Acoustic emission from a notched glass-fibre-reinforced polymer in bending

Abstract

Acoustic emission from notched three-point bend specimens of a unidirectionally reinforced and a crossply reinforced polymer has been measured. The unidirectional material gave no acoustic emission prior to catastrophic fracture whereas crossply material showed a gradual accumulation of acoustic emission, proportional to the square root of the area of a damage zone at the notch tip, preceding fracture. The acoustic emission correlated with the stress intensity factor of the sharpened notch although the correlation was particular to the angle of the fibres to the notch.