Calculations Methodology of the Instabilities for Thin Shell Structures

摘要

This paper presents a calculation methodology of the instabilities applicable for the design of axisymmetric thin structures against buckling risk. The application case discussed here is a tank loaded by external pressure and seismic effects. The calculations have been made by the Finite Element Method with the CASTEM System Codes. In a first step, the structure is supposed perfect and the calculations are made with an axisymmetric thin shell model. The axisymmetric model gives good results for high circumferential modes. In the case of earthquake, simulated by lateral loads, complementary results about shear buckling modes are obtained using a three dimensional model. However, the real structure is not perfect but includes necessarily initial imperfections. Consequently, in a second step, the study consists in determining the critical load reduction due to the introduction of an initial imperfection. (ERA citation 09:028349)