横向超声随焊控制铝合金焊接热裂纹倾向数值模拟研究

从力学角度出发,提出横向超声随焊控制铝合金焊接热裂纹的新方法。讨论了铝合金焊接热裂纹产生的条件,建立脆性温度区间(BTR)金属材料-力学性能匹配模型,采用弹塑性有限元方法对BTR区域金属产生的挤压塑性流变行为和应变场变化进行了分析。模拟结果表明,横向超声冲击对BTR区金属产生横向压缩塑性应变,并依靠BTR区金属的塑性变形把应变传递到焊缝中心,随着横向超声冲击加载功率的增加,在焊缝中心处产生的挤压应变也随之增大。通过实验测定实际情况下BTR区金属的横向压缩塑性应变值,实验结果与模拟结果吻合良好,进一步证明了该方法的可靠性。

Numerical Simulation of Transverse Ultrasonic for Controlling the Tendency of Welding Hot Cracking in Aluminum Welding

A new method was presented from the view of mechanics to prevent welding hot cracking for aluminum alloy by employing transverse ultrasonic during welding. The mechanical condition of welding hot cracking was discussed. The material-mechanical properties matching model within brittle temperature region (BTR) metals was established and the plastic flow and the variation of the strain field in welds by transverse ultrasonic were analyzed numerically. The simulation results show that the transverse ultrasonic impact produces transverse compressive plastic strain in BTR metal, and the plastic deformation is transferred to the weld centre through the metal within BTR. With the ultrasonic load amplitude increasing, the compressive stress in weld centre increases. Experiment was carried out through the ultrasonic extrusion in BTR area. It is indicated that the simulation results and the experiment results are in good accordance, which proves the reliability of the new method