Experimental and theoretical plasticity analyses of steel materials deformed under a nonlinear strain path

Abstract

In this study, the macroscopic mechanical behavior of extra-deep drawing quality (EDDQ) and transformation-induced plasticity (TRIP1180) steels subjected to nonlinear-strain-path modes of deformation was investigated. For the nonlinear-strain-path experiments conducted on steels, an optimized experimental approach was proposed for deforming the material using two linear loading segments with a single abrupt change in the strain path. A specific medium-scale uniaxial tension specimen was designed for the pre-strain stage. The advantage of this approach over existing methods was that it enabled testing of various strain-path changes for steels with strengths greater than 1 GPa within a reasonable load range. In addition, this approach produced a more uniform strain field, which is important during the pre-strain stage. After the uniaxial pre-strain, various specimens were extracted from the uniformly deformed area for use in experiments involving changes in the strain path. To predict the material behavior under nonproportional loading, the homogeneous anisotropic hardening (HAH) distortional plasticity model was selected. The predictions of the HAH model were compared with the corresponding experimental results to assess the suitability of the constitutive model to accurately reproduce the observed effects of strain-path changes.