Progressive failure of composite wind blades with a shear-web spar subjected to static testing

Abstract

Composite wind blades of 1m long comprising glass-fabric/epoxy skins and a sandwich plate-type spar were designed and fabricated for static testing. In the composite wind blades, the spar supports the top and bottom skins to form the airfoil shape of NACA4418. The blades were tested to failure and the failure modes were identified at different loading stages. A structural failure analysis method which consists of a geometrically nonlinear finite element (FE) model and appropriate phenomenological failure criteria is used to study the progressive failure behaviours of the blades subjected to different types of quasi-static loads. The experimental load-displacement curves as well as failure loads and locations for different failure modes are used to validate the suitability of the proposed failure analysis method.