Deflection and vibration in shear-deformable beams and laminated composites made of bimodular and multimodular materials /

Abstract

Also, presented is a closed-form solution of the static equilibrium equation for a bimodular composite laminate in cylindrical bending. The resulting shear-stress distribution is used to obtain expressions for the Timoshenko-type shear correction coefficient and the maximum dimensionless transverse shear stress. Based on this more accurate prediction of shear correction coefficient for bimodular materials, a new theory is developed for the vibration of a bimodular sandwich beam with thick facings which agrees much better with experimental results than classical sandwich theory.

A transfer-matrix analysis is presented for determining the static and dynamic behavior of thick, orthotropic beams of "multimodular materials" (i.e., materials which have different elastic behavior in tension and compression, with nonlinear stress-strain curve approximated as piecewise linear, with four or more segments). Also, an exact solution is presented for cases in which the neutral-surface location is constant along the beam axis. Results for axial displacement, transverse deflection, bending slope, frequency, bending moment, transverse shear force, axial force, and location of neutral surface are presented for different load and boundary conditions. In addition, comparisons are made among multimodular, bimodular, and unimodular models for a beam with aramidcord-rubber properties taken from experimental stress-strain curves.