-5 材料の疲労挙動と損傷評価1), M&M材料力学カンファレンス, Vol.2011, pp."OS0508-1"-"OS0508-3", 2011.07, Many rolling contact fatigue failures, such as those that occur in railway rails, rolling bearings and gears, are due to the high repeated shear load. In order to prevent such fatigue a failure, the resistance of the material against such a load must be determined. The fatigue crack growth rate is dependent on the Mode II stress intensity factor range ΔK_. However, the Mode II crack propagation characteristic varies according to different experiment methods. Therefore, in this study, we measured the effective Mode II stress intensity factor range ΔK_. As it is difficult to carry out the Mode II fatigue crack propagation in the laboratory, this test was carried out using a bending load in this study. This bending load was applied to the tips of a double cantilever specimen and the Mode II fatigue crack propagation could be carried out between the two cantilevers. Furthermore, in order to measure the ΔK_, several strain gauges were applied to the specimen around the crack tip. Using this technique, some ΔK_ value during the Mode II fatigue crack propagation tests will be reported.. |
| 61. |
木下 拓也, 濱田 繁, 野口 博司, OS0520 難燃性Mg合金を例にとった,微小き裂材の平均応力下における疲労限度の評価法の提案(OS5-5 寿命予測,OS-5 材料の疲労挙動と損傷評価2), M&M材料力学カンファレンス, Vol.2011, pp."OS0520-1"-"OS0520-3", 2011.07, Evaluation method of the fatigue limit of material with small crack under tensile mean stress, using the stress ratio parameter and effective threshold stress intensity factor range (ΔK_), was proposed. By this method, the fatigue limit can be evaluated in high mean stress area and low mean stress area separately. In order to define the crack size, which is applied to the evaluation method, the variation of the small crack area affected by stress ratio was shown, using the relationship between threshold stress intensity factor range (ΔK_| ) and the projected area of crack size in the direction of the load (√). The higher stress ratio is, the smaller the upper crack size of small crack area is considered to be. Taking non-combustible Mg alloy as an example, tension-compression fatigue tests were carried out. Using the results of the tests, the validity of the proposed evaluation method was examined.. | |
| 62. |
呉 昊, 濱田 繋, 野口 博司, OS0523 析出強化型ステンレス鋼A286の疲労特性に及ぼす硬さの分布の影響(OS5-5 寿命予測,OS-5 材料の疲労挙動と損傷評価2), M&M材料力学カンファレンス, Vol.2011, pp."OS0523-1"-"OS0523-3", 2011.07, In order to clarify the relationship between fatigue strength and hardness of precipitation strengthening type stainless steel: A286, tensile tests, fatigue tests and Vickers hardness tests were performed. As a result of the tests, A286 steel have high tensile strength as well as low fatigue strength. Then, from the result of hardness test, there is large variability in hardness distribution of A286 steel. High hard zone and low hard zone were found in a specimen of A286 steel. The hardness of the zone in which many cracks initiated, is lower than the zone in which few cracks initiated. It is considered that high tensile strength is based on average both high hardness zone and low hardness zone when tensile test, and low fatigue strength was caused by the fatigue cracks which are easy to initiate and propagate in low hardness zone. Therefore, this is the reason why the fatigue strength ratio of A286 steel is lower than most steel.. |
| 63. |
濱田 繁, 佐々木 大輔, 中田 伸生, 土山 聡宏, 上田 正治, 高島 和希, 野口 博司, OS0527 パーライト鋼平滑材における疲労き裂発生起点解析方法の体系化(OS5-6 応力集中・き裂発生,OS-5 材料の疲労挙動と損傷評価2), M&M材料力学カンファレンス, Vol.2011, pp."OS0527-1"-"OS0527-3", 2011.07, In order to systemize the analysis method of fatigue crack initiation origin (fatigue failure maximum weak part), fatigue failure maximum weak part and the relationship to material texture were analyzed. Pearlitic steel smooth material was used for the material made into the example. First, a mechanical engineer's focus and technology were used, specification of a fatigue failure maximum weak part in pearlitic steel smooth material was performed, and relation between material texture and a fatigue failure maximum weak part was clarified. Then, analysis to material texture was carried out using the knowledge and analysis technology of crystallography of a metallurgist. A fatigue test and analysis showed that a flat face existed at the fatigue crack initiation origin of pearlitic steel smooth material. In addition, as a result of the analysis of a flat face, the formation mechanism of fatigue crack initiation origin (flat face) was able to be clarified, and systematization of analysis was able to be attained.. |
| 64. |
石名 敏之, 濱田 繁, 野口 博司, OS2021 欠陥を有するMg合金の引張強さの評価(OS20-4 疲労と強度,OS-20 HCP金属の実験力学と計算力学), M&M材料力学カンファレンス, Vol.2011, pp."OS2021-1"-"OS2021-3", 2011.07, It is difficult to evaluate the strength of material which has defects, because the strength differs variously by the stress concentration, the defects size and the temperature. In this study, the evaluation method for material with defects was studied. As an example, non-combustible magnesium alloys to which some silicon was added were applied. At first, observation of the fracture surfaces of specimens with a small hole was carried out. Although some dimple can be observed near the hole on the fracture surface of specimen tested in 250℃, no dimple was in room temperature. By the observation it was clarified that the fracture mode near the defect can be divided into two modes, i.e. brittle fracture and ductile fracture. In addition, by tensile tests of specimens with a notch, change of the fracture mode was also observed by degree in stress concentration. Understanding the two problems, i.e. degree in stress concentration of the defects in material and relationship between the defects size and strength are future tasks.. |
| 65. |
Shigeru Hamada, Katsu Ohnishi, Hide-aki Nishikawa, Yasuji Oda, Hiroshi Noguchi, SIMS analysis of low content hydrogen in commercially pure titanium, JOURNAL OF MATERIALS SCIENCE, 10.1007/s10853-009-3783-2, Vol.44, No.20, pp.5692-5696, 2009.10. |
| 66. |
Noguchi H, Aramaki T, Hamada S, Miyaji S, Tachikawa T, Tatsumi A, Kayamoto T, Strength evaluation of alumina's spray coating (5th report, consideration of the strength in sprayed structure for thermal stress), Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 10.1299/kikaia.75.1177, Vol.75, No.757, pp.1177-1186, 2009.09, In this study fracture probability at thermal stress distribution is calculated with the dangerous volume quantification method that was proposed in the former report Fracture stress calculation by thermal stress is based on finite element method with fracture temperature and aluminum creep properties. The fracture strengths predicted with the proposed method are appropriate to experimental results obtained by heat tests. The calculated dangerous volume intended for 90% of product in alumina's spray coating on aluminum layer is part of 96% or more of maximum stress. Therefore the dangerous volume calculation in thermal stress distribution is enough to think experienced dangerous volume calculation method that dangerous volume is volume of 90% or more of maximum stress. And it is shown that fracture origin is located in the dangerous volume calculated with this study method and fracture strengths predicted with fracture origin size is almost equal to the fracture strengths predicted with this study.. |
| 67. |
Noguchi H, Aramaki T, Hamada S, Miyaji S, Tachikawa T, Tatsumi A, Kayamoto T, Strength evaluation of alumina's spray coating (4th report, consideration of spray structure strength for mechanical stress), Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 10.1299/kikaia.75.1097, Vol.75, No.756, pp.1097-1105, 2009.08, In this study, in order to calculate dangerous volume at various stress distribution, the dangerous volume quantification method is proposed. And in order to predict stress distribution of spray coating, an easy calculation method of residual stress distribution based on the first report is proposed. The calculated dangerous volume in alumina's spray coating on titanium layer is different from alumina's spray oating single layer. The difference is based on stress distribution in alumina's spray coating. The fracture strengths predicted with the proposed method and the third report are appropriate to experimental results obtained by 4-point bending tests. Therefore dangerous volume calculation in thermal stress distribution that is different from mechanical stress distribution also become possible.. |
| 68. |
Sonoda A, Hamada S, Noguchi H, Analysis of small spalling mechanism on hot rolling mill roll surface, Memoirs of the Faculty of Engineering, Kyushu University, Vol.69, No.1, pp.1-14, 2009.03, In order to analyze the small spalling mechanism on the surface of the hot rolling mill high speed steel roll, an actual hot rolling mill roll was investigated, and the thermal cycle and Mode II fatigue crack growth tests, which reflect the results of the investigation, were carried out. From the investigation of the actual hot rolling mill roll, it was proven that the small spalling was generated by heat crack initiation by thermal cycling and Mode II fatigue crack growth. The crack due to the thermal cycling was initiated in the oxide area. Estimation of the small spalling hot rolling mill roll life on the roll surface became possible based on the relationship between the crack growth rate da/dN and threshold Mode II stress intensity factor range ΔKIIth, and it was clarified that the life of the Mode II fatigue crack growth was longer than that of the crack initiation life by thermal cycling.. |
| 69. |
Morishige K, Maeda Y, Hamada S, Noguchi H, Fatigue strength characteristics of non-combustible Mg alloy (2nd report, effect of mean stress on fatigue strength), Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 10.1299/kikaia.74.115, Vol.74, No.1, pp.115-121, 2008.01, Rotating bending tests and tension-compression fatigue tests on non-combustible magnesium alloy were carried out to investigate effect of mean stress on fatigue strength at N=107 The ignition point of non-combustible magnesium alloys is about 300 K higher than that of normal magnesium alloys because of calcium addition. It was clarified as follows. (1) In the range of σm MPa, fatigue strength at N=107 of small hole specimens was about 30-150% higher than that of small crack specimens. (2) In the range of σm>100MPa, fatigue strength at N=107 of small hole specimens decreased because of static cracks initiating around small hole at the first loading. (3) In the range of σmax |
| 70. |
Nishikawa H, Hamada S, Ohnishi K, SIMS analysis of hydride in commercially pure titanium, Memoirs of the Faculty of Engineering, Kyushu University, Vol.67, No.4, pp.191-197, 2007.12, Commercially pure titanium (CP-Ti) usually contains a few tens of ppm hydrogen. In order to clarify the fatigue behavior of CP-Ti, it is important to know the distribution of such hydrogen. In this study the distribution of hydrogen formed as hydride was analyzed by secondary ion mass spectrometry (SIMS). The hydrides could be detected interior the grain and at the grain boundaries. On the basis of the results, the points to be paid attention for the investigation of fatigue strength are discussed.. |
| 71. |
Daisuke Katagiri, Yoshinori Yokoyama, Hiroo Sakamoto, Shigeru Hamada, Bonding strength evaluation for hermetic seal of MEMS package, Zairyo/Journal of the Society of Materials Science, Japan, 10.2472/jsms.56.926, Vol.56, No.10, pp.926-931, 2007.10, In order to secure the certain operation of MEMS devices, it is very important to design a hermetically sealed package which protects the device from wet environments, taking into account the reliability of cap bonding of MEMS packages. Anodic bonding is a popular cap bonding method. In this process, glass and single crystal silicon are bonded at high temperature under high voltage conditions. In this study, the new production method of device size specimen with an interface crack by wafer process is proposed. And an attempt is made to establish a method of testing the cap bonding strength of packages and to make clear the interface strength of anodic bonding between the glass and single crystal silicon. © 2007 The Society of Materials Science.. |
| 72. |
Fujii Takumi, Morishige Kazunori, Hamada Shigeru, Noguchi Hiroshi, Sakamoto Michiru, Ueno Hidetoshi, OS4-5-5 Fatigue Strength Characteristics of Non-combustible Mg Alloy, Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics, Vol.2007, No.6, pp."OS4-5-5-1"-"OS4-5-5-4", 2007.09, The ignition point of non-combustible Mg alloy is about 300K higher than that of normal magnesium alloy. It is expected that the non-combustible Mg alloy is used in substitution for Al alloy for structures. In this paper, the fundamentals, those are a notch effect, and a long or small crack effect on fatigue strength of a non-combustible Mg alloy, are investigated. Moreover, the fatigue strength characteristics of the non-combustible Mg alloy are compared with that of Al alloy to clarify differences of fatigue strength characteristics between Mg alloy and Al alloy.. |
| 73. |
平田 善明, 番 政広, 山口 靖雄, 奥村 美香, 末次 英治, 濱田 繁, 陽極接合による封止構造を有するMEMSデバイスの開発と実用化(平成17年度日本材料学会技術賞受賞,新技術・新製品トピックス), 材料, Vol.55, No.12, 2006.12. |
| 74. |
濱田繁, 多結晶シリコン微小構造体の強度, 日本機械学会材料力学部門ニュースレター, No.29, p.9, 2005.09. |
| 75. |
濱田繁，堀川牧夫，谷周一，大谷浩，番政広, 微小ポリシリコン構造体における強度と表面粗さの関係, 三菱電機技報, Vol.78, No.6 pp.433-436, 2004.06. |
| 76. |
濱田 繁, 谷 周一, 番 政広, 微小ポリシリコン構造体における強度と表面粗さの関係 (特集 マイクロ・ナノテクノロジー適用例とその評価・解析技術), 三菱電機技報, Vol.78, No.6, pp.433-436, 2004.06. |
| 77. |
濱田繁，谷周一，堀川牧夫，大谷浩，吉川英治, 微小ポリシリコン構造体の強度特性評価, 三菱電機技報, Vol.75, No.11，pp.713-716, 2001.11. |
| 78. |
濱田 繁, 谷 周一, 堀川 牧夫, 微小ポリシリコン構造体の強度特性評価 (特集1 広がりゆくマイクロマシン), 三菱電機技報, Vol.75, No.11, pp.713-716, 2001.11. |
