THE BENDING STIFFNESS OF LAMINATED COMPOSITE-MATERIAL I-BEAMS

The bending behavior of graphite-epoxy 1-beams was examined. The beams used in this study were made of T300/934 graphite-epoxy with three di fferent layups. Short-beam shear tests, using three-point bending, wer e used. The shear-deflection and bending-deflection contributions were separated using Timoshenko Beam Theory. The equivalent bending stiffn ess was obtained from the deflection due to bending. The bending stiff ness was calculated in two ways: using a method based on lamination th eory, and using a transformed-section method developed especially for composites. A comparison of analytical and experimental results indica tes that both methods are accurate tools for predicting the bending st iffness of composite material beams.