On obtaining material parameters for general purpose finite element models

In general purpose finite element modeling, constitutive relations are vital because they are expected to represent the behavior of a material at different strains, temperatures and strain rates equally well. In order to add to the applicability of a finite element model, therefore, material parameters appearing in constitutive relations need to be identified in a general manner. This paper uses an illustrative example to show how this may be achieved by means of a multi-objective identification framework. The selected material, constitutive law, and data are, respectively, Ti-6Al-4V alloy, the Johnson-Cook metal-plasticity model, and compression quasi-static and dynamic Hopkinson bar experiments with varying temperature and strain rates [1,2]. The effect of interactions among model parameters is discussed. Independent quasi-static and high-rate shear punch test simulations are also performed and compared to experimental data to verify the viability of the identified parameters. Extensions for further generalization of the identification process are pointed out.