A cylindrical shaft of circular cross section is subjected to a bending moment of constant amplitude over its entire length. The deformation of the shaft material can be approximated by an elastic-perfectly plastic constitutive model and the yield strength in tension can be considered equal to that in compression. If the outer fibers of the shaft yield plastically over a depth of 1/4 of the diameter during the application of the bending moment, qualitatively discuss the development and distribution of mechanical residual stresses along the diameter of the shaft when the bending moment is fully removed.