Suspensions of solid particles within a solvent display a variety of interesting rheological behaviour. The viscosity can vary with applied stress, resulting in materials which become thinner or thicker as they are driven more strongly. Thickening can become so severe that the flow becomes erratic on a macroscopic level, suggesting that the material acquires a solid-like character, at least transiently. This idea is supported by recent experiments in which initially fluid suspensions are transformed into a persisting solid upon shearing. Behaviour reminiscent of this can be observed in granular materials. For example, the flow of grain from a hopper under gravity is often halted as ‘arches’ of force bearing particles form. In such a situation, the solidity of the material arises only as a result of applied forces and transient flow. There has been much speculation regarding the nature of these jamming phenomena, in particular whether or not there is a link between jamming and the glass transition. In this thesis, we present a model in which jamming is treated as a stress induced glass transition. This leads to predictions of the rheological behaviour and the structural dynamics in such a scenario. We also discuss the link between rheology and the glass transition more generally, arguing that common explanations for thickening in dense colloids are unlikely to be complete, as they essentially ignore the presence of the glass transition. Finally, we discuss the relevance of jamming phenomena to the industrial process of granulation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:652525 |
| Date | January 2004 |
| Creators | Holmes, Colin |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14086 |
Page generated in 0.0021 seconds