Material Characterization of Pultruded Laminates and Shapes

This paper discusses the material characterization of wide flange pultruded structural shapes (E-glass, Vinylester). The material was subjected to three loading conditions: tension, shear, and bending. Coupon samples were obtained from web and flanges of the I-section for tension and shear tests. Tensile properties were obtained from rectangular coupons with end tabs loaded in tension to failure. Shear properties were obtained from two different test methods: Iosipescu shear test method and torsion of rectangular samples. Experimentally determined material properties were compared to analytical predictions based on micro and macromechanics. Micromechanical models are used for the prediction of individual laminae (roving layers, continuous strand mat, nexus veils) properties. Classical lamination theory (CLT) is then used to predict the laminate properties. In addition, I-beams were tested in bending to evaluate their response and the experimental results were compared to predictions using Mechanics of Laminated Beams (MLB) approach. Results indicate a good correlation between experimental data and theoretical predictions, showing that the properties of pultruded composites can be predicted with sufficient accuracy. The superiority of the torsion test for determination of in-plane shear stiffness is demonstrated.