BOUNDARY BEAM CHARACTERISTICS ORTHONORMAL POLYNOMIALS IN ENERGY APPROACH FOR VIBRATION OF SYMMETRICAL LAMINATES .1. CLASSICAL BOUNDARY-CONDITIONS

An investigation on the effects of boundary constraints on the vibrato ry characteristics of symmetrically laminated rectangular plates is ca rried out. The research findings are reported in a two-part paper. Vib ration frequency parameters and mode shapes for symmetric laminates wi th classical boundary conditions are reported in Part I and elasticall y restrained boundaries in Part II. The analysis is performed based on the use of admissible beam characteristics orthonormal polynomial fun ctions in the Rayleigh-Ritz method to derive the governing eigenvalue equation. In this paper, several examples for laminates with different combinations of free, simply supported and clamped edges are solved t o demonstrate the accuracy and flexibility of the present method. Disc ussion on the effects of boundary conditions, fiber orientations and s tacking sequences on the vibrational response is included.