Imperfections on thin axisymmetrical shells: Fluid-structure interaction aspects

A finite element method is developed for the calculation of fluid-structure interaction aspects in problems involving thin axisymmetrical shells with imperfections. The method consists of a Fourier serie expansion of the equilibrium equations. Application of the method on a structure, representative of LMFBR internals, show that the imperfections can significantly affect mode shapes and natural frequencies. Implications for seismic design and buckling analysis of such structures are indicated. (orig.)