This paper on "Reliable Three-Dimensional Shell Elements for Arbitrarily Large Deformations" was presented at the NAFEMS World Congress on Design, Simulation & Optimisation: Reliability & Applicability of Computational Methods - 9-11 April 1997, Stuttgart, Germany.

Abstract

Well-known finite element concepts like the Assumed Natural Strain (ANS) and the Enhanced Assumed Strain (EAS) techniques are combined to derive efficient and reliable finite elements for a continuum based, three-dimensional shell formulation including thickness stretch. The formulation is capable to handle large strain and rotation problems. Furthermore any three-dimensional constitutive law, either linear-elastic, hyperelastic, elastic-plastic or others, can be implemented without modifications.
For the derivation of the non-linear EAS formulation, an alternative way to the one proposed by Simo and Armero [19] is chosen. In context of the question for a sensible choice of trial functions the relation of hybrid stress and EAS elements is investigated. A modification and extension of the thickness strains is necessary to eliminate "thickness" locking problems resulting from the three-dimensional stress and strain state.