A general form of Drucker-Prager type smooth and convex plastic potential. Part 1: Definition and features

A general form of Drucker-Prager type plastic potential suitable for concrete and soil is proposed, allowing to distinguish qualitative difference between stress states with prevailing tension from those with dominant compression. The potential includes six material constants and one arbitrarily chosen function g describing deviatoric section of the potential surface. The influence of the parameters on the shape of the considered yield surface is discussed. The verification of convexity of the proposed potential is carried out in order to impose conditions on the parameters and the unknown function g. The calibration based on results of typical tests for concrete presented in the literature is proposed and the values of the coefficients are given out in relation to the yield limit in uniaxial compression test for common proportions of yield limits for other basic tests.