Crystal-level defects are generally known to influence the initiation of explosives by shock waves at extreme pressures, but a detailed understanding of shock interactions with these defects is lacking. Using a range of techniques, such as laboratory-based gas guns, explosive plane-wave sources and X-ray microscopy, the successful applicant will study the process of explosives shock initiation to develop new knowledge in this area.
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It is generally understood that internal defects within crystalline explosives can promote the formation of ‘hot-spots’ under shock initiation, and that this is a mechanism for sensitisation to impact. Prior studies have often focused on the preparation of compositions that contain nitramines such as RDX, in which the microstructure of the explosive content is varied by different methods of recrystallisation. However, these studies have mostly used powdered RDX within an inert binder composition, and the particle-composite mesostructure of such materials can also provide several different hot-spot impact-sensitisation mechanisms.
This project proposes to attempt to study the influence of defects in large single crystals, thus removing the influence of the particle-composite nature of previous studies.There are envisaged three aspects to the work:
a) The growth of large HMX crystals with microstructural defects, with focus on generating these defects reproducibly.Another group in the Centre for Defence Chemistry has ongoing research interest in this type of work, and there is scope for collaboration by the student with that group;
b) The non-destructive examination and characterisation of the induced defects, either in-house or in collaboration with the Diamond Light Source;
c) The experimental measurement of shock initiation in the resulting specimens, and comparison with literature studies of pure HMX crystals.
It is suggested that an explosively-generated shock would be required, to produce the high pressures (~10 GPa) required to initiate this type of target and is beyond the capability of the single-stage gun at Shrivenham. The experimental method (requiring development) would be of the gap test type, with particular attention paid to the control of the curvature of the wave emanating from the attenuator.
At a glance
- Application deadline12 Aug 2020
- Award type(s)PhD
- Start date28 Sep 2020
- Duration of award4 years
- EligibilityUK, EU
- Reference numberPHDCFI12
Applicants should have a first or second class UK honours degree or equivalent in a related discipline. This project would suit an applicant with a strong physics or materials science background
To be eligible for this funding, applicants must be a UK national. We require that applicants are under no restrictions regarding how long they can stay in the UK i.e. have no visa restrictions or applicant has “settled status” and has been “ordinarily resident” in the UK for 3 years prior to start of studies and has not been residing in the UK wholly or mainly for the purpose of full-time education. (This does not apply to UK or EU nationals). Due to funding restrictions all EU nationals are eligible to receive a fees-only award if they do not have “settled status” in the UK.
About the sponsor
Sponsored by AWE, EPSRC and Cranfield University, this studentship will provide a bursary of up to £17,000 (tax free) plus fees* for 4 years.
NOTE: If a student is in receipt of government funding for their degree course the advert must state that they will not eligible to apply for a Postgraduate Doctoral Loan.
How to apply
For further information please contact: Dr Chris Stennett or Dr Ranko Vrcelj
Email: firstname.lastname@example.org / email@example.com
T: (0) 1234 750111 Ext: 5392
For information about applications please contact: CDSAdmissionsoffice@cranfield.ac.uk
If you are eligible to apply for this PhD, please complete the online application form.