Abstract. There is a growing requirement within QinetiQ to develop models for assessments when there is very little experimental data. A theoretical approach to developing equations of state for geological materials has been developed using Quantitative Structure Property Modelling based on the Porter-Gould model approach. This has been applied to well-controlled sand with different moisture contents and particle shapes. The Porter-Gould model describes an elastic response and gives good agreement at high impact pressures with experiment indicating that the response under these conditions is dominated by the molecular response. However at lower pressures the compaction behaviour is dominated by a micro-mechanical response which drives the need for additional theoretical tools and experiments to separate the volumetric and shear compaction behaviour. The constitutive response is fitted to existing triaxial cell data and Quasi-Static (QS) compaction data. This data is then used to construct a model in the hydrocode. The model shows great promise in predicting plate impact, Hopkinson bar, fragment penetration and residual velocity of fragments through a finite thickness of sand.
A closed water-filled cylinder test for characterizing non-ideal explosives AIP Conf. Proc. 429, 871 (1998); 10.1063/1.55604 Gap test modeling to predict wedge tests initiation of PBXN-103 AIP Conf.
Abstract.Knowledge of the sensitivity of high explosives to shock is important to avoid unwanted detonations in service. The large-scale gap test (LSGT) is used in the UK as one of the key qualification tests for energetic materials. This geometry consists of a donor charge, a (poly)methyl methacrylate (PMMA) attenuator (or gap) and a test or acceptor charge. The gap thickness is varied until 50% of test acceptors are detonated. In this work the shock to detonation behaviour of a UK secondary explosive formulation was measured. Manganin pressure gauges were embedded at various longitudinal positions and radii in acceptor charges of varying lengths, and the charges were subjected to varying gap output pulses, characterized in earlier work. For longer acceptor lengths and higher gap output pressures, detonation was observed. Curvature was also measured. The test configurations were modelled using a reactive model derived from parallel work done using plate impact. The predictions of the hydrocode and the results of the experiments are compared.
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