Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 21, 2020 - September 23, 2021
From the low-cycle fatigue test and its in-situ observation by the synchrotron radiation CT, we confirmed that the fatigue crack was initiated by the simultaneous breakage of a number of Si particles, that is, the chain fracture of hard particles. Focusing on this fracture process, we conducted the large-scale finite element analyses to simulate the sequential failure of Si particles by deleting the particle which has the highest first principal stress. In this simulation, we employed two-step analyses: global and local zooming analyses. The global model consists of the voxel elements to include as many inclusion particles as possible. The local model consists of the tetrahedron elements to represent the accurate geometry which improves the accuracy of stress evaluation through the zooming analysis. The sequential failure analysis was performed for two sites: the crack initiation site and a site around the solely broken Si particle far from the initiation site. As a result, the maximum first principal stress kept a high value and the number of highly stressed particles did not decrease during the sequential failure in the crack initiation site, although the maximum stress and the number of highly stressed particles both decreased in the far site from the crack initiation. This result is consistent with the experimental result and proved the chain fracture mechanism of Si particles.
