基于有限元模拟的平行双通道挤压与单通道转角挤压的仿真比较

Simulation comparison of parallel double-channel extrusion and single-channel angular extrusion based on finite element analysis

以比较两类模具对挤压效果影响为目的,通过Deform-3D塑性变形模拟软件分别对两道次下单通道ECAP和单道次平行双通道ECAP过程进行了模拟,分析了挤压冲头的载荷行程曲线和试样的等效应力应变情况。结果表明,转角区域45°斜截面产生剪切变形,随着挤压的推进,试样边缘小面积高应变区会不断扩充直到形成新的平面应变区。尽管平行双通道挤压理论上相当于单通道挤压两道次的效果,但前者比后者提高了6倍轴向应变量,相应地平行双通道挤压后的试样总体等效应变比两道次单通道挤压提升了约35%,从而获得了更好的应变强化效果,同时凸模载荷提升了2倍,达到了255 kN,对模具材料强度有更高的要求。

For comparison of extrusion effect made by two kinds of dies,the extrusion processes of two-pass single-channel ECAP and onepass parallel double-channel ECAP were simulated respectively by Deform-3D. The load-stroke curves of extrusion punch and equivalent stress and strain of samples were analyzed. The results show that shear deformation takes place in 45°angular district,and small area and high-strain sections on sample edges expand constantly until the new plane strain sections emerge with the extrusion. Even though the effects of parallel double-channel extrusion and two-pass single-channel extrusion are the same in theory,the former is improved six times in axial strain deformation than the latter,and correspondingly the total effective strain increases about 35%. Therefore,a better strain hardening effect is obtained. Meanwhile,load of punch increases twice up to 255 kN,whicch results in a higher requirement on die material strength.