ABSTRACT
This chapter describes a refined plastic-zone analysis based on the finite element method. This plastic-zone finite element analysis is applicable to the in-plane analysis of framed structures of arbitrary geometry where the behavior of the members can be described adequately by beam-column theory. The nonlinear analysis can be used to solve in-plane stability problems of columns, beam-columns, arches, and frames. The chapter also describes a finite element computer program, Nonlinear Inelastic Frame Analysis (NIFA), written by the author in the FORTRAN 77 language. It provides the theoretical basis of the program and several examples illustrating the capability and accuracy of the program. There are two main approaches which have been used by researchers to model the partial plastification of members in a second-order inelastic analysis, although in both cases the member needs to be subdivided into several elements along its length to model the behavior accurately.
