摘要研究了服役载荷作用下铝锂合金蒙皮 – 桁条 T 型接头的焊接残余应力演变规律。首先建立了 T 型接头双激光束双侧同步焊接过程的 3D 热 – 结构有限元模型，并通过试验验证了该模型的合理性，以获取准确的焊接残余应力。随后，将焊接残余应力、应变分布和总等效塑性应变作为初始条件，采用弹塑性结构模型，进行有限元数值分析，以研究 T 形接头在服役载荷下的残余应力再分布情况。结果表明，施加载荷结束后，结构表面的纵向应力松弛明显（尤其是在焊缝处），桁条中间的纵向应力对服役载荷不敏感。
Abstract：This study reveals the evolution rule of welding residual stress of aluminum–lithium alloy skin-stringer T–joint under service load. Firstly, the 3D thermal-structural finite element model of T–joint dual laser-beam doubleside synchronous welding process was established, and the reliability of the model was verified by experiments to obtain accurate welding residual stress. Subsequently, the welding residual stress, strain distribution and total equivalent plastic strain were taken as initial conditions, and the finite element numerical analysis was combined with the elastic-plastic structural model to study the residual stress redistribution of the T–joint under service load. The results show that after the end of the applied load, the longitudinal stress relaxation of the skin is obvious (especially at the weld), and the longitudinal stress in the middle of the stringer is not sensitive to the service load.
2020, 
