Research on carbon fiber reinforced thermal polymer/stainless steel laser direct joining

Abstract

To improve the numerical simulation accuracy of carbon fiber reinforced thermal polymer (CFRTP)/stainless steel laser direct joining (LDJ), a fitting formula of thermal contact conductance was established based on experiments in this paper. Taking into account the thermal contact resistance, a three-dimensional finite element thermal contact model of LDJ was established, and the theoretical simulation and experimental results were compared and analyzed. The result showed that the thermal contact model was more consistent with the reality compared with the traditional model. This thermal contact model could be used to characterize the influence of clamping pressure on the laser joining quality. When the laser power was 318 W and the clamping pressure was 0.1 MPa, the relative error of the melting width was 17.8% for the traditional model and 6.7% for the thermal contact model considering the thermal conductivity. The numerical simulation accuracy could be improved in the process of LDJ. With this numerical model, relationships between the thermal behaviors and the joining parameters were studied numerically. The CFRTP/stainless steel laser joining experiments were also carried out, and the result showed that the joint width measured agreed well with the numerical result.