Numerical study on the size effect in the ultra-thin sheet's micro-bending forming process
Numerical study on the size effect in the ultra-thin sheet's micro-bending forming process
复制标题
DOI：
10.1016/j.msea.2007.11.101
复制
发表时间：
2009-01
期刊：
影响因子：
6.4
通讯作者：
Lemin Li;Q. Zhou;Y. Zhou;J. G. Cao
中科院分区：
文献类型：
--
作者：
Lemin Li;Q. Zhou;Y. Zhou;J. G. Cao
尺寸效应是金属微成形技术发展中最具挑战性的问题，提出了理解尺寸效应的迫切要求。本文基于应变梯度塑性的概念，对超薄板微弯成形过程中的尺寸效应现象进行了数值研究。结果表明，板材厚度对板材的力学响应有很大影响。当薄板厚度接近材料特征长度时，挠度曲线和应力应变分布与经典塑性理论预测的结果有很大不同。当板材厚度远大于材料特征长度时，尺寸效应消失，结果与经典塑性理论预测的结果基本一致。因此，在微成形过程中，工艺参数的选择应考虑尺寸效应。
Size effect is the most challenging problem for the development of metal micro-forming technologies, and the urgent requirement for understanding the size effect is presented. In this paper, size effect phenomena in the ultra-thin sheet's micro-bending forming process are studied numerically based on the concept of strain-gradient plasticity. Results show that the sheet's mechanical response is strongly influenced by the sheet thickness. When the sheet's thickness is close to the material characteristic length, the deflection curve and the distributions of stress and strain are greatly different from those predicted by classical plasticity. If the sheet's thickness is considerably larger than the material characteristic length, the size effect disappears and the results tend to be the same as those predicted by classical plasticity. Hence, in the micro-forming process, the size effect should be taken into account in the selection of the technical parameters.