Acoustic emission wave propagation in a viscoelastic plate

In loaded materials the strain-energy release due to microstructural change s results in stress-wave propagation. Acoustic emission deals with the reco gnition of such waves over the material surfaces and for this reason the ap plication of acoustic emission techniques to the monitoring of the mechanic al integrity of materials and structures is appropriate. Nevertheless, the use of such techniques in the case of polymer-based composite materials nee ds a clearer understanding of the relationships between the recorded signal , the damage process and the structure geometry. In this work a model is pr oposed of the propagation in a viscoelastic plate of waves due to a damage event. The microfailure event has been represented as a point source and ra y theory has been applied to develop the physical model of wave propagation . The spectral analysis technique has been applied to the solution of the w ave equations. Model calculations in the frequency domain have been compare d with experimental spectra resulting from fiber breakage in different fibe r;matrix systems from single-fiber fragmentation tests. (C) 1999 Elsevier S cience Ltd. All rights reserved.