Effects induced in metallic materials due to non-proportional cyclic loading

The paper presents an experimental evaluation of effects arising during deformation induced by non-proportional cyclic loading along circular path. Three engineering materials were taken into account: MO58 brass, 55 steel and PA6 aluminium alloy manufactured according to Polish Standards. A problem of additional hardening/softening due to non-proportional loading in comparison to cyclic loading along proportional path is studied experimentally for aluminium alloy and steel. In order to assess the influence of prior cyclic deformation on mechanical properties of the materials tested, the yield surface concept was applied.