A New Approach for Finite Element Analysis
of Sandwich Shells

Ala Tabiei and Romil R. Tanov
Center of Excellence in LS-DYNA Analysis
Department of Aerospace Engineering and Engineering Mechanics
University of Cincinnati, OH 45221-0070, USA

ABSTRACT: A new finite element approach to sandwich shells is proposed. It uses existing shell finite elements formulated for homogeneous shells. The "sandwich" nature of the problem is hidden from the main finite element program. Based on several assumptions the proposed homogenization procedure calculates stress increments in a homogeneous fictitious material, called "equivalent", which correspond to the strain increments in the equivalent material points. The stresses in the equivalent material are calculated based on the stress and strain fields in the sandwich layers, which are determined from the incoming strain field for the equivalent material. The approach can be combined with shell elements formulated for homogeneous materials, based on Reissner-Mindlin shell theory or with elements based on a higher order shell theory. It avoids the necessity of formulating special shell elements for sandwich constructions, which in most cases, due to their large number of degrees of freedom, significantly decrease the computational efficiency of the finite element analysis. The sandwich homogenization procedure can be combined with a composite micromechanics-based model for composite laminates to analyze sandwich shells with composite faces.

Keywords: sandwich shells, finite element analysis, sandwich homogenization, shell elements, composite faces, plate deformations

REFERENCE: Tabiei, A. and Tanov, R., "A New Approach for Finite Element Analysis of Sandwich Shells", Journal of Sandwich Structures & Materials, submitted for publication, 1999.