超声冲击改善6061铝合金焊接残余应力的数值模拟

Numerical simulation of ultrasonic impact treatment on 6061 aluminum alloy welding residual stress

运用ANSYS有限元软件对无应力和存在焊接残余应力的6061铝合金试板的超声冲击过程进行了数值模拟,并和实测结果进行了对比.结果表明,对于无应力试板,冲击中心表面为压应力,周围为拉应力;在冲击中心沿板厚方向,应力状态逐渐由压应力转变为拉应力,随冲击过程的进行,材料整体应力水平不断提高;对于存在焊接应力的试板,增加载荷位移,冲击区域的应力降幅也随之增大,最大拉应力逐渐向母材区转移且其峰值也不断下降,应力降幅符合实测结果.

The ultrasonic impact treatment on the thin 6061 aluminum alloy plate without and with welding residual stress was analyzed by means of the finite element software ANSYS.The simulated result was compared with the tested one.In the case of the existence of no welding residual stress,the result shows that the surface stresses are compressive at the impact center,and tensile around the center after treatment.Along the depth of the sample,compressive stresses turn into tensile ones.The whole stress state increases gradually with the treatment.In the case of the existence of welding residual stress,with the increase of the displacement load,stresses at the impact zone decrease greatly and the highest stress locates the area away from the weld.The simulated result of the stress change accords well with the tested one.