Large deformation elastic-plastic analysis of space frames

Abstract

A method for large deformation elastic-plastic analysis of space frames is presented. The method is based on a large deformation formulation, which was developed initially for elastic systems, and is extended herein to include elastic-plastic effects. The method takes into consideration the effects of large joint translations and rotations. Local member force-deformation relationships are based on the beam-column approach, and the changes in member chord lengths caused by axial strain and flexural bowing are taken into account. The material is assumed to be ideally elastic-plastic, and yielding is considered to be concentrated at member ends in the form of plastic hinges. The effect of axial force on member bending and torsional stiffness, and on plastic moment capacity, is included in the analysis. Numerical solutions are presented for four structures, which indicate that the method of analysis is highly accurate in predicting large deformation elastic-plastic responses of structures.