HIGHER-ORDER THEORY AND ITS FINITE ELEMENT METHOD FOR THICK LAMINATED COMPOSITE CYLINDRICAL SHELLS

In this paper, an improved LCW-type refined higher-order, thick-laminated-shell theory is presented to analyze vibration of thick cylindrical shells. The new displacement model is developed, which is in the form of a cubic function of the thickness coordinate and is in the form of a quadric function. Using the boundary conditions, transverse shear forces of the upper and nether surfaces are zero, the above- mentioned displacement field is predigested and unknown quantities are reduced to seven. A finite element expression based on the above theory is suggested. The accuracy of the present theory is examined by applying it to a typical free vibration problem. The results are compared with analytic solutions of higher-order shear deformation theory by Soldatos and Lam. The present theory shows the deflections more accurately than those obtained from the previous works. In this paper, the variation of fundamental frequency parameter for a thick shell with the L/R ratio shows that, owing to including effects of normal stress and normal strain, the present theory is more adaptive to structures with small length-to-radius L/R ratios.