Modelling of damage and failure of glass/epoxy composite plates subject toimpact fatigue

An investigation has been carried out to study the impact fatigue damage of glass/epoxy laminated composites. Accumulation of damage, such as matrix c racking, delamination and fibre breakage, with repeated impact of the compo site material may reduce the overall stiffness. These damage modes have bee n combined in a very complicated way to describe damage growth and fracture . A model is proposed for characterising the damage as a function of the no rmalised impact number. The scalar variable D, which characterises the mate rial damage, is written as a function of the life duration beta, using a mo dified form of the Mankowsky empirical law [Int J Solids Struct 32(11) (199 5) 1607]. The macroscopic failure mode and the internal damage in laminated specimens of glass/epoxy as a consequence of impact fatigue are analysed a t different levels of incident impact energy. The impact fatigue tests have been conducted on an apparatus built in our laboratory. (C) 2001 Elsevier Science Ltd. All rights reserved.