拉深筋对板材力学特性的影响

板材通过拉深筋时经过弯曲与反弯曲变形,塑性性能发生较大的变化,必然影响板材的后续成形。该文利用拉深筋结构影响实验及后续性能测试实验,对通过拉深筋后板材的力学性能进行研究,分析了半圆形拉深筋的结构参数——筋圆角半径和拉深筋高度对板材变形的影响。结果显示,板材通过拉深筋时产生预变形,预变形量与拉深筋结构有关,随筋圆角半径增大,预变形量降低;随拉深筋高度增大,预变形量增大。与未变形板材的性能相比,通过拉深筋后板材的力学性能发生了很大的变化,而且这些变化与预变形量有关,随预变形量增大,屈强比增大,断裂延伸率呈指数下降,板材的后续塑性变形能力显著降低。

The influence of drawbead upon mechanical property of sheet

Plastic property of sheet is changed rather greatly while it going through the drawbead because of bending and unbarnding,which necessarily affect its subsequent forming.The tests of drawbead structure influence and the subsequent performance of the sheet are performed to investigate the mechanical property of the sheet after it goes through drawbead,and also the influences of semicircle drawbead structure parameters,the round corner radius and the heighten of drawbead on deformation of sheet are analyzed.The results show that,the pre-deformation is caused by the deformation while the sheet going through drawbead,and the pre-deformation depends on the structure of drawbead.The pre-deformation decreases as the round corner radius increases,the pre-deformation increases as the heighten of drawbead increases,and the subsequent forming characteristics of sheet going through drawbead are remarkable different from undeformed sheet and these differences heavily depend on the pre-deformation.With increases in pre-deformation,the yield ratio increases,but the subsequent elongation exponential decreases.These means deformability of the sheet is significant reduced.