جستجوی مقالات مرتبط با کلیدواژه « composite shell » در نشریات گروه « مواد و متالورژی »

In this study, the vibration of a composite cylindrical shell in the presence of a longitudinal and circumferential crack was investigated. The governing equations were derived based on the first-order shear deformation theory and could be converted to Donnell’s, Love’s, and Sanders’ theories by selecting proper parameters. A multi-domain generalized differential quadrature method was used to solve the problem. In this technique, a physical domain was decomposed into several elements. Then, a generalized differential quadrature method was employed to discretize the governing equations, boundary conditions at shell edges, and the compatibility conditions at the interface boundaries of adjacent elements in both longitudinal and circumferential directions. Assembling these discretized equations led to a system of algebraic equations, which could be solved through an eigenvalue solution to calculate the natural frequency of the shell. This procedure was coded in Matlab environment. Numerical results obtained by the presented method were compared with Abaqus results and those available in the literature. After verifying the accuracy and precision of the proposed method, it was employed to study the effect of different parameters on the vibrational behavior of cracked composite shells. The obtained results can be used as a benchmark for further studies.

In this paper, the free vibration of a composite shell with and without a rectangular cutout was studied based on the first-order shear deformation theory. The equations were derived in a general form and can be converted to Donnell`s, Love`s, and Sanders` theories. To investigate the perforated shell a physical domain was decomposed into several elements with uniform boundary and loading conditions in each element edges. In each element, the governing equations were discretized in both longitudinal and circumferential directions by the use of generalized differential quadrature method (GDQM) as well as the boundary conditions at the cutout edges, and the compatibility conditions at the interface boundaries of adjacent elements. Assembling these discretized relations, a system of algebraic equations was generated. Finally, the natural frequencies were calculated by an eigenvalue solution. To validate the presented method, the results of GDQM were compared with the available ones in the literature and also with the ABAQUS finite element model. Then a parametric analysis was performed to investigate the effects of different parameters on the vibrational behavior of the shells with and without cutouts. This study illustrated that small cutouts (c/L<0.3) had no significant effect on the natural frequency of the shell. This was independent of both shell material and layup. In addition, decreasing the length to radius ratio or increasing the shell thickness decreased the effect of cutout on natural frequency. Moreover, circumferential cutouts had less effect than longitudinal ones.