Large Deformation Analysis of Elasticplastic Frames

A numerical procedure for large deformation analysis of elastic‐plastic frames is presented. The procedure is based on an Eulerian formulation, which was developed initially for elastic systems and is extended herein to include elastic‐plastic effects. Local member force‐deformation relationships are based on the beam‐column approach and changes in member chord lengths due to axial strains and flexural bowing are taken into account. A computational technique for determining the nonlinear response is described in detail. The technique utilizes an incremental load approach with Newton‐Raphson iteration to satisfy joint equilibrium equations. Numerical solutions are presented for three structures and are compared to those reported by previous investigators.