Stress - Strain - Temperature Relationship for Structural Steel

This paper presents a new mathematical relationship for representing the stress-strain behavior of structural steel at elevated temperatures. The relationship is constructed by fitting two versatile, continuous equations to experimental data. The first equation, a general stress-strain equation previously proposed by Poh, is used for characterizing the stress-strain data. The second equation is proposed in this paper. It is used for representing the variation of the stress-strain behavior with temperature. A simple two-stage procedure is used for fitting the equations to the experimental data. This gives a set of curve fitting coefficients that can be simply expressed in a matrix format. It is shown that the resulting relationship accurately represents the experimental data. Furthermore, since the relationship comprises only two equations and a coefficient matrix, it can be easily incorporated into computer analysis programs. It can also be readily used for establishing the properties of other steels.