scholarly journals Elastic–plastic modelling of shaped charge jet penetration

2006 ◽  
Vol 462 (2076) ◽  
pp. 3663-3681 ◽  
Author(s):  
Roman Novokshanov ◽  
John Ockendon
Keyword(s):  
Free Boundary ◽  
Local Scale ◽  
Shaped Charge ◽  
The Self ◽  
High Rate ◽  
Metal Target ◽  
Elastic Plastic ◽  
Shaped Charge Jet ◽  
Self Consistency ◽  
Penetration Velocity

This paper concerns the mathematical modelling of high-rate penetration of a metal target by a shaped charge device that produces a high-velocity jet. A key objective is to predict the penetration velocity, be it subsonic, transonic or supersonic. We do this by considering, on the local scale near the tip of the penetrated cavity, an elastic–plastic free boundary problem that takes into account the residual stresses produced by the moving plasticized region of the target. It is the self-consistency of this elastic–plastic model that dictates predictions for the penetration velocity.

Investigation of a Nickel-Aluminum Reactive Shaped Charge Liner

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Philip Church ◽  
R. Claridge ◽  
P. Ottley ◽  
I. Lewtas ◽  
N. Harrison ◽  
...  
Keyword(s):  
Formation Process ◽  
Microstructural Analysis ◽  
Target Material ◽  
Shaped Charge ◽  
High Rate ◽  
X Rays ◽  
Nickel Aluminum ◽  
Dendritic Microstructure ◽  
Reactive Powder ◽  
Shaped Charge Jet

A nickel/aluminum (NiAl) reactive powder system has been investigated to determine its mechanical properties under quasi-static and high rate compression to understand its deformation behavior. A shock recovery system has been used to define shock reaction thresholds under a triaxial loading system. Two nickel/aluminum (NiAl) shaped charge liners have been fired into loose kiln dried sand to determine whether the jet material reacts during the formation process. A simple press tool was developed to press the liners from a powder mixture of nickel and aluminum powder and a simple conical design was used for the liner. The shaped charge jet particles were recovered successfully in the sand and subjected to a detailed microstructural analysis. This included X-ray diffraction (XRD) and optical and electron microscopy on selected particles. The analysis demonstrated that intermetallic NiAl was detected and all the aluminum was consumed in the particles examined. In addition, different phases of NiAl were detected as well as silicon oxide in the target material. There was also some evidence that the aluminum had melted along with evidence of a dendritic microstructure. This is the clearest evidence that the shaped charge jet material has reacted during the formation process. Simulations have been performed using the GRIM Eulerian hydrocode to compare with flash X-rays of the jet.

scholarly journals Development and Evaluation of Small Shaped Charge Jet Threats

2017 ◽  
Vol 8 (1) ◽  
pp. 23-38
Author(s):  
Arthur DANIELS ◽  
Stan DEFISHER ◽  
Greg STUNZENAS ◽  
Nausheen AL-SHEHAB ◽  
Ernest L. BAKER
Keyword(s):  
Lower Cost ◽  
Threat Assessment ◽  
Shaped Charge ◽  
International Standards ◽  
High Rate ◽  
Continuum Models ◽  
Severe Reaction ◽  
Explosive Charges ◽  
Shaped Charge Jet ◽  
Aluminium Target

Because of their prolific nature on the battlefield, rocket propelled and gun-launched grenades are of particular concern to the soldier, particularly because of the severe reaction that occurs when a munition is hit by the shaped charge jet. As a result of the danger that such a detonation poses, it is necessary to more precisely understand the behaviour of munitions subjected to these types of devices. In response to these threats, standardized 81 mm and 40 mm shaped charge warheads were developed for use during threat assessment testing to act as a consistent, lower-cost representative of shaped charge projectiles commonly encountered on the battlefield, and to help quantify the interaction of these jest with explosive charges. The international standards for shaped charge jet threat testing uses the Held initiation criteria V2D, where V is the jet velocity and D is the diameter. V2D was computationally predicted using the high-rate continuum models CALE and ALE-3D. The surrogate warheads were test fired through aluminium target plates to strip off jet mass to adjust the V2D to the threat munition.

scholarly journals Simulating Lateral Drift of a Shaped Charge Jet in ALEGRA

2019 ◽  
Author(s):  
Matthew J. Coppinger ◽  
W. Casey Uhlig ◽  
John H. J. Niederhaus
Keyword(s):  
Velocity Gradient ◽  
Explosive Charge ◽  
Shaped Charge ◽  
Analytical Models ◽  
Depth Of Penetration ◽  
Lateral Drift ◽  
The Difference ◽  
Shaped Charge Jet ◽  
Jet Axis ◽  
Penetration Velocity

Abstract Shaped charge jet (SCJ) research has long been an active area for industrial, academic, and defense organizations. Traditionally, the depth of penetration (DOP) has been one of the most important metrics for the evaluation of shaped charge jet performance, and early 1D analytical penetration models based on hydrodynamic penetration were created with this metric in mind [1]. As the standoff of a shaped charge jet increases, the DOP reaches a maximum and then begins to decrease. A simple 1D hydrodynamic penetration model must account for the totality of the jet material on axis penetrating, and as a result experimental DOP at longer standoffs is lower than the analytical models predicted. Some analytical models reasoned that since a velocity gradient evolves as a SCJ forms, contributions to penetration from jet material below a minimum jet or penetration velocity should be eliminated. These were better able to account for the difference between analytical hydrodynamic and experimental DOPs [2]. The actual difference between analytical hydrodynamic penetration theory and experimentally recorded values is now regarded to be a result of 3D phenomena including particle tumbling and motion transverse to the jet axis known as lateral drift [2]. The origins of these 3D phenomena have been attributed to sources including variability in the uniformity of the explosive charge or the microstructure of the liner [2,3].

A Bayesian View on the Hilbert Transform and the Kramers-Kronig Transform of Electrochemical Impedance Data: Probabilistic Estimates and Quality Scores

2020 ◽  
Author(s):  
Jiapeng Liu ◽  
Ting Hei Wan ◽  
Francesco Ciucci
Keyword(s):  
Power Generation ◽  
Electrochemical Impedance Spectroscopy ◽  
Hilbert Transform ◽  
Electrochemical Impedance ◽  
The Self ◽  
Impedance Data ◽  
The Hilbert Transform ◽  
Validation Tests ◽  
Self Consistency ◽  
Mathematical Relations

<p>Electrochemical impedance spectroscopy (EIS) is one of the most widely used experimental tools in electrochemistry and has applications ranging from energy storage and power generation to medicine. Considering the broad applicability of the EIS technique, it is critical to validate the EIS data against the Hilbert transform (HT) or, equivalently, the Kramers–Kronig relations. These mathematical relations allow one to assess the self-consistency of obtained spectra. However, the use of validation tests is still uncommon. In the present article, we aim at bridging this gap by reformulating the HT under a Bayesian framework. In particular, we developed the Bayesian Hilbert transform (BHT) method that interprets the HT probabilistic. Leveraging the BHT, we proposed several scores that provide quick metrics for the evaluation of the EIS data quality.<br></p>

An Empirical Shaped Charge Jet Breakup Model

2014 ◽  
Author(s):  
Ernest L. Baker ◽  
James Pham ◽  
Tan Vuong
Keyword(s):  
Shaped Charge ◽  
Jet Breakup ◽  
Shaped Charge Jet ◽  
Breakup Model
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