Numerical model for a failure process of an ice sheet
Arttu Polojärvi
Abstract
Model for describing a three-dimensional continuous failure process of an ice sheet is introduced. The presented model is based on the combined finite-discrete element method. The ice sheet consists of polyhedral rigid discrete elements joined by a lattice of Timoshenko beam elements, which go through cohesive softening upon sheet failure. The contact model accounts for inter-particle friction and local failure of ice in contacts. The model is carefully validated against a laboratory experiment, where an ice sheet is pushed against an inclined plane. Convincing agreement between the modelled and experimental failure process is found. The effect of ice sheet tessellation and element size is tested and found to be only moderate. The model compares favorably to earlier ones: The modelling and the experimental results agree, the domain sizes used can be large, and the modelled failure processes are long in duration. Requirements for numerical modelling of ice failure processes are discussed.