A modal acoustic emission signal classification scheme derived from finite element simulation

Abstract

The ability of broadband modal acoustic emission to classify the most common forms of damage mechanisms occurring within a polymer matrix composite material with rod type geometry has been shown. The composite under study was a unidirectional hybrid polymer matrix composite material, with carbon and glass fibers reinforcing a high temperature epoxy matrix. Signal discrimination was achieved through the development of a classification scheme derived from explicit finite element simulation of the most common deformation mechanisms. The classification scheme identified the type of failure mechanism, as well as the material of origin, based upon the spectral content of the signal which is directly influenced by the wave modes that propagate. The classification scheme was used to evaluate the effect that atmospheric aging at elevated temperature had on the hybrid composite subjected to flexure loading at various time periods. Advantages of the proposed method include computational efficiency, the ability to inherently account for geometric and material boundary layer reflections, as well as the ability to be readily adapted to complex part geometries.