Theory of steady-state creep with a complex stress state

Abstract

1. A theory of steady-state creep in a complex stress state was proposed. The theory is based on similarity of creep curves with different principal-stress ratios. 2. An optimum method described for obtaining the equations makes it possible to adequately describe creep within a broad range of types of stress states on the basis of a limited amount of empirical data. 3. Using the example of nodular iron, we demonstrated the existence of similarity among creep curves. This makes it possible to take Eqs. (5) as the fundamental equations of steady-state creep. 4. The values obtained for the coefficients k andZ show that the creep of nodular iron at high temperatures is anisotropic in nature. After the rest of the components of the anisotropy tensor A are determined, equations can be obtained for any type of complex stress state.