Compressive Failure Behaviour of Kevlar Epoxy and Glass Epoxy Composite Laminates Due to the Effects of Cutout Size and Variation in Fibre Orientations

Abstract

AbstractAt present, rigorous research are carried out to produce the finest possible properties of composite materials. This phenomenon has made it possible to expand the application of composite laminates, which originally meant for only defence and aeronautical industries towards more public and general applications. To avoid catastrophic failure of composite structures, its failure behaviour should be established. Nevertheless, composite laminates may deform in various modes and thus, these modes of failure should be well understood before designing a composite structure, especially with the cutouts. This paper aims to study the effect of the circular cutout on the failure behaviour of Kevlar Epoxy and Glass Epoxy composite laminates with various fibre orientations. The work was conducted in two stages. The preliminary work involved mesh convergence analysis and numerical validation. The laminate modelling and failure analysis was performed using a finite element software (ANSYS). The model with stacking sequence is [θ4/04/−θ4]s and various fibre orientation, θ from 0° to 90° were investigated. Failure was determined using Maximum Stress Theory. The results show substantial strength reduction between composite laminates with and without circular cutout. Comparing Kevlar Epoxy and Glass Epoxy at 0° fibre angle, the results show that the circular cutout has more influence on Kevlar Epoxy (10 times weakened) than the Glass Epoxy (3 times weakened). However, when the fibre angle varied, both composites exhibit the similar trend of failure. Therefore, it is proven that the current study is essential in understanding the failure behaviour of composite plates with circular cutout.KeywordsFailure analysisGlass EpoxyKevlar EpoxyCircular cutoutANSYSMaximum Stress Theory