Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Hiroshi Noguchi Last modified date:2018.06.09

Professor / Strength of Materials / Department of Mechanical Engineering / Faculty of Engineering


Presentations
1. A. Nishimoto, Y. Oda, Hiroshi Noguchi, Loading frequency effects on the fatigue crack growth rate and fracture surface morphology of low carbon steel in case of long-term use in hydrogen gas, 10th International Conference on Fracture and Damage Mechanics, FDM2011, 2012, Loading frequency effects on FCGR and fracture surface morphology were investigated on pre-strained low carbon steel in high FCGR range. Loading frequency effects showed the different trend between internal hydrogen and environmental hydrogen. The effects of combined condition hydrogen revealed similar tendency of environmental hydrogen..
2. T. Matsueda, Hiroshi Noguchi, Intergrated evaluation method for fatigue limit of notched steel with ΔKth value, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, 2012, It is the big problem to evaluate the fatigue limit σw in order to safely design structures and machines. Under the condition of the fatigue crack initiation limit σw1, the present author defined the initial crack size √area using the characteristic elastic field of the notch, the half length of the fatigue crack a and a notch depth t. Using this √area, the methods of calculating ΔKth and σw1 were proposed. In addition to it, in this condition it is made sure that ΔKth exists on the band from ΔK th prediction line of the micro fatigue crack within 18% error. Using ΔKth calculated by the prediction line and the value of Vi, this evaluating method of σw1 was confirmed with annealed 0.35% carbon steel. As a result, it was confirmed that this method to evaluate σw1 is within 18% error. Moreover it was also confirmed that the σw1 value by this prediction method is within 10% error when the predicted σw1 value is greater than σw2..
3. Koki Tazoe, Yasuji Oda, Hiroshi Noguchi, Hydrogen gas effects on the fatigue crack growth behavior of Cr-Mo Steel CT specimen in extremely low rate range, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, 2012, In order to investigate extremely slow fatigue crack growth characteristics of JIS SCM440 CT specimen in 9 MPa hydrogen gas environment, stress intensity factor range (ΔK) decreasing tests with in-situ observation were carried out. Fatigue crack growth rate (FCGR) in hydrogen gas did not show threshold behavior but FCGR in helium and air showed threshold behavior clearly. Fatigue crack in hydrogen gas showed sudden increased after a temporary stop in growth. The sudden increase in growth was induced by coalescing with a new micro-crack initiated in front of the main crack tip. The fractographic analysis showed the existence of intergranular facets. The intergranular facets were observed in all over the fracture surface. The amount of the intergranular facets in hydrogen gas decreased with decreasing the ΔK. However, facets were still observed in the extremely low rate region. On the other hand, there was no facet in fracture surface tested in helium and in air in the extremely low rate region. The formation of facets was supposed to be one of the causes of non-threshold behavior in hydrogen gas..
4. Komei Hayashi, Shigeru Hamada, Ichinori Shigematsu, Michiru Sakamoto, Hiroshi Noguchi, Effect of friction stir welding condition on fatigue limit of welded non-combustible Mg alloy, 10th International Conference on Fracture and Damage Mechanics, FDM2011, 2012, The atigue strength of Friction Stir Welding is affected by the structure and the welding defect size. The welding defect sizes have a scatter. Therfore, the effect of Friction Stir Welding condition on fatigue limit of welded noncombustible Mg alloy was investigated with the specimen which has a controlled defect size. As a result, the good correlation between the fatigue limit and the hardness of the welding area was clarified..
5. Toshiyuki Ishina, Shigeru Hamada, Hiroshi Noguchi, Ductile to brittle transition in magnesium alloy with a crack, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, 2012, We evaluated the strength of a cast non-combustible magnesium alloy that is intended for use in automobile engines. This alloy contains thin sheet-like oxides because of its production process. The size of these thin sheet-like oxides varies, and this means that the temperature dependency of the strength characteristics of the alloy cannot be determined by a tensile test alone. Initially, specimens of the alloy having an artificial pre-crack of 5 [mm] to simulate the sheet-like oxides were subject to tensile testing. The testing was carried out at room temperature (23 [°C]), 150 [°C], 200 [°C] and 250 [°C]. 250 [°C] is the temperature of the environment in which the alloy will be used in automobile engines. All the fractures propagated from the artificial pre-crack and the alloy exhibited its maximum strength at 150 [°C]. To investigate the temperature dependency of the fracture mechanism, a scanning electron microscope (SEM) was used to observe the region near the tip of the pre-crack on the fracture surface of the specimens tested at room temperature and at 250 [°C]. On the fracture surface of the specimen tested at 250 [°C], some dimples were observed over some of the surface near the tip of the artificial pre-crack; however, the fracture surface of the specimen tested at room temperature showed brittle fracture surface morphology over the entire area. For the magnesium alloy, the critical resolved shear stress for non-basal slip, which is a characteristic of a hexagonal close-packed metal, is dependent on temperature. Therefore, ductile to brittle transition was considered to be occurred at a temperature between room temperature and 250 [°C]. Mechanical restraint is also considered to be affected the ductile to brittle transition..
6. Junji Sakamoto, Yoshimasa Takahashi, Hiroshi Noguchi, Applicability of a FIB-notch as a small initial crack for fatigue limit evaluation, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, 2012, In this study, we propose a method for assessing the applicability of an artificial defect as a small initial crack for fatigue limit evaluation. The proposed method is applied to drill holes and sharp notches introduced using a focused ion beam (FIB) technique in annealed 0.45% carbon steel. It is found that under rotating bending fatigue, an FIB notch can be used as a small initial crack for fatigue limit evaluation, whereas a drill hole cannot, for of ∼50 μm. Here, is the square root of the area obtained by projecting the defect onto a plane perpendicular to the load axial direction. The results indicate that an FIB notch can be used as a small initial crack for fatigue limit evaluation in a greater number of materials than those in which a drill hole can be used..
7. T. Kinoshita, K. Hayashi, Shigeru Hamada, I. Shigematsu, Hiroshi Noguchi, Evaluation of joint defects on FSW of mg alloy using statistical method, 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012, 2012.01, To select the welding conditions that can ensure a particular fatigue strength for safe use in a structure produced by the FSW (Friction Stir Welding) of Mg alloys, this paper proposes a method for determining the range of welding conditions that can ensure a particular joint defect size limit. The welding parameters used are the rotation speed of the tool ω and the welding speed v. Generally, a welding condition is selected using only the fatigue strength as an index. However, ensuring the fatigue strength in a particular welding condition does not insure the strength and reliability of a welded part, because actual welding is not typically carried out in a particular welding condition. Therefore, a range of conditions that can ensure a particular fatigue strength is required. Moreover, we also consider parameters that represent the factors that decrease fatigue strength, namely, √area, HV, and R, because the welding conditions that can ensure a particular fatigue strength are determined by an evaluation of these factors, as well. Therefore, in this study, a method for determining a range of welding conditions that can ensure a welding defect size limit is proposed. Furthermore, FSW welding tests were carried out and the validity of the proposed method was evaluated. X-ray transmission measurements were carried out to measure the welding defect size obtained using the method. Then, the prediction of the maximum welding defect size was carried out for a welding length of 25 [m], which is representative of body of a the Shinkansen rolling stock car..
8. Yoshimasa Takahashi, Hiroaki Yoshitake, Takahiro Shikama, Hiroshi Noguchi, Masanori Takuma, Giga-cycle property of a new age-hardened aluminium alloy containing excess solute magnesium, 12th International Conference on Fracture and Damage Mechanics, FDM 2013, 2014, The giga-cycle property of a newly developed Al alloy, which contains 0.5wt.% excess Mg solute compared to a standard age-hardened 6061 alloy (6061-T6), was investigated by using smooth specimens subjected to ultrasonic fatigue. The fatigue strength of the new alloy was higher than that of a normal 6061 alloy particularly at relatively low stress amplitude level. Several analyses (surface crack observation, fractography, FIB cross-sectioning, etc.) were also conducted to reveal the micro-mechanism of the observed strength properties. The following results were obtained: i) No fatigue limit was confirmed for both 6061 and new alloy. ii) Total life (Nf) of 6061 and new alloys was determined by a single fatigue crack initiated from a surface PSB crack. iii) Crack initiation resistance defined by N25 (number of cycles to reach ρ = 25 mm-2, where ρ is the PSB crack number density) for new alloy was higher than that of 6061. iv) The higher fatigue strength of new alloy was explained by the effect of excess Mg solute which increased the resistance against the formation of PSB cracks..
9. Takahiro Shikama, Shinji Yoshihara, Yoshimasa Takahashi, Hiroshi Noguchi, Analysis of small fatigue crack in Al-Mg-Si aluminum alloy, 14th International Conference on Aluminium Alloys, ICAA 2014, 2014.01, In general, aluminum alloy does not exhibit distinct fatigue limit (knee point) in the S-N diagram. The growth of a small fatigue crack of precipitation-hardened Al-Mg-Si system alloy (6061-T6) was investigated to clarify the mechanism of non-appearance of distinct fatigue limit (knee point) in the S-N diagram. The small crack was analysed in detail by replica method, scanning electron microscope (SEM), and Electron Back Scatter Diffraction Patterns (EBSD). On the other hand, the existence of distinct fatigue limit (knee point) of new developed aluminum alloy by adding excess Mg to the 6061 alloy was found. In this study, the resistance of small crack growth of the developed alloy was compared with standard 6061 alloy. It was revealed that the resistance of crack growth of new developed alloy was higher than that of standard 6061 alloy in short crack region (l<1.0 mm)..
10. S. F. Anis, Motomichi Koyama, Hiroshi Noguchi, Investigation on Mode I propagation behavior of fatigue crack in precipitation-hardened aluminum alloy with different Mg content, 5th International Conference on Engineering and Innovative Materials, ICEIM 2016, 2017.01, The influence of excess Mg on the Mode I propagation of fatigue crack was examined in newly developed precipitation-hardened Al alloy containing Zr and excess Mg. The aim of this study was to evaluate the underlying factor affecting fatigue crack growth rate in the stage II region. For this purpose, the rotating bending fatigue tests were performed in constant amplitude loading, and replication technique with an optical microscope was used to measure the crack growth in the Al alloys. Through analyses of the crack propagation on the specimen surface and striation formation of the fracture surface, the effects of excess Mg in the Al alloys were clarified to promote the occurrence of mode I fatigue crack, and decelerate the fatigue crack propagation. These facts suggest that the dynamic strain aging of Mg induces the formation of fatigue striation and reduce the driving force of the crack propagation. The findings were supported by the fractographic observations in the fatigue crack propagation region..
11. 小川 卓郎, 野口 博司, Motomichi Koyama, Experimental approach to clarify hydrogen effects on strain aging in carbon steel, EUROMAT2015, 2015.09, In late years, many researchers have been taking attention to influences of hydrogen on the fatigue limit of steels. Strain aging in carbon steel is one of the significant factor in non-propagating crack behavior at fatigue limit. On the other hand, it ha.
12. 金 鍾天, 野口 博司, Investigation of fatigue crack growth behavior on the shot-peened carbon steel by residual stress relaxation, ICSP12, 2014.09.
13. 石名 敏之, 野口 博司, Derivation of Non-dimensional Number for Elastic-perfectly Plastic Continuum Body and Elastic-perfectly Plastic Solid Materials in Linear Elastic Fracture Mechanics, 20th European Conference on Fracture, 2014.07.
14. 伊藤 嵩, 野口 博司, Influence of Punched Hole on Fatigue Properties of TiC-Precipitation-Strengthened Steels, LCF7, 2012.06.
15. 石名 敏之, 野口 博司, Characteristic of threshold stress intensity factor range for small crack on magnesium alloys, ICM11-International Conference on the mechanical behavior of Materials, 2012.06.
16. 松枝 剛広, 野口 博司, Fatigue Limit Evaluation of Blunt-Notched Specimen Using ⊿Kth Value of Small Crack, ICM11-International Conference on the mechanical behavior of Materials, 2012.06.
17. 呉 昊, 野口 博司, Fatigue strength properties of precipitation strengthening stainless steel A286 focused attention on small fatigue crack behaviour, ICM11-International Conference on the mechanical behavior of Materials, 2012.06.
18. 横川秀斗, 野口 博司, MODE II DELAMINATION FATIGUE CRACK GROWTH CHARACTERISTICS OF GFRP LAMINATES WITH WASTE GFRP MILLED CHIPS INTERLEAF, The European Society for Composite Materials, the fifteenth European Conference on Composite Materials, 2012.06.
19. 内田直希, 野口 博司, 表面損傷を持つ アルミ合金鍛造品における疲労強度の定量的評価, ICSMA16, 2012.08.
20. 木下拓也, 野口 博司, 統計的手法を用いたMg合金のFSWによる接合欠陥の評価, 第19回 Europian Conference on Fracture, 2012.08.
21. 藤澤友也, 野口 博司, パーライト鋼平滑材における疲労き裂発生と組織との関係, 第19回 Europian Conference on Fracture, 2012.08.
22. 田添広喜, 野口 博司, Hydrogen Gas Effects on the Fatigue Crack Growth Behavior of Cr-Mo Steel CT Specimen in Extremely Low Rate Range, 第19回 Europian Conference on Fracture, 2012.08.
23. 松枝剛広, 野口 博司, ΔKthを用いた切欠き材の統合的疲労限度予測法, 第19回 Europian Conference on Fracture, 2012.08.
24. 劉敏健, 野口 博司, モードII疲労き裂進展の有効応力拡大係数の測定, 第19回 Europian Conference on Fracture, 2012.08.
25. 坂本惇司, 野口 博司, 機械・構造物に用いる材料の長期安全性の迅速な評価法に関する研究, 第19回 Europian Conference on Fracture, 2012.08.
26. The Effect of a Hydrogen Gas Enbironment on Fatigue Crack Growth Characteristics of 0.13%C Steel.
27. Fatigue Crack Growth Characteristics of Welder Pipeline Steel in a Hydrougen Gas Environment.
28. Fatigue Properties of Pure Titanium.
29. Fatigue Strength Characteristics of Non-Combusible Mg Alloy Welded Joint.
30. Fatigue Strength Characteristic of Notched Specimens of Noncombustible Magnesium Alloy.
31. Fatigue Strength of Notched Specimens of Non-combusible Magnesium Alloy.
32. The Effect of Pre-strain on Fatigue Limit and Crack Growth Characteristics.
33. Fatigue Crack,Growth Characteristics of a few Alloys in Hydrogen Gas Environment.
34. Fatigue Strength of Notched Specimens of Non-combustible Magnesium Alloy.
35. Effect of Hydrogen Environment on Fatigue Crack Growth of Friction Sir Welded Joints of A6061-T6 Aluminum Alloy.
36. Effects of Hydrogen Environment on Fatigue Crack Growth Rate and its Dependence on Testing Frequency.
37. Strength Reliability of Micro Polycrystalline Silicon Structure.
38. Fatigue Characteristics of Carbon Steel in Hydrogen Engironment.
39. The Investigation of Fatigue Experinment in Hydrogen Plasma as a Substitute for High Pressure Hydrogen Gas Environment.
40. The Effect of Pre-strain on the Fatigue Characteristic of Age-hardened Aluminum Alloy.
41. The Effect of Non-woven Tissue on Fatigue Characteristics of CFRP Cross-Ply Laminate.
42. Study of Fatigue Life Prediction Method of Natural Rubber for Automobile Engine-Mount.
43. Development of Incident Report Data Base System for Organizational Learning.
44. The Effect of Stress Ratio on Fatigue Characteristics of Stitched GFRP.
45. Fatigue behavior of SUS304 near Fatigue limit in Hydrogen Gas Environment.
46. Tje Effect of Mean Stress on Fatigue Strength of Non-combusible Magnesium Alloy.
47. The Effect of Pre-strain on the Fatigue Characteristic of Age hardened Aluminum Alloy A6061-T6.
48. Prediction of Fatigue Limit Reliability of Aluminum Cast Alloy.
49. Simple Estimation for Stress Concentration Factors of Orthotropic Finite Width Plates.
50. Effect of Hydrogen Gas Environment on Fatigue Crack Growth Rate in Austenitic Stainless Steels.
51. Effect of Mean Stress on Fatigue Strength of Non-combustible Magnesium Alloy.
52. Effect of Hydrogen Environment on Non-propagation and Propagation of Fatigue Crack in a SUS304 Steel with Small Blind Holes.
53. Relation between Effects of Pre-strain and Surface Condition on Fatigue.
54. System's Acceptance Limit for Expectation of a Society in the Aspect of System Continuation.
55. A Study of Quantitative Index to Visualize the Safety of Organization.
56. Fatigu Crack Growth Characteristics of Austenitic Steels in a Hydrogen Gas Environment.
57. Effect of Hydrogen Gas Environment on Fatigue Limit of Austenitic Stainless Steels.
58. Fatigue Characteristics of GFRP with Stiched UD Layers.
59. Effects of Mean Stress on Fatigue Strength of Non-Combustible Magnesium Alloy.
60. Relation between Fatigue Strength and Pre-Strain in A6061-T6.
61. Consideration on the Quality of Information from Incidents to Achieve System Safety.
62. Fatigue limit of metal specimen with complex surface is predicted..
63. Reliability Problem Prevention Method for Automotive Components
is proposed based on GD3 Activity and DRBFM..
64. Quantitative estimation for a system performance with hierachized celluar
automata is discussed..
65. Fatigue strength of materials is evaluated from meso-characteristics..
66. Influence of welding parameters on fatigue strength considering nugget size is discussed..
67. Fatigue characteristics of aluminum alloy with cast skin is evaluated..
68. Proposal of the Basic Consept of System Safety and its Application to Safety Managemant in Japanese Hospital.
69. Fatigue Characteristics of Austenitic Stainless Steels in Hydrogen Gas Environment.
70. In-situ SLM observation of austenitic stainless steel in hydrogen environment is carried out..
71. Fatigue strength characteristics of non-combustion Magnesium alloy is clarified..
72. Quantitative evaluation method of fatigue limit of metal with an arbitrary crack is proposed under stress controlled condition in case of a stress ratio R ≥-1..
73. Vibration fatigue reliability of BGA IC-package with Pb-free solder and Pb-Sn
solder is reseached..
74. Concept of System Safety and its Application to Safety Management in Japanese Hospital.
75. Estimation of Strength of Aluminum Alloy Joint Made by Laser Welding.
76. Efftect of Hydrogen Environment on Fatigue Characteristics in an Austenitic
Stainless Steel.
77. Effects of Hydrogen Enviroment on Fatigue Characteristics in a Type 304
Austeinit Stainless Steel.
78. Consideration on Welding Conditions by which Strength is Stabilized in the
Aluminum Alloy Joint Made by Laser Welding.
79. Fatigue limit reliability of metal specimen with complex surface is evaluated from meso-analysis..
80. Fatigue characteristics of aluminum cast alloy under mean stress is discussed..
81. Phenomenon occurrence distribution is estimated with maximum likelihood
method..
82. SLM Observation of Fatigue Crack Growth Behavior of Austenitic Stainless Steel in a Hydrogen Gas Environment.
83. Crack can be detected with the method with strain gauge and boundary element method..
84. High-cycle fatigue life of aluminum cast alloy is evaluated from meso-level consideration..
85. Fatigue limit reliability of high-strength steel from meso-level consideration is evaluated..
86. Fatigue strength of Hybrid Composites with Non-woven carbon tissue are reseached..
87. Fracture toughness analysis of single crystal is simulated with combined model of (Molecular Dynamics + Micromechanics)..