Acoustic Emission from Single and Multiple Kevlar 49 Filament Breaks

Abstract

Acoustic Emission (AE) was monitored during single filament tension tests of Kevlar 49 fiber. AE was also monitored during dry and lubricated bundle tests of the same material. These later tests were carried out in such a way that the individual filament breaks could be independently verified. Statistical studies were made of the AE event characterization parameters for the source mechanism of filament failure. Studies of effect of cumulative damage, test fixturing, first vs. second AE sensor hit, and friction between fibers were made. Characterization by AE events made up of multiple filament fractures was examined relative to events due to single filament fracture in a bundle. These results are preliminary studies prior to using AE to study fundamental variables which control damage progression in fiber composites upon repeated loading.