Rate-dependent behavior and constitutive model of DP600 steel at strain rate from 10-4 to 103 s-1

Uni-axial quasi-static tests at strain rates 10(-4), 10(-3), and 10(-2) s(-1) and dynamic tensile tests at strain rates 500, 1100 and 1600 s(-1) have been carried out to study the mechanical behavior for the dual phase steel 600 (DP600 steel) used in the automotive industry. The stress-strain curves of DP600 steel in the strain-rate range from 10(-4) to 1600 s(-1) have been obtained. The effects of the strain rate on yield phenomenon and rate-dependent mechanical behavior are discussed. A plastic flow law based on the Johnson-Cook rate-dependent constitutive model was proposed to describe the mechanical behavior of DP600 steel sheet in the strain-rate range from 10(-4) to 10(3) s(-1). The new rate-dependent constitutive model for DP600 steel at various strain rates was developed and implemented into the ABAQUS by using the user material subroutine VUMAT. The tensile deformations for a three-dimensional solid element at low and high strain rates were simulated. The numerical simulating results at the six strain rates are in excellent agreement with the experimental data, which illustrates that the new constitutive model can describe the mechanical behavior for DP600 steel at low and high strain rates perfectly. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.