Analysis of free vibration of laminated composite cylindrical shells with rectangular cutout

In this paper, the free vibrations of multi-layered composite cylindrical shells with rectangular cutout are analyzed analytically. Cylindrical shell equilibrium equations are derived based on classical shell theory (CST) and using Newton's method. Boundary conditions of the two-headed shell are considered simply supported. According to the boundary conditions, the displacement components are written as double Fourier series expansions. Relationships of the strain-displacement and curvature displacement are considered based on Love’s approximation theory. Modeling of the cutout by distribution function (Heaviside) is considered based on the equilibrium equations of the composite cylindrical shell. In order to obtain the natural frequency of the rectangular cutout composite cylindrical shell, the equations of motion have been solved using the Galerkin method. For validation, firstly, the results of the composite cylindrical shell have been compared with the Abaqus finite element software and the Previous literature in this field, that there is a good match between them. Finally, the effect of the geometrical parameters of the composite cylindrical shell with cutout, such as the length, radius, thickness and layering of the cylindrical shell, as well as the dimensions, direction and location of the cutout, on the natural frequency of the structure was investigated, that the results show that with increasing The dimensions of the cutout increase the reduction of the natural frequency of the structure.