STABILITY AND VIBRATION OF INITIALLY STRESSED PLATES COMPOSED OF SPATIALLY DISTRIBUTED FIBER COMPOSITES

Three groups of elastic constants, defined as orthotropic constants, h ave been introduced in this paper, and utilizing these constants enabl es the transformed stiffness to be expressed in rather simple forms. T o simulate spatial fiber orientation in a preferred direction, a distr ibution function controlled by two parameters is introduced. The equiv alent composite elastic properties are then simulated by an aggregated model. Three special cases for fiber orientation have been discussed and the closed-form stiffnesses have bene obtained. Equations of motio n for a composite plate in a general state of non-uniform initial stre sses, when the effects of transverse shear and rotatory inertia are in cluded, are derived by using Trefftz equations and the variational pri nciple. Finally, the stability and vibration equations are solved for simply supported rectangular plates in a state of normal stresses plus an edge twisting stress. The effect of fiber orientation on the funda mental frequencies and buckling loads has been discussed. (C) 1997 Aca demic Press Limited.