Environmentally enhanced fatigue damage in glass fibre reinforced composites characterised by acoustic emission

A series of tests has been conducted to investigate the effect of sea water absorption on fatigue damage accumulation in a glass fibre reinforced poly ester laminate of the type widely used in the marine and offshore industrie s, using four-point bend flexural loading to ensure peak strain in the oute r layers of the material most subject to seawater absorption. Pre-exposure was found to reduce the flexural strength and enhance damage, accumulation in fatigue by stimulating matrix cracking, fibre debonding and delamination . Acoustic emission (AE) was used to characterise damage accumulation. Thes e results were found to correlate well with independent measurements of cha nging bending stiffness and with microstructural observations of the damage d sections. (C) 2000 Elsevier Science Ltd. All rights reserved.