超並列有限要素解析によるアルミニウム鋳造合金の介在物群まわり繰り返し弾塑性応力評価

抄録

Fatigue crack is initiated by the fracture of Si particles or debonding of Al-Si interface in low-cycle of cast aluminum alloys. To fully utilize the synchrotron X-ray CT image and evaluate the precise stress and strain in the microstructure under a cyclic loading, a large-scale finite element model was constructed based on the CT image. The outer surface, pores, Si particles and intermetallics were fully considered in this model. The voxel finite element was employed for simulation with stabilization. The number of finite elements was about 150 million. The analysis and post-processing were performed on the supercomputer by the massively-parallel computing with the domain decomposition techniques. The material and geometrical nonlinearities were considered, and the two cycle of loading was calculated. The result showed that the effect of free surface was predominant on the accumulation of plastic strain in matrix phase and the gradual increase of stress in silicon phase. The availability of massively-parallel computing to the large-scale micromechanical analysis was demonstrated. Moreover, the geometrical analyses of silicon particles were performed, then the correlation between mechanical and geometrical parameters were investigated statistically, where we found that the high stress concentration was occurred on silicon particles with complex shape and ones at the near of which other particle was present.