Free vibration analysis of laminated composite cylindrical shells

Abstract

Free vibration of cylindrical shells made up of laminated composite material is studied by using Finite Element approach in software-based method. Vibration theory of laminated composite shell using First-order Shear Deformation Theory (FSDT) is presented in this paper. The equations of motions are based on First-order Shear Deformation Theory (FSDT) of shell. The effects of transverse shear deformation and rotatory inertia are taken in to account. An eight-noded serendipity elements with 5 degrees of freedom at each node is considered. Finite element approach is employed for finding the shape functions. The natural frequency of the laminated composite shell is computed using MATLAB programming. Some of the results obtained in the analysis are compared with those present in the existing literature. Several numerical results are also presented for selected material parameters, shell geometry and support condition to study the free vibration characteristics of various laminated composite cylindrical shells. The natural frequency for different number of layers and thickness and other conditions found out. The obtained values are compared with the values available in the literature Reddy [20] & Liu [25]. Effects of material properties and geometric parameters on the free vibration of laminated composite shells are discussed and some related mode the constants generating by the integrating process are disposed by gauss quadrature integration, and thus the equations of motion of total system including the boundary condition are transformed into an algebraic program. Then natural frequencies of the laminated composite structures are directly obtained by solving these programs. Stability and accuracy of the present method are verified through convergence and validation studies. Some new results for laminated composite cylindrical shell with variable thickness and arbitrary boundary conditions are presented, which may serve as benchmark solution.