Free-edge stress fields in generic laminated composites via higher-order kinematics

Abstract

The present work introduces a numerical approach for the study of the free-edge effects that arise in generic laminated composites with arbitrary geometries. The model is based on the use of a higher-order beam theory that employs only displacement unknowns over the cross-section domain, the so-called Lagrange expansion (LE). This allows for the representation of arbitrary sections of laminated structures through a two-dimensional distribution of mathematical domains, accounting for layerwise (LW) kinematics and high refinements towards the free edges. Subsequently, the finite element method (FEM) is employed to solve the problem along the laminate's length, thus enabling the user to introduce arbitrary boundary conditions. Benchmark solutions of the free-edge stresses in symmetric laminates under extension, bending and twisting are included to assess the model. Then, new solutions of a composite C-section beam made of an asymmetric lamination are provided.