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Comparison of multiaxial fatigue damage models under variable amplitude loading
Hong Chen,De-Guang Shang,Yu-Jie Tian,Jian-Zhong Liu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11
Based on the cycle counting method of Wang and Brown and on the linear accumulation damage rule of Miner, four multiaxial fatigue damage models without any weight factors proposed by Pan et al., Varvani-Farahani, Shang and Wang, and Shang et al. are used to compute fatigue damage. The procedure is evaluated using the low cycle fatigue experimental data of 7050-T7451 aluminum alloy and En15R steel under tension/torsion variable amplitude loading. The results reveal that the procedure is convenient for engineering design and application, and that the four multiaxial fatigue damage models provide good life estimates.
Geng Hou,De-Guang Shang,Lin-Xuan Zuo,Lin-Feng Qu,Ming Xia,Yi-Er Guo,Xiang Yin,Shao-Dong Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1
Fatigue test of a needled C/SiC composite with a notch under tension-tension cyclic loading was completed, and the main fatigue crack propagation curve of the needled composite was obtained by the in situ observation of the fatigue process. By analyzing the influence of the failure number and distribution on the tensile loading subjected by 0° fiber bundles, the relationship between the main fatigue crack propagation and the distribution of 0° fiber bundles in the needled composite was established. By observing the fracture microstructure (especially the distribution of 0° fiber bundles) of the needled composite through scanning electron microscopy, the reasons for the varying fatigue resistance of different notched specimens were also explained. In addition, acoustic emission (AE) was also used to analyze the AE energy characteristics during the fatigue crack propagation process of the needled composite.
Effect of single-pulse laser irradiation energy on healing fatigue damage for copper film
Chong-Gang Ren,De-Guang Shang,Lu Wang,Yu-Bo Guo 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4
In this study, the optimum laser process parameter was determined by fatigue experiment for the treated copper film specimens withthickness of 25 μm. The mechanism of healing fatigue damage was analyzed by the numerical simulation of temperature field induced bylaser irradiation and the microstructure changes on the surface of specimens. The results showed that the fatigue damage of copper filmspecimens can be healed when the applied energy density is in the range from 4×10³J/m² to14×10³ J/m², and the fatigue life can increaseby about 5 times when the applied energy density is 7×10³ J/m². The process hardening and grain refinement in the surface layer aremainly responsible for extending fatigue life.
Finite element simulation of unconstraint vibration treatment for fatigued copper film
Hai-Meng Zhang,De-Guang Shang,Shuai Lv,Xiao-Dong Liu,Yu Zhang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.9
In this paper, in order to investigate the residual strain relief in the fatigued copper film with a thickness of 33 μm, an unconstraint vibration treatment process was simulated by finite element (FE) method. The experimental processes, including fatigue and unconstraint vibration processes, were simulated. The fatigue process for the original specimen and the vibration process for the damaged specimen were analyzed by the static and transient dynamic analysis, respectively. The simulation results showed that the unconstraint vibration treatment can lead to the residual strain of the fatigued copper film to be reduced and redistributed. The effect of the vibration parameters on the treatment effectiveness was analyzed by the different fatigue experiments and unconstraint vibration treatments, and the results showed that the FE simulation results are in agreement with the experimental observations.