Stress-strain relationship for periodic loading

A mechanical model for the inelastic periodic deformation of a material is proposed. According to the model, axial plastic strain results from plastic shears in four planes of maximum shear stresses. The plastic shears in these planes are determined by the deformation strength of the material, which is assumed to be different in different systems of sites and depends on the deformation direction. Deformation strength characteristics of materials are proposed. The model and known deformation strength characteristics allow an analytical description of the strain hardening and softening of materials. An example of calculating strain curves of a hypothetical material under soft loading is given.