A Refined Theory of Anisotropic Thick Plates

For the deformation of anisotropic plates with arbitrary thickness, a refined theory is proposed to derive approximate equations with any desired accuracy, and general two-dimensional equations in the n-th order approximation are presented. The approximate equations presented are solved for a graphite/epoxy composite plate subjected to a sinusoidally distributed load at the upper surface, and the solutions are compared with the exact one and with those of several other approximate theories by numerical calculation. The results obtained are as follows: (1) The accuracy of solutions of equations in any given order of approximation decreases with increase in the strength of anisotropic property as well as in the plate-thickness. (2) As the order of approximation is increased, the accuracy of solutions is improved and the solutions approach the exact one asymptotically. (3) When the accuracy of solution is appointed for a plate with any thickness and elastic properties, the order of approximation of equations to be used can be determined by preliminary calculation as shown in this paper.