Modelling the effective elasto-plastic properties of unidirectional composites reinforced by fibre bundles under transverse tension and shear loading

The effect of fibre bundling on the effective transverse properties of unidirectional fibre composites has been investigated by way of finite element method and micromechanics models of fibre bundles. Based on the micromechanical model of single-fibre composites, plane strain models for composites reinforced by fibre bundles are presented. The effective elasto-plastic stress–strain behaviour was obtained numerically by analysing a boron/aluminium composite reinforced by three-fibre and four-fibre bundles. The results are compared with the modelled behaviour for the composites reinforced by single fibres. The study shows that there is a remarkable influence of fibre bundling on plastic deformation, transverse tension and shear tangent stiffness of composites, while the influence on effective elastic properties can be ignored, fibre bundling enhances the transverse tangent stiffness of plastic deformation of composite materials, and the transverse normal stress–strain relations are more sensitive to fibre bundling than the transverse shear stress–strain relations.