Staff publications (CDS)

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Browsing Staff publications (CDS) by Publisher "AIP American Institute of Physics"

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    Deviatoric response of an armour-grade aluminium alloy
    (AIP American Institute of Physics, 2009-12-31T00:00:00Z) Appleby-Thomas, Gareth J.; Hazell, P. J.; Millett, J.; Bourne, Neil K.; Buttler, W. T.
    Aluminium alloys such as 5083 H32 are established light-weight armour materials. As such, the shock response of these materials is of great importance. The shear strength of a material under shock loading provides an insight into its ballistic performance. In this investigation embedded manganin stress gauges have been employed to measure both the longitudinal and lateral components of stress during plate-impact experiments over a range of impact stresses. In turn, these results were used to determine the shear strength and to investigate the time dependence of lateral stress behind the shock front to give an indication of material response.
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    The dynamic behaviour of ballistic gelatin
    (AIP American Institute of Physics, 2009-12-31T00:00:00Z) Shepherd, C. J.; Appleby-Thomas, Gareth J.; Hazell, P. J.; Allsop, D. F.
    In order to characterise the effect of projectiles it is necessary to understand the mechanism of both penetration and resultant wounding in biological systems. Porcine gelatin is commonly used as a tissue simulant in ballistic tests because it elastically deforms in a similar manner to muscular tissue. Bullet impacts typically occur in the 350–850 m/s range; thus knowledge of the high strain-rate dynamic properties of both the projectile and target materials are desirable to simulate wounds. Unlike projectile materials, relatively little data exists on the dynamic response of flesh simulants. The Hugoniot for a 20 wt.% porcine gelatin, which exhibits a ballistic response similar to that of human tissues at room temperature, was determined using the plate-impact technique at impact velocities of 75–860 m/s. This resulted in impact stresses around three times higher than investigated elsewhere. In US−uP space the Hugoniot had the form US = 1.57+1.77 uP, while in P−uP space it was essentially hydrodynamic. In both cases this was in good agreement with the limited available data from the lit
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    Initiation of secondary explosives measured using embedded electromagnetic gauges
    (AIP American Institute of Physics, 2009-12-31T00:00:00Z) Stennett, C.; Cooper, G. A.; Hazell, P. J.; Appleby-Thomas, Gareth J.; Elert, ML, Buttler, WT, Furnish, MD, Anderson WW, Proud, WG.
    There is considerable evidence that secondary explosive materials having a relatively large (10-12%) proportion of HTPB binder do not exhibit DDT under cook-off. However, the understanding of the mechanisms controlling the growth of reaction in such experiments is incomplete. Most importantly, it is not known whether a mechanistic reason exists to preclude DDT; it is possible that existing techniques to explore cook-off simply do not offer the correct conditions to allow DDT to occur. We present experiments in which impacts were made against a RDX/HTPB PBX using a single-stage light gas gun. Electromagnetic particle velocity gauges were embedded within the targets at different distances from the impact face to record the onset of reaction, and in some cases detonation. These experiments were also performed against RDX/TNT targets. The time-resolved particle velocity histories have allowed comparison of some of the factors governing growth of reaction, and have provided run-to-detonation distance data for different impact stresses.
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    Shock compression and recovery of microorganism-loaded broths and an emulsion
    (AIP American Institute of Physics, 2009-12-31T00:00:00Z) Hazell, P. J.; Groves, K.; Stennett, C.; Beveridge, C.
    The microorganisms Escherichia coli, Enterococcus faecalis and Zygosaccharomyces bailii and an oil-based emulsion, have been subjected to shock compression using the flyer-plate technique to initial pressures of 0.8 GPa (in the suspension). In each experiment, a stainless steel capsule was used to contain the broths and allow for recovery without contamination. Where cavitation was mostly suppressed by virtue of simultaneous shock and dynamic compression, no kill was observed. By introducing an air gap behind the suspension, limited kill was measured in the yeast. Results also suggest that stable emulsification occurs in coarse oil- based emulsions that are subjected to shock.