Vibration analysis of FML cylindrical shell optimized according to maximum natural frequency under various boundary conditions

In this paper optimized the arrangement of the fiber metal laminate for cylindrical shells to achieve the maximum natural frequencies. In order to maximize the FML shell natural frequencies the sequence of the composite –metal layers and fiber orientation are changed frequently and for each case, the sample natural frequency is calculated. Finally FML shell with maximum natural frequencies is found. Hamilton‘s principle and energy method is used to define the equation of motion and First order shear deformation theory (FSDT) is utilized for vibration analysis in the shell’s equilibrium equation .In order to solve free vibration problem the double Fourier series is used to obtained the eigenvalue problem. For this purpose, through a MATLAB program linked to the finite element software of ABAQUS .different shells with various layer sequence and fiber orientation are created and studied from optimization aspect. This comprehensive program is able to analyses the FML shells with various arrangements of composite –metal layers, fiber orientation and boundary condition. The simply-simply and clamp-clamp boundary conditions are applied on edges. The applicable fiber orientations are 0,30,60,90 degrees.