Numerical simulation and experimental verification of temperature field in induction welding process of CFRTP L-shaped stringer and skin based on magneto-thermal coupling

Induction welding is a suitable and promising technique for assembling thermoplastic composite structural components. In this work, a magneto-thermal coupling model has been developed to simulate the induction welding process of carbon fiber–reinforced thermoplastic composite L-shaped stringers. To verify the accuracy and applicability of this model, a series of experiments were conducted, and an infrared thermometer was utilized to calibrate the simulation temperature field. The accuracy and applicability of the model for the induction welding process were validated by comparing the experimental results with the simulated results. Specifically, the induced current density and the magnetic field distribution during induction heating were examined, and the temperature distribution of the carbon fiber–reinforced thermoplastic composite L-shaped stringers during heating was analyzed. It was found that the temperature field on the induction element was distributed in a semi-elliptical shape, extending from the boundary to the middle and intersecting in a butterfly shape at the center. Furthermore, the evolution of the temperature field under different process parameters was investigated, focusing on the influence of coil current and heating time. Based on the simulation results, the optimum process parameters were the coil current of 4 A and the heating time of 40 s.