铝合金型材拉弯成形回弹的有限元模拟

Springback analysis for stretch bending of aluminum profile

对回弹进行有效预测与控制是提高型材弯曲件精度的关键.为了分析轴向作用力对拉弯制件回弹的影响,采用动力显式有限元仿真软件Pam-Stamp2000对中空矩形截面铝型材AA6082(T5)转臂式拉弯成形过程进行了数值模拟,并与实验结果进行了对比.结果表明:增加预拉可以减小制件的回弹,但预拉达到一定水平后,继续加大预拉力对减小回弹将基本不起作用;当预拉不充分时,增加补拉同样有利于减小制件的回弹,但过大的补拉力对于减小回弹几乎没有任何帮助.可见,型材拉弯成形制件的回弹不仅与加载顺序及加载程度密切相关,同时也受到材料应变硬化特性的制约.

Stretch-wrap bending of rectangular hollow section aluminum profile AA6082(T5) is simulated numerically with the dynamic-explicit finite element simulation software Pam-Stamp2000. Which is focused on the effect of pre-stretching and post-stretching on reduction of springback. The main tendencies of sprinback observed in experiments are well represented in the numerical analysis. Springback shows a decreasing tendency with increase of pre-stretching, however, when pre-stretching elongation reaches a certain value, the effect of applying additional pre-stretching to reduce the amount of springback almost vanishes. When pre-stretching is not enough, increase of post-stretching can also reduce springback, but too much post-stretching will have hardly any benefit on further reduction of springback. The main parameters influencing the springback are the strain hardening properties of the material, the amount of pre-stretching and post-stretching as well as the tensile sequences.