A New Method for Ascertaining the Strength of Metals

This paper decribes a strain-limit strength theory; the strength of a material is established from the normal strain equations by considering: (1) the principal strains determine the strength of a material, (2) that the intermediate normal strain equations are defined by the relative magnitudes of the principal strains, and (3) that the strength of a metal coincides with the occurence of a maximum permissible strain. The process is demonstrated for plane stresses that cause an arbitrary condition of strain. From these equations, two yield criteria are derived by introducing Hooke’s law and by using the onset of plastic flow as the limit strain event. The equations produced are similar to the von Mises and Tresca yield conditions.