Abstract

The elastic-plastic multi-scale finite element method is formulated and applied to the analysis of the fracture test on compact tension specimen with 304 stainless steel. The calculation was carried out on ABAQUS. The elastic-plastic stress field near the crack tip, and the plastic zone are first determined in sufficient detail. The numerical results show that elastic-plastic stress singularity exists at the crack tip. Then, the critical updated Mises stress intensity factors of compact tension specimen and middlecrack tension specimen with 304 stainless steel are determined by using the fracture test results of the specimens. It is found that the magnitudes of these two critical updated Mises stress intensity factors are related to the specimen and differ greatly, they cannot be regarded as a characterization of the inherent fracture toughness of 304 stainless steel. This study shows that: the elastic-plastic multi-scale finite element method can offer the numerical results of the mechanical parameters of the singular stress field near the crack tip accurately enough, it provides an analytical basis for the development of fracture criteria of elastic-plastic fracture mechanics; combined with the fracture experiments of the cracked specimens, the elastic-plastic multi-scale finite element method provides an effective numerical analysis for the experimental verification of elastic-plastic fracture criterion.

Keywords:Multi-scale finite element method; Incremental theory of plasticity; Compact tension specimen; Elastic-plastic stress singularity; Fracture toughness