13th International Conference on the Technology of Plasticity (ICTP 2021): Tuesday Keynote
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Tuesday 7:30 AM
July 27, 2021
Room: Virtual: Keynote
Location: Virtual
Session Chair: Jian Cao, Northwestern University; Frederic Barlat, Pohang University of Science and Technology
7:30 AM Keynote
Numerical Modeling of Ductile Damage during Metal Forming: State of the Art and Future Challenges: Pierre-Olivier Bouchard1; 1Mines ParisTech
Despite numerous studies, the prediction of ductile damage and failure during metal forming processes still needs further investigations in particular for complex loading paths. Ductile damage analysis is usually addressed through uncoupled failure criteria or coupled damage models. Both approaches rely either on micromechanical bases or on phenomenological considerations. After a short review of these different approaches, the talk will focus on the main complexities related to damage analysis during metal forming processes. Strain rate and temperature effects, complex multiaxial stress states, non-proportional and cyclic loading conditions will be addressed with examples given at the process scale, whereas a micro-scale finite element framework will also be presented to get a better understanding of some of the physical mechanisms arising in such complex loading conditions.
8:15 AM Keynote
Recent Advances on Modeling Plastic Deformation of Textured Metals with Applications to Metal Forming: Oana Cazacu1; 1University of Florida
An accurate description of the yield surface defining the onset of plastic deformation is essential for high-fidelity numerical predictions of forming processes. Due to the ease in calibration from simple tests, generally von Mises isotropic criterion and Hill orthotropic criterion are used in industry. While more advanced 3-D yield criteria have been developed, generally such criteria are written in terms of eigenvalues of transformed stress tensors and as such the anisotropy coefficients are not directly expressible in terms of mechanical properties. Using general representation theorems, generalizations of the isotropic invariants J2 and J3 such as to account for plastic anisotropy have been developed. Using these anisotropic invariants, the anisotropic form of any isotropic yield function can be obtained simply by replacing J2 and J3 with their respective anisotropic generalizations. This framework ensures that the minimum number of anisotropy coefficients is specified. Illustrative examples of full three-dimensional yield criteria expressed in terms of generalized invariants and their application to the prediction of formability of single crystals and polycrystalline FCC, BCC and HCP materials are presented.