随焊超声波激振法控制铝合金薄板焊接应力及变形

摘要

A new method of welding with trailing ultrasonic vibration (WTUV) to control the welding distortion of high strength aluminum alloy sheet was put forward, and the mechanism was illustrated. Based on numerical simulation analysis, the model of thermo-mechanical coupled welding with ultrasonic vibration was established using Marc software. The optimal welding parameters and the best distance between the vibrating position and heat source are obtained. The welding experiments were conducted on the self-developed device. The results show that when the distance between vibrating point and heat source is 22 mm, the residual tensile stress in the middle cross-section in longitudinal direction reduces from 248 MPa of conventional welding to 63 MPa. The maximum compressive residual stress reduces from-77 MPa to-27 MPa, which is below the critical buckling stress of the sheet, the deflection distortion disappears entirely, and the maximum deflection of plate edges drops from 8.66 mm to 0.9 mm. There are better agreements between the test results and simulation results.%从力学角度出发提出随焊超声波激振控制高强硬铝合金薄板焊接变形的新方法，阐明其控制焊接应力及变形的机理。基于数值模拟分析，利用 Marc 建立铝合金薄板的随焊超声波激振热力耦合模型，找出最优焊接参数以及加载冲击与热源的最佳距离。利用自行研制的随焊超声波激振装置进行焊接试验。结果表明：激振距离为22 mm时，板长方向中截面残余拉应力峰值由常规焊的248 MPa下降到63 MPa，压应力峰值从-77 MPa降低到-27 MPa，低于薄板的临界失稳应力，薄板挠曲变形完全消失，且板边最大挠度由8.66 mm下降到0.9 mm。试验结果与模拟结果吻合较好。