Abstract
A new dynamic stress-strain rate type constitutive model for mixed hardening material has been developed using evolutional Gurson type yield function for solving problems of rigid plastic porous materials. During the plastic process of ductile materials in many engineering problems, the failure of materials is mainly induced by the damage behaviors such as the nucleation of micro void, their evolutions and the coalescence. With the aid of some concept of parameters and formulations, such as generalized triaxiality function in stress space, void fraction, effective stress with micro void interaction and void induced effective strain rate, generalized triaxiality ratio and so on, the dynamic void evolutional process of mixed hardening material has been analyzed in detail. Based on the above constitutive law the rigid-plastic finite element modeling and the FEM computer system including the damage evolutional process have been developed. The micro damage phenomena caused by collision of a flying projectile on to a target is simulated in order to reveal the applicability of the method. The inherent relations between the penetration and perforation process, and damage evolution process during the impact of target plate by projectile are revealed.
