Overview

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 two research aims are to:

(1) investigate crevasse propagation in viscous glacier ice using conduct full-Stokes fracture mechanics models; and

(2) develop fracture-physics-based calving schemes for depth-integrated, higher-order Stokes flow approximations in ice sheet models.

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.

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.

Publications

1. Duddu, R., Jimenez, S., and J. N. Bassis. “A nonlocal continuum poro-damage mechanics model for hydrofracturing of surface crevasses in grounded glaciers.” Journal of Glaciology, 66(257): 415-429, 2020, doi: 10.1017/jog.2020.16 (link)
2. Sun, X., Duddu, R., and Hirshikesh. “A poro-damage phase field model for hydrofracturing of glacier crevasses.” Extreme Mechanics Letters, 2021 doi:10.1016/j.eml.2021.101277 (link).

Conference/Workshop Presentations

1. Huth, A., Smith, B. E., and Duddu, R. Modeling ice shelf weakening with the material point method and damage mechanics. American Geophysical Union, Fall Meeting 2018, Abstract #C34A-02, Washington, D.C., December 10 – 14, 2018.
2. Duddu, R., Jimenez, S., and Bassis, J. N. A comparison of fracture-physics-based calving models including hydrofracturing. American Geophysical Union, Fall Meeting 2018, Abstract #C31C-1547, Washington, D.C., December 10 – 14, 2018.
3. Duddu, R. Modeling tensile and shear fracture in ice using damage mechanics. Community Earth System Model (CESM) Annual Workshop, National Center for Atmospheric Research, Boulder, CO, June 17 – 19, 2019.
4. V. K. Devendiran and R. Duddu. “An appropriate crack driving force function for the phase field approach to model mixed-mode brittle fracture.” ASCE EMI 2019 Conference, Pasadena, CA, June 18 – June 21, 2019.
5. Duddu, R., Jimenez, S., Huth, A., and Bassis, J. N. A poro-damage approach to simulating hydrofracture of glaciers and ice shelves. West Antarctic Ice Sheet (WAIS) Workshop 2019, Camp Cedar Glen, Julian, CA, October 16 – 18, 2019.
6. Huth, A., Duddu, R., and Smith, B. E. A generalized interpolation material point (GIMP) method for shallow shelf approximation of ice flow. Community Earth System Model (CESM) Annual Workshop, National Center for Atmospheric Research, Boulder, CO, February 10 – 12, 2020.

Seminar Talks

1. Simulating rift propagation in Antarctic ice shelves using nonlocal continuum damage mechanics, Marine Geology and Geophysics Group, Lamont Doherty Earth Observatory, Columbia University, New York, NY, October 14, 2020.
2. Modeling Fracture Propagation in Marine-Terminating Glaciers and Ice Shelves Using Continuum Damage Mechanics. Biweekly Solid Earth and Planetary Physics Seminar (BISEPPS), Harvard University, Cambridge, MA, July 1, 2020.
3. Modeling crevasse propagation in glaciers due to hydromechanical fracture. Georgia Institute of Technology, Atlanta, GA, August 22, 2019.

Students

Vignesh Kumar Devendiran M. S. student, Graduated: May 2019 Research project: Modeling mixed-mode fracture in ice under biaxial compression in using phase field damage models

Xiangming Sun Ph. D. student, Graduated: December 2020 Research project: A poro-damage phase field model for hydraulic fracturing of glacier crevasses.

Gourab Ghosh Ph. D. student, Graduated: May 2021 Research project: A poro-damage cohesive zone model for hydraulic fracturing of glacier crevasses.

Postdocs

Hirshikesh Ph. D. from IIT Madras Research project: A poro-damage phase field model for hydraulic fracturing of glacier crevasses.