An Investigation on Strength of Composite Laminates with Cutouts Under Tensile Loads

Abstract

Holes/cutouts helps in lightening composite laminates used as aerospace structures. However, they create stress concentration in the vicinity of the discontinuities resulting in low strength of the structure. Unlike isotropic materials, composite materials experience change in stress values due to different parameters such as geometric, material and loading parameters. The present study is devoted to primarily determine whether geometric or material parameters have dominant influence on strength of composite laminates under tensile loads. Geometric parameters such as cutout shape, size, orientation, proximity (in case of multiple holes) as well as edge interaction are taken into consideration. Among material parameters, fiber material, fiber orientation and stacking sequence are varied. Numerical study using ABAQUS CAE software is employed for the analyses. The numerical model is validated against experimental results of Open Hole Tension specimen from literature. Results reveal that geometric parameters have much significant influence on stress concentration factor and thereby the strength of composite laminates, when compared to material parameters. Among the geometric parameters, edge interaction is the most critical factor affecting the stress concentration. An elliptical cutout is seen to have comparatively more adverse effect on strength of laminate, when compared with other cutout shapes.