Thin porous Ni‐foam enhanced CFRP/Al adhesive joint inserted by ultrasonic vibration

Abstract

To enhance the mechanical properties of the adhesive layer in joints, a thin–structural open–cell porous Ni–foam was embedded into the adhesive interface through ultrasonics (US) assisted. The porous metal foam is effective in interlocking itself with adhesive. After the ultrasonic vibration was applied for 0.17 s, the adhesive penetrated Ni–foam, generating enough residue. This technique effectively improves the energy absorption and shear strength of the CFRP/Al single lap joint by more than 250.33% and 118.4% with a 0.5 mm thick Ni–foam insert, respectively. The fatigue resistance increased by 154% with a 0.3 mm thick Ni–foam insert based on the fatigue testing results and the Weibull distribution method. The S–N curves were established at different reliabilities for engineering applications. With the Ni–Foam insert, the failure modes were changed through crack deflexion, Ni–Foam degumming, and crack blocking.Highlights Ultrasonic vibration assisting Ni‐foam inserts CFRP/Al adhesive joints. The shear strength of joints with Ni‐foam was maximally increased by 118.4%. The fracture forms of joints with Ni‐foam were changed. The fatigue life of the joints with Ni‐foam was maximally increased by 154%. S–N curve of joint with Ni–foam of different reliability levels was got.