采用模拟与实验相结合的方式研究激光透射焊接件拉伸过程中的应力分布和拉伸件的失效行为。以PA66激光透射焊接件为研究对象，建立了焊后拉伸数值模拟模型，模拟得到了焊接件的拉伸载荷-位移曲线和拉伸变形情况，并与拉伸实验进行对比和验证；对拉伸过程中焊接件的剪切应力和Von Mises应力分布进行分析，从剪切和拉伸失效方面探究拉伸件的失效行为。拉伸实验验证了拉伸数值模拟模型能较好地预测焊接件的拉伸变形情况；数值模拟得到最大剪切应力发生在焊接界面上长方形焊接区域的4个角点附近，即剪切失效的起始位置，且由于最大剪切应力远小于PA66的剪切强度，拉伸件发生剪切失效的可能性较小。预测的焊接件拉伸失效形式及失效位置与实验结果吻合，验证了数值模拟方法的准确性和拉伸数值模拟模型良好的可靠性。

Stress distribution and failure behavior of laser transmission welding parts are studied by means of simulation and experiment during the tensile process. The welding parts of PA66 are chosen as the research object and the numerical simulation model of the tensile experiment is established. The tensile deformation and the corresponding load-displacement curves of welding parts are simulated and compared with the results of tensile experiments. Analysis of the shear and Von Mises stress distribution of welding parts during the process of tensile experiment is carried out. The failure behavior of tensile specimen can be studied from the aspect of shear and tensile failure. The numerical simulation model can well predict the tensile deformation of the welding parts. The maximum shear stress occurs in the vicinity of the four corners of a rectangular weld area near the weld interface, which are also the starting positions of the shear failure. Because the maximum shear stress is much less than the shear strength of PA66, the tensile shear failure is less likely to occur. The predicted tensile failure and the failure position of welding parts by numerical simulation are consistent with the experimental results. The accuracy of numerical simulation method for analyzing and predicting the tensile failure behavior of the welding parts and the reliability of the numerical simulation model of tensile process are verified.