Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 23, 2018 - November 25, 2018
Crack growth in the elastic-plastic fracture is an important issue for structural integrity, because seismic wave causes low cycle fatigue in the engineering structure. Many researchers have worked for many experiments and numerical analyses, however general criterion cannot be developed until now. In order to develop a three-dimensional fracture criterion, the fully automated and state-of-the-art FE crack growth simulation should be realized. CT specimen is used for evaluation of crack propagation under Mode I condition. Fatigue experiment, tension and compression experiment, was conducted. An FE analysis is also computed based on the experiment. Quantitative trends of FE analysis result agree with the experimental result well. Maximum load of FE analysis is higher than the experimental one. This is reason why measurements of crack front shapes and material nonlinearity are not enough to reproduce load and load line displacement. The obJectives of this research are to obtain a strain range for determination of cyclic stress-strain relation and precise fracture surface including crack front shape, share-lip and unstable fracture surface. Chaboche model isn't enough for reproduction of low cycle fatigue using CT specimen, because Chaboche model agrees with an experimental stress-strain relation in a limited strain range. Therefore, as Chaboche model is used for the simulation of low cycle fatigue, we have to find an applicable strain range to determine coefficients of Chaboche model.
