机械喷丸对7A52铝合金焊接接头残余应力改善的有限元模拟

Finite element analysis of shot peening treatment to improve welding pesidual stress of 7A52 aluminum alloy

分别建立了7A52铝合金双丝MIG焊热力耦合计算模型及GCr15钢弹丸撞击7A52铝合金试板的三维简化模型.在不影响计算结果的前提下,适当增大了焊接试板弹丸撞击区域网格尺寸.获得了焊接接头的残余应力场计算结果,并分析了弹丸大小、弹丸速度对喷丸残余应力场的影响规律,进而优化了喷丸参数.在此基础上利用隐式求解器与显式求解器之间的数据传递方法,将铝合金试板焊后残余应力场与喷丸处理过程进行耦合计算.结果表明,焊后试板喷丸处理对焊缝及近缝区表面残余应力、试板厚度方向残余应力分布状态均有较明显改善.

A coupled thermal-mechanical FE( finite element) model of 7A52 aluminum alloy TANDEM welding and a simplified FE model for single-GCr15 shot impact simulation were developed separately. The element size of welded joint region which was impacted by shots was amplified reasonably.Based on the premise,the numerical results would not be affected by this simplification. The computational results of welding residual stress were obtained,and the influences of ball's dimension and impact velocity on induced residual stresses were analyzed subsequently. On the basis,the coupling computation of residual stress field in aluminum alloy welded joint and the shot peening treatment were performed by means of data transfer based on the standard and explicit solver of ABAQUS software.The computational results showed that the residual stresses on the surface and depth direction of welded joint were improved remarkably after shot peening.