Research on material model and parameters of metal thin plate under close-in explosion load

Abstract. The Johnson Cook material model and Cowper Symonds material model are commonly used models to describe the dynamic response of metal materials. To obtained the parameters of brass sheet materials under close-in explosion loading, close-in explosion loading on brass sheets experiments with different equivalent explosives were carried out, and then the displacement-time curve of center point of the sheet was measured. Besides, a joint simulation of genetic algorithm and finite element simulation program was developed to automatically calibrate the parameters of Johnson Cook material model and Cowper Symonds materials model. In addition, simulation of close-in explosion loading experiments on brass sheets were carried out. Meanwhile, the theoretical calculation was taken. The results show that the theoretical values, simulation values, and experimental values have good consistency. Under different conditions of explosion loading, the maximum deflection errors from JC model simulation and CS model simulation are 4.46% and 4.84%, respectively. Compared to the JC model, the strain rate sensitivity of the CS model is more significant. As the load increases, the maximum deflection value calculated by the CS model is larger than that of the JC model. The material model parameters obtained from the research have a high accuracy. The research provides a new method for calibrating the material model parameters of metal sheets, which has certain reference value for damage assessment and designation of protective structure.