Quantitative Fracture Mode Analysis of Composites by Acoustic Emission

The acoustic emission (AE) source characterization has been developed to understand the dynamic process of microfracture in composites. AE signals can be represented as the convolution integral of the source function due to microfracture of materials, the dynamic Green’s function of the media and the transfer function of the measuring system. We developed the advanced analysis system to evaluate AE signals quantitatively. Source location of each AE is determined from the signals recorded using multi-transducers. Each dynamic Green’s function of the specimen is calculated by a finite difference method. The transfer function of the measuring system is calibrated by the breaking pencil lead method. Source components are determined by the developed deconvolution algorithm. Then fracture mode of microcracking is obtained from the moment tensor. This analysis system was applied to the materials testing in glass matrix composites and the fracture process in these materials will be discussed.