THE BAUSCHINGER EFFECT IN COMPRESSION TENSION OF SHEET METALS

It is important to know how sheet metals behave under complicated loading conditions, since yielding and hardening of a metal are actually dependent upon the stress state and deformation history. An example is the Bauschinger effect, which is manifested as a loss of yield strength during reverse loading upon plastic prestraining. Quantitative analysis of the Bauschinger effect is required for better understanding of this problem. In this study, experiments carried out by subjecting sheet metals to uniaxial compression-tension tests show that the Bauschinger effect varies with the material properties and the magnitude of prestrain. On the basis of the experiments and the continuum theory of plasticity, parameters defining the Bauschinger effect are proposed, which interpret the combined effect of work hardening and work softening of a material during forward and reverse straining, and a model revealing the Bauschinger effect on the subsequent yield surface is finally presented.