中文摘要：

微细观结构对材料动态损伤、破坏的影响是目前国内外力学领域的研究热点之一．基于相关文献的实验结果，通过理论分析，给出了一个新的反映晶粒尺度效应的孔洞成核模型，并将其耦合到延性金属材料层裂损伤模型中．采用数值方法分析了晶粒尺度对高纯铜材料层裂损伤演化过程的影响．计算结果显示：随着材料平均晶粒尺度的增加，自由面速度回跳点降低，回跳后速度曲线的斜率增加；损伤材料内部的孔洞数减少、平均孔洞尺寸增大．计算结果与相关文献所报道的实验分析结果定性上符合较好．该结果对于层裂损伤的深入研究具有一定的启发性．

英文摘要：

In the paper, we propose a new nucleation rate function, which combines grain size, and models for nucleation and growth of voids in a ductile polycrystalline metal. The proposed model is used to analyse the effects of grain size on the dynamic tensile damage of high purity Cu samples with different grain sizes. Numerical results show that pull-back minima and void number decrease with grain size increasing, slope after pull-back and average void diameter increase with grain size increasing. The computed results are in qualitative agreement with experimental results.