Plate waves produced by transverse matrix cracking

Transverse matrix cracks were induced in cross-ply laminate graphite/epoxy coupons by tensile loading. The resulting acoustic emission (AE) was shown to consist of plate waves. Both the extensional mode and flexural mode were detected. The extensional mode contained higher frequency components of larger amplitude than the flexural mode. By filtering out the flexural wave components, the location accuracy of the conventional AE analyser was improved by an order of magnitude. The use of a broader bandwidth, point-like transducer is discussed and conclusions are drawn about the use of pencil lead breaks for location calibration. The simplicity of the results in this paper suggests that they will have many practical applications.