Failure analysis of woven kevlar/epoxy composite laminates under compression due to variations in fiber orientation

Abstract

Studies have shown that the angle of fiber orientation significantly affects the mechanical properties of a composite laminate. Although investigations on the properties of the composite material have been conducted, there is still a lack of studies related to Kevlar/Epoxy laminate. Therefore, this study aims to investigate the effects of the angle of fiber orientation to woven Kevlar/Epoxy laminates under a compression state. The study was conducted in two stages comprising of numerical validation and failure analysis. Maximum Stress Theory and Tsai-Wu Failure criteria were selected for the failure prediction. The laminates were made of 24 layers woven Kevlar/epoxy and the stacking sequence was (θ₄/0<₄-θ₄)s. The angle of fiber orientation, θ, was varied from 0° to 90° and failure loads for both flat plate and flat plate with circular hole were determined. The trend of displacement and failure behaviour for both type of plates were compared. From the results, it is found that the effects of the fiber angle on the plate with circular hole are more significant than the flat. Therefore, it can be reasoned that the current study is useful in contributing significant knowledge to better understand the failure behaviour of composite plate.