Francois Guillard

Senior Lecturer in Geotechnical Engineering, University of Sydney
Granular materials such as sand and snow have the ability to behave both as solids (in sand dunes and snowdrifts) and as fluids (in hourglasses and avalanches). Dr François Guillard studies the properties and behaviours of granular materials and of brittle porous media, which have implications for industries including construction, mining, agriculture and pharmaceuticals.

"Granular materials are present everywhere in nature and in industry, but they exhibit extremely complex and rich behaviours that we don't yet fully understand. For example, no one knows quite how sandcastles hold together, how we can walk on sand or snow, or what happens inside a box of cereal.

"My research focuses particularly on the behaviour of granular materials when they are flowing, and how they transition between this behaviour and their solid state.

"I'm also studying how brittle porous media - such as rocks and sandstone, snow, volcanic ashes and even bones - behave under load and chemical degradation. I use puffed rice grains as a model material, for example, which can be brittle when dry but become soft and mushy when they stay too long in a liquid such as milk. These principles are of tremendous importance for both natural and artificial brittle porous materials that are compacted under load and soaked in water.

"In addition, I am involved in advancing the technology used to study granular materials. Currently we cannot see the behaviour of the grains below the surface, so I am developing X-ray radiography methods to study in real time and in three dimensions how granular materials flow internally.

"A better understanding of the properties and behaviours of such materials, combined with better experimental investigation techniques, can improve the safety and efficiency of numerous industrial processes, including the construction industry's use of sand, concrete and composite materials; the mining industry's methods of ore extraction and processing; the agricultural industry's storage, transport and processing of cereal grains; and the pharmaceutical industry's bulk handling and delivery of drugs in powdered form.

"I've been working in this field since 2010, and I joined the University of Sydney in 2013. Working here has greatly broadened my research interests and afforded me more direct access to the practical implications of my research. It also provides access to state-of-the-art infrastructure and facilities, which is of tremendous help in developing and addressing my research questions."