爆炸和冲击载荷下金属材料及结构的动态失效仿真
摘要
Studying the dynamic failure laws of metal materials and structures under blast and impact loading through numerical simulation is of great significance for characterizing the damage effects of explosive shock and designing novel impact-resistant structures. The metals’ failure under strong dynamic loading involves multiple complex physical processes, such as the large deformation, the thermo-mechanical coupling and the material state changes. These complex physical processes bring great challenges to numerical simulation, including the geometric description of complex dynamic failure modes such as cracks and shear bands, the determination of failure criteria and the description of plasticity-damage coupled evolution, etc. In response to these challenging issues, a theoretical and computational thermal elasto-plastic phase field model was established based on the energy variational principle to describe metals' dynamic failure. For the model, a unified description of the crack and shear band was realized, and an efficient solving strategy of explicit finite elements was proposed. The model was further applied to 3 typical metals’ dynamic failure issues under blast and impact loading: the transition between brittle and ductile failure modes of metals, the self-organization of adiabatic shear bands (ASBs) and the transition between failure modes of thin-walled disks under shock waves. The results verify the accuracy of the theoretical model and the robustness of the computational model. This work lays a foundation for the subsequent development of damage assessment and protective structure design against blast and impact loading based on simulation.