Modeling a Material’s Instantaneous Velocity during Acceleration Driven by a Detonation’s Gas-Push

Backofen, Joseph E.

doi:10.1063/1.2263475

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…The ratio of v i to V i is between 4 and 13; therefore, the energy obtained by the prefabricated fragment in the "detonation products acceleration stage" and the energy obtained by the prefabricated fragment in the "metal-medium interaction stage" is between 15 and 168, which indicates that the "detonation product acceleration stage" is the main stage at which the initial velocity of the prefabricated fragments is obtained. This shows that the acceleration ability of the detonation products to the prefabricated fragments is much greater than that of the detonation wave and the shock wave [26].…”

Section: Simulation Results Of the Three-stage Detonation Drive Modelmentioning

confidence: 92%

Study on Axial Dispersion Characteristics of Double-Layer Prefabricated Fragments

Guo

Wang

et al. 2023

Materials

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The axial distribution of initial velocity and direction angle of double-layer prefabricated fragments after an explosion were investigated via an explosion detonation test. A three-stage detonation driving model of double-layer prefabricated fragments was proposed. In the three-stage driving model, the acceleration process of double-layer prefabricated fragments is divided into three stages: “detonation wave acceleration stage”, “metal–medium interaction stage” and “detonation products acceleration stage”. The initial parameters of each layer of prefabricated fragments calculated by the three-stage detonation driving model of double-layer prefabricated fragments fit well with the test results. It was shown that the energy utilization rate of detonation products acting on the inner-layer and outer-layer fragments were 69% and 56%, respectively. The deceleration effect of sparse waves on the outer layer of fragments was weaker than that on the inner layer. The maximum initial velocity of fragments was located near the center of the warhead where the sparse waves intersected, located at around 0.66 times of the full length of warhead. This model can provide theoretical support and a design scheme for the initial parameter design of double-layer prefabricated fragment warheads.

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Section: Simulation Results Of the Three-stage Detonation Drive Modelmentioning

confidence: 92%

Study on Axial Dispersion Characteristics of Double-Layer Prefabricated Fragments

Guo

Wang

et al. 2023

Materials

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“…The spherical surface approach has been shown to be more accurate for smaller charge to mass ratios without any loss of agreement at larger charge to mass ratios. It should be recognized that this analytic modeling approach neglects initial acceleration due to shock processes [7] and is therefore anticipated to be more accurate as the initial shock process damps out. The model as expressed does not consider the fact that the cylinders thin during radial expansion.…”

Section: Analytic Cylinder Modelmentioning

confidence: 99%

Theory and calibration of JWL and JWLB thermodynamic equations of state

Baker¹,

Murphy²,

Stiel

et al. 2010

WIT Transactions on the Built Environment

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Structure geometric configuration and response can be strongly coupled to blast loading particularly for close-in blast loading configurations. As a result, high rate continuum modeling is being increasingly applied to directly resolve both the blast profiles and structural response. In this modeling, the equation of state for the detonation products is the primary modeling description of the work output from the explosive that causes the subsequent air blast. The JonesWilkins-Lee (JWL) equation of state for detonation products is probably the currently most used equation of state for detonation and blast modeling. The Jones-Wilkins-Lee-Baker (JWLB) equation of state is an extension of the JWL equation of state that we commonly use. This paper provides a thermodynamic and mathematical background of the JWL and JWLB equations of state, as well as parameterization methodology. Two methods of parameter calibration have been used to date: empirical calibration to cylinder test data and formal optimization using JAGUAR thermo-chemical predictions. An analytic cylinder test model that uses JWL or JWLB equations of state has been developed, which provides excellent agreement with high rate continuum modeling. This analytic cylinder model is used either as part of the formal optimization or for post parameterization comparison to cylinder test data.

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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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Modeling a Material’s Instantaneous Velocity during Acceleration Driven by a Detonation’s Gas-Push

Cited by 5 publications

References 3 publications

Study on Axial Dispersion Characteristics of Double-Layer Prefabricated Fragments

Study on Axial Dispersion Characteristics of Double-Layer Prefabricated Fragments

Theory and calibration of JWL and JWLB thermodynamic equations of state

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

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