ANALYSIS OF BUCKLING PERFORMANCE OF LAMINATED CYLINDRICAL SHELL WITH CUTOUT

Abstract

The rapid development in the automotive and aerospace industries asks for the development of the materials having high strength and lightweight, composite materials fulfill this requirement. The other advantage with these materials is that there strength can be tailored in the desired direction. The structures and components made of composite materials are used in various applications to take different types of loads (static load and dynamic load) and can be subjected to various boundary conditions. Thus it is necessary to understand the behavior of composite structures in different loading conditions. The laminated cylindrical shells are one of the common structures made up of composite materials used for different applications such as pressure vessels, structural members, aerospace structures etc. A shell is a thin body whose middle surface is curved at least in one direction. Cylindrical and conical shells have only one direction in which the middle surface is curved, on the other hand, in spherical shells there is curvature on both directions. These shell structures are subjected to various types of loads such as compressive load, internal pressure, external pressure (or combination of all). The present research work deals with the buckling behavior of laminated composite cylindrical shell (of 500 mm height and 500 mm diameter and 1.25 mm thickness) with centrally located cutout subjected to axial compression at one circumferential end (fixed end i.e. all degrees of freedom are zero) and clamped at the other circumferential end. Buckling performance of laminated shell with cutout can depend upon many parameters such as lamination sequence, shape of cutout, size of cutout. In the present study, the influence of above stated parameters on the buckling behavior of shell is presented, since these structures are used with different cutouts (provided for different purposes) in different applications, therefore the effect of the cutouts of different shapes and sizes on the buckling behavior is observed. In the analysis, cutouts of three shapes are taken (circular, rectangular, and square). The area of all the cutouts is kept same. The eigen value and non linear analysis both are carried out to study the buckling behavior of the shell. The eigen value analysis is carried out to calculate the critical buckling load and the nonlinear analysis is carried out to study the load deflection path around the cutout. The buckling behavior of the shell is also investigated under transient loading. In the study prime objective is to investigate the local response of the shell around the cutouts of different shapes. A comparative study is made among different models of the shells having cutout of different shapes. An attempt is made to make the v structures more stable by providing reinforcement around the cutouts. The reinforcement is provided around the cutouts by using different material and by increasing the shell thickness around the cutout. The standard finite element code ANSYS is used for the analysis. vi