冲击压缩下准脆性材料含微裂纹损伤的本构模型

Micro-cracks Damage Constitutive Model of Quasi-brittle Materials Subjected to Shock Compression

基于准脆性材料中翼型拉伸裂纹的成核准则,运用细观损伤理论推导了翼型裂纹损伤对材料弹性模量的弱化作用。考虑裂纹扩展对材料动态断裂的滞后效应,建立了动态裂纹扩展准则,并给出损伤演化方程,在此基础上建立了准脆性材料单轴冲击压缩下的动态损伤本构模型。结合氧化铝陶瓷材料独特的力学响应和破坏特性,讨论了模型中微裂纹成核参数、微裂纹尺寸对动态断裂强度的影响,并用该模型计算了单轴压缩下氧化铝陶瓷的应力应变曲线,数值结果与实验结果吻合良好。

Based on the nucleation criterion of wing tension crack of quasi-brittle material, the decrease of elastic moduli of material resulted from the crack damage are derived utilizing micro-mechanics theory. The influence of crack growth velocity on dynamic failure toughness is considered in dynamic growth criterion. The damage constitutive model for brittle materials subjected to compressive loading is developed. The influence of parameters of micro-cracks nucleation, initial crack size on dynamic failure strength are discussed. The stress-strain curves under high strain rate for alumina are compared to the experimental results and a good correlation is obtained.