Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability
The Impact and Crashworthiness Lab at Massachusetts Institute of Technology participated in the Sandia Fracture Challenge and predicted the crack initiation and propagation path during a tensile test of a compact tension specimen with three holes (B, C, and D), using a very limited number of materia...
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| Format: | Article |
| Language: | English |
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Springer Netherlands
2016
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| Online Access: | http://hdl.handle.net/1721.1/103046 https://orcid.org/0000-0003-3075-9598 https://orcid.org/0000-0001-9390-9691 |
| _version_ | 1811079731262521344 |
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| author | Pack, Keun Hwan Luo, Meng Wierzbicki, Tomasz |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Pack, Keun Hwan Luo, Meng Wierzbicki, Tomasz |
| author_sort | Pack, Keun Hwan |
| collection | MIT |
| description | The Impact and Crashworthiness Lab at Massachusetts Institute of Technology participated in the Sandia Fracture Challenge and predicted the crack initiation and propagation path during a tensile test of a compact tension specimen with three holes (B, C, and D), using a very limited number of material properties, including uniaxial tensile tests of a dog-bone specimen. The maximum shear stress and modified Mohr–Coulomb fracture models were used. The predicted crack path of A–C–E coincided with two out of thirteen experiments performed by Sandia National Laboratories, and the maximum load, as well as the load level at the first and second crack initiation, was accurately captured. However, the crack-tip opening displacements (CODs) corresponding to the initiation of the two cracks were overestimated by 12 and 24 %, respectively. After the challenge ended, we received the leftover material from Sandia and did full plasticity and fracture calibration by conducting extra fracture tests, including tensile tests, on a specimen with two symmetric round notches, a specimen with a central hole, and a butterfly specimen with double curvature. In addition, pure shear tests were carried out on a butterfly specimen. Newly identified fracture parameters again predicted the A–C–E crack path, but the force–COD response could be reproduced almost perfectly. Detailed calibration procedures and validation are discussed. Furthermore, in order to investigate the influence of the machining quality on the results, a pre-damage value was introduced to the first layer of finite elements around the starter notch, A, and the three holes, B, C, and D. This accelerated shear localization between holes A and D (and between D and C as well) and changed the crack path to A–D–C–E. Parametric study on the pre-damage value showed that there exist two competing crack paths, and the corresponding force–COD curve is influenced by the pre-damage value. The effect of mesh size and boundary conditions are also discussed. |
| first_indexed | 2024-09-23T11:19:39Z |
| format | Article |
| id | mit-1721.1/103046 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:19:39Z |
| publishDate | 2016 |
| publisher | Springer Netherlands |
| record_format | dspace |
| spelling | mit-1721.1/1030462022-09-27T18:46:05Z Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability Pack, Keun Hwan Luo, Meng Wierzbicki, Tomasz Massachusetts Institute of Technology. Department of Mechanical Engineering Massachusetts Institute of Technology. Impact and Crashworthiness Laboratory Pack, Keun Hwan Luo, Meng Wierzbicki, Tomasz The Impact and Crashworthiness Lab at Massachusetts Institute of Technology participated in the Sandia Fracture Challenge and predicted the crack initiation and propagation path during a tensile test of a compact tension specimen with three holes (B, C, and D), using a very limited number of material properties, including uniaxial tensile tests of a dog-bone specimen. The maximum shear stress and modified Mohr–Coulomb fracture models were used. The predicted crack path of A–C–E coincided with two out of thirteen experiments performed by Sandia National Laboratories, and the maximum load, as well as the load level at the first and second crack initiation, was accurately captured. However, the crack-tip opening displacements (CODs) corresponding to the initiation of the two cracks were overestimated by 12 and 24 %, respectively. After the challenge ended, we received the leftover material from Sandia and did full plasticity and fracture calibration by conducting extra fracture tests, including tensile tests, on a specimen with two symmetric round notches, a specimen with a central hole, and a butterfly specimen with double curvature. In addition, pure shear tests were carried out on a butterfly specimen. Newly identified fracture parameters again predicted the A–C–E crack path, but the force–COD response could be reproduced almost perfectly. Detailed calibration procedures and validation are discussed. Furthermore, in order to investigate the influence of the machining quality on the results, a pre-damage value was introduced to the first layer of finite elements around the starter notch, A, and the three holes, B, C, and D. This accelerated shear localization between holes A and D (and between D and C as well) and changed the crack path to A–D–C–E. Parametric study on the pre-damage value showed that there exist two competing crack paths, and the corresponding force–COD curve is influenced by the pre-damage value. The effect of mesh size and boundary conditions are also discussed. MIT/Industrial Fracture Consortium 2016-06-07T19:56:10Z 2016-06-07T19:56:10Z 2014-01 2013-08 2016-05-23T12:07:14Z Article http://purl.org/eprint/type/JournalArticle 0376-9429 1573-2673 http://hdl.handle.net/1721.1/103046 Pack, Keunhwan, Meng Luo, and Tomasz Wierzbicki. “Sandia Fracture Challenge: Blind Prediction and Full Calibration to Enhance Fracture Predictability.” International Journal of Fracture 186, no. 1–2 (January 10, 2014): pp. 155–175. https://orcid.org/0000-0003-3075-9598 https://orcid.org/0000-0001-9390-9691 en http://dx.doi.org/10.1007/s10704-013-9923-3 International Journal of Fracture Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ Springer Science+Business Media Dordrecht application/pdf Springer Netherlands Springer Netherlands |
| spellingShingle | Pack, Keun Hwan Luo, Meng Wierzbicki, Tomasz Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title | Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title_full | Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title_fullStr | Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title_full_unstemmed | Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title_short | Sandia Fracture Challenge: blind prediction and full calibration to enhance fracture predictability |
| title_sort | sandia fracture challenge blind prediction and full calibration to enhance fracture predictability |
| url | http://hdl.handle.net/1721.1/103046 https://orcid.org/0000-0003-3075-9598 https://orcid.org/0000-0001-9390-9691 |
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