利用高精度同步辐射X射线三维成像技术,对激光-电弧复合焊缝的气孔率进行测定,并将其作为GTN损伤模型中的初始孔洞体积分数。通过建立含余高与不含余高的复合焊接接头的细观损伤力学有限元模型,得到了拉伸接头主应力和孔洞体积分数的分布。通过对拉伸断口金相组织进行分析,发现了几何和材料的不连续性是导致接头失效的重要原因。 The stomatal ratio of the laser-arc composite weld was measured by high-precision synchrotron radiation X-ray three-dimensional imaging and used as the initial pore volume fraction in the GTN damage model. Through the establishment of the mesomechanical damage mechanics finite element model of composite welded joint with residual height and without residual height, the distribution of the principal stress and the volume fraction of the cavity are obtained. Through the analysis of the microstructure of the tensile fracture, it is found that the geometric and material discontinuities are the main reasons leading to the failure of joints.