Damage detection on flexural loading of hybrid laminated composite by acoustic emission

Abstract

Fibers with different inherent characteristics are industrially hybridized for further improving the mechanical loading responses of the fiber-reinforced composites. The difference in the matrix-fiber affinity of such fibers makes similar and alternative interfaces in the laminate. Although recent studies have shown that strategic placement of fibers at appropriate location within the composite for a pre-determined loading type (bending, tensile, or compression) improves the mechanical behavior, the underlying damage mechanisms still need detailed investigation using modern technologies. So, in this study, novel hybrid laminates of various symmetric hybrid configurations were fabricated with industrially active carbon, basalt, aramid, and glass fibers using compression molding. The bending behavior of the configurations at various (1, 5, 10, and 20 mm/min) strain rates were monitored by both load–displacement curves and load-induced acoustic signals. The density of acoustic waves, classified and disintegrated by the types of stimuli they originated from, were correlated with the internal structure, types of cracks, and loading rates. Results showed that the acoustic emission (AE) assisted in predicting the internal damage mechanisms and fracture behavior of the composites at different loading rates. This information can be used for Structural Health Monitoring (SHM) during the service life of the composites as components.