Dynamic Characters of Stiffened Composite Conoidal Shell Roofs with Cutouts: Design AIDS and Selection Guidelines

Abstract

Dynamic characteristics of stiffened composite conoidal shells with cutout are analyzed in terms of the natural frequency and mode shapes. A finite element code is developed for the purpose by combining an eight-noded curved shell element with a three-noded curved beam element. The code is validated by solving benchmark problems available in the literature and comparing the results. The size of the cutouts and their positions with respect to the shell centre are varied for different edge constraints of cross-ply and angle-ply laminated composite conoids. The effects of these parametric variations on the fundamental frequencies and mode shapes are considered in details. The results furnished here may be readily used by practicing engineers dealing with stiffened composite conoids with cutouts central or eccentric.