I am struggling to define the temperature-dependent properties required to model the plasticity transition for carbon steel at elevated temperatures due to the limitations of the input parameters being in a two-dimensional tabular format.

The properties work as expected for the Young's modulus and 0.2% yield strength through linear interpolation of the values entered from EN 1993-1-2: Eurocode 3 for structural fire design of steel buildings and are shown below.

My problem is encountered when trying to establish the temperature-dependent properties for the elastic-plastic transition as the inputs are limited to Yield, Plastic Strain and Temperature. It is therefore inappropriate to enter this information in a tabular form as the values required to plot the curve using the first two columns change with each increment of temperature.

The stress-strain curve and tangent modulus shown above are derived from the relationships shown in EN 1993-1-2 and reproduced below.

Is it possible to get these properties handled correctly as I am struggling to implement it correctly. If I ignore the plasticity transition, it shall only produce displacement values at the elastic limit and that is not appropriate for the analysis required.