Interfacial stress analysis of geometrically modified adhesive joints in steel beams strengthened with FRP laminates

One major problem when using bonded Fiber Reinforced Polymer laminates is the presence of high interfacial stresses near the end of the composite laminate which might govern the failure of the strengthening schedule. A method that has been proposed for reducing the magnitude of the interfacial stresses is laminate end tapering, which can be used with or without adhesive fillets.In this paper, a comprehensive FE study has been conducted to investigate the effect of using normal and reverse tapering with and without adhesive fillets on the interfacial stress distribution in the adhesive joints at different locations, including the mid-thickness of the adhesive layer, as well as interfaces. The results indicate that using the correct combination of tapering and adhesive fillet can reduce the magnitude of the interfacial stresses significantly. However, the inappropriate use of tapering and adhesive fillets might cause higher stresses than those in joints without geometrical modification.