中文摘要：

运用有限元分析方法，对低碳钢表面机械研磨处理（SMAT）过程进行了数值模拟，分析计算了材料表面层的应力和应变分布情况，初步探讨了应变量和应变速率对材料塑性变形机制的影响。结果表明，经SMAT后样品表面发生了明显的塑性变形，其表面层的应变、应变速率和应力沿厚度方向均逐渐减小，这与其微观组织相对应；塑性变形时的应变量和应变速率对于样品晶粒细化和处理后最终晶粒尺寸的大小起重要作用。在系统激振频率为50Hz时，SMAT过程中样品最表面层的应变速率最大可达681s^-1。

英文摘要：

By means of finite element method, surface mechanical attrition treatment（SMAT） processes, such as strain, strain rate and stress of surface layer of the treated sample during the SMAT, were investigated. Effect of strain rate on deformation and grain refinement mechanisms of low carbon steel during the SMAT was also analyzed. It is showed that there exist severe plas- tic deformation evidences in the surface layer, and strain, strain rate and stress gradually decrease along the depth of the treated sample during SMAT, which is in agreement with the microstruc- tures observed in corresponding locations. Strain and strain rate play an important role in the grain refinement process and the resultant grain sizes upon plastic deformation. When the vibra- tion frequency of the system is varied up to 50 Hz during the SMAT, the strain rate calculated is about 681s^-1 on the top surface of the treated sample.