Effect of Cyclic Corrosion and Joining Method on the Strength of Multimaterial Double Lap Joints

The effect of cyclic corrosion on the static performance of multi-material double lap joints is investigated. Carbon-Fiber-Reinforced thermoplastic composite substrates are joined to Aluminum substrates using bonding-only, bolting-only, or by hybrid bonding-and-bolting methods. Polyurethane-based or epoxy-based structural adhesives are used. Surface roughness is maintained constant and evaluated with an optical profilometer. The quasi-static performance of baseline joints is assessed, and the results from the various joining methods are compared. Cyclic corrosion testing of Double Lap joints is performed in accordance with a GMW14872 3-stage laboratory standards for 30 one-full-day cycles. Quasi-static lap shear tests of test samples are performed at various stages of corrosion cycling, and progressive strength degradation is observed for bonded-only and hybrid bonded-and-bolted joints. Bolted-only joints do not show significant performance loss. Results, discussion, and conclusions are provided.