Constitutive Equations of Sheet Stamping Steel Based on DIC Measurement

Abstract Digital image correlation (DIC) is a full-field and non-contact technique for the measurement of displacement and strain. It has considerately high precision for measuring large deformation. Based on the experimental data of true stress-strain measured by DIC combined with the data from a tensile test machine, the methodology for establishing a constitutive model for sheet stamping steel is presented in this paper. The procedure is demonstrated by developing the constitutive equations for the DP600 sheet metal with a cold rolled advanced high-strength steel, designed predominately for the automotive industry, with enhanced ductility and formability. To verify the constitutive equations, a force-displacement diagram is simulated by finite element analysis (FEA). A comparison of force-displacement diagram obtained by FEA and the data from the tensile test machine shows that the method for establishing the constitutive equations for stamping steel presented in this paper is reliable and has reasonable accuracy. As a material constitutive model, the establishment of constitutive equations of stamping steel provides the experimental validation for FEA. It is particularly valuable when evaluating non-linear numerical simulation of the stamping process of structural parts with complicated geometry.