Application of equivalent stiffness to consider coupling effects in bimodular beam

Abstract

In bimodular material (different elastic properties in tension and compression) beam, shear-extension, twisting-stretching, bending-twisting coupling are present irrespective of stacking sequence, ply-angle unlike unimodular materials. The presence of these coupling parameters can affect transverse deflection when beam is subjected to pure bending. In this paper an attempt is made to take consideration of these coupling by implementing equivalent stiffness methods along with classical beam theory. The objective is to find out the effects of these couplings on transverse deflections, neutral surface positions and on stress and strain distribution throughout the thickness of the beam. Transverse deflection, neutral surface position, through the thickness stress and strain distribution are obtained for simply supported and clamped-clamped boundary conditions. The analysis shows that results obtained for neutral surface position, positive and negative half cycle frequencies, transverse deflection and even strain, strain distribution through the thickness by considering the coupling parameters are different from the results obatained by neglecting the couplings.