Research associate, Royal Institute of Technology, Stockholm,
Pages: 7 Published: Jan 1988
A method to predict failure of adhesive joints is described. The fracture criterion is based on material-induced singularities that appear at the terminus of the joint. The criterion can be interpreted physically in terms of the elastic strain energy density. The criterion is formulated in terms of a singular intensity factor Q that is analogous to the stress intensity factor for the case when cracks are present. The strengths of the singularities are dependent on the elastic properties of the adhesive and the adherends and on the geometry of the bond terminus, but are postulated to be independent of loading and global geometry.
For the case of an adhesive joint, the different materials inducing the singularities may be the adherend and the adhesive. The criterion assumes that no cracks are present in the vicinity of the material-induced singularity and that fracture will occur as a cohesive fracture in the adhesive layer. It has been shown earlier that the criterion predicts with good accuracy the fracture load of test specimens loaded in combined tension and shear. The fracture load of the single-lap joint is predicted and compared with experimentally obtained values.
The presented method of predicting fracture in adhesive joints may be applicable to general joint geometries.
adhesive joints, finite element analysis, fracture criterion, material-induced singularities
Paper ID: STP23248S