Comparison of Johnson-Cook Model and an ISV Plasticity Damage Model in Penetration Simulation

Abstract

This paper compares Johnson-Cook model and an internal state variable (ISV) damage model developed by Bammann and Horstemeyer in simulating damage behavior of materials during penetration process. Bammann and Horstemeyer’s ISV damage model employs internal state variables and their rate equations to capture the evolution of internal states of materials during high speed impact and penetration. From the calculated internal states, observable states or global penetration and perforation response of materials can be decided. Compared to the JC model, the ISV damage model closely reflect history of materials’ mechanical behavior during the penetration and perforation process. Moreover, the damage model links the global impact and penetration performance of the materials to their microstructural evolution, such as the nucleation, growth, and coalescence of micro voids and cracks. Therefore, it possesses an enhanced predicative capability for high speed impact, penetration, and perforation problems. To demonstrate the reliability of the presented ISV model, that model is applied for studying penetration mechanics of aluminum and the numerical results are validated by comparing with simulation results yielded from the Johnson-Cook model as well as analytical results calculated from an existing theoretical model.