Effect of CF/PEEK plasticity behavior on the mechanical performance of interference-fit joint

摘要

Carbon fiber reinforced polyetheretherketone polymer (CF/PEEK) thermoplastic composites have a marked plastic yield stage compared to thermoset composites with epoxy matrix. During the interference fit riveting process, extrusion between rivet and composites laminate creates plastic deformation on the hole wall, which will enhance the bearing capacity of composites hole. Therefore, it is expected that the interference fit will play a greater advantage in enhancing the bearing strength of CF/PEEK riveted joint. Numerical and experimental study are applied to investigate the effect of interference fit on bearing strength of CF/PEEK riveted joint. Results show that the plastic deformation of CF/PEEK composites hole wall is positively correlated with the bearing strength of CF/PEEK riveted joint. When the interference fit size exceeds 2.6%, the bearing capacity of CF/PEEK riveted joint reduces because of the increase of fiber damage. It is concluded that the plastic deformation of riveted hole wall can enhance the bearing capacity of CF/PEEK riveted joint, while fiber damage reduces the bearing capacity of CF/PEEK riveted joint. As the increase of interference-fit size, bearing strength of CF/PEEK riveted joint raises first then decreases, the appropriate interference-fit size is in the range of 2.0% similar to 2.6%, which is larger than that of thermoset composites.