Simulation and experimental study of laser transmission welding considering the influence of interfacial contact status

The traditional finite element model (FEM) of laser transmission welding (LTW) is generally assumed that the interface of transparent and opaque materials is ideal. This assumption ignores the influence of real interfacial contact status on welding results. For this problem, the volumetric heat source model is constructed based on the Lambert-Beer law in this paper. And thermal contact model of LTW is constructed in the mode of volumetric absorption. Then the numerical simulation of temperature contours during LTW process is taken into thermal contact modeL Under the condition of no interface gap (S = 0), the weld temperature contours and weld profile of transparent and opaque PA66 are obtained by numerical simulation and experiment. Furthermore, under the condition of interface gap (S = 20), the weld temperature contours and weld profile of thermal contact model are analyzed and predicted. The results show that thermal contact model is more consistent with real model when compared with traditional model. And thermal contact model can reasonably predict the changes of weld temperature contours and weld profile. Therefore, thermal contact model can be used to characterize the influence of interfacial contact status on welding results and improve the accuracy of numerical simulation in the process of LTW. (C) 2015 Elsevier Ltd. All rights reserved.