Browsing by Author "Cooper, G. A."

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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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    Penetration of a woven CFRP laminate by a high velocity steel sphere impacting at velocities of up to 1875 m/s
    (Elsevier Science B.V., Amsterdam., 2009-12-31T00:00:00Z) Hazell, P. J.; Cowie, A.; Kister, G.; Stennett, C.; Cooper, G. A.
    The impact of a woven 6 mm thick CFRP laminate has been subjected to impact by an annealed steel sphere up to velocities of 1875 m/s. It was observed that above a threshold impact energy, the percentage of kinetic energy dissipated by the laminate was constant. Further, the level of damage, as measured by C-Scan and through-thickness microscopy remained roughly constant as the impact energy was increased. However, the size of the hole formed increased. This suggested that the energy transferred to the target in the velocity range of interest became independent of the delamination. Consequently, the main energy transfer mechanism at the high velocities of impact is thought to be due to the cavity expansion and more importantly, the kinetic energy of the particulates.