Harmonic Wave Propagation in Composite Laminates Using State Space Approach

A mixed method of elastodynamics, termed state space approach, is presented for analyzing the dynamic response of laminated composite plates. In principle, the method reduces the governing three-dimensional equations to a set of two-dimensional equations while keeping the field equations in their exact form The interlayer continuity conditions are satisfied exactly Natural frequencies are obtained for the vibration of two-layered plates with dissimilar degrees of orthotropy of layers. The numerical solution is exact in that it is sought from closed form expressions. Comparisons are made with the results obtained by solving the exact elasticity equations of plates in plane strain The numerical results from the present theory are seen to be exactly the same as that obtained from the exact solution of field equations even for plates with large thicknesses.