Non-destructive evaluation of erosion damage on E-glass/epoxy composites

A non-destructive evaluation method for predicting the residual tensile strength of erosion damaged fiber-reinforced composites was developed based on monitoring the acoustic emission (AE) activity of the composite specimens during uniaxial tensile loading. The developed method was used for estimating the residual strength of E-glass/epoxy composite with ply sequence of [45 / 45 /0 /45 / 45 /0 ]S. A mixture of air and SiC particles with diameter of 400–500 lm was blasted to the composite specimens at various impact angles and durations to induce the local damage. Subsequently, uniaxial tensile tests were carried out on the specimens subjected to solid particle erosion as well as undamaged specimens while monitoring the acoustic emission activity. The extent and mechanisms of damage due to tensile loading of composite specimens were explored by examining the failure surface upon completion of tensile tests under a scanning electron microscope (SEM) and by measuring the distribution of AE events by event duration, ring down counts and energy distribution during tensile tests. Weibull probability distribution model and AE stress delay parameter model were developed to relate the AE activity to the erosion damage and residual strength. The results show that the developed non-destructive method is capable of predicting the residual strength of composites subjected to solid particle damage. 2007 Elsevier Ltd. All rights reserved.