Vibration of unsymmetrically laminated thick quadrilateral plates

The problem of free vibration of arbitrary quadrilateral unsymmetrically la minated plates subject to arbitrary boundary conditions is considered. The Ritz procedures supplemented by the simple polynomial shape functions are e mployed to derive the governing eigenvalue equation. The displacements are approximated by a set of polynomials which consist of a basic boundary func tion that impose the various boundary constraints. A first-order shear defo rmable plate theory is employed to account for the effects of the transvers e shear deformation. The numerical accuracy of the solution is verified by studying the convergence characteristics of the vibration frequencies and a lso by comparison with existing results. The new results of this study incl ude the sensitivity of the vibration responses to variations in the laminat ion, Boundary constraints and thickness effects, and also their interaction s. These numerical values are presented for a typical graphite/epoxy materi al, in tabular and graphical forms. (C) 1999 Acoustical Society of America. [S0001-4966(99)04403-3].