Properties of AFRP in Hot-Wet Environmental Exposure by Acoustic Emission Method.

Abstract

It is well known that Aramid Fiber Reinforced Plastic (AFRP) is degraded by hot and wet environment. Environmental influence on tensile fracture mechanisms of [0/+45/-45/90°]s AFRP was investigated using microscope and acoustic emission method. Specimens were immersed in pure water at 80 degrees centigrade for 320 days. Water absorption, accelerated by high temperature, reduced interfacial strength, degradation of resin and fiber, also causing occurrence of the edge delamination. Relation between fracture phenomena and the frequency distribution was investigated. On unidirectional reinforced material, fiber debonding around fibers was found, and occurred a peak at 150 kHz, from initial fracture to final fracture. But for the used material, peak effect of edge delamination at 90°/90°interlaminar of [0/+45/-45/90°]s was observed at 60 kHz. It was possible to conclude that the variations of fracture mechanisms caused by water absorption were direct relation with the variation of fracture sound frequency distribution between virgin and immersed material.