A Study on the Deformation Theory of Plasticity in a Rotating Disc

Abstract

It is a question yet to be studied whether the deformation theory may be used reasonably instead of the flow theory for the calculation of stresses and strains in a plastically deformed rotating disc. In this paper, the question is solved for a disc, which rotates at a speed that increases with time. At first the conditions, under which both theories give the same results referring to such a rotating disc, were studied based upon the theory of Ilyushin, and from these conditions it was deduced that the deformation theory was applicable to discs except partially plastic ones, which have elastically and plastically deformed regions. Secondly, methods to calculate stresses and strains in a partially plastic rotating disc by applying the deformation and the flow theories were developed, and the calculated results by those methods gave a fairly good coincidence with each other ; it shows that the deformation theory is applicable also to a partially plastic rotating disc.