基于LS-DYNA软件平台对6061-T6铝合金汽车前碰撞横梁拉弯成形过程中的回弹量进行了模拟;研究了预拉力、补拉力和摩擦因数对回弹量的影响,并对拉弯模具弧面进行修正以补偿回弹量,最后进行了试验验证.结果表明:预拉力的变化影响型材横截面内的应力分布情况,随着预拉力增大至型材横截面积与材料屈服强度的乘积(Aσs)时,回弹量减小;在一定范围内,随着补拉力从Aσs逐渐增大,有利于减小拉弯成形件的回弹量;摩擦因数越大,回弹量越大;通过修正模具的弧面尺寸可以补偿回弹量;模拟结果与试验结果吻合较好,所建立的有限元模型能准确预测汽车前碰撞横梁的拉弯成形回弹量.

The springback during stretch bending process of the 6061-T6 aluminum alloy vehicle bumper was simulated based on the LS-DYNA software platform.The effects of pretension,post-tension and friction coefficient on the springback were investigated.The stretch bending mold profile was modified to compensate for springback,the verification experiments were performed.The results show that change of the pretension influenced the stress distribution in the cross section of the profile.When the pretension increased to the product (A·σs)of the profile cross section area and the material yield strength of the stretch bending parts,the springback decreased.With the gradually increasing post-tension from A·σs in a extent,it was benefited to decrease the springback of the stretch bending parts.The larger the friction coefficient,the larger the springback.The springback could be compensated through modifing the mold globoidal size.The simulated results were in agreement with the experimental results.The established finite element model could accurately predict the stretch bending springback of the vehicle bumper.