Study On Temporal And Spatial Evolution Of Dynamic Stress And Corresponding Failure Modes

The research interest on the failure mode of structure under dynamic load such as explosion and impact is mainly from military application.In most cases,the damage and destruction of weapons and armor structures is one of the most important processes and the damage process is directly related to the armor and weapon effects.Thus the study on the dynamic stress and impact compression failure modes can provide the theoretical basis for the design and optimization of weapons and protective armor.This paper focuses on the plate and cylinder structure.This paper has elaborated on the modified elastic wave theory which established by Liu's research group.To focus on the basic structural characteristics of the elastic stress wave,the plate under compressive impact was studied.The modified theory was simplified in this situation and the surface effect was concerned by using discontinuity surface theory.The propagation of stress wave in plate has been studied through numerical simulation method.The propagation and reflection of the independent voluminal wave and half coupling deviatoric wave in the plate were found.Two failure modes in the plate were found: the compressive shear failure in the loading surface and the spall near the free surface.Whereafter,the modified stress wave theory was written into the cylindrical coordinate system and applies to an infinitely long cylinder,where the surface effect was also established.Also,the numerical simulation of the infinitely long cylinder under explosive and implosive loading has been carried out.Burst damage under the explosive loading and the spiral damage in the inner surface under the implosive loading were predicted and analyzed.