高速变形材料塑性及JC和MSV断裂准则的表达能力

Material Plasticity under Super-High Deformation Rate and Performance of JC and MSV Fracture Criteria

研究了超高变形速率下材料的塑性(延性)演化规律和断裂行为。通过45钢、Ti-6Al-4V、Al2024-T3和Al2024-T351四种材料高速变形数据,考察了JC断裂准则和MSV断裂准则对于高应变率下材料失效行为的表达能力。研究发现,JC断裂准则中材料的失效应变随着应变率的增加单调增大,JC断裂准则能够描述中低应变率范围内(0-10~3/s)材料的断裂情况;对于应变率更高(≥10~4/s)情况下材料的断裂行为,JC断裂准则不能描述。材料的MSV在约10~4/s时突然增大,MSV断裂准则能够描述超高应变率下材料的断裂趋势。

To explore material deformation and fracture mechanism under super-high strain rate, discussion was con- ducted to investigate material plasticity under super-high deformation rate. The ability of JC fracture criterion and MSV frac- ture criterion to express material fracture behavior under high and super-high strain rate by taking 45# steel, Ti-6AI-4V, A12024 -T3 and A12024 -T351 as reference materials was verified. It was found that material failure strain increased with the increase of strain rate,JC fracture criterion can describe material fracture behavior between strain rate 0 to 103/s,but can not for much higher strain rate（ ~ 104/s）condition. MSV increases abruptly around strain rate 104/s, MSV fracture cri- terion can express qualitatively material fracture tendency under super-high strain rate.