Novel Method to Characterize and Model the Multiaxial Constitutive and Damage Response of Energetic Materials (original) (raw)
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Recent Trends in Research on Energetic Materials at Cambridge
Central European …, 2009
Recent work in our laboratory has established a time-temperature superposition law for a PBX. This was achieved by performing uniaxial compression testing over a wide range of strain rates and temperatures along with Differential Thermal Mechanical Analysis (DMTA). The classic WLF (Williams, Landel, Ferry) transform was found not to fit the shift factor needed to align the data whereas a simple log-linear fit did. The thermal properties (diffusivity, conductivity, heat capacity) of a PBX have been measured three different ways and found to agree (within experimental error) with the classic equation relating these three parameters. This gives us confidence that, for example, hot-spot ignition mechanisms of this class of energetic materials can be accurately modelled using their measured thermal properties. A modular instrumented testing facility has been designed and built to simulate and control the conditions experienced by novel heavy-metal-free (green) primers contained within ammunition. Physical data obtained from the facility, when compared with data from live fire tests, will give a greater understanding of which characteristics are important to functionality. As explosives are granular materials, the techniques developed for studying such materials are being applied to determine the effect of particle size distribution and shape on sensitivity.
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