The Improvement of Formability using the Polar-coordinate FLD with Strain Path Independence

경로의존성 없는 극좌표계 성형한계도를 이용한 판재 성형성 향상 기술

Bae, M.K.;Hong, S.H.;Choi, K.Y.;Yoon, J.W.;Kim, Y.S.

  • Received : 2015.05.12
  • Accepted : 2015.07.13
  • Published : 2015.10.01


The PEPS(Polar-coordinated Effective Plastic Strain) FLD(Forming Limit Diagram), a new type of FLD based on a polar representation of the EPS(Effective Plastic Strain), appears to be an effective solution to the problem of non-linear strain path effects. This method has the advantages of the familiar strain-based diagram for linear loading, but without the strain-hardening limitations of the stress-based diagram, or non-intuitive aspects of alternate Cartesian diagrams based on effective plastic strain. In the current study, the PEPS FLD was applied to the development process of an aluminum automobile-body panel, including the necking or crack prediction, die design, and die modification. As a result, the PEPS FLD provided improved formability of aluminum sheet as compared to deriving the potential formability with non-linearity.


FLD;FLC;Non-linear FLD;Stress-based FLD;Polar-EPS FLD;Aluminum Sheet;Automobile-body Panel