Critical buckling load analysis on spherical shells under various geometric imperfections

Abstract

Abstract The strength of shell structures is mainly determined by their ability to resist buckling. However, the presence of geometric imperfections – a condition which the geometry is no longer the same as the original condition – significantly deteriorates the critical load and often leads to catastrophic failure. Ratio between the actual critical buckling load to the theoretical prediction is called knockdown factor. The study aims to analyse the critical buckling load on spherical dome elastic shells under various geometric imperfections. This study was conducted into several thicknesses (10, 16, 20, 37, 50 mm) and fixed base radius of 4000 mm. Analyses of linear buckling and nonlinear static are performed and aided with finite element program using MIDAS FEA. The result of this study reveals that the critical buckling load decreases sharply in the beginning of imperfection, then reach for quite slow progression until a constant value of Kd = 0.1. In addition, the higher minimum knockdown factor is obtained as the shell thickness increases.