Experimental and numerical investigation of susceptor-aided continuous induction welding of low-melt PAEK composites

This study enhances the continuous induction welding of unidirectional carbon fiber-reinforced low-melt PAEK, addressing the challenge posed by the anisotropic electrical conductivity of carbon fibers, which causes uneven eddy current distribution, inadequate heating, and weak joint strength. A metallic susceptor moving with the coil along the weld line but not remaining in the bonding interface was introduced to selectively heat the weld area, preventing unnecessary matrix melting. Experimental validation and Finite Element (FE) simulations confirmed the approach's effectiveness in achieving uniform heating and stronger joints. A key parameter in 3D simulation was the electrical conductivity of the laminate, which was lay-up dependent and challenging to measure directly. This work proposed a novel method to estimate electrical conductivity for anisotropic materials by aligning measured and simulated temperature profiles during static induction welding. The model accurately predicted temperature distribution and crystallinity at the interface under different coil speeds. Results demonstrated the feasibility of using a removable steel susceptor to enhance continuous induction welding of UD carbon fiber laminates with a low-melt PAEK matrix. The proposed experimental and numerical approach offers a valuable tool for defining a processing window and optimizing stacking sequences, improving the induction welding of UD carbon fiber composites and non-conductive fiber laminates. Highlights: Continuous induction welding of unidirectional carbon fiber-reinforced composites. Induction heating assisted by a movable steel susceptor. Composite electric conductivity determined by an iterative numerical procedure. Temperature prediction during continuous induction welding. Crystallinity prediction as a function of coil speed during induction welding.