Calibration of the constitutive equations for materials with different levels of strength and plasticity characteristic based on the uniaxial tensile test data

Today finite elements method (FEM) modeling and calculation are used for analysis current state and forecasting reliability lifetime period of components and constructions. Essential issues for correctness of obtained results in FEM analysis are: proper interpretation of boundary conditions and right constitutive equation of material in terms of high stresses and strains. Standard procedure obtaining of material constitutive relation directly from experimental tensile test data does not proper result for every type of material. Method of constitutive equation creation for elastic-plastic material for a high level of plasticity based on data obtained during tensile test is presented. The proposed calibration method was verified on materials with different levels of strength and plasticity characteristics: S355JR and 42CrMo4 steels and ADI cast iron. Plastic deformation level, triaxiality stress state parameter and Lode factor were taken into account during created of the constitutive equation.