OPTIMUM BUCKLING DESIGN OF CYLINDRICAL STIFFENER SHELL UNDEREXTERNAL HYDROSTATIC PRESSURE

Abstract

This paper present an investigation of the collapse load in cylinder shell under uniform external hydrostatic pressure with optimum design using finite element method via ANSYS software. Twenty cases are studied inclusive stiffeners in longitudinal and ring stiffeners. Buckling mode shape is evaluated. This paper studied the optimum design generated by ANSYS for thick cylinder with external hydrostatic pressure. The primary goal of this paper was to identify the improvement in the design of cylindrical shell under hydrostatic pressure with and without Stiffeners (longitudinal and ring) with incorporative technique of an optimization into ANSYS software. The design elements in this research was: critical load, design variable (thickness of shell (TH), stiffener’s width (B) and stiffener’s height (HF). The results obtained illustrated that the objective is minimized using technique of numerical optimization in ANSYS with optimum shell thickness and stiffener’s sizes. In all cases the design variables (thickness of shell) was thicker than the monocoque due to a shell’s thicker is essential to achieve the strength constraints. It can be concluded that cases (17,18,19, and 20) have more than 90% of un-stiffened critical load. The ring stiffeners causes increasing buckling load than un-stiffened and longitudinal stiffened cylinder