A Systems Approach to Nonlinear Finite Element Analysis of Shell Structures

Abstract

This report describes a systems approach to the nonlinear finite element analysis of shell structures. The research objective is to understand the structure a small language and computational environment should take so that matrix and nonlinear finite element computations can interact in a seamless manner.<P>One four-node-thick shell finite element and one eight-node-thick shell finite element is formulated and implemented in ALADDIN [1]. The finite elements are based on a three-dimensional continuum formulation, and are simplified by assuming a flat element geometry. Numerical experiments are presented for in- plane displacements of a flat plate, and out-of-plane bending of a cantilever structure. In each case, material nonlinearities are modeled with bi-linear and Ramberg-Osgood stress-strain curves. The report concludes with recommendations for further work in the areas of nonlinear finite element solution procedures and enhancements to ALADDIN's problem-solving infrastructure.