3-D FEM Stress Analysis and Strength Prediction of Band Scarf Adhesive Joints Subjected to Static Bending Moments

Abstract

The interface stress distributions in band scarf adhesive joints with similar and dissimilar adherends under static bending moments are analyzed using three-dimensional finite element calculations. It is found that the maximum principal stress decreases as Young's modulus ratio E1/E2 between the dissimilar adherends decreases, as the adhesive Young's modulus increases, as the adhesive thickness increases, and as the number of bonded interface parts decreases. The number N is optimal as N=2. It is observed that the maximum principal stress is minimal when the scarf angle θis around 60˚, therefore　the　joint　strength　of　band　scarf　adhesive　is assumed　to　be　maximal　for　scarf　angle　of　60˚. The　maximum　principal　stress　in　the　joint　with　two interface　bonded　parts　subjected　to　linear　stress distributed　to　partial　region　is　smaller　than　that distributed　to　the　whole　region.　The　strength　of the band　scarf　adhesive　joint　with　the　30%　reduced interface　bonded　area　is　approximately　the　same　asthat　with　the　completely　bonded　area　at　the interfaces. The strains in the adherends and the joint strengths were measured in the experiments. The measured strains and joint strengths are in fairly good agreement with those obtained from 3-D FEM calculations.