A frequency spectral analysis of the fiber failure acoustic emission signal in a single fiber composite

A new acoustic emission failure mode analysis methodology for composite materials was developed. A single carbon fiber composite based on a polyester matrix has been used as a simple model. Fiber breakage during tensile loading tests was observed by using a polarized light microscope and simultaneously detected by a resonant acoustic probe. The resonant probe was used as a trigger for recording the fiber failure events. Single acoustic emission events from a wide band probe were recorded for fast Fourier transform analysis. The single fiber specimen, having an unique failure mode, presents advantages for standardization of AE techniques for quantitative analysis of failures in polymer composite materials. The same procedure can be exploited to investigate the other failure modes, namely fiber-matrix debonding and matrix cracking.