Analysis of Profile Ring Rolling for Rolling Rings having V-groove or Trapezoidal Protrusion by the Upper-Bound Elemental Technique

To diversify the area of application of UBET to the analysis of ring rolling which produces rings having more complex cross-sectional configuration, an element of triangular cross-section has been introduced and the corresponding Cinematically admissible velocity field has been derived while considering the material flow between neighboring elements. The theoretical predictions in roll torque and profile formation show good agreement with the experiments. The effect of process parameters such as feed rate and taper angle of the roll groove has been discussed

UBET에 의한 형상 환상압연의 해석

학위논문(박사) - 한국과학기술원 : 생산공학과, 1991.8, [ ix, 114 p. ]Since the material flow involved in profile ring rolling shows non-steady and three-dimensional characteristics, it has been very difficult to describe accurately the flow or the deformation pattern during rolling. In this study an analytical method using the upper-bound elemental technique has been proposed for the simulation of closed-pass profile ring rolling. In order to describe the plastic flow of material, the whole deforming zone is divided into elements of simple configuration. Three types of elements are introduced for the modular approach of the UBET to the profile ring rolling process. Almost every shape of profiled ring can be assembled by the simple combination of elements of rectangular cross-section with elements of triangular cross-section and/or elements with an arbitrarily curved oblique side. The corresponding kinematically admissible velocity field which includes the expression for the material flow between neighboring elements as well as the closing speed of the pressure roll is derived for each type of element. Comparing with the experimental results, the calculated results of the present analysis shows good agreement in the estimations of roll torque and profile formation. For a comprehensive simulation of profile ring rolling, the effects of several process parameters have also been predicted and compared with the experimental work on open-pass rolling of rings. The computed results showing such effects are found to be in reasonable agreement with experimental results. As a simple but versatile engineering tool, the upper-bound elemental technique has been applied successfully to the theoretical analysis of the profile ring rolling process.한국과학기술원 : 생산공학과