Friction of Shear-Fracture Zones

A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous selflubrication. A “weak shear zone” is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstra…

A discrete-element model for viscoelastic deformation and fracture of glacial ice

a b s t r a c t A discrete-element model was developed to study the behavior of viscoelastic materials that are allowed to fracture. Applicable to many materials, the main objective of this analysis was to develop a model specifically for ice dynamics. A realistic model of glacial ice must include elasticity, brittle fracture and slow viscous deformations. Here the model is described in detail and tested with several benchmark simulations. The model was used to simulate various ice-specific applications with resulting flow rates that were compatible with Glen's law, and produced under fragmentation fragment-size distributions that agreed with the known analytical and experimental results.

Discrete element model for viscoelastic materials with brittle fracture : applications on glacier dynamics

Application of the lattice-Boltzmann method for simulating attachment of ink particles in paper

In this thesis the basic properties of the lattice- Boltzmann method (LBM) are introduced. Also, a particle model used in combination with LBM is presented, and the combined model is then applied to ink propagation in samples of paper. Simulation geometries were acquired with two different methods, namely confocal microscopy and X-ray tomography. The effect of simulation parameters and paper properties on ink propagation was considered. Promising results were acquired with both image acquiring techniques, but for a better consistency between simulations and experiments the methods should be combined so as to get images that include the full thickness of the sample together with the ink dist…

A particle based simulation model for glacier dynamics

This publication is contribution number 22 of the Nordic Centre of Excellence SVALI, “Stability and Variations of Arctic Land Ice”, funded by the Nordic Top-level Research Initiative (TRI). The work has been supported by the SVALI project through the University of Lapland, Arctic Centre, and through the University Centre in Svalbard. Funding was also provided by the Conoco-Phillips and Lunding High North Research Program (CRIOS: Calving Rates and Impact on Society). A particle-based computer simulation model was developed for investigating the dynamics of glaciers. In the model, large ice bodies are made of discrete elastic particles which are bound together by massless elastic beams. These…