Abstract
This work investigates the potential of the Weld-Bonding concept to improve the fatigue performance of friction spot joints. Therefore, friction spot joints of AA2024-T3/CF-PPS (carbon-fiber-reinforced polyphenylene sulfide) were produced with an additional thermoplastic film interlayer. Two joining conditions manufactured with low and high heat inputs were investigated. The fatigue performance of those joints was evaluated at 35%, 50% and 75% of their respective ultimate lap shear force (ULSF). It was observed that process-related microvoids decreased the fatigue strength of the joints in high cycle fatigue (HCF). Superior fatigue life of the joints with interlayer in comparison with those without interlayer was observed. At 105 cycles, typical qualification requirement of the aircraft industry, the interlayer joint showed fatigue strength of 51% of ULSF, whereas the fatigue strength of the joint without interlayer was 37% of ULSF. In the whole spectrum, the joint with interlayer showed a fatigue life approximately four times higher than the joint without interlayer.
