Investigation on Elastic Behaviour of DP800 Dual Phase Steel

摘要

The elastic relaxation behavior of dual phase steel DP800 is studied in this investigation, based on experimental and numerical methods the true stress-true strain curve obtained from a standard uniaxial tensile test differs according to angular rolling direction The relationship between true stress and true strain are presented in the form of power law equation. This form of material constitutive model shows that the strength coefficient and strain hardening exponent vary significantly in describing the nonlinear true stress-true strain relationship of the material. Finite Element (FE) calculations with Belytschko-Lin-Tsay shell element formulation are performed using the non-linear FE code Ls-Dyna to predict the plastic deformation of the material. Power Law Isotropic Plasticity criterion is adopted for these numerical analyses. The local strains in plastic deformations zone and true stress-strains characteristics obtained by experiment are compared. Using the same parameter the simulation was applied in different modes which are known as Isotropic Elastic-Plastic Model and Piecewise Linear Isotropic Plasticity Model providd in Ls-Dyna simulation for comparison. In general, good agreement in results is obtained between Power Law Isotropic Plasticity Model is obtained compared to Isotropic Elastic-Plastic Model and Piecewise Linear Isotropic Plasticity Model. It is demonstratedthat the behavior of the strain and the Power law criterion can be determined from uniaxial tensile test with the aid of non-linear FE analyses.