Determination of Reinforcement Unbonding of Composites by a Vibration Technique

Abstract

An experimental technique was developed to determine the condi tions for the onset of reinforcement unbonding in composite materials. The technique is based upon the continuous measurement of the dynamic moduli and damping of tensile specimens. The samples are subjected to low amplitude longitudinal and torsional oscillations superimposed on the tensile loading. Experiments were performed at room temperature on quartz particle filled resin specimens. The results for specimens with epoxy binder indicated that unbonding did not occur prior to overall failure. Those for the polyester specimens, however, showed that early particle separation occurred under certain conditions.