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https://hdl.handle.net/123456789/1471| Τύπος: | Ανακοίνωση σε συνέδριο |
| Τίτλος: | Enlightening critical details of a standardized procedure used to determine the fracture toughness of brittle structural materials |
| Συγγραφέας: | [EL] Πάσιου, Ερμιόνη[EN] Pasiou, Ermioni [EL] Λουκίδης, Ανδρόνικος[EN] Loukidis, Andronikos [EL] Τριάντης, Δήμος[EN] Triantis, Dimos [EL] Κουρκούλης, Σταύρος[EN] Kourkoulis, Stavros |
| Ημερομηνία: | 31/05/2021 |
| Περίληψη: | An experimental protocol is described aiming to enlighten some crucial aspects of the standardized procedure adopted for the determination of the Mode-I fracture toughness (KIC) of brittle structural materials. Notched Straight Through Brazilian Disc (NSTBD) specimens made of Dionysos marble were tested. Their diameter was equal to D=100 mm and their thickness equal to t=10 mm. Three groups of specimens were tested with variable length (2a) and width (w) of the notch, keeping the ratio w/2a equal to about 1/10. Waterjet cutting technology was used to machine the notches. The issues confronted are related to the actual load causing fracture initiation, the point from which fracture starts (the latter is of utmost importance for the validity of the whole experimental procedure given that the mechanically machined notches are by no means equivalent to mathematical cracks with singular tips) and the role of the length of the notch. All experiments were carried out using an electromechanical MTS loading frame of capacity equal to 10 kN. The discs were diametrally loaded between rigid metallic curved jaws (according to the respective ISRM standard) under quasi-static loading conditions and displacement control mode, at a constant rate equal to 0.02 mm/min. During loading, the area around the notch was captured by the two cameras of a 3D-Digital Image Correlation (3D-DIC) system, in order to accurately determine the displacement field of this part of the specimens and detect the onset of fracture initiation. All specimens were fractured along the vertical axis of symmetry of the discs (i.e., along the loading axis), however a number of secondary exfoliations and/or cracks were observed, emanating from various points of the disc-jaws contact rims. The results obtained by the DIC technique were satisfactory enabling the detection of the point from which the crack is about to propagate. The experience gained indicated that the critical load causing onset of crack propagation is well below the maximum load attained during each test. Moreover, it was pointed out that the maximum load attained is linearly linked to the ratio 2a/D of the specimens, at least for the specific geometric characteristics studied. Concluding, it was indicated that, in order for a reliable value of KIC to be obtained, a proper sensing technique must be employed during the experimental procedure permitting spatiotemporal detection of the onset of the crack propagation. |
| Γλώσσα: | Αγγλικά |
| Τόπος δημοσίευσης: | Turin, Italy |
| Σελίδες: | 29 |
| DOI: | https://doi.org/10.53255/IGFTUBE.IGF26.83 |
| Θεματική κατηγορία: | [EL] Επιστήμη υλικών, χαρακτηρισμός και δοκιμές[EN] Materials Science, Characterization and testing [EL] Μηχανική, γενικά[EN] Engineering, general |
| Λέξεις-κλειδιά: | Brazilian disc; Central notch; fracture toughness; Digital image correlation |
| Κάτοχος πνευματικών δικαιωμάτων: | © ESIS Publishing House |
| Διατίθεται ανοιχτά στην τοποθεσία: | https://www.youtube.com/watch?v=pi_xIavOdT4 |
| Όνομα εκδήλωσης: | 26th International Conference on Fracture and Structural Integrity (IGF26) |
| Τοποθεσία εκδήλωσης: | Turin, Italy |
| Ημ/νία έναρξης εκδήλωσης: | 26/05/2021 |
| Ημ/νία λήξης εκδήλωσης: | 28/05/2021 |
| Σημειώσεις: | 26th International Conference on Fracture and Structural Integrity (IGF26) - https://www.fesi.org.uk/events/igf26/ “This research is carried out / funded in the context of the project “Critical assessment and revision of the standard regarding the determination of the Mode I fracture toughness, KIC, of brittle building materials using a combination of innovative experimental techniques, numerical simulations and analytical methods” (MIS 5049181) under the call for proposals “Researchers' support with an emphasis on young researchers- 2 nd Cycle”. The project is co-financed by Greece and the European Union (European Social Fund - ESF) by the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020.” |
| Εμφανίζεται στις συλλογές: | Ερευνητικές ομάδες |
Αρχεία σε αυτό το τεκμήριο:
| Αρχείο | Περιγραφή | Σελίδες | Μέγεθος | Μορφότυπος | Έκδοση | Άδεια | |
|---|---|---|---|---|---|---|---|
| PASIOU_Enlightening critical details_final.pdf | 2.51 MB | Adobe PDF | - |  | Δείτε/ανοίξτε |