Resistance welding process for glass fiber‐reinforced polypropylene composite joints: Parameter optimization and performance assessment

Abstract Thermoplastic composites are extensively utilized in aircraft, transportation, medical, and various other sectors due to their superior damage tolerance, ease of repair, and consistent processing capabilities. This work focuses on glass fiber reinforced polypropylene composite (GF/PP) composites, specifically the preparation of GF/PP resistance welding single‐lap joints. The optimization aim was the single lap shear strength, and the optimal combination of process parameters was identified through orthogonal testing and response surface methodology as a welding current of 16.7 A, welding pressure of 20 N, and welding time of 75.6 s. Subsequently, the resistance welding process was assessed regarding thermal parameters, mechanical properties, and failure interfaces. The results indicate that the resistance welded joint, under optimal parameters, exhibits a shear strength of 6.656 ± 0.475 MPa, achieving 84% of the benchmark value for hot compression. Its primary failure mode is characterized by a combination of adhesive failure and interlayer damage within the heating element. As the energization time increases, the LSS rises to a maximum peak and subsequently declines, with the maximum shear strength occurring during the reduction in welding displacement. Highlights Combining orthogonal experimental design with response surface methodology. Quantification of process parameter‐mechanical property connections. Welded joints can produce 6.656 shear strength, 84% of the norm for hot pressing. Resistance‐welded joints have peak shear strength when displacement is reduced.