A-UIT处理对7075铝合金焊接应力影响的数值模拟

利用ABAQUS有限元分析软件，建立了7075铝合金激光焊的热-力耦合模型；随后利用数值传递法，建立了焊接及超声冲击处理耦合模型；在此基础上引入时效处理的热-力耦合模型，建立焊后A-UIT处理模型，分析了不同处理方法下残余应力分布情况及特点，旨在研究不同处理方法对7075铝合金焊接残余应力场的影响. 结果表明，A-UIT处理能够显著改善焊缝及附近区域的残余应力分布，焊缝中心位置表面纵向残余应力由焊后的180.21 MPa转变为?150.26 MPa，转变率高达183.4%，且相较于单超声冲击处理，A-UIT处理可以缓解超声冲击直接作用区附近的残余拉应力集中问题.

Numerical simulation of effect of A-UIT treatment on welding stress of 7075 aluminum alloy

Using ABAQUS finite element analysis software, the thermodynamic model of 7075 aluminum alloy laser welding was established. Then, the numerical transfer method was used to carry out UIT on the joint, and the coupling model of welding and UIT was established. On this basis, the thermodynamic model of aging treatment was introduced to establish A-UIT treatment model after welding, and the distribution and characteristics of residual stress under different treatment were analyzed in order to study the effect of different treatments on the improvement of welding residual stress field of 7075 aluminum alloy. The results show that A-UIT treatment can significantly improve the residual stress in the weld and its adjacent area. The residual tensile stress in the center of the weld changes from 180.21 MPa to ?150.26 MPa, and the conversion rate is as high as 183.4%. Compared with the single ultrasonic impact treatment, A-UIT treatment can alleviate the residual tensile stress concentration near the direct impact zone.