Towards the effective behaviour of polycrystalline materials for sheet bulk metal forming processes

authored by: E. Lehmann, Stefan Loehnert, Peter Wriggers
Abstract: During sheet bulk metal forming processes the microstructure of both, flat geometries and three-dimensional structures change their shape significantly while undergoing large plastic deformations. As for metal forming processes, FE-simulations are often done before in situ experiments, a very accurate model for respective structures is required, performing well at small geometries possessing small curvatures in forms with wide as well as lateral characteristics. Because of the crystalline nature of metals, certain anisotropies have to be taken into account. Macroscopically observable plastic deformation under tension as well as compression is traced back to dislocations within considered slip systems in the crystals causing plastic anisotropy on the microscopic and the macroscopic level. A crystal plasticity model for large deformations is used to model the behaviour of polycrystalline materials in representative volume elements (RVEs) representing the microstructure. In order to circumvent singularities stemming from the linear dependency of the slip system vectors, a viscoplastic power-law is introduced providing the evolution of the plastic slips and slip resistances. The model is validated with experimental microstructural data under deformation. Through homogenisation and optimisation techniques, effective stress-strain curves are determined and can be compared to results from real forming processes, leading to an effective elastoplastic material model which is suitable for processes in the sheet bulk metal forming field.
Organisation(s): Institute of Continuum Mechanics
Type: Article
Journal: AIP Conference Proceedings
Volume: 1353
Pages: 1179-1184
No. of pages: 6
ISSN: 0094-243X
Publication date: 25.04.2011
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.1063/1.3589676 (Access: Unknown)
: Details in the research portal "Research@Leibniz University"

BibTeX

@article{036a833c1f0449099ef970cad6c7a643,
title = "Towards the effective behaviour of polycrystalline materials for sheet bulk metal forming processes",
abstract = "During sheet bulk metal forming processes the microstructure of both, flat geometries and three-dimensional structures change their shape significantly while undergoing large plastic deformations. As for metal forming processes, FE-simulations are often done before in situ experiments, a very accurate model for respective structures is required, performing well at small geometries possessing small curvatures in forms with wide as well as lateral characteristics. Because of the crystalline nature of metals, certain anisotropies have to be taken into account. Macroscopically observable plastic deformation under tension as well as compression is traced back to dislocations within considered slip systems in the crystals causing plastic anisotropy on the microscopic and the macroscopic level. A crystal plasticity model for large deformations is used to model the behaviour of polycrystalline materials in representative volume elements (RVEs) representing the microstructure. In order to circumvent singularities stemming from the linear dependency of the slip system vectors, a viscoplastic power-law is introduced providing the evolution of the plastic slips and slip resistances. The model is validated with experimental microstructural data under deformation. Through homogenisation and optimisation techniques, effective stress-strain curves are determined and can be compared to results from real forming processes, leading to an effective elastoplastic material model which is suitable for processes in the sheet bulk metal forming field.",
keywords = "Finite Crystal Plasticity, Homogenisation, Sheet Bulk Metal Forming",
author = "E. Lehmann and Stefan Loehnert and Peter Wriggers",
year = "2011",
month = apr,
day = "25",
doi = "10.1063/1.3589676",
language = "English",
volume = "1353",
pages = "1179--1184",
journal = "AIP Conference Proceedings",
issn = "0094-243X",
publisher = "American Institute of Physics",
}