On the problem of bare-to-cased charge equivalency

Grisaro, Hezi Y.; Dancygier, Avraham N.

doi:10.1016/j.ijimpeng.2016.03.004

Cited by 30 publications

(8 citation statements)

References 11 publications

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“…A general observation is that it is not always clear how the TNT equivalency is calculated. For example, the TNT equivalency is not simply the impulse or overpressure ratio between two measurements of explosive charges at the same distance as was claimed by Hutchinson (2011) and was discussed by Grisaro and Dancygier (2016).…”

Section: Introductionmentioning

confidence: 91%

“…To perform such calculation, the "reference line" equation should be known (in this case-the "reference lines" are the scaled curve of TNT for impulse and overpressure). This approach is given in details in Grisaro and Dancygier (2016) for impulse and will be detailed here also for overpressure. The following equations were chosen to fit the variation of the overpressure and scaled impulse of TNT with the scaled distance by the least square method where R (m) is the absolute distance, C is the charge mass (kg), and the constants A and B are derived from the curve fitting procedure.…”

Section: Determination Of the Tnt Equivalencymentioning

confidence: 99%

“…The blast wave pressure parameters satisfy the Hopkinson–Cranz scaling laws (Baker, 1973; Cooper, 1996; Grisaro and Dancygier, 2016), which are based on the Buckingham π theorem. The law defines a dimensional parameter of scaled distance that is R/C 1/3 , where R is the distance and C is the charge mass.…”

Section: Introductionmentioning

confidence: 99%

“…To carry these calculations, the explosive and the air should be modeled in a Eulerian mesh. The air is commonly modeled with the ideal gas equation of state (EOS) and the explosive charge with the JWL EOS (Grisaro and Dancygier, 2016). The JWL parameters are calibrated to various explosive types (ANSYS, Inc., 2016).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical investigation of explosive bare charge equivalent weight

Grisaro

Edri

2017

International Journal of Protective Structures

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Peak overpressure and impulse are the most important parameters in the explosive performance estimation. Available models commonly consider trinitrotoluene explosive as the standard charge. In this article, the trinitrotoluene equivalency factor is studied through verified one-dimensional numerical simulations. The equivalency factors for impulse and overpressure are different and found to be constant with the scaled distance (3-40 m/kg 1/3), which means that a unique value for the equivalency factor is suitable for the equivalency factor calculation for each distance. Comparison of the equivalency factor with available models shows that it strongly depends on the internal energy ratio of the explosive in interest, relative to trinitrotoluene, and a new formula for equivalency factor for overpressure is proposed. A verified simulation method is presented in which the explosive is modeled with an equivalent "air bubble" with the same internal energy and ideal gas equation of state. A new approach using the energy flux density calculation is presented to calculate the equivalency factor for impulse and overpressure from a single gauge measurement of overpressure-time history, at a specific distance.

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Section: Introductionmentioning

confidence: 91%

Section: Determination Of the Tnt Equivalencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of explosive bare charge equivalent weight

Grisaro

Edri

2017

International Journal of Protective Structures

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“…Limited initiation energy or external stimulation may cause incomplete detonation in a warhead charge. Complete warhead detonation has been fully studied (Mott and Linfoot, 1943;Mott, 1947;Grisaro and Dancygier, 2016;Held, 1990), but less study has been done on quantitatively characterizing charge energy release for incomplete detonation such as explosion and deflagration. This makes it difficult to evaluate warhead charge initiation and detonation ability.…”

Section: Introductionmentioning

confidence: 99%

Method of evaluating energy released by a warhead charge based on average fragment quality

Liu³

et al. 2021

Lat. Am. j. solids struct.

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Limited initiation energy or external stimulation may cause incomplete detonation in a warhead. At present, there is no quantitative method to characterize the energy release of a warhead charge for incomplete detonation such as explosion and deflagration. We propose a method based on average fragment quality to characterize the energy released by a warhead charge. The theoretical study shows that the average fragment quality after warhead initiation is inversely proportional to the initial fragment velocity. The relationship between the average fragment quality and explosive energy release is established and verified by experiment. This relation can be used to determine the charge energy released after warhead initiation. It provides a theoretical basis for optimizing efficiency of charge energy use in high-energy conventional damage technology and warhead design, and provides a quantitative method for evaluating insensitive ammunition.

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Analyzing the effectiveness of the Gurney method for small scale fragmentation propulsion using Exploding Bridgewire detonators

Bauer

Johnson

2023

Propellants Explo Pyrotec

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Explosives are common in military, mining, and construction applications where the explosive properties are understood, but mechanics of how the explosive's energy fragments and throws materials are less known. Considering the type of confining material around an explosive, creates variability in fragmentation behavior due to the individual material characteristics. The most common method for assessing fragmentation behavior is the Gurney method, which eliminates any consideration of fragmenting material properties. The Gurney method assumes that, on a large scale, the inconsistencies in material are irrelevant and only the mass of the confiner need be considered. However, it is known in many fields that energy is consumed in the breaking of a material. In this paper, the detonation and resultant fragmentation propulsion of Exploding Bridgewire (EBW) detonators with the same explosive material, but different casing characteristics, is observed. The Gurney method was used to predict fragmentation velocities of the casing following detonation, which were compared to the behavior observed through high-speed video of the actual event. The EBWs were selected to provide variability in casing material, casing thickness, charge length, and charge diameter. It was found that when the amount of explosive is small, the material properties of the casing play a significant role, with 70 % of the total explosive mass lost in fragmenting PMMA EBWs and 30 � 3 % lost in Aluminum EBWs. There is significant energy loss to breaking the casing material that cannot be ignored on the small scale and could impact large explosives with high casing to explosive ratios.

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On the problem of bare-to-cased charge equivalency

Cited by 30 publications

References 11 publications

Numerical investigation of explosive bare charge equivalent weight

Numerical investigation of explosive bare charge equivalent weight

Method of evaluating energy released by a warhead charge based on average fragment quality

Analyzing the effectiveness of the Gurney method for small scale fragmentation propulsion using Exploding Bridgewire detonators

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