탄성 변형 영역을 고려한 비정상 평면 변형 이상 공정 이론

Nonsteady Plane-strain Ideal Forming with Elastic Dead Zone

  • 이원오 (서울대학교 재료공학부) ;
  • 정관수 (서울대학교 재료공학부, 서울대학교 신소재공동연구소) ;
  • ;
  • 강태진 (서울대학교 재료공학부)
  • 발행 : 2004.10.01


Ever since the ideal forming theory has been developed for process design purposes, application has been limited to sheet forming and, fur bulk forming, to two-dimensional steady flow. Here, application for the non-steady case was performed under the plane-strain condition based on the theory previously developed. In the ideal flow, material elements deform following the minimum plastic work path (or mostly proportional true strain path) so that the ideal plane-stram flow can be effectively described using the two-dimensional orthogonal convective coordinate system. Besides kinematics, fur a prescribed final part shape, schemes to optimize a preform shape out of a class of initial configurations and also to define the evolution of shapes and boundary tractions were developed. Discussions include the two problematic issues on internal tractions and the non-monotonous straining. For demonstration purposes, numerical calculations were made for a bulk part under forging.


  1. K. Chung and O. Richmond, 1992, 'Ideal forming- I. Homogeneous deformation with minimum plastic work', Int. J. Mech. Sci., Vol. 34, pp. 575-591
  2. O. Richmond and M.L. Devenpeck, 1962, 'A die profile for maximum efficiency in strip drawing', Proc. 4th. U.S. Natl. Congr. Appl. Mech., R.M. Rosenberg (Ed.), ASME, New York, pp. 1053-1057
  3. O. Richmond and H.L. Morrison, 1967, 'Streamlined wire drawing dies of minimum length', J. Mech. Phys. Solids, Vol. 15, pp. 195-203
  4. R. Hill, 1967, 'Ideal forming operations for perfectly plastic solids', J. Mech. Phys. Solids, Vol. 15, pp. 223-227
  5. O. Richmond, 1968, 'Theory of streamlined dies for drawing and extrusion', Mechanics of the solid state, F.P.J. Rimrott and J. Schwaighofer (Eds.), Univ. of Toronto, Toronto, pp. 154-167
  6. H.F. Weinberger, 1997, 'On the nonexistence of certain ideal forming operations for extrusion and drawing dies' , J. Mech. Phys. Solids, Vol. 45, pp. 1275-1280
  7. K. Chung and O. Richmond, 1993, 'A deformation theory of plasticity based on minimum work paths', Int. J. Plasticity, Vol. 9, pp. 907-920
  8. K. Chung and O. Richmond, 1994, 'The mechanics of ideal forming', J. Appl. Mech., Vol. 61, pp. 176-181
  9. O. Richmond and S. Alexandrov, 2000, 'Nonsteady planar ideal plastic flow: general and special analytic solution', J. Mech. Phys. Solids, Vol. 48, pp. 1735-1759
  10. 정관수, 이원오, 유웅렬, 2002, '비정상 평면 변형에서의 이상유동', 한국섬유공학회지, 제 39권, 제4호, pp. 407-413
  11. 정관수, 이원오, O. Richmond, 2002, '평면변형 하에서의 비정상 이상공정이론', 춘계학술대회 논문집, 한국소성가공학회, pp. 66-69
  12. K. Chung, W. Lee, T.J. Kang and J.R. Youn, 2002, 'Nonsteady plane-strain ideal forming without elastic dead zone', Fiber Polym., Vol. 3, pp. 120-127