2022 年 62 巻 1 号 p. 191-199
The elastoplastic deformation behavior of a 440-MPa hot-rolled steel sheet subjected to many linear stress paths is precisely measured using biaxial tensile tests with cruciform specimens (ISO 16842: 2014) and multiaxial tube expansion tests to determine appropriate material models for finite element analysis (FEA). It is found that the Yld2000-2d yield function correctly reproduces the contours of plastic work and the directions of the plastic strain rates. Differential hardening (DH) models are determined by varying the values of the exponent and material parameters for the Yld2000-2d yield function as functions of the reference plastic strain. Moreover, a finite element analysis of hole expansion in the test material is performed. The DH model correctly predicts the minimum thickness position, which matches the fracture position of the specimen in the experiment.
