极端冲击条件下脆性破坏的物理机制

Physical Mechanism of Brittle Material Failure under Critical Shock Conditions

对近十年来玻璃和陶瓷介质在极端冲击条件下的实验研究、破坏现象和物理模型进行了总结 ,重点分析了低于Hugoniot应力弹性极限时玻璃介质中的破坏波现象和陶瓷中的拉伸 /压缩损伤过程 ,指出了Rasorenov的表面微裂纹扩展机制和Clifton的相变机制在解释脆性材料破坏过程中的合理性及其不足之处 ;分析了Espinosa的微裂纹多面模型和Partom的自持续破坏波模型在模拟玻璃介质中的破坏波现象时存在的主要问题 ;并指出应力冲量决定损伤的累积 ,由损伤的演化决定玻璃介质中破坏波的传播 。

The experimental investigation, failure phenomena and physical models of glass and ceramics under the critical shock condition are reviewed. A perspective insight is given into the failure wave phenomena in glass and the tension/compression damage in ceramics below the Hugoniot elastic limit ( σ HEL ). The applicability and shortcomings are pointed out of surface microcracking mechanism by Rasorenov and phase transition mechanism by Clifton in explaining failure process of brittle materials. The principal problems are cleared out in describing the failure waves in glass by use of Espinosa's microcracking multi plane model and Partom's self sustaining model. In this paper it is proposed that the stress impulse determines the accumulation of damage in glass and the damage evolution controls the propagation of failure waves in the medium, it is noted that the failure delay phenomenon is characterized by introducing Headviside function into the damage evolution equation.