Dynamic Tensile Behavior of Dual Phase Steel Using Digital Image

Fuel efficiency of vehicles and increase the safety of passengers lead the automotive industry to incorporate of new materials and technologies into today's vehicles. Advanced high strength steels offer excellent strength and formability properties. One the main important grade of advanced high strength steels is Dual Phase (DP) steel. Dynamic behavior of the material must be considered in crashworthiness studying of the vehicles. In this paper the dynamic tensile characteristics of Dual Phase (DP) steel sheets at low and moderate strain rates ranging from 0.0009 s-1 to 0.1 s-1 are investigated. All the tests were performed by the tensile test machine with the cross-head speed of 4 mm/min and 500 mm/min. Digital Image Correlation method was employed to study the strain rate sensitivity, stress-strain curves and the strain fracture of DP800. In the numerical analysis, an isotropic hardening model with rate dependence was used to predict the experimental behavior. The fracture behavior of the material was simulated by using of ductile criterion model. The local strains in fracture zone obtained by the experiments and finite element analysis are compared and good agreement is obtained.