Toughening induced by the formation of facets in mode I+III brittle fracture: Experiments versus a two-scale Cohesive Zone model

Autor: M.L. Hattali, T. Cambonie, Véronique Lazarus
Přispěvatelé: Fluides, automatique, systèmes thermiques (FAST), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Tribologie et Dynamique des Systèmes (LTDS), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Ecole Nationale d'Ingénieurs de Saint Etienne (ENISE)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Ecole Nationale d'Ingénieurs de Saint Etienne-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-EDF R&D (EDF R&D), Université Paris-Saclay, CNRS, FAST, 91405 Orsay, France, Laboratoire de Tribologie et Dynamique des Systèmes - Ecole Nationale des Travaux Publiques d’Etat (LTDS-ENTPE)
Rok vydání: 2021
Předmět:
Toughness
Materials science
02 engineering and technology
0203 mechanical engineering
[SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph]
Factory roof pattern
Composite material
Elasticity (economics)
ComputingMilieux_MISCELLANEOUS
Microscale chemistry
Critical load
Mechanical Engineering
[PHYS.MECA]Physics [physics]/Mechanics [physics]
021001 nanoscience & nanotechnology
Condensed Matter Physics
Microstructure
Mode I+III
Shear (sheet metal)
Cohesive zone model
020303 mechanical engineering & transports
[SPI.MECA.STRU]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Structural mechanics [physics.class-ph]
Brittle fracture
Mechanics of Materials
Effective fracture toughness
Fracture (geology)
Tilted facets
0210 nano-technology
Linear Elastic Fracture Mechanics
Zdroj: Journal of the Mechanics and Physics of Solids
Journal of the Mechanics and Physics of Solids, 2021, 156, pp.104596. ⟨10.1016/j.jmps.2021.104596⟩
Journal of the Mechanics and Physics of Solids, Elsevier, In press, ⟨10.1016/j.jmps.2021.104596⟩
Journal of the Mechanics and Physics of Solids, Elsevier, 2021, 156, pp.104596. ⟨10.1016/j.jmps.2021.104596⟩
ISSN: 0022-5096
Popis: International audience; When subjected to some anti-plane shear mode III loading, segmentation of the crack front frequently occurs during propagation: even if the crack is initially planar, propagation produces facets/segments rotated toward the shear free direction. Here, we examine, both experimentally and theoretically, the effect of this microstructure on the effective macroscale brittle fracture toughness. Experiments performed on PMMA beams reveal that the critical load leading to abrupt rupture increases with mode III to mode I ratio. This apparent macroscopic toughening is usually taken into account by invoking a specific mode III toughness in addition to the mode I one. By applying thoroughfully a micro/macroscale Cohesive Zone (CZ) model that we have recently developed, we demonstrate that an additional material constant is useless here since this toughness increase can be attributed mainly to the presence of the facets at the microscale, whose geometry can be anticipated to depend on the classical mode I material constants. More precisely, two related physical mechanisms are generated due to the formation of a disconnected crack front: (i) changes in fractured surface area in comparison to a straight propagation, and (ii) crack shielding caused by the facets that reduce the effective crack opening. While the first effect is obvious to quantify, we show that the second plays an essential role but is more complex to take into account: it depends on the solution of the three-dimensional elasticity problem in presence of the facets, that is considered in the CZ model. We illustrate on the experiments how to use this approach in practice to determine the critical fracture threshold.
Databáze: OpenAIRE
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