Numerical and Software Requirements for General Nonlinear Finite Element Analysis

Abstract : In this work, the theoretical formulations are again considered, however, primary emphasis has been placed on design and implementation of the computer software. The governing equations of nonlinear continuum mechanics, usually expressed in tensor form, are given in matrix notation familiar to most structural engineers. Both geometric and material nonlinearities are considered. The classical equations of the Lagrangian description are cast into the finite element method. Specific matrices are given for large deformations of a three dimensional solid to illustrate the procedure. A general purpose, user-oriented software system, FINITE, for static linear and nonlinear analysis is described. FINITE relies upon the POLO supervisor for problem-oriented-language translation, data management, and dynamic memory allocation. FINITE supports multi-level user-defined substructuring and condensation for linear and nonlinear analysis. Isolation of the element and material model libraries from the system enables rapid entry of new modeling capabilities.