Delamination failure of composite top-hat stiffeners using finite element analysis

Abstract

The paper presents the finite element analysis of top-hat stiffeners (transversely loaded keel support structure) under a static load where splitting–delamination is the primary mode of failure. A set of experiments is conducted on the composite top-hat stiffeners with three different lay-up arrangements. The experimental study, together with the finite element modelling to capture the delamination failure, is presented. Fracture initiation is predicted using an interlaminar-strength-based criterion. A fracture-mechanics-based formulation is used to predict delamination propagation by connecting the composite layers with two-dimensional and three-dimensional interface elements using the commercially available MSC Marc Mentat 2008 r1 finite element software package. Reasonable agreement between the experiments and finite element analysis was achieved. The reserve strength identified by the experimental testing is successfully modelled. The factors affecting the fibre–matrix interface strength are studied. The failure location and mode for fracture initiation and propagation are determined.