Plastic Stress-Strain Relationships—Some Experiments to Derive a Subsequent Yield Surface

Experiments have been carried out on thin tubular specimens of alpha brass subjected to various combinations of torque and transverse tension, after initial overstrain in torsion. The loading paths were based upon a yield function expressing one degree of anisotropy which had been found previously to give good correlation of initial radial loading paths. The primary definition of yield used was the “Taylor-Quinney, Lode”; however, “Limit of Proportionality” and “Initial Loading Slope Tangent” definitions have also been investigated. The derived yield surface (Taylor-Quinney) shows strong positive cross effect, rotation, and a Bauschinger effect extending over the whole reversed quadrant to initial loading. No indication of the formation of a corner on the yield surface was found.