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Akama Makoto

  (赤間 誠)

Profile Information

Affiliation
Professor, Faculty of Engineering, Department of Mechanical Engineering for Transportation, Osaka Sangyo University
Degree
Doctor Engineering(Tohoku University)
博士（工学）(東北大学)
Researcher number
70425867
J-GLOBAL ID
201301098055797812
researchmap Member ID
7000005156

Research Areas

 1

Education

 3

Committee Memberships

 2

Papers

 32
  • Wijitpatima Chawanat, Makoto Akama
    Tribology Online, 19(4) 277-286, Jul 7, 2024  Peer-reviewed
    A railway wheel flat occurs when the wheel locks and slides along the rail, forming a white etching layer (WEL) just under the flat surface where rolling contact fatigue cracks often form that can propagate into the wheel and spall during service. This study comprehensively investigated the influencing factors on wheel crack propagation that lead to spalling. Experiments were conducted to test wheel specimens with WELs of various dimensions, and simulations were performed to evaluate the stresses near the WELs as well as the rate and direction of crack propagation.
  • WANG Wutong, AKAMA Makoto, TSUKAHARA Masahiro, MISAKA Yoshitaka, MATSUDA Shinya, GUENNEC Benjamin, SAKAI Tatsuo
    Journal of the Society of Materials Science, Japan, 72(3) 161-167, Mar 15, 2023  Peer-reviewed
    Rotating bending fatigue tests were performed to investigate the effect of induction hardening (HQI) on the very high cycle fatigue (VHCF) properties of the axle steel. In addition, finite element analyses (FEA) and scanning electron microscope (SEM) observations were conducted to elucidate the fundamental behavior. The results obtained are summarized as follows; (1) It was found that the fatigue strength of the axle steel was improved by almost 300 MPa in VHCF region by HQI, (2) A lot of specimens of the HQI had fractured in VHCF region, therefore, the consideration of VHCF properties should be taken into account in the design of railway axles, (3) Crack initiation sites can be classified into three forms; the surface of the HQI layer in the minimum section, the base metal beyond the HQI layer in the axial direction, and the internal base material in the minimum section. These can be reconfirmed through the comparison between the local fatigue strength distribution and the bending stress distribution obtained by FEA.
  • TAKAHASHI Yuma, AKAMA Makoto
    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS, 67(8) 567-580, Aug 15, 2022  Peer-reviewed
    Trains often operate as a shuttle service. When a train arrives at the terminal station, its direction of travel is reversed, and therefore so is the rolling direction of the wheels. It is therefore important to investigate how the crack propagation, and wear on the wheel tread are changed by reversing the rolling direction. In this study, twin disc wear-fatigue tests were carried out under various conditions to study the effect on the behaviour of rolling contact fatigue (RCF) cracks and wear. Also, finite element analyses (FEA) were performed in order to clarify the results of these tests. In the lubricated condition, the cumulative wear tended to increase when the rolling direction of the wheel specimen was reversed if the slip ratio was 1%. On the other hand, in the dry condition, there was almost no change in the wear before and after reversing. FEA suggested that, when the wheel specimen was reversed, lubricant was trapped in the RCF crack and the friction coefficient between the crack faces was reduced, leading to shear mode crack growth and increased the fatigue wear.
  • Makoto AKAMA, Kiyoshi MATSUBARA
    Transactions of JSCES, (20200017), Sep 10, 2020  Peer-reviewed
    鉄道レールのシェリングは、列車の車輪が繰り返し通過することにより発生する表面の転がり接触疲労き裂である。本研究では、シェリングの水平裂の進展について数値シミュレーションを実施した。成長は、ヘルツ接触圧が負荷される2次元傾斜き裂の応力拡大係数（K値）の境界要素解析に基づいて行った。このような2次元き裂を複数並列に配置し、その先端を結ぶことで、3次元半楕円水平裂のK値を近似的に求めることができる。この方法は、完全な3次元で解析された方法と比較して、計算速度で優位性がある。進展はモードI/II及びモードI/IIIの非比例混合モード試験のデータを用いて、Richardによって提案された等価K値範囲を用いるパリス型き裂進展則で求めた。分岐の方向はHourlier-Pineau規準で予測した。
  • Makoto AKAMA, Takafumi KIMATA
    Wear, 448-449(15), Jan 28, 2020  Peer-reviewed
    A numerical model is developed to simulate the competition between RCF-initiated short crack propagation and wear in a wheel tread. The crack is assumed to initiate when the total accumulated plastic shear strain reaches the critical value. In the early crack growth simulations, the two-stage short crack growth model proposed by Hobson is applied. With regard to wear, the Archard model is adopted as the basis. The model is shown to operate properly when applied to the results of unidirectional twin disc tests. When an outward route comprising a 1000 km straight run is simulated based on the Shinkansen routes, it is found that the tread is hardly damaged. The results obtained from the rolling reversal fatigue tests show that if the rolling direction of the wheel is reversed, the delamination wear becomes dominant.
  • Makoto AKAMA, Akira KIUCHI
    Applied Sciences, 9(14), Jul 18, 2019  Peer-reviewed
    Rolling contact fatigue cracks in rail and wheel undergo non-proportional mixed mode I/II/III loading. Fatigue tests were performed to determine the coplanar and branch crack growth rates on these materials. Sequential and overlapping mode I and III loading cycles were applied to single cracks in round bar specimens. Experiments in which this is done have been rarely performed. The fracture surface observations and the finite element analysis results suggested that the growth of long (does not branch but grown stably and straight) coplanar cracks was driven mainly by mode III loading. The cracks tended to branch when increasing the material strength and/or the degree of overlap between the mode I and III loading cycles. The equivalent stress intensity factor range that can consider the crack face contact and successfully regressed the crack growth rate data is proposed for the branch crack. Based on the results obtained in this study, the mechanism of long coplanar shear-mode crack growth turned out to be the same regardless of whether the main driving force is in-plane shear or out-of-plane shear.
  • Makoto AKAMA, Mamoru Murahashi
    Tetsu-to-Hagané, 105(6) 70-81, Jun 1, 2019  Peer-reviewed
    A numerical model was developed to simulate the competition between crack initiation and growth by rolling contact fatigue (RCF) and wear in a railhead. The simulation model assumes that the materials are polycrystalline ferrite and pearlite and that RCF crack initiation is determined by the total accumulated plastic shear strain. The growth of short cracks is calculated using the Hobson model and the Archard model is used to calculate wear. In order to validate the developed model, twin disc rolling-sliding contact fatigue tests were performed. It was confirmed that the crack occurred at the nonmetallic inclusion/ferrite and ferrite/pearlite boundary at almost the same locations, therefore, the assumption of the model for the initiation was validated. It was also found that cracks of almost the same length and the direction existed in the vicinity of the contact surface at the same rolling cycles. Regarding wear, it was found that accurate analyses can be performed by considering the change of the contact pressure distribution and selecting an appropriate wear coefficient.
  • Makoto AKAMA
    Applied Sciences, 9(10), May 16, 2019  Peer-reviewed
    Fatigue tests were performed to estimate the coplanar and branch crack growth rates on rail and wheel steel under non-proportional mixed mode I/II loading cycles simulating the load on rolling contact fatigue cracks. Long coplanar cracks were produced under certain loading conditions. The fracture surfaces observed by scanning electron microscopy and the finite element analysis results suggested that the growth was driven mainly by in-plane shear mode (i.e., mode II) loading. Crack branching likely occurred when the degree of overlap between these mode cycles increased, indicating that such degree enhancement leads to a relative increase of the maximum tangential stress range,based on an elasto–plastic stress field along the branch direction, compared to the maximum shear stress. Moreover, the crack growth rate decreased when the material strength increased because thismade the crack tip displacements smaller. The branch crack growth rates could not be represented by a single crack growth law since the plastic zone size ahead of the crack tip increased with the shearpart of the loading due to the T-stress, resulting in higher growth rates.
  • Makoto AKAMA, Akira KIUCHI
    Tetsu-to-Hagané, 104(11) 689-698, Nov 1, 2018  Peer-reviewed
    Fatigue tests were performed to obtain co-planar and branch crack growth rates on rail and wheel steel under non-proportional mixed mode I/III cycles. Experiments showed that a long co-planar crack could be produced under certain loading conditions. Based on the fracture surface observations by SEM and the results of FEA, the long co-planar crack growth is thought to be driven mainly by mode III loading and the role of mode I is an assistant, keeping the crack face opened. It was observed that the cracks were apt to branch when the strength of the material increased. It was also observed that the crack branched when the degree of overlap between the mode I and mode III cycles increased. We proposed the equivalent stress intensity factor range for branch crack that can consider the crack face contact and successfully regressed the crack growth rate data. Comparing the fracture surfaces and the co-planar crack growth rates data under non-proportional mixed mode I/III loading with that under I/II loading, it is found that the mechanism of shear mode crack growth is essentially the same regardless of whether the main driving force is in-plane shear or out of-plane shear.
  • Makoto Akama, Akira Kiuchi
    PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT, 226(F5) 489-500, Sep, 2012  Peer-reviewed
    Fatigue tests have been performed to obtain the co-planar crack growth rate in rail steel under non-proportional mixed mode I and mode III cycles. In addition, a finite element analysis (FEA) has been performed to investigate the crack growth behaviour under this loading. The experiments showed that a long co-planar crack could be produced under this loading. Based on fracture surface observations obtained using a scanning electron microscope and FEA, the long co-planar crack growth was thought to be driven mainly by mode III loading and the role of mode I was as an assistant; keeping the crack face open. It was also observed that the crack tended to branch when the degree of overlap between the mode I and mode III cycles increased. Comparing the crack growth rate data under loading with that under non-proportional mixed mode I and II cycles, it was found that the co-planar growth rates were similar regardless of whether the main driving force was in-plane shear or out-of-plane shear.
  • M.Akama, H. Matsuda, H. Doi, M.Tsujie
    Journal of Computational Science and Technology, 6(2) pp.54-69, Jun, 2012  Peer-reviewed
    レールの頭部き裂の発生寿命を予測するための手法を開発した。これは主として、車輪とレール間の接触荷重による材料の応答を三次元有限要素法で解析することによって行なった。解析から得られた結果は、限界距離理論と限界面アプローチを結合して検討した。予測した結果は、現地調査から得られたデータと比較した。現地では車輪とレールの接触位置がかなり変動すること、高い静水圧下の材料は、破壊までの応力及びひずみが増大することなどを考慮すると、予測結果は妥当であることが分かった。
  • M. Akama, T. Nagashima
    PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT, 223(3) 209-221, May, 2009  Peer-reviewed
    Recently, attempts have been underway to simulate rolling contact fatigue (RCF) crack growth in the railhead, including also the effect of wear on maintaining the integrity of the rail and saving cost. At this juncture, it is essential to confirm whether the past analyses are adequate and what extent of differences exists when the different mechanisms or numerical procedures are applied to the same conditions in the RCF problem. Therefore, boundary-element analyses of stress intensity factors (SIFs) at the inclined surface crack tip under RCF conditions have been performed. Comparisons were made between SIFs calculated by the present analyses and those done by the numerical procedures of other researchers in the RCF problem. From this study, it was recognized that a special program should be developed to analyse the SIFs when the fluid pressure is taken into account. It was also found out that, for the analyses of SIFs, the iteration procedure with convergence calculation to specify the extent and location of locked, slipped, and separated regions on the crack faces should be used.
  • M. Akama, M. Sasakura, K. Furuno
    PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT, 223(1) 45-59, Jan, 2009  Peer-reviewed
    The finite-element and boundary-element methods were applied to develop the low-stress and low-noise lightweight railway wheel. First, stress analyses for the existing wheels under the condition of drag braking or track loading were performed. Following these analyses, a design methodology was developed and applied, leading to the development of new plate shapes of the wheel, whose stresses generated were lower than those of conventional wheels. Candidate plate shapes were selected based on the analyses. Next, eigenvalue analyses and transient dynamic analyses were carried out for the wheels. At the same time, to verify the analytical results, these wheels were manufactured and experiments implemented. Finally, acoustic analyses were performed and results compared with those obtained by field measurements. From this study, a new plate shape of the lightweight railway wheel was obtained, which reduces the radiated noise as well as the maximum stresses generated in the plate region to a remarkable extent.
  • Haruo Sakamoto, Hiromichi Ishiduka, Makoto Akama, Kenichi Tanaka
    Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 75(759) 1447-1453, 2009  Peer-reviewed
    Induction hardened axles have been used since the start of the Shinkansen (Japanese Bullet train) service in 1964. Axles are subjected to cyclic loading, and induction hardened axles are used under cyclic compressive stress conditions because of the large compressive stress state caused by induction hardening along the axle surface. Japanese Railways regularly inspect its axles, and if any crack larger than 0.15 mm in depth is found, the axle is taken out of service. The compressive stress is around -500 MPa, and magnetic particle inspection is conducted at intervals of 2.2 × 108 and 4.4 ×108 rotation. The issue of whether or not a crack more than 0.15 mm in depth will propagate under cyclic large compressive stress conditions is of great importance from the viewpoint of railroad safety. From the above mentioned background, an experiment of fatigue crack extension under a cyclic large compressive stress condition was conducted. The result shows that the crack did extend in the range of around 3.6∼5.2×108 cycles under the condition of -500∼0MPa cycle. An elastic perfectly-plastic stress analysis was also conducted, and shows 89 MPa tensile stress origination at the crack tip when unloading. This can explain such a crack extension. Whereas, the analysis of -560∼-440 MPa cycle for actual maximum stress in the field shows compressive when unloading.
  • Makoto Akama, Ippei Susuki
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN, 93(9) 607-613, Sep, 2007  Peer-reviewed
    Fatigue crack growth under mixed mode loading is an important problem in railway fields. Therefore, a method was developed and prepared to observe the fatigue crack propagation under mixed loading of tensile and in-plane shear modes by an in-plane biaxial fatigue machine. In the experiments, sequential and overlapping mode I and mode II cycles were applied to the crack in the cruciform specimen trade of wheel or rail steel. Growth rate laws for wheel and rail steel were obtained by means of least square regression analysis in terms of both the effective stress intensity factor ranges. The fracture surfaces near the crack tip region of tested specimens were observed by SEM and discussed to relate the superiority of pearlite structure over tempered martensite structure in detail.
  • 赤間誠, 横家力
    日本機械学会 論文集B編, 73(730) pp.1280-1288, Jun, 2007  Peer-reviewed
    東北新幹線の八戸－新青森駅間における冬期間の分岐器の凍結防止を目的とした直接加熱式ヒータの出力及び配置を評価するため、有限要素法の熱伝導シミュレーションによる検討を実施するとともに、実物の分岐器の一部を船岡高架橋に設置し、加熱時のポイント各部及びクロッシング各部の温度測定を行った。その結果、クロッシング部については、当初予定のヒータの配置では許容最低温度基準を満足することができないことが分かり、ヒータの個数を倍増することを提案した。
  • 赤間誠, 笹倉実, 古野一裕
    日本機械学会 論文集A編, 73(730) pp.677-685, Jun, 2007  Peer-reviewed
    本研究では、最初に陰解法有限要素法を用いて、板部に発生する応力を、現用の軽量車輪である波打ち車輪よりも低減できる板部形状を開発した。次にこの中の二種類の候補形状について、波打ち車輪とともに固有値解析及び陽解法有限要素法による時刻歴応答解析を実施し、板部の振動振幅、振動周波数をそれぞれ求めた。最後にその結果から境界要素法による騒音解析を実施し、質量及び剛性は波打ち車輪と同等で、板部の発生応力が大幅に減少し、同時に騒音も低減できる板部形状が得られた。
  • 赤間誠, 森忠夫
    日本計算工学会 論文集, (20070012), Mar, 2007  Peer-reviewed
    境界要素法を用いてヘルツ型接触圧分布が表面を移動する半無限体内の二次元表面傾斜き裂先端のK値解析を行った。流体の作用については、三つのメカニズムを考慮し、き裂面の接触状態を特定する反復収束計算を行った。その結果、流体潤滑機構を用いた解析では、完全に反転するKII値変動が得られたが、KI値は無視できる程度の値であった。流体閉じ込め機構を用いた解析では、KI値とKII値が重なった複雑な変動をすることがわかった。
  • M Akama, M Saka
    ENGINEERING FRACTURE MECHANICS, 72(2) 319-334, Jan, 2005  Peer-reviewed
    The direct-current potential drop technique was applied to the quantitative estimation of the size and shape of the crack generated in railway components. First, calibration equations that relate the potential drop to the crack depth and crack length along with its location were derived where the boundary element method was used for the electric potential problem. The crack depth, crack length and its location were then determined by analyzing an inverse problem by using the quasi-Newton method which compared the potential drop obtained by the calibration equations with measurements using a carbon steel specimen containing a crack. Although the values of depths were slightly scattered because depth estimations were sensitive to the crack location and changed with even a minimal change in distance between the crack and probes, the estimations of lengths and locations were adequate. (C) 2004 Elsevier Ltd. All rights reserved.
  • M Ishida, M Akama, K Kashiwaya, A Kapoor
    FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES, 26(10) 909-919, Oct, 2003  Peer-reviewed
    The paper describes the Japanese understanding and practice with regard to wheel rail interface problems and their management. Rolling contact fatigue, especially squat defects, grinding, corrugations and lubrication, have been considered. The understanding has been developed through a combination of theoretical modeling, laboratory-based experiments and field trials. Measures have been introduced to mitigate he detrimental effects of these problems and are resulting in benefits to the Japanese railway companies. However, more work is required to better understand wheel rail interface problems and to provide effective solutions.
  • M Akama, T Mori
    WEAR, 253(1-2) 35-41, Jul, 2002  Peer-reviewed
    This study performed the boundary element analysis of the cycle of stress intensity factors at the surface initiated rolling contact fatigue crack tip under Hertzian contact stress including an accurate model of friction between the faces of the crack and the effect of fluid inside the crack. A two-dimensional model of a rolling contact fatigue crack has been developed. The model includes the effect of Coulomb friction between the faces of the crack. The fluid in the crack was assumed not only to lubricate the crack faces and reduce the crack face friction coefficient but also to generate a pressure. The obtained results are compared with those of other researchers showing good consistency. (C) 2002 Elsevier Science B.V. All rights reserved.
  • M Akama
    RELIABILITY ENGINEERING & SYSTEM SAFETY, 75(3) 321-332, Mar, 2002  Peer-reviewed
    Bayesian analysis was performed to estimate an appropriate value of the uncertain propagation rate of cracks that can be initiated at the wheelseat of a Shinkansen vehicle axle. In the analysis, fatigue life distribution obtained by numerical simulation that employed the crack propagation rate obtained from small specimens was used as the prior distribution. Then it was modified by the results of the fatigue test of full-scale models as additional information to obtain the posterior distribution. It was indicated that the variances of fatigue life distribution reduced through the analysis. By using the crack propagation rate obtained from the posterior fatigue life distribution, the failure probabilities of the Shinkansen vehicle axle in operation, that were calculated previously by using the crack propagation rate due to the experiment of small specimens were recalculated. The resulting probabilities of failure were almost the same as those that were not modified, but were slightly lower. Although the difference was not so significant, it was thought that more confident values of the failure probability were obtained. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • 赤間誠, 坂真澄
    非破壊検査, 47(5) pp.322-330, May, 1998  Peer-reviewed
    直流電位差法によって探傷精度を向上させ、車軸の車輪圧入部に発生するき裂の寸法・形状を、車輪を圧入したままで評価するための手法の基盤技術を提案した。まず境界要素法によって、電流の入出力位置を種々変化させた場合の三次元表面き裂の寸法・形状と電位差との関係を求めた。得られた較正関係式と、試験片の計測結果から、き裂の寸法・形状と位置を求める最適化解析を実施した。
  • M Akama, H Ishizuka
    STRUCTURAL SAFETY AND RELIABILITY, VOLS. 1-3, 38(3) 1173-1180, 1998  Peer-reviewed
    A reliability analysis of the Shinkansen vehicle axle using probabilistic fracture mechanics is presented. Failures of the axles are assumed to occur as the result of the growth of cracks originating from fretting corrosion in a wheelseat. Cracks are considered to be randomly distributed in size, and cyclic stresses induced during train operation are used in conjunction with the crack growth characteristics of the material to predict the variation of the crack size with the distance traveled. The probability of failure is considered to equal the probability of having a crack larger than the corresponding critical size. The effects of in-service inspections are evaluated for two different induction-hardened axles. Finally a series of calculations were performed in order to assess the influence of various factors on these probabilities.
  • 石塚弘道, 赤間誠, 佐藤康夫, 本松啓美, 花岡立定
    日本機械学会 論文集A編, 62(603) pp.2527-2533, Nov, 1996  Peer-reviewed
    本研究では、新幹線車軸に中ぐり加工または拡大中ぐり加工を施して疲労試験を実施し、き裂の進展性に関する評価を行うとともに、き裂の進展性に及ぼす中ぐり加工の影響を評価した。
  • 大石橋宏次, 赤間誠, 上山且芳
    溶接学会論文集, 14(2) pp.435-442, May, 1996  Peer-reviewed
    汎用有限要素法ソフトを用いて、鋼のガス圧接及び熱間せん断に関する実験の数値シミュレーションを行い、応力分布及び塑性変形状態を求め、最終的に傷の発生機構との関係を検討した。シミュレーション結果は、実験結果と比較し、その妥当性を検証した。
  • 石塚弘道, 赤間誠, 花岡立定, 佐藤康夫, 本松啓美, 手塚和彦
    日本機械学会 論文集A編, 60(578) pp.2200-2206, Oct, 1994  Peer-reviewed
    本研究では、新幹線車軸の車輪座に発生したフレッティング疲労き裂の停留限界深さを破壊力学的に評価することを目的として、車輪座端部に人工傷を設けた実物の車軸を用いた疲労試験を実施し、その結果を応力拡大係数によって評価することを試みた。
  • 赤間誠, 石塚弘道
    日本機械学会 論文集A編, 60(569) pp.46-51, Jan, 1994  Peer-reviewed
    確率論的破壊力学を新幹線車軸の健全性評価に適用し、今後の車軸の設計基準、定期検査周期の見直しなどに資するため、走行距離に対する車軸の破壊確率及び種々の因子が破壊確率に与える影響を評価した。その結果、表面焼き入れによる圧縮残留応力が、車軸の健全性に最も有益な影響を与えることが分かった。
  • M AKAMA, S MATSUYAMA
    ISIJ INTERNATIONAL, 29(11) 947-953, 1989  Peer-reviewed
    種々の熱処理を施して硬さ及び組織を変化させたレール鋼について、繰返し打撃試験を行い、塑性流動特性を調べた。併せてその機構を詳細に解明するため、低サイクル疲労試験を実施した。変形量は、焼戻しマルテンサイト組織よりもパーライト組織の方が大きいこと、焼戻しマルテンサイト組織は変形の初期において加工軟化が起こることなどが分かった。
  • Makoto AKAMA, Sinsaku MATSUYAMA
    Tetsu-to-Hagané, 74(9) pp.1824-1831, Sep, 1988  Peer-reviewed
    種々の熱処理を施して硬さ及び組織を変化させたレール鋼について、繰返し打撃試験を行い、塑性流動特性を調べた。併せてその機構を詳細に解明するため、低サイクル疲労試験を実施した。変形量は、焼戻しマルテンサイト組織よりもパーライト組織の方が大きいことなどが分かった。
  • 赤間誠, 松山晋作
    潤滑学会論文集, 31(12) pp.876-882, Dec, 1986  Peer-reviewed
    西原式及び大越式摩耗試験機を用いて、車輪とレール材料の摩耗特性を明らかにした。西原式摩耗試験では、多くの場合摩耗量の変化は車輪側、レール側とも初期に多く、その後減少した。大越式摩耗試験では、すべての組合せにおいてレールの比摩耗量はほぼ同一の滑り速度で極大値を示し、その大きさは硬さが同じならば、パーライト系の方がソルバイト系よりもかなり小さい。
  • M AKAMA, S MATSUYAMA
    JOURNAL OF JAPAN SOCIETY OF LUBRICATION ENGINEERS, 31(12) 876-882, 1986  Peer-reviewed
    西原式及び大越式摩耗試験機を用いて、車輪とレール材料の摩耗特性を明らかにした。西原式摩耗試験では、多くの場合摩耗量の変化は車輪側、レール側とも初期に多く、その後減少した。大越式摩耗試験では、すべての組合せにおいてレールの比摩耗量はほぼ同一の滑り速度で極大値を示し、その大きさは硬さが同じならば、パーライト系の方がソルバイト系よりもかなり小さい。上の二つの試験のいずれにおいても、パーライト系の組織の耐摩耗性がソルバイト系組織よりも優れていた。

Misc.

 4

Books and Other Publications

 2
  • 赤間誠, 阿部豊, 石塚弘道, 于強, 織田伸吾, 加藤肇彦, 河本洋, 小熊規泰, 酒井達雄, 桜井茂雄, 佐藤憲一, 白木渡, 白鳥正樹, 鈴木誠, 坪井学, 服部成雄, 藤山一成, 吉永隆治, 吉村達彦 (Role: Joint author)
    養賢堂, Nov, 2008 (ISBN: 9784842504452)
    信頼性工学の基礎概念・基礎理論・試験及び設計法など、実製品の信頼性保証技術が纏められており、産業界の現場で実際に信頼性工学を応用する際に必要となる具体的な応用手法を中心テーマとしている。私の担当部分では、新幹線電車車軸の輪座で発生するき裂の不確かな進展速度の値を評価するために、ベイズ解析を行なった。その結果、破壊確率のより信頼性のある値が得られた。
  • M. Akama, H. Ishizuka, E. Andersson, H.V.Bahr, E.Berg, H.Bj?rck, J.Blomerius, A.H.Kaas, J.Madejski, J.Grabczyk, L.Hhoudour, D.Dooze, J.L.Bruyelle, A.Filip (Role: Joint author)
    WITPRESS, 1999 (ISBN: 1853127841)
    鉄道の安全性は、特に最近の高速鉄道における速度向上により、関心が高まっている。そこでこの本は、各国の専門家による広範囲にわたる安全性の評価手法の適用例を含んだものである。第一章は私による確率論的破壊力学の新幹線車軸への適用、第二章はステンレス車体の衝突解析、第三章はドイツ浮上式鉄道トランスラピッドの安全性技術などが収録されている。

Presentations

 57
  • Makoto AKAMA, Yuma TAKAHASHI
    The Fifth International Conference on Railway Technology (Railways 2022), Aug 23, 2022, Elsevier, Civil-Comp Press
    In this study, we conducted a series of twin-disc wear and fatigue tests and FE simulations of the tests. The results are as follows. In the wet conditions, the wear rate increased when the rolling direction of the wheel disc was reversed. In contrast, in the dry conditions, the wear rate was much higher than in the wet conditions, however, it changed little before and after the reversal. The Archard model could not explain the increase in wear rate after the reversal in wet conditions, because the model does not take into account the delamination wear induced by the fluid. Some discs after the test were sectioned and photographed to observe the crack morphologies and microstructural changes by optical metallography. In wet conditions, when the wheel disc was reversed, the cracks clearly tended to propagate parallel to the surface, and the resulting long and thin wear sheets delaminated. In this case, the crack is filled with fluid just before its mouth reaches the contact area between the wheel and rail discs, whereupon the mouth is sealed. Therefore, the fluid is trapped in the crack and acts as a lubricant to reduce the friction coefficient, and cracks tend to propagate easily and large delamination sheets are apt to form. In order to explain the increase in wear rate after the reversal under wet conditions, CTSDs were obtained by FE analyses. In the wet conditions, the ΔCTSD after the reversal was almost twice as large as that before the reversal. This means that the amount of crack propagation after the reversal is higher than that before the reversal. In contrast in the dry conditions, the ΔCTSD is almost the same before and after the reversal. Therefore, the amount of crack propagation before and after the reversal is considered to be almost the same.
  • 王 呉桐, 赤間 誠, 塚原真宏, 三阪佳孝, 松田伸也, GUENNEC Benjamin, 酒井達雄
    日本材料学会 第71期通常総会・学術講演会, May 30, 2022, 日本材料学会
    本研究では，高周波表面焼入れを施した車軸鋼相当試験片を用いた超高サイクル領域までの回転曲げ疲労試験を行ってS-N曲線を作製した。同時にFEM解析を行い，試験結果を考察した。またSEMによって破面観察を実施した。その結果，未焼入れ材の10^7時間強度はほぼ300MPaであるのに対して，焼入れ材の同時間強度はほぼ700MPaであり，高周波焼入れによって疲労強度は，ほぼ400MPaも向上すること，焼入れ材では10^7サイクル以上で破断した試験片がかなり存在し，表面焼入れを行っている新幹線車軸は超高サイクル領域での疲労特性の解明が不可欠であることなどがわかった。
  • 高橋優雅, 赤間誠
    日本トライボロジー学会トライボロジー会議予稿集(CD-ROM), Oct 29, 2021
  • Yuuma TAKAHASHI
    日本機械学会 関西学生会2020年度学生員卒業研究発表講演会, Mar 16, 2021, The Japan Society of Mechanical Engineers
    鉄道車両は運用中に様々な損傷を受ける．その中でき裂と摩耗は車輪の寿命を決定することが知られている．本研究では，車輪の転がり方向逆転によるき裂と摩耗の挙動への影響を研究するため，西原式二円筒摩耗試験機による試験及び有限要素法(FEM)を用いた数値解析を実施した．
  • 赤間誠, WANG Wutong, 塚原真宏, 三阪佳孝, 松田伸也, 酒井達雄
    信頼性シンポジウム講演論文集, 2021
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Professional Memberships

 6
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Research Projects

 1

Industrial Property Rights

 3

研究テーマ

 2
  • 研究テーマ（英語）
    転がり接触疲労に関する研究
    キーワード（英語）
    転がり接触疲労，車輪，レール，数値解析
    概要（英語）
    車輪とレールには，接触によってき裂が発生する場合がある。そのき裂の発生時期，き裂の進展速度などを，数値解析手法で予測する。
    研究期間（開始）（英語）
    2001/04/01
  • 研究テーマ（英語）
    鉄道部材の健全性評価に関する研究
    キーワード（英語）
    健全性評価，車軸，車輪，レール，数値解析
    概要（英語）
    車軸，車輪，レールなどの鉄道車両部品，軌道部材について，数値解析的手法で発生応力などを解析し，それらの構造健全性を評価する。
    研究期間（開始）（英語）
    2001/04/01
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