Material Modeling of 980 MPa Dual Phase Steel Sheet Based on Biaxial Tensile Test and In-plane Stress Reversal Test

Abstract

Uniaxial and biaxial tests were conducted to investigate the deformation behavior of dual phase steel sheet with a tensile strength of 980 MPa. Detailed measurements were made of the contours of plastic work and the directions of plastic strain rate at different levels of work-hardening for linear stress paths in the first, second and fourth quadrants in the principal stress space. Cruciform specimens were used in the first quadrant and the pure shear yield stresses in the second and fourth quadrants were measured using combined tension-compression tests. The most appropriate anisotropic yield function for the material was determined by comparing the measured data with those calculated using selected yield functions. In-plane compression tests were also performed using the comb-shaped dies proposed by one of the authors. The measured work contours and directions of plastic strain rates were in good agreement with those calculated using the Yld2000-2d yield function with an exponent of 4. The stress-strain curves measured for the in-plane stress reversal tests were in fair agreement with those calculated using the Chaboche-Rousselier model; however, this model is not capable of reproducing the nonlinear behavior of the material during unloading.