On the inconsistency of the asymmetric‐sandwich gurney formula when used to model thin plate propulsion

Hirsch, E.

doi:10.1002/prep.19950200404

Cited by 3 publications

(2 citation statements)

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“…Consequently,t he assumptiono falinearg as profile leads to overestimating the energy partitioned into expandingt he detonation products and underestimating the energyd elivered to the flyerf or these cases. This effect is discussed by Hirsch for spheres, cylinders, and sandwiches [ 45,46]. Second, Hirsch notedt hat the asymmetric (tamped)G urney equation begins to underpredict the open-faced Gurney equation for ag iven value of M/C for certain relativev alues of M/C vs. N/C if both ratios are sufficiently small.…”

Section: Resultsmentioning

confidence: 99%

Validation of the Gurney Model in Planar Geometry for a Conventional Explosive

Loiseau

Georges

Higgins

2016

Propellants Explo Pyrotec

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1IntroductionThe high-velocity projection of materials is one of the primary uses of condensed phase explosives. As such,t he efficacy with which ag iven high explosive accelerates material, and the velocity with which materiali st hrown for ag iven configuration, are essential considerations. Af ully rigorous modelling treatment of the acceleration of am etal flyer by ah igh explosive typically involves the use of ah ydrocode with detonation product equation of state data fitted to cylinder test experiments. However,a nalytical tools are often desirablei ne ngineering design, scaling studies, and as am etric for comparing the efficiency of explosives.The analyticalm odel developed by Gurney is the seminal method for estimating the terminal velocity of metals accelerated by high explosive [ 1].G urney'sm ethoda llows for an analytic estimation of terminal material velocity for alarge number of charge geometries using asingle,empirical parameter representingt he energetic yield of ap articular explosive. This parameter,t ermed the Gurney energy, can be extracted from aw ide variety of experiments. Because of the elegance, simplicity,a nd reasonable accuracy of the method, extensions to the Gurney modelh ave been widely used for seventy years.T he Gurney energy of an explosive remains an essentialm etric by which the propulsive capabilityo fa ne xplosive is judged and is ubiquitouslyr eferenced in most literature sources studying the explosive acceleration of metals, particularly in the context of cylinder test experiments [2][3][4].While ac omprehensive literature review is not possible in this paper,w ew ould point to some key references:K ennedy [5,6] and Jones [7] present re-derivationso ft he ex-Abstract:T he analytical modeld eveloped by Gurney is as eminal tool for analyzingt he acceleration of metal flyers driven by detonating high explosives.D espite the continued relevance of this model, relatively few experimental validations over aw ide range of flyer-to-chargem ass ratios exist in the openl iterature. The current study presents experimental results for planar aluminum flyers propelled by ac onventional explosive over ar angeo fm ass ratios varying from 4.65 to 0.03. Flyer velocityw as measured via Het-erodyne Laser Velocimetry (PDV),p ermitting ac ontinuous measurement of the acceleration process. Measured flyer velocities are compared to terminal velocity estimations from the Gurneym odel. Experimental terminal velocities are compared to theo pen face and asymmetric sandwich Gurney models. Excellent agreement is observedf or terminal velocity predictionsc onsideringt he gasdynamic simplificationsi nherent in the model formulation.

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Section: Resultsmentioning

confidence: 99%

Validation of the Gurney Model in Planar Geometry for a Conventional Explosive

Loiseau

Georges

Higgins

2016

Propellants Explo Pyrotec

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“…The work proposed by Gurney in 1943 [13] stands as fundamental when referring to velocities of fragments from explosively-driven metal casings [14][15][16][17].…”

Section: Theoretical Approachmentioning

confidence: 99%

Numerical Simulation and Experimental Tests on Explosively‐Induced Water Jet Phenomena

Enache

Trană

Rotariu

et al. 2016

Propellants Explo Pyrotec

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This study addresses some aspects regarding water jet propulsion during high explosives detonation. A number of theoretical and experimental studies have shown that using Gurney equation and the relationships derived, one can provide fair results regarding initial velocity of metallic fragments for explosively‐driven metal casings. However, an investigation on Gurney equations utilization for the prediction of water velocity has not been performed yet. By carrying out simple experimental tests and numerical simulations, water has been investigated in terms of total mass average velocity and tip velocity. Based on the available data, the findings indicate that Gurney equations overestimate the water mass average velocity. For water tip velocity evaluation, further studies should be made.

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