ポリアミド樹脂を接着剤に用いたCFRP/Alの摩擦撹拌点接合

抄録

CFRP with thermosetting resin as a matrix cannot be welded to metals because thermosetting resins have crosslinked structure and cannot be melted. We have developed a new welding method known as Friction Stir Spot Welding (FSSW) in which by inserting the thermoplastic resin PA12 is inserted between Al alloy and carbon fiber reinforced epoxy matrix composite. ISO 14272 and 14273 joint strength evaluation of resistance spot welding specify tensile shear tests and cross tensile tests. In order to ensure the reliability of welding, it is necessary to evaluate the strengths of each tests and clarify the fracture mechanism of CFRP/Al welded by this method. In this study, CFRP and Al were welded by FSSW using polyamide as an adhesive, and the tensile shear test and cross tensile test were performed to evaluate their strength. Since PA12 and epoxy resin decomposed and disappeared under the welding tool, CFRP and Al are not welded at this area, and the welded strength is maintained at the outer area of this decomposed area. For the tensile shear test, the strain distribution on the specimen surface was measured using a non-contact 3D displacement and strain measurement system. Since Al occurs plastic deformation earlier than CFRP, a crack initiated from the Al side to the center of welded area, and the maximum load was reached followed by sudden fracture. In the tensile shear test, a strength of 7.9 ± 0.1 kN, which was higher than the standard value of resistance spot welding of steel was obtained. In the cross tension test, 1.4 ± 0.1 kN of cross tensile test strength was obtained.