Principle Supervisor: Dr. Simon Bland
Measurements of the strength of materials at high pressure are important for a multitude of areas in physics and engineering – for instance the strength of the ablator material in inertial confinement fusion capsules is one factor determining stability during implosion; whilst the strength of armour determines projectile penetration. Making measurements of strength is, however, quite difficult especially at relatively high pressures (>10s of kbar); and often relies on comparison of secondary effects (e.g. the redistribution of mass in a corrugated target after an experiment) to computer models rather than direct measurements of strength itself.
Recently colleagues at Sandia National Laboratories pioneered a new form of strength measurement – MAPS – Magnetically applied pressure shear. Here a large current applied through a strip line compresses a material sample; whilst the action of an externally applied ~5T magnetic field introduces shear stress. The movement of the material in relation to compression and shear can be well diagnosed using transverse velocimetry, giving direct information on strength.
As part of the PhD the student will develop a MAPS system for the Institute of Shock Physics on site pulsed power facility, MACH, and look at extending this technique to examine metals, metal alloys and ceramics. Simultaneously the student will also examine ways to make shear strength measurements of materials under high pressure due to shock waves generated by the Institutes new 100mm gas gun, and both ramp and shock waves generated by the soon to be completed high energy laser system. By comparing the actions of materials under different rates of loading, and through the different diagnostics available on each experiment, new information relating the materials microstructures and meso-structure to its strength can be obtained.