free vibration analysis of composite hemispherical shells with cut-out

Nowadays growing interest is shown in structural design in different branches of modern technology. Hence various theories for analysis of shell-type structures are developed. The analysis of shells of revolution such as cylindrical and spherical shells for their applications in engineering fields،i. e.، aerospace equipment and high speed rockets are immensely interesting subjects for researchers. Since composite materials are widely used because of their structural advantages، mathematical modeling of such structures is of prime interest and importance. In this paper، with using semi analytical finite element، free vibration of composite hemi-spherical shells with cut-out at apex was investigated. The effect of amount of cut-out at apex، fiber angles and boundary conditions were studied، too. For deriving of strain relationship first order shear deformation theory was used. The obtained results from the present analysis are compared with some available published results to show the accuracy and robustness of the present work.