Experimental Evaluation of Stiffness of Laminated Composite Beam Elements under Flexure

Abstract

The objectives of this study are: (1) to define upper and lower bounds for the stiffness of laminated beam elements under flexure, (2) to correlate experimental effective beam moduli with analytical predictions, and (3) to obtain a threshold aspect-ratio that limits the range of application of various analytic methods. Experimental tests were conducted to characterize the load-displacement response of laminated beam elements under flexure, and the results were correlated with available analytic approaches. Angle-ply laminated beam elements were chosen to distinctly show the differences between various analytic methods. Three-point bending tests were performed, both flatwise (out-of-plane) and edgewise (in-plane), on rectangular lay-up specimens made of AS-4/3501-6 carbon-epoxy. Recommendations are made for the analytical prediction of stiffness under various conditions.