A PRECISE STRESS-STRAIN RELATION OF MILD STEEL IN THE PROPORTIONAL DEFORMATION UNDER COMBINED LOADING

Abstract

With the appearance of electronic computer, more ditailed theories which can simulate accurately actual phenomena are evolved by taking into account the secondary effect hitherto neglected for avoiding mathematical difficalties in analyzing phenomena. In the plastic deformation, such a theory will be needed also for making precise estimations in the structural analysis and the deformation analysis of plastic work. According to the recent experiments, it has been made clear that the conventional plastic flow theory cannot simulate acculately the plastic deformation of metals under complex loading. In the present paper, as a first step of formulating in detail the plastic features of real materials under complex loading, an experiment is performed on the proportional deformation by applying a combined load of axial force and torsion to a thin-walled tube of mild steel. The stress-strain relation is formulated by using a fundamental tensorial equation from the experimental result.