Upper-bound approach to plane strain strip rolling with free deformation zones

A recently developed extension of the upper-bound theorem is applied to the problem of rigid/plastic deformation in case where the surface configuration of the concerned body is previously unknown. By assuming a simple velocity field the strip rolling process is analysed by considering the free deformation zones in front of, and behind the roll gap. The results so obtained show that the transitional plastic deformation zone exists only in front of the roll gap without any bulge. Furthermore, we find that this zone becomes larger with increase of the strain sensitivity as well as the strain rate sensitivity of material.