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Description
Ice shelves are large floating plates of ice in the ocean that are still connected to the inland ice of a glacier. Due to elevations in the bathymetry, the ice shelf can be partially grounded. These areas are called pinning points and satellite images show that cracks often form at these locations.
To better understand the crack formation, three-dimensional fracture simulations are carried out. The crack is modeled using the phase field method for fracture, where an additional scalar field represents whether the material is intact or broken.
Glacier ice is a Maxwell-type material with a short-term elastic and long-term viscous behavior. In addition to the viscoelastic behavior, ice is a non-Newtoinian fluid with a strain-thinning behavior characterized by Glen’s flow law. The viscosity of glacier ice is influenced by the stress and temperature distribution within the ice shelf. These material characteristics are taken into account in the crack simulation by incorporating a nonlinear viscosity into the phase field method for the fracture of a viscoelastic material. Finite strain theory is used to adequately represent the high strains typically found in ice shelves.
This approach allows the simulation of crack initiation at pinning points and contributes to the understanding of ice shelf dynamics and calving processes.
