Effect of anisotropic yield function evolution on formability of sheet metal

H. J. Choi, Y. Choi, Kyoung Jin Lee, J. Y. Lee, K. Bandyopadhyay, M. G. Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution


For the evaluation of anisotropic yield functions and hardening models, formability has been often investigated in the forming of sheet metals. The formability has been investigated in many ways, but a common conclusion is that it is significantly influenced by sheet anisotropy, especially the directional differences in yield stress and r-value along the material direction. Therefore, numerous works have been presented in terms of the accurate modeling of anisotropic behavior of sheet metals and its implementation into the finite element simulations. The previous efforts include the effects of quadratic or non-quadratic yield functions, their associated or non-associated flow rules and isotropic or non-isotropic hardening laws on formability. However, most of these works assumed that the anisotropic yield functions maintain their initial shapes, while they evolve by isotropic expansion or kinematic translation. Then, they could not consider the anisotropic evolution under monotonic loading with different deformation modes. In the present work, various anisotropic constitutive models were comparatively evaluated for the performance in predicting the earing profile in the cup drawing and the forming limit diagram. The constitutive models include the Hill48 quadratic yield function with associated and non-associated flow rules, and the non-quadratic Yld2000-2d function with associated flow rule. For both yield functions, the evolution of anisotropy was employed by considering the anisotropic coefficients as a function of equivalent plastic strain. The influence of the anisotropy evolution was comparatively evaluated by the computational simulations.

Original languageEnglish
Title of host publicationProceedings of the 20th International ESAFORM Conference on Material Forming, ESAFORM 2017
EditorsDermot Brabazon, Inam Ul Ahad, Sumsun Naher
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735415805
Publication statusPublished - 2017 Oct 16
Event20th International ESAFORM Conference on Material Forming, ESAFORM 2017 - Dublin, Ireland
Duration: 2017 Apr 262017 Apr 28

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other20th International ESAFORM Conference on Material Forming, ESAFORM 2017

Bibliographical note

Funding Information:
All authors appreciate the support from POSCO. MGL appreciates partial supports by the National Research Foundation of Korea (NRF) Grant funded by Korean government (NRF-2012R1A5A1048294) and (NRF-2014R1A2A2A11052889).

Publisher Copyright:
© 2017 Author(s).

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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