Acoustic emission and ultrasonic imaging in pultruded GRP composites

Some experiments in which acoustic emissions (AEs) and ultrasonic tomography were concurrently performed on samples of glass reinforced plastic (GRP) composites are described. Direct tensile tests were performed on rectangular plates of GRP samples, in which a circular hole was machined in their centers. Cracks that propagated from this hole were monitored by AEs throughout the loading phase, and by ultrasonic tomographic imaging at regular intervals. Analysis of this data indicated that the crack propagation seems to be controlled by the glass fiber breakage. The region of damage seems to extend well away from the visible crack