金属细丝扭转尺寸效应及其有限元模拟研究

RESEARCH ON THE SIZE EFFECT DURING THE THIN-METAL-WIRE TORSION AND ITS FEM SIMULATION

尺寸效应是金属微细塑性成形研究中的热点和难点之一。目前采用应变梯度理论能对金属变形过程尺寸效应的影响进行较好的分析,但是将之应用于金属微细塑性成形过程分析及其有限元模拟的研究并不多。因此将应变梯度强化引入材料本构模型,深入剖析在金属细丝扭转过程,应变梯度强化与应变强化之间的关系,探讨应变梯度对流动应力起主要强化作用的区间。同时基于Abaqus有限元软件平台,编制可实现应变梯度计算的单元子程序,模拟验证现有文献中细铜丝扭转实验,模拟结果与实验基本吻合。

Research about the size effect had been the major subject in the research of micro forming for the past few years. By now, the strain gradient theory had been used well in explaining the size effect, but there was little research about the metal micro-forming basing on the strain gradient theory. Further research about the strain gradient hardening on the flow stress during the thin-metal-wire torsion was conducted. And a new user-defined subroutine considering the strain gradient hardening was coded basing on the finite element software： Abaqus. Using the subroutine, the simulation of the thin-copper-wire torsion experiment was conducted to study the influence of the strain gradient hardening during the torsion. Compared with the experiment, the simulation results matched well with the experiment.