Discuss the cyclic deformation of a material in terms of the two-element Masing model, assuming elastic-perfectly plastic response.
(a) Construct the hysteresis loops for a small amplitude at which only the softer elements yield plastically and for a larger amplitude at which both elements yield plastically.
(b) Show that the so-called 'permanent softening' is expected only in one of the two cases and that the amount of permanent softening is equal to twice the internal back stress in the soft elements.
(c) Considering both cases, can permanent softening be considered an unambiguous measure of the back stress?
(d) Describe the occurrence of the Bauschinger effect in terms of deformation-induced internal