Numerical Determination of Parameters of Johnson-Cook Material Model

Abstract

In the analysis of structures that are subjected to dynamic loads, knowledge and understanding of the influence of strain rate on the deformation mechanism of complete constructions are very important. Performing experiments in areas like automotive and military industry, aircraft production, metal cutting and forming and others are quite complicated and expensive, so the numerical simulation procedure is justified in the analysis of the dynamic behavior of structures with large deformation rates. Johnson-Cook material model has appeared during the eighties and was primarily intended to shock, ballistic penetration and explosives. The model proved to be fairly handy, so that is encountered in the application of scientific institutions, military laboratories and other entities that have to deal with large deformation at different deformation rates. Properly definition of the constitutive model and his parameters that best describes the different material or group of materials is a major problem in the numerical analysis. This paper represents numerical procedures for determination of these parameters which involves several different tests that isolate certain groups of parameters, and this is one of the main advantages of Johnson-Cook material model.