  In this paper it is presented a detailed numerical investigation of acoustic
emission signals obtained from test samples of fibreglass reinforced polymeric
matrix composites, when subjected to tensile and flexural tests. Various
fractal indices, characteristic of the signals emitted at the different
structural failures of the test samples and which satisfy non-stationary
distributions, have been determined. From the results obtained for these
indices, related to the Hurst analysis, detrended fluctuation analysis, minimal
cover analysis and to the boxcounting dimension analysis, it has been shown
they can discriminate the different failure mechanisms and, therefore, they
constitute their signature.
