Temporal and Spatial Detection of the Onset of Local Necking and Assessment of its Growth Behavior
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Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg Martensstr. 3, 91058 Erlangen, Germany
2
Institute of Manufacturing Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 13, 91058 Erlangen, Germany
*
Author to whom correspondence should be addressed.
Materials 2020, 13(11), 2427; https://doi.org/10.3390/ma13112427
Received: 23 April 2020
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Revised: 19 May 2020
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Accepted: 21 May 2020
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Published: 26 May 2020
(This article belongs to the Special Issue Formability of Materials)
This study proposes a method for the temporal and spatial determination of the onset of local necking determined by means of a Nakajima test set-up for a DC04 deep drawing and a DP800 dual-phase steel, as well as an AA6014 aluminum alloy. Furthermore, the focus lies on the observation of the progress of the necking area and its transformation throughout the remainder of the forming process. The strain behavior is learned by a machine learning approach on the basis of the images when the process is close to material failure. These learned failure characteristics are transferred to new forming sequences, so that critical areas indicating material failure can be identified at an early stage, and consequently enable the determination of the beginning of necking and the analysis of the necking area. This improves understanding of the necking behavior and facilitates the determination of the evaluation area for strain paths. The growth behavior and traceability of the necking area is objectified by the proposed weakly supervised machine learning approach, thereby rendering a heuristic-based determination unnecessary. Furthermore, a simultaneous evaluation on image and pixel scale is provided that enables a distinct selection of the failure quantile of the probabilistic forming limit curve.
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Keywords:
pattern recognition; machine learning; deep learning; classification; segmentation; artificial intelligence; forming limit curve; sheet metal forming
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MDPI and ACS Style
Jaremenko, C.; Affronti, E.; Merklein, M.; Maier, A. Temporal and Spatial Detection of the Onset of Local Necking and Assessment of its Growth Behavior. Materials 2020, 13, 2427. https://doi.org/10.3390/ma13112427
AMA Style
Jaremenko C, Affronti E, Merklein M, Maier A. Temporal and Spatial Detection of the Onset of Local Necking and Assessment of its Growth Behavior. Materials. 2020; 13(11):2427. https://doi.org/10.3390/ma13112427
Chicago/Turabian StyleJaremenko, Christian, Emanuela Affronti, Marion Merklein, and Andreas Maier. 2020. "Temporal and Spatial Detection of the Onset of Local Necking and Assessment of its Growth Behavior" Materials 13, no. 11: 2427. https://doi.org/10.3390/ma13112427
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