Elastico-Plastic Straining when the Principal Stresses Rotate

Abstract

IN recent years there has arisen a controversy, on theoretical grounds¹, on whether post-yield straining of metals should be analysed by considering : (I) plastic increment-strain components only (Levy, about 1870, and Mises later²); (II) plastic total-strain components only attained instantaneously (Nadai, 1931 ³) ; (III) plastic + elastic increment-strain components (Prandtl, 1924, and Reuss, 1930 ⁴); (IV) plastic + elastic total-strain components attained incrementally (Swainger, 1945 ⁵). It is shown in this communication that, from experimental evidence, none of these theories is correct ; but that a simple modification to my theory in (IV) leads to correct predictions ; that is, one must consider (V) plastic increment-strain components + elastic total-strain components attained incrementally.