Inelastic Thermal Analysis of Preloaded Steel Trusses Undergoing Heating and Cooling Stages

Abstract

The inelastic nonlinear behaviors of preloaded steel trusses undergoing heating and cooling cycles, a problem not well treated previously, are studied in this paper. A bilinear elastoplastic model with a kinematic strain-hardening rule is adopted for steel at varying temperatures. The material softening effects at elevated temperatures are taken into account via the Eurocode 3 reduction factors. The plastic strain resulting from strain reversal upon unloading at a given temperature is considered in updating the stress-strain curve for the next temperature increment. Two simple trusses are adopted to illustrate the physical phenomena involved. All the equations are presented in incremental form, consistent with the updated Lagrangian formulation. The results for the trusses are believed to be new and can be adopted as the benchmarks for validating other numerical approaches used in treating problems involving the heating and cooling stages.