Article
Engineering, Civil
Thin Thin Htut, Satoyuki Tanaka, Donghui Ma, Jun Okada, Masahito Honnami, Kaoru Shinoda, Masamitsu Abe, Takeru Katayama
Summary: A novel fatigue test specimen was developed to investigate the fatigue fracture behaviors of a shell and tube heat exchanger. The specimen consisted of a single tube and a tubesheet joined by welding to form a tube-to-tubesheet welded joint. A fatigue test was conducted under tensile cyclic load, and defects were generated from the root of the joint, propagating with complex crack front trajectories. Crack propagation (CP) simulation was performed using the extended finite element method (X-FEM) to study the CP behavior. The experimental and numerical studies successfully revealed the fundamental fracture characteristics of the welded joint.
ENGINEERING STRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Jeong Ho Hwang, Geun Dong Song, Dae-Woong Kim, Nae Hyung Tak, Jae-Yong Lim, Seong-Gu Hong
Summary: The microstructure and mechanical properties of TP310HCbN welded joints were investigated. The welded joint exhibited material inhomogeneity due to the significantly different microstructure formed in each welding zone. The soft dendrite core region in the welded joint acted as a crack nucleation site, leading to premature failure and reduced mechanical properties. An energy-based unified fatigue life prediction model was developed, successfully predicting the fatigue life of the welded joint.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Engineering, Civil
Peng Gao, Tianyu Du, Jianfu Zhang, Pingfa Feng, Dingwen Yu
Summary: The fatigue behavior of Q345B low alloy structural steel single-lap bolt-welded joint was studied compared to bolted and welded joints. Experimental results showed that the bolt-welded joint has higher fatigue strength, and the usage of welds and bolts can enhance fracture resistance and bearing capacity of the joint. The local strain energy density method provides a better estimation of fatigue life for bolt-welded joint.
Article
Engineering, Mechanical
T. Suresh Kumar, A. Nagesha, K. Mariappan, Manmath Kumar Dash
Summary: The beneficial influence of prior thermal ageing on the cyclic life of a type 316 LN austenitic stainless steel weld joint under thermomechanical fatigue was demonstrated through experiments. It was found that crack initiation mostly occurred in the heat affected zone in the as-welded joint, but shifted to the weld region following thermal ageing. Mechanisms governing life variations between the as-welded and aged joints were identified through detailed EBSD investigations.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Jeong Ho Hwang, Geun Dong Song, Dae-Woong Kim, Yong-Hak Huh, Byong Chon Park, Junhee Hahn, Seong-Gu Hong
Summary: The study investigated the tensile and fatigue properties of Super304H welded joint at elevated temperatures up to 750 degrees C, focusing on the operating temperature range of 500-700 degrees C. It was found that the tensile strength of the welded joint was similar to that of the base metal, but a significant reduction in elongation and fatigue resistance at low strain amplitudes was observed in the welded joint.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
T. Vuherer, M. Milcic, S. Glodez, D. Milcic, L. Radovic, J. Kramberger
Summary: This study focuses on the fatigue and fracture behavior of Friction Stir Welded AA2024-T351 joints at different welding speeds. Experimental results show that a welding speed of 116 mm/min exhibits the highest resistance against crack extension.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Optics
Jiecai Feng, Liqun Li, Yanbin Chen, Yingzhong Tian, Yongle Sun, Xuanjun Zhang, Jie Zhang
Summary: The study investigated the inhomogeneous microstructure and fatigue crack propagation of a 30 mm thick-section high strength steel welded joint using double-sided hybrid fiber laser-arc welding. The results showed that the laser zone had smaller grain size, higher dislocation density, and higher fatigue crack propagation resistance compared to the arc zone.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Engineering, Mechanical
WangSub Shin, Kyong-Ho Chang, Shazia Muzaffer
Summary: The research analyzed the fatigue performance of cruciform fillet welded joints with full and incomplete penetration under load carrying and non-load carrying conditions. It was found that welding deformation, residual stresses, and stress magnitude affect the fatigue crack initiation and fatigue life of welded structures.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Engineering, Mechanical
Huijing Zhang, Xiaohui Zhao, Yu Liu
Summary: The research results indicate that HFIR treatment can refine the grain sizes on the surface of welded joints and increase the hardness, elastic modulus, and residual stress, effectively extending the fatigue crack growth life of welded joints.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Materials Science, Multidisciplinary
Jintao Chen, Haizhou Li, Yingzong Liu, Xu Zhao, Yuhua Cai, Hui Chen, Yarong Chen, Aixin Feng, Hao Wang, Zhongtao Sun
Summary: The deformation behavior and microstructure characteristics of laser-welded Ti-6Al-4V titanium alloy joints under variable amplitude fatigue were investigated. It was found that the fatigue limit of the joint was 339 +/- 5 MPa. Fractography analysis revealed that fatigue cracks originated from the surface in the weld metal and were caused by differences in grain size and texture orientation. Larger average grain size and the presence of acicular alpha' martensite with preferred orientation in the weld metal contributed to fatigue crack initiation.
MATERIALS CHARACTERIZATION
(2023)
Article
Nanoscience & Nanotechnology
Yuxuan Song, Yi Ma, Haofeng Chen, Zhibo He, Hu Chen, Taihua Zhang, Zengliang Gao
Summary: This study investigated the creep-fatigue interactions on the long-term service damage of P92 welded joint by conducting tensile and compressive tests under different applied strains. Using nanoindentation, the local mechanical properties of the welded joint were examined, while scanning electron microscope was used to analyze fracture morphologies and internal defects after CF tests, revealing the effects of holding type on the local creep behavior and fracture mechanism of the welds.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Multidisciplinary
Yuebing Li, Yuxuan Song, Pan Liu, Ting Jin
Summary: The CF experiments were conducted at 923 K with holding times ranging from 30 to 900 s on a Chinese P92 steel welded joint. Results showed that the failure stage of the welded specimens accounted for 45% of the lifetime fraction, indicating accelerated fracture mechanisms with longer holding times. The absence of a third softening stage in longer-held specimens suggested a transition from fatigue-dominated damage to creep-fatigue interaction.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Multidisciplinary
Robert Owsinski, Dorian S. Lachowicz, Cyprian T. Lachowicz, Roberto Gil, Adam Nieslony
Summary: LFW technology offers versatile use and high integrity joints, potentially contributing to sustainable engineering in the future. However, limited research on LFW of steel components and lack of information on fatigue strength and fracture behavior may hinder its wider industrial adoption.
PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY
(2021)
Article
Mechanics
Ceferino Steimbreger, Nenad Gubeljak, Tomaz Vuherer, Norbert Enzinger, Wolfgang Ernst, Mirco Chapetti
Summary: This study analyzes the fatigue behavior of ultra-high strength steel butt-welded joints through experimental testing and fracture mechanics approach. Different welding techniques result in different fatigue strengths, and joint geometry alone cannot fully explain the differences. Microstructure and defect size play important roles in early crack growth.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
Thomasprabhu Selvaraj, Shogo Ishida, Jinta Arakawa, Hiroyuki Akebono, Atsushi Sugeta, Yasuhiro Aoki, Hidetoshi Fujii
Summary: The study investigated the fatigue life and fracture mechanism of friction stir spot welded tension-shear joints using 590-MPa class steel as a base material, focusing on welding dimension variations caused by tool wear. The fatigue limit of the FSSW joint was found to be significantly lower than its static tensile strength, showing two different failure morphologies: base metal fracture and weld area fracture. However, changes in welding state due to tool wear leading to different fracture modes related to welding rip diameter had no effect on fatigue strength regardless of the applied load.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Tianyu Zhang, Xiaowei Wang, Wei Zhang, Tasnim Hassan, Jianming Gong
Article
Mechanics
Xiaowei Wang, Tianyu Zhang, Wei Zhang, Magd Abdel Wahab, Jianming Gong
Summary: This study presents an improved unified viscoplastic model to simulate the various behavior of P92 steel under low cycle fatigue (LCF) and creep fatigue interaction (CFI) loadings. By adjusting the parameters and rules in the model, good agreement is achieved with experimental results.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2021)
Article
Engineering, Civil
Wei Zhang, Cheng Miao, Chang-Yu Zhou, Xiao-Hua He
THIN-WALLED STRUCTURES
(2020)
Article
Materials Science, Multidisciplinary
Wei Zhang, Zhikang Zhu, Changyu Zhou, Xiaohua He
Summary: Experimental results show that commercially pure titanium biaxial tensile samples have higher strength than uniaxial samples, with equi-biaxial samples exhibiting the highest strength. Additionally, an increase in strain rate leads to a significant improvement in tensile strength. Fractographic analysis indicates that the shape and size of dimples are dependent on the load ratio and strain rate.
Article
Nanoscience & Nanotechnology
Peng Yin, Wei Zhang, Shen Guo, Jianbin Wen, Guodong Zhang, Fei Xue, Yanfen Zhao, Changyu Zhou
Summary: In this study, TMF tests were conducted to investigate the cyclic deformation and damage mechanisms of P92 steel under different strain rates. The results showed that increasing strain rate significantly improved fatigue life, with OP-TMF leading to more severe damage compared to IP-TMF. The presence of dynamic strain ageing (DSA) was found to be dependent on strain rate, fatigue cycle, and phase angle, affecting fatigue life in combination with fatigue cracks, creep voids, and oxidation.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Mechanics
Wei Zhang, Xiaowei Wang, Zitong Kang, Tianyu Zhang, Yong Jiang, Xiancheng Zhang, Jianming Gong
Summary: This study quantitatively evaluated the evolution of microstructure and micro-region properties of P92 steel weldments during interrupted fatigue tests and subsequent creep fracture using high-resolution characterization techniques. The results showed that the average grain size of the weld metal increased, and all regions exhibited three cyclic softening behavior during the fatigue process.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
Shen Guo, Wei Zhang, Peng Yin, Tian-Hao Ma, Jian-Bin Wen, Guo-Dong Zhang, Fei Xue, Yan-Fen Zhao, Chang-Yu Zhou
Summary: The present work investigates the thermomechanical fatigue behavior and life prediction of P92 steel welded joints under various mechanical strain amplitudes and phase angles. The results show that welded joints exhibit significant cyclic softening during fatigue process, with fatigue life being dependent on both strain amplitude and phase angle. A decrease in strain amplitude and an increase in phase angle lead to an increase in fatigue life, while fracture position changes significantly with changes in strain amplitude and phase angle. Finally, a modified energy-based life prediction model is proposed by considering the effects of phase angle and mean stress.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Materials Science, Multidisciplinary
Wei Zhang, Xiaowei Wang, Zitong Kang, Tianyu Zhang, Yong Jiang, Xiancheng Zhang, Jianming Gong
Summary: This study investigated the cyclic softening and remaining creep behavior of different micro-regions of P92 steel weldment using EBSD and nanoindentation. The experimental results showed that the intercritical heat-affected zone was most sensitive to CFI loading, with changes in microstructure and decreased remaining creep life as the number of fatigue cycles increased.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Engineering, Mechanical
Ning Gao, Wei Zhang, Peng Yin, Fei Liang, Guodong Zhang, Xianxi Xia, Yanfen Zhao, Changyu Zhou
Summary: High temperature multiaxial fatigue tests were performed at 600 degrees C with different strain amplitudes and strain ratios. The cyclic deformation and damage mechanisms were analyzed using dynamic strain ageing (DSA) analysis and microstructure characterization. The results indicate that increasing strain amplitude and strain ratio accelerate cyclic softening. The DSA behavior depends on strain amplitude, strain ratio, and loading direction. Moreover, increasing strain amplitude promotes subgrain growth and dislocation structure transformation, while increasing strain ratio promotes planar slip of dislocation.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
Wei Zhang, Xiaowei Wang, Zitong Kang, Tianyu Zhang, Yong Jiang, Xiancheng Zhang, Jianming Gong, Shantung Tu
Summary: The deformation and damage mechanisms of welded joints were investigated, revealing that the weakest position moves to the base material after fatigue loading. The early saturated grain growth in the inter-critical heat-affected zone (ICHAZ) contributes to this movement. Additionally, a fatigue damage parameter based on nanoindentation microhardness was proposed.
MATERIALS CHARACTERIZATION
(2022)
Article
Engineering, Mechanical
Peng Yin, Wei Zhang, Qiaofa Yang, Fei Liang, Guodong Zhang, Xianxi Xia, Yanfen Zhao, Changyu Zhou
Summary: Thermomechanical fatigue tests were conducted on austenitic stainless steel in the temperature range of 250-400 degrees C. The results demonstrate that an increase in strain amplitude leads to a decrease in fatigue life and a greater impact of phase angle. The occurrence of dynamic strain aging (DSA) is observed only under out-of-phase in the tensile direction, while under other phase angles it occurs in the compression direction at a low strain amplitude. Slip bands with a high dislocation density enhance fatigue resistance, and at high strain amplitudes, dislocations tend to form cell structures. Furthermore, oxidation damage significantly contributes to the reduction of fatigue life at high strain amplitudes.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Nanoscience & Nanotechnology
Le Chang, Chao Lv, Takayuki Kitamura, Wei Zhang, Chang -Yu Zhou
Summary: The low cycle fatigue behavior of commercially pure titanium under different loading directions was investigated. The study found that the loading direction had significant effects on fatigue properties. Through a comprehensive analysis, the anisotropic slip behavior was found to play a critical role in fatigue behavior.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Peng Yin, Wei Zhang, Yi Zhang, Qiaofa Yang, Fei Liang, Le Chang, Changyu Zhou
Summary: The thermomechanical fatigue behavior of 316L was investigated by analyzing internal stress and microstructural characteristics at different cyclic stages. The results showed that cyclic stress response exhibited initial hardening followed by cyclic softening at high strain amplitudes, while continuous cyclic hardening was observed as the strain amplitude decreased. Out-of-phase TMF always resulted in cyclic softening regardless of strain amplitude. The contributions of back stress and friction stress to initial and subsequent cyclic hardening were highlighted. The hardening of back stress and friction stress was attributed to dislocation proliferation at grain boundaries and increased dislocation interactions within grains, respectively. The cyclic softening of friction stress was attributed to the annihilation of dislocations due to cross-slip. The hysteresis curves revealed that the intensity of dynamic strain aging depended on strain amplitude, loading history, and phase angle, which were related to cross-slip occurrence, solute atom diffusion rate, point defect density, and vacancy mobility. The effect of loading conditions on fracture behavior, including crack sources, secondary cracks, creep cavities, and oxidation damage, was demonstrated.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Mechanical
Tianyu Zhang, Xiaowei Wang, Yunnan Ji, Wei Zhang, Tasnim Hassan, Jianming Gong
INTERNATIONAL JOURNAL OF FATIGUE
(2020)
Article
Mechanics
Xiaolong Liu, Kelian Luo, Pengcheng Gao, Tao Cong, Xi Wang, Wenjing Wang
Summary: This paper investigates the formation mechanisms of the zig-zag crack region on the shattered rim of railway wheels. The zig-zag crack region, identified as a typical region for crack propagation in rolling contact fatigue behavior, was observed using scanning electron microscopy and transmission electron microscopy. The formation of the zig-zag morphology is attributed to the periodic deflection of the propagation path relative to the initial propagation plane, caused by the limited plastic deformation zone at the crack tip. Grain refinement and secondary cracks in the zig-zag crack region are a result of the large compressive and shear stresses induced by rolling contact loading.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Anastasia Iziumova, Aleksei Vshivkov, Ivan Panteleev, Virginia Mubassarova, Oleg Plekhov, Denis Davydov
Summary: The aim of this study was to investigate the correlation between structural, acoustic emission, and thermal characteristics of fatigue crack growth in titanium alloys. Cluster analysis of the acoustic emission signals revealed two different types of signals observed during the fatigue crack development. It was experimentally demonstrated that the stored energy tends to reach an asymptotic value at the final stage of fatigue crack growth and this is correlated with the twinning process intensification in titanium alloy Ti Grade 2. A correlation was assumed between the stages of change in heat flux, the cumulative energy of the first cluster of acoustic emission signals, and the crack length.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
M. Vieira de Carvalho, I. A. Rodrigues Lopes, F. M. Andrade Pires
Summary: This study investigates the numerical challenges of fracture mechanics models within implicit quasi-static frameworks and proposes an instability criterion. The ratio of cohesive to internal power is identified as a crucial factor. Two strategies for handling fracture problems with instabilities are discussed and a comparative assessment is performed. The study also examines more complex material responses, including transformation-induced plasticity effects.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Thomas Duminy, Aurelien Doitrand, Sylvain Meille
Summary: This study conducted in situ wedge splitting tests on millimeter-size PMMA samples and proposed a method to determine the material tensile strength and critical energy release rate using digital image correlation and a full finite element implementation of the coupled criterion.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Xin Chang, Xingyi Wang, Chunhe Yang, Yintong Guo, Yanghui Wan
Summary: The influence of cyclic thermal shock and high-temperature acid etching on the Mode I fracture of shale was investigated in this study. It was found that cyclic thermal shock severely degrades the strength and fracture toughness of shale, while high-temperature acid etching treatment improves the fracture toughness. These findings are valuable for optimizing process parameters to reduce initiation pressure in deep shale formations.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Liaojun Yao, Mingyue Chuai, Zhangming Lyu, Xiangming Chen, Licheng Guo, R. C. Alderliesten
Summary: Methods based on fracture mechanics have been widely used in fatigue delamination growth (FDG) characterization of composite laminates. This study proposes appropriate similitude parameters to represent FDG behavior with different R-ratios.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Zesheng Zang, Zhonghui Li, Yue Niu, Shan Yin
Summary: This study conducted experiments and recorded signals to investigate the fracture behavior and damage evolution characteristics of coal samples. The results showed that as loading proceeds, the stress, electric potential (EP), and acoustic emission (AE) values increase, and EP and AE signals are excited when stress drops. The fracture behavior of coal samples is altered by flaw inclination, and the destruction mode becomes increasingly complicated. The damage evolution characteristics of coal samples can be evaluated and analyzed by defining the coefficient of variation (CV value) of EP and the b value of AE.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Clotilde Berdin, Nathalie Prud'homme
Summary: In this study, zirconia layers with different fractions of tetragonal phase and thicknesses were tested for multi-cracking behavior. Cracks perpendicular to the tensile direction were observed, showing a blunting effect into the substrate. The ratio of crack spacing at saturation to layer thickness decreased as the layer thickness increased. Unit cell modeling was used to establish a relationship between crack spacing and layer strength, which fell within the bounds of Hu and Evans model and was found to be insensitive to the tetragonal zirconia fraction.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Huadong Zhang, Weichen Kong, Y. H. Liu, Yuh J. Chao
Summary: Williams' series expansion crack tip solution in linear elasticity is modified to include a uniform crack face pressure. Practical methods to calculate T-stress from near crack tip stresses are outlined. The analytical results are consistent with numerical results.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Jiahao Kong, Haoyue Han, Tao Wang, Guangyan Huang, Zhuo Zhuang
Summary: This paper introduces a phase-field model for polymer foam materials by combining the phase-field method with the crushable foam model. The model is calibrated using experimental data and successfully simulates the fracture processes of polyurethane under different loading conditions. The study is important for the engineering applications of polymer foam materials.
ENGINEERING FRACTURE MECHANICS
(2024)