Impact of welded tabs on mechanical testing of CF/PAEK thermoplastic composites

This article addresses the poor bonding strength of continuous carbon fiber-reinforced thermoplastic polyaryletherketone resin (CF/PAEK) composites, which makes the mechanical test results of tabbed specimens easily affected. It investigates the effects of resistance-welded reinforcement tabs on the performance test results of 0° tensile and 0° compression specimens. Through analysis of the temperature distribution during the welding process and multiple sets of experimental results, it shows that the heat conduction of unidirectional specimens significantly affects the welding strength of the tabs near the working section of resistance-welded specimens, resulting in lower test results for 0° compression specimens but not for 0° tensile specimens or single-lap shear specimens. Adding an insulation layer to prevent edge heat dissipation improves the test results for 0° compression specimens. However, the two rapid temperature changes caused by resistance welding reduce the crystallinity of the specimens within the tabs without affecting the working section. This often leads to damage at the interface between the working section and the tab, so the compressive strength test results remain lower than those of adhesively bonded specimens.