ADHESION IN FIBER-REINFORCED PLASTICS INVESTIGATED BY MEANS OF ACOUSTIC-EMISSION

The nature of fibre-matrix adhesion, its strength and failure mode hav e been investigated via the acoustic emission (AE) technique. When uni directional composites are subjected to transverse tension, the predom inant fracture mechanism is failure events in the interface region who se stress waves are detected as acoustic emission at ultrasonic freque ncies by a piezoelectric transducer placed in intimate contact with th e test specimen. The stress and strain range over which these AE event s occur determine the strength of the fibre-matrix interface region, w hile the relative total number of recorded AE events give indication a s to the failure mode. The method developed here has been applied to a variety of composite systems and shows potential as a simple and conv enient means of monitoring adhesion, its' strength and failure mode in fibre reinforced plastics.