Green layer (arrowed) is cyanobacteria living in shocked rock from an impact crater

The dynamic behaviour of materials presents a number of theoretical, numerical and above all, experimental challenges. The response of a system varies markedly with the rate at which a stimulus is applied. Such stimuli vary from quasi-static to shock waves where accelerations of the order of 1011 g (gravities) are experienced. The fracture group of SMF has developed a range of diagnostic techniques to collect high-quality data and provide insight into fundamental physical processes.

Failure front following behind shock wave propagating in glass.

Research Areas for Development

• The dynamics of foam, granular and composite systems. These materials pose strong theoretical and practical challenges, defining and measuring the fundamental processes such as void collapse, fracture, internal displacement
• High-rate temperature studies. With rapid compression, materials heat, the amount of energy manifested as heat is important in defining the equation of state of a system. A long term aim is to develop high-speed, high-accuracy temperature systems which can be used over a range of material types e.g. opaque, transparent, porous
• Structural effects. Phase changes are associated with materials under high-pressure in a variety of disciplines, planetary science, chemical processing. Using high-speed x-ray systems in conjunction with stress and optical techniques provides a powerful method for understanding material behaviour.

Comparison of experiment with theory for the shear produced by diametric compression of a disc.

Predictive modelling is dependent on understanding of the processes in materials and complex systems. By performing small, high-precision experiments we aim to develop theoretical understanding and provide practical data to a wide range of systems. Current projects include links to space exploration, oil and gas exploitation, safety and energy efficient replacements for older, heavier technologies.