Variable stiffness composite laminated beams- nonlinear free flexural vibration behavior using a sinusoidal based shear flexible structural theory accounting for Poisson's effect

摘要

In the present work, formulation for the nonlinear free vibrational behavior of laminated variable stiffness composite beams with curvilinear fibers is made incorporating sinusoidal function for representing the trans-verse shear flexibility, geometrical nonlinearity, and accounting for Poisson's effect through the constitutive equation for analyzing beams with general composite lay-up. Applying Hamilton's principle combining with a finite element approach based on three-noded C-1 beam element, the governing equations are formed through matrices. The solutions for the developed governing equations are evaluated iteratively by introducing eigenvalue analysis and the results are viewed through the frequency-amplitude relationship. A large number of design parameters like curvilinear fiber angles in a layer, number of layers, lay-up sequence, thickness ratio, etc. is assumed to visualize the nonlinear free vibration characteristics of VSCL beams. Also, for the practical situation, the influence of thermal environment and restraint elastically against beam ends rotation, to accommodate other than classical boundary conditions, hybrid beam (consisting of constant and variable stiffness layers) on the non-linear free vibrational behavior is presented.