Numerical Modelling of Carbon Fibre Reinforced Polymer Composites for Hole Size Effect

Abstract

Carbon Fibre Reinforced Polymer (CFRP) composites are widely used in several high performance structures such as aeroplanes, automobiles and wind turbines. In these applications holes are made for access to view, cut-outs for weight reduction as well as joining of composite members. However, these hole possess a threat to the strength and damage tolerance of composites in service. The strength of composites varies with hole diameter known as hole size effect. The hole size effect, becomes more complex once associated with specimen size effect (strength variation with specimen size) as well as anisotropy and heterogeneity of composite material. The leading influencing factors linked with the hole size effect are in-plane and transverse plane thickness, stacking sequence and hole diameter of the specimen. Extensive experimental, analytical and Finite Element (FE) based studies have been done by the researchers in past on this account. Despite these studies, differences still persist among composite researchers on the extent of these influencing factors on hole size effect. The current paper presents numerous FE models to investigate the stresses and stress concentrations influenced by the diameter to width ratios of rectangular plate subjected to axial loading. FE models are developed both for isotropic and anisotropic/orthotropic materials. FE models for anisotropic/orthotropic materials have been developed using different lamina stacking configurations to investigate their effect on stresses and stress concentrations in parallel with hole size effect. The effect of laminas orientations in case of anisotropic/orthotropic materials with global (reference or loading axes) orientations has also been investigated through coordinate transformation technique. The effect on the use of laminate effective material properties for designing of engineering structures is also evaluated. The comparison deduce significant considerations for designing of the composite materials containing central circular holes subjected to axial loadings.