In this study, elasto-plastic dynamic behaviours of a plate subjected to line-loading by a low-velocity impactor are analyzed. The equilibrium equation associated with the Hertzian contact law is formulated to evaluate the transient dynamic behaviour of the impacted plate. Compared with an elastic analysis, the effects of material plasticity are discussed. In the case of elasto-plastic analysis, it is observed that the impulse decreases, displacements increase and contact time duration is longer than the elastic case. And the time variation of the impacting load is not significant due to the plasticity except at the beginning of impact duration, and the induced stresses of the plate are more realistic.
Interest about impact problems is growing in many technical applications mainly due to safety requirements. Previous studies on a plate impacted by a low velocity impactor has been limited to elastic analysis(Choi, 1990), which is unrealistic in nature since plastic deformations are found in most cases. In this study, elasto-plastic dynamic behaviours of a plate subjected to line-loading by a low-velocity impactor are analyzed to focus on the plasticity effects on the low velocity impact problems. Assuming that the behaviours of the plate are uniform across the width, the plane strain approach is adopted for analyzing the plate. Also, assuming that the impactor is much stiffer than the plate, the impactor is treated as a rigid body. The equilibrium equation associated with the Hertzian contact law is formulated to evaluate the transient dynamic behaviour of the impacted plate(Choi, 1990, Sankar & Sun, 1985, Tan & Sun, 1985). A plain strain finite element formulation and a central difference method are employed for space and time domains, respectively. In order to consider the effect of plasticity, the plastic flow rule associated with von Mises yield criterion and an isotropic hardening property are applied.
