A stress singularity parameters approach for evaluating adhesive strength.

The stress and displacement fields at the close vicinity of a bonding edge show singularity behaviors. So, the adhesive strength evaluation method using maximum stresses, which were calculated by numerical stress analysis such as the finite element method, is generally not valid. In this paper, a new method, which uses two stress singularity parameters, is presented for evaluating adhesive strength. This method is applied to several kinds of molded models, composed of epoxy base resin and Fe-Ni alloy sheets. Predictions about the initiation and extension of delamination are compared with the results of observations made by ultrasonic tests on molded models.