{"dp_type": "Project", "free_text": "Fracture Mechanics"}
[{"awards": "1847173 Duddu, Ravindra", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Fri, 07 Jul 2023 00:00:00 GMT", "description": "Iceberg calving is a complex natural fracture process and a dominant cause of mass loss from the floating ice shelves on the margins of the Antarctic ice sheet. There is concern that rapid changes at these ice shelves can destabilize parts of the ice sheet and accelerate their contribution to sea-level rise. The goal of this project is to understand and simulate the fracture mechanics of calving and to develop physically-consistent calving schemes for ice-sheet models. This would enable more reliable estimation of Antarctic mass loss by reducing the uncertainty in projections. The research plan is integrated with an education and outreach plan that aims to (1) enhance computational modeling skills of engineering and Earth science students through a cross-college course and a high-performance computing workshop and (2) increase participation and diversity in engineering and sciences by providing interdisciplinary research opportunities to undergraduates and by deploying new cyberlearning tools to engage local K-12 students in the Metro Nashville Public Schools in computational science and engineering, and glaciology. This project aims to provide fundamental understanding of iceberg calving by advancing the frontiers in computational fracture mechanics and nonlinear continuum mechanics and translating it to glaciology. The project investigates crevasse propagation using poro-damage mechanics models for hydrofracture that are consistent with nonlinear viscous ice rheology, along with the thermodynamics of refreezing in narrow crevasses at meter length scales. It will develop a fracture-physics based scheme to better represent calving in ice-sheet models using a multiscale method. The effort will also address research questions related to calving behavior of floating ice shelves and glaciers, with the goal of enabling more reliable prediction of calving fronts in whole-Antarctic ice-sheet simulations over decadal-to-millennial time scales. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "United States Of America; GLACIER MOTION/ICE SHEET MOTION", "locations": "United States Of America", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Duddu, Ravindra", "platforms": null, "repositories": null, "science_programs": null, "south": null, "title": "CAREER: Fracture Mechanics of Antarctic Ice Shelves and Glaciers - Representing Iceberg Calving in Ice Sheet Models and Developing Cyberlearning Tools for Outreach", "uid": "p0010423", "west": null}, {"awards": "0739444 Rice, James", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Wed, 16 Jan 2013 00:00:00 GMT", "description": "Rice 0739444\u003cbr/\u003e\u003cbr/\u003eThis award supports a project to study the mode of formation and causes of glacial earthquakes. The paradigm for glacial flow has been that glaciers flow in a viscous manner, with major changes in the force balance occurring on the decade timescale or longer. The recent discovery of a number of even shorter timescale events has challenged this paradigm. In 2003, it was discovered that Whillans Ice Stream in West Antarctica displays stick-slip behavior on the 10-30 minute timescale, with ice stream speed increasing by a factor of 30 from already high speeds. In the past year, the minimum timescale has been pushed shorter by recognition that a class of recently discovered 50-second-long, magnitude-5 earthquakes are closely associated with changes in the force balance near the calving fronts of large outlet glaciers in both Greenland and East Antarctica. With no adequate theory existing to explain these relatively large earthquakes associated with outlet glaciers, we have begun to investigate the physical mechanisms that must be involved in allowing such a response in a system traditionally not thought capable of generating large variations in forces over timescales less than 100 seconds. The intellectual merit of the work is that large-amplitude, short-timescale variability of glaciers is an important mode of glacier dynamics that has not yet been understood from a first-principles physics perspective. The proposed research addresses this gap in understanding, tying together knowledge from numerous disciplines including glaciology, seismology and fault rupture dynamics, laboratory rock physics, granular flow, fracture mechanics, and hydrogeology. The broader impacts of the work are that there is societal as well as general scientific interest in the stability of the major ice sheets. However, without an understanding of the physical processes governing short time scale variability, it is unlikely that we will be able accurately predict the future of these ice sheets and their impact on sea level changes. The project will also contribute to the development and education of young scientists.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Rapid Glacial Motions; Not provided; Hydrogeology; Fracture Mechanics; Glacier Dynamics; Glacial Earthquakes; Granular Flow; Glacial Underflooding; Glaciology; Ice Stream Margins; Outlet Glaciers", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Rice, James; Platt, John; Suckale, Jenny; Perol, Thibaut; Tsai, Victor", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Transient and Rapid Glacial Motions, including Glacial Earthquakes", "uid": "p0000709", "west": null}, {"awards": "0125754 Hulbe, Christina", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Thu, 07 Jun 2007 00:00:00 GMT", "description": "This award supports a project to develop computational models to simulate ice-shelf rift propagation using a combination of well-established ice-shelf creep-flow models and new crevasse models, based on linear elastic fracture mechanics (LEFM). The overall objective of the proposed work is to simulate rift propagation and eventual large iceberg calving,and place those processes within a larger ice sheet and climate context. The work will proceed in stages, first developing models of single-and multiple-crevasse propagation; then using those models to evaluate propagation sensitivity to various environmental conditions; and third developing models that incorporate both crevasse propagation and advection within an ice- shelf system. Model development will be guided by and evaluated according to satellite observations of rift propagation in several characteristic locations on Antarctic ice shelves. New numerical models of fracture in ice will have applications to many problems in glaciology. The research proposed here is directed toward large rift formation in ice shelves and subsequent iceberg calving. It is motivated by the need to understand observed changes in modern ice shelves,and their connection to climate. Where it has been sampled, the sedimentary record of the Weddell Sea sector implies Peninsular ice shelf variability on millennial time scales. The ability to simulate iceberg calving in a credible way will improve our ability to reproduce such events and place the complete cycle of ice shelf advance and retreat in an ice-dynamics context. That will, in turn, enable us to place ice-shelf cycles within the climate cycles that ultimately drive ice-sheet mass balance.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Hulbe, Christina", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Ice-Shelf Rift Propagation: Computational Simulation Using a Fracture Fracture Mechanics Approach", "uid": "p0000270", "west": null}]
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| Project Title/Abstract/Map | NSF Award(s) | Date Created | PIs / Scientists | Dataset Links and Repositories | Abstract | Bounds Geometry | Geometry | Selected | Visible | |
|---|---|---|---|---|---|---|---|---|---|---|
|
CAREER: Fracture Mechanics of Antarctic Ice Shelves and Glaciers - Representing Iceberg Calving in Ice Sheet Models and Developing Cyberlearning Tools for Outreach
|
1847173 |
2023-07-07 | Duddu, Ravindra | No dataset link provided | Iceberg calving is a complex natural fracture process and a dominant cause of mass loss from the floating ice shelves on the margins of the Antarctic ice sheet. There is concern that rapid changes at these ice shelves can destabilize parts of the ice sheet and accelerate their contribution to sea-level rise. The goal of this project is to understand and simulate the fracture mechanics of calving and to develop physically-consistent calving schemes for ice-sheet models. This would enable more reliable estimation of Antarctic mass loss by reducing the uncertainty in projections. The research plan is integrated with an education and outreach plan that aims to (1) enhance computational modeling skills of engineering and Earth science students through a cross-college course and a high-performance computing workshop and (2) increase participation and diversity in engineering and sciences by providing interdisciplinary research opportunities to undergraduates and by deploying new cyberlearning tools to engage local K-12 students in the Metro Nashville Public Schools in computational science and engineering, and glaciology. This project aims to provide fundamental understanding of iceberg calving by advancing the frontiers in computational fracture mechanics and nonlinear continuum mechanics and translating it to glaciology. The project investigates crevasse propagation using poro-damage mechanics models for hydrofracture that are consistent with nonlinear viscous ice rheology, along with the thermodynamics of refreezing in narrow crevasses at meter length scales. It will develop a fracture-physics based scheme to better represent calving in ice-sheet models using a multiscale method. The effort will also address research questions related to calving behavior of floating ice shelves and glaciers, with the goal of enabling more reliable prediction of calving fronts in whole-Antarctic ice-sheet simulations over decadal-to-millennial time scales. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. | None | None | false | false | |
|
Transient and Rapid Glacial Motions, including Glacial Earthquakes
|
0739444 |
2013-01-16 | Rice, James; Platt, John; Suckale, Jenny; Perol, Thibaut; Tsai, Victor | No dataset link provided | Rice 0739444<br/><br/>This award supports a project to study the mode of formation and causes of glacial earthquakes. The paradigm for glacial flow has been that glaciers flow in a viscous manner, with major changes in the force balance occurring on the decade timescale or longer. The recent discovery of a number of even shorter timescale events has challenged this paradigm. In 2003, it was discovered that Whillans Ice Stream in West Antarctica displays stick-slip behavior on the 10-30 minute timescale, with ice stream speed increasing by a factor of 30 from already high speeds. In the past year, the minimum timescale has been pushed shorter by recognition that a class of recently discovered 50-second-long, magnitude-5 earthquakes are closely associated with changes in the force balance near the calving fronts of large outlet glaciers in both Greenland and East Antarctica. With no adequate theory existing to explain these relatively large earthquakes associated with outlet glaciers, we have begun to investigate the physical mechanisms that must be involved in allowing such a response in a system traditionally not thought capable of generating large variations in forces over timescales less than 100 seconds. The intellectual merit of the work is that large-amplitude, short-timescale variability of glaciers is an important mode of glacier dynamics that has not yet been understood from a first-principles physics perspective. The proposed research addresses this gap in understanding, tying together knowledge from numerous disciplines including glaciology, seismology and fault rupture dynamics, laboratory rock physics, granular flow, fracture mechanics, and hydrogeology. The broader impacts of the work are that there is societal as well as general scientific interest in the stability of the major ice sheets. However, without an understanding of the physical processes governing short time scale variability, it is unlikely that we will be able accurately predict the future of these ice sheets and their impact on sea level changes. The project will also contribute to the development and education of young scientists. | None | None | false | false | |
|
Ice-Shelf Rift Propagation: Computational Simulation Using a Fracture Fracture Mechanics Approach
|
0125754 |
2007-06-07 | Hulbe, Christina | No dataset link provided | This award supports a project to develop computational models to simulate ice-shelf rift propagation using a combination of well-established ice-shelf creep-flow models and new crevasse models, based on linear elastic fracture mechanics (LEFM). The overall objective of the proposed work is to simulate rift propagation and eventual large iceberg calving,and place those processes within a larger ice sheet and climate context. The work will proceed in stages, first developing models of single-and multiple-crevasse propagation; then using those models to evaluate propagation sensitivity to various environmental conditions; and third developing models that incorporate both crevasse propagation and advection within an ice- shelf system. Model development will be guided by and evaluated according to satellite observations of rift propagation in several characteristic locations on Antarctic ice shelves. New numerical models of fracture in ice will have applications to many problems in glaciology. The research proposed here is directed toward large rift formation in ice shelves and subsequent iceberg calving. It is motivated by the need to understand observed changes in modern ice shelves,and their connection to climate. Where it has been sampled, the sedimentary record of the Weddell Sea sector implies Peninsular ice shelf variability on millennial time scales. The ability to simulate iceberg calving in a credible way will improve our ability to reproduce such events and place the complete cycle of ice shelf advance and retreat in an ice-dynamics context. That will, in turn, enable us to place ice-shelf cycles within the climate cycles that ultimately drive ice-sheet mass balance. | None | None | false | false |
