An ultrasonic interface-wave method for predicting the strength of adhesive bonds

Abstract

A thin adhesive film, located between two bonded adherents, is capable of localizing the energy of elastic waves in the form of an interface wave. Under study are the phase velocity and transmission losses of the interface wave which were measured during the entire course of polymerization of the adhesive. It is shown that the phase velocity of the interface wave and the effective shear modulus of the interface film, calculated from the velocity data, are related to the strength of the adhesive bonds. The general transmission loss factor, which is a function of the relaxation maximum of losses arising during the course of polymerization of the adhesive, is another parameter correlated with the strength. The shear strength of the joint was determined on a special specimen in the form of a lap joint, which was also used for acoustic measurements.