Browsing by Author "Millett, Jeremy C. F."

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    The mechanical and optical response of Polychlorotrifluoroethylene to one-dimensional shock loading
    (Springer, 2015-07-24) Millett, Jeremy C. F.; Lowe, Michael R.; Appleby-Thomas, Gareth J.; Roberts, Andrew
    A series of plate impact experiments have been performed to probe the shock behavior of polychlorotrifluoroethylene (PCTFE), in terms of its optical and mechanical response. Interfacial velocity measurements using interferometric techniques have shown differences between measured and actual velocities, and been used to determine changes in refractive index due to shock-induced density increases. These have further been used to determine an optical correction factor, and allow the possibility of PCTFE being used as an optical window in future shock loading experiments. The shear strength of shock loaded PCTFE has also been shown to be near-constant behind the shock front, in common with other fluorinated polymers, although the strength variation with impact stress is greater than other similar materials. It has been suggested that the presence of a larger chlorine atom replacing a fluorine allows for a degree of tacticity between polymer chains, with local variations of charge density along the chain (due to the presence of the chlorine atom) also having an effect.
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    The shock Hugoniot of hydroxy-terminated polybutadiene
    (AIP, 2004-08-04) Meziere, Y.; Akhavan, Jacqueline; Stevens, G. S.; Millett, Jeremy C. F.; Bourne, Neil K.
    The response of polymers to shock loading is becoming of increasing importance, both as binder systems in plastic-bonded explosives (PBXs) and as structural materials in their own right. In this paper, we report on the shock Hugoniot of hydroxy-terminated polybutadiene (HTPB), which is commonly used as a binder system in PBXs, but whose shock response has yet to be presented in the open literature. Results indicate that the shock velocity --- particle velocity relationship is linear, similar to some but not all polymer-based materials.
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    The Strength of two HMX based plastic bonded explosives during one dimensional shock loading
    (Springer, 2017-03) Millett, Jeremy C. F.; Taylor, P.; Roberts, Andrew; Appleby-Thomas, Gareth J.
    A series of experiments have been performed to probe the mechanical response of two HMX based plastic bonded explosives to one dimensional shock loading. Manganin stress gauges in longitudinal and lateral orientation to the loading axis have been used as the diagnostic. Results indicate that despite major differences in the binder phase and smaller differences in the HMX crystal loading and morphology, the Hugoniot and shear strengths behind the shock front are near identical. We have proposed that this is due to the HMX crystals forming a network that supports the bulk of the applied stress.