CESS Seminar: How moving cracks in brittle solids choose their path
Event details
| Date | 29.11.2019 |
| Hour | 12:15 › 13:00 |
| Speaker | Prof. Jay Fineberg, the Racah Institute of Physics, the Hebrew University of Jerusalem |
| Location | |
| Category | Conferences - Seminars |
Abstract:
While we have an excellent fundamental understanding of the dynamics and structure of cracks propagating in brittle solids, we do not fully understand how the path of a moving crack is determined. Here we experimentally study cracks that are propagating between 10-95% of their limiting velocity within a brittle material. We deflect these cracks by either allowing them to interact with sparsely implanted defects or driving them to undergo an intrinsic oscillatory instability in defect-free media. By dense measurements of the strain fields surrounding the crack tips via high speed imaging, we determine what governs a crack’s direction when it is strongly deflected. We reveal that the paths selected by these rapid and strongly perturbed cracks are entirely governed by the direction of maximum energy density and not by the oft-assumed principle of local symmetry. This fundamentally important result may potentially be utilized to either direct or guide running cracks.
Bio:
Pr. Jay Fineberg is professor at The Racah Institute of Physics, The Hebrew University of Jerusalem. Pr. Jay Fineberg’s laboratory has a variety of different research interests. Each of these projects is interesting in itself, fundamentally important, an intrinsically nonlinear process. Some of these, in broad strokes, are: (i) the physics of dynamic (rapid) fracture in brittle materials, (ii) the pattern formation and interactions of nonlinear waves, and (iii) the physics of the onset of frictional motion and laboratory modeling of earthquakes. Prof. Fineberg has published over 100 research articles in the leading journals in the sciences and Physics. 16 of his papers have been published in Nature or Science magazines and about 40 in the Physical Review Letters.
While we have an excellent fundamental understanding of the dynamics and structure of cracks propagating in brittle solids, we do not fully understand how the path of a moving crack is determined. Here we experimentally study cracks that are propagating between 10-95% of their limiting velocity within a brittle material. We deflect these cracks by either allowing them to interact with sparsely implanted defects or driving them to undergo an intrinsic oscillatory instability in defect-free media. By dense measurements of the strain fields surrounding the crack tips via high speed imaging, we determine what governs a crack’s direction when it is strongly deflected. We reveal that the paths selected by these rapid and strongly perturbed cracks are entirely governed by the direction of maximum energy density and not by the oft-assumed principle of local symmetry. This fundamentally important result may potentially be utilized to either direct or guide running cracks.
Bio:
Pr. Jay Fineberg is professor at The Racah Institute of Physics, The Hebrew University of Jerusalem. Pr. Jay Fineberg’s laboratory has a variety of different research interests. Each of these projects is interesting in itself, fundamentally important, an intrinsically nonlinear process. Some of these, in broad strokes, are: (i) the physics of dynamic (rapid) fracture in brittle materials, (ii) the pattern formation and interactions of nonlinear waves, and (iii) the physics of the onset of frictional motion and laboratory modeling of earthquakes. Prof. Fineberg has published over 100 research articles in the leading journals in the sciences and Physics. 16 of his papers have been published in Nature or Science magazines and about 40 in the Physical Review Letters.
Practical information
- Informed public
- Free
Organizer
- Prof. Brice Lecampion & Prof. Alexandre Alahi
Contact
- Prof. Marie Violay & Dr Francois Passèlegue (LEMR)