爆炸和冲击载荷下金属材料及结构的动态失效仿真

Dynamic Failure Simulation of Metal Materials and Structures Under Blast and Impact Loading

通过数值模拟研究爆炸冲击载荷下金属材料和结构的动态失效规律,对表征爆炸冲击毁伤效应及设计新型抗冲击结构有重要意义.强动载下金属材料失效涉及材料大变形、热力耦合、材料状态变化等多个复杂物理过程,给数值仿真带来了极大挑战,其中包括裂纹、剪切带等复杂失效模式的几何描述、动态失效准则的确定、塑性与损伤耦合演化的描述等问题.针对这些挑战性问题,基于能量变分建立描述金属动态失效过程的热弹塑性相场理论和计算模型,实现了断裂与剪切带失效模式的统一描述,并提出了其显式有限元高效求解策略.进一步将该模型应用于爆炸冲击载荷下金属脆韧失效模式转变、绝热剪切带(ASBs)自组织及冲击波作用下薄壁圆盘失效形式转变三个典型金属动态失效问题,验证了理论模型的准确性及计算模型的稳健性.该工作为后续开展基于仿真的爆炸冲击毁伤评估及防护结构设计研究奠定了基础.

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.