Characterisation of the complex shock initiation of conventional and insensitive high explosives using in-material gauges
Supervisor: Dr Paul Hazell
The sensitivity of an explosive formulation to an external insult is an important safety property that must be considered when designing all explosive charges. For an insult to generate detonation in an explosive then a high shock stress is usually required. The sustained shock loading of an explosive charge is an idealisation and realistic insult scenarios will generally result in a more complex shock-loading profile. For example an impact by a piece of munitions casing will input a short duration shock pulse into a nearby explosive charge. External layers protecting the explosive from any insult will modify the shock profile received, resulting in a potentially complex loading regime, depending on the nature of the layers and the insult.
For this PhD, the student will be expected to use a single stage gas-driven plate impact facility at Cranfield University's Shrivenham campus and a new powder-driven single-stage plate impact facility to perform complex shock initiation experiments on explosive compositions. The main diagnostic will be embedded magnetic particle velocity gauges which provide an in-situ measurement of the material particle velocity following the shock passage. Initially the focus will be upon replicating sustained pulse results to prove the diagnostic capability before moving on to short pulse and stepped pulse initiation of a conventional explosive, building on previous work. Finally, it is expected that the student will develop and implement novel techniques for inputting a ramp-wave loading into the sample.
The PhD is envisaged as being principally experimental. It will involve interaction with the explosive modelling community and the student will have access to several subject matter experts in the field.