Behaviour and Optimization Aids of Composite Stiffened Hypar Shell Roofs with Cutout under Free Vibration

Abstract

A scrutiny of the literature reveals that the free vibration characteristics of stiffened composite hypar shell with cutout are missing. So a generalized finite element formulation for the stiffened hyperbolic paraboloidal shells bounded by straight edges (commonly called as hypar shells) is attempted using an eight-noded curved quadratic isoparametric element for shell with a three-noded beam element for stiffener. Numerical problems of earlier investigators are solved as benchmark problems to validate the approach. A number of problems are further solved by varying the size of the cutouts and their positions with respect to the shell centre for different edge constraints. The results are presented in the form of figures and tables. The results are further analysed to suggest guidelines to select optimum size and position of the cutout with respect to shell centre considering the different practical constraints.

Mode frequency analysis of antisymmetric angle-ply laminated composite stiffened hypar shell with cutout

“…Applications of various shell theories such as classical, shear deformation, 3D, and nonlinear for various shell geometries have received extensive attention from scholars round the globe [1][2][3][4][5][6][7][8]. Some studies used higher order shell theories [9][10][11][12][13][14][15][16], whereas others [17][18][19][20][21][22][23] considered finite element approach based on the first-order shear deformation theory to study the free vibration aspects of stiffened shell panels of different forms, that is, cylindrical, elliptic paraboloid, hyperbolic paraboloid, hypar, conoid, and spherical shells in the pres-ence of cutout. But the analysis of stiffened shells with cutout for higher modes is scanty in the literature.…”