Some modifications of an isoparametric shell element

The subject of this paper is the eight-node shell element of Reference 1. The following options in element formulation are discussed: an alternate form of co-ordinate transformation between global and shell co-ordinates, use of stiffness coefficients for sandwich construction and inclusion of internal degrees of freedom. Numerical examples show the effects of adding internal freedoms, and serve to compare stresses calculated directly at element nodes with those obtained by extrapolation from values at the Gauss points.