An evaluation of measured and predicted air blast parameters from partially confined blast waves

Langenderfer, Martin; Williams, Kelly; Douglas, A.; Rutter, Barbara; Johnson, Catherine E.

doi:10.1007/s00193-021-00993-0

Cited by 7 publications

(7 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The bridge waves show an opposite trend of becoming more overdriven with increasing radius indicating that the bridge wave regions may be overdriven when they reach the scaled distance safe standoff radius of 4.7 m. For the star both the bridge and primary waves become more underdriven with increasing radius indicating that both primary and bridge waves from the star will be underdriven at the scaled distance safe standoff radius. The star demonstrated the highest degree of overdriving as measured at the explosive boundary with the modified plate dent test [20] but will be underdriven at scaled distance safe radius indicating that under some conditions blast wave overdriving can be used to significantly increase work output in the fireball field with the potential benefit of reduced overpressure at safe scaled distances.…”

Section: Resultsmentioning

confidence: 97%

Evaluating blast wave overpressure from non‐spherical charges using time of arrival from high‐speed video

Johnson

Williams

2023

Propellants Explo Pyrotec

View full text Add to dashboard Cite

Scaled distance is used to predict blast wave overpressure surrounding the detonation of a known mass of explosive under the assumption that the charge geometry is spherical. Altering charge geometry from spherical overdrives regions of the blast wave resulting in areas of higher overpressures than predicted by scaled distance calculations. Empirical data can be used to scale the blast wave overpressure to cylindrical charges, but available overpressure data for more complex geometries is not available in published literature. In the present study the time of arrival of the blast wave was measured from high-speed video and the Rankine-Hugoniot relationship used to measure blast wave overpressure for varied explosive geometries. The radial overpressure of prismatic charges with cross-sectional shapes of triangle, rectangle, and 5-point star isotropic were compared to the radially isotropic overpressure distribution produced by a cylindrical explosive charge. The rectangle produced the highest overpressure measuring 3.5 times that of the cylinder while the triangular charge had the greatest presented surface area and was only overdriven 3.0 times. From the high-speed video the fireball of detonation products surrounding the star appears significantly overdriven from the internal angle, but this orientation was underdriven at 2.0 meters. The blast wave overpressure downstream from the outside corners of the rectangular and triangular prismatic charges were similar to that of the cylinder at 1.5 meters but trended higher at increasing distance.

show abstract

Section: Resultsmentioning

confidence: 97%

Evaluating blast wave overpressure from non‐spherical charges using time of arrival from high‐speed video

Johnson

Williams

2023

Propellants Explo Pyrotec

View full text Add to dashboard Cite

show abstract

“…The overpressure time histories in Case 3 (Fig. 3g-i) has two peaks, The appearance of two peaks may be influenced by factors such as flame interference, multiple reflections of waves [38][39][40] , edge clearing effects, charge shape 37 and detonation configuration, judging from the interval time between the two peaks, the most likely cause is the extension wave of bridge waves behind end waves of cylindrical charges (also known as secondary end waves 36 ). Simulations were carried out in LS-DYNA software 41,42 and AUTODYN software 20,43 respectively (described in the next section), the two peaks of the simulation results in LS-DYNA are smaller than test results, and it was found that the test and simulation achieved consistent results when the charge was deflected upwards by 9.4 degrees in AUTODYN (Fig.…”

Section: Discussionmentioning

confidence: 99%

Blast loads and variability on cylindrical shells under different charge orientations

Yin

Zhi

Fan

et al. 2023

Sci Rep

View full text Add to dashboard Cite

Cylindrical shells are widely used in public buildings and military protection fields, and it has a high risk of terrorist attacks and military attacks, it is of great social benefit to carry out the anti-blast design of cylindrical shells, which needs to consider building shape and the shape of blast waves. In this paper, cylindrical charges in five directions were detonated on the outer ground of the scaled cylindrical shell, blast loads of the cylindrical shell were measured and blast waves were photographed. The variation of blast load is analyzed by combining the test and simulation results, the difference in peak overpressure of the blast waves on the end face between five orientations is nearly twice. The blast loads in the axial direction of cylindrical charges have a secondary peak phenomenon, and the blast loads between the axial direction and radial direction of cylindrical charges change abruptly at a specific angle. The experimental and simulation methods provide a reference for establishing a blast load database of typical buildings.

show abstract

“…Explosives have played a key role in the mining and defense industries for centuries (Cooper, 1937; Damnenderg, 1970; Johnson, 2010; Van Gelder Hugo Schlatter, 1928). In these professions, explosives are deliberately used in confined spaces to expedite basic processes such as mine blasting or tactical breaching (Langenderfer et al, 2021; Rutter and Johnson, 2017). In the chemical and manufacturing industries, the risk of explosion during an industrial accident presents a risk for personal and surrounding structures.…”

Section: Introductionmentioning

confidence: 99%

“…Empirical data, used to produce the Kingery-Bulmash and CONWEP blast models, validated the formula for blast waves expanding in free air, but the Friedlander waveform is only observed when a blast wave expands through the air unimpeded by rigid obstacles (Dewey, 2010, 2015; Karlos et al, 2016). The current predictive tools are not validated for blast wave predictions in situations such as bombings in urban areas, explosions inside buildings, or blasts in underground mines where reflective surfaces can direct the flow of energy from the blast wave (Cullis et al, 2016; Cullis, 2001; Ethridge et al, 1984; Langenderfer et al, 2021; Remmenikov, 2005; Rutter and Johnson, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…These reflected waves follow behind the initial wave and, due to their higher pressure, gradually catch up and coalesce with the initial, incident blast wave (Apazidis and Eliasson, 2019; Ben-Dor, 2007; Gault et al, 2019). Extreme underestimations of maximum overpressures are a consequence of assuming the Friedlander waveform is representative of blast wave behavior in confined environments (Cullis et al, 2016; Langenderfer et al, 2021; Rutter and Johnson, 2017; Sherkar and Whittaker, 2010). Operating under this false assumption could lead to design and safety decisions that fail to account for reflected overpressures up to eight times higher than what was predicted.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An experimental and simulated investigation into the validity of unrestricted blast wave scaling models when applied to transonic flow in complex tunnel environments

Johnson

Grahl

Langenderfer

et al. 2022

International Journal of Protective Structures

View full text Add to dashboard Cite

Since the inception of high explosives as an industrial tool, significant efforts have been made to understand the flow of energy from an explosive into its surroundings to maximize work produced while minimizing damaging effects. Many tools have been developed over the past century, such as the Hopkinson–Cranz (H-C) Scaling Formula, to define blast wave behavior in open air. Despite these efforts, the complexity of wave dynamics has rendered blast wave prediction difficult under confinement, where the wave interacts with reflective surfaces producing complex time-pressure waveforms. This paper implements two methods to better understand blast overpressure propagation in a confined tunnel environment and establish whether scaled tests can be performed comparatively to costly full-scale experiments. Time–pressure waveforms were predicted using both a 1:10 scaled model and three-dimensional air blast simulations conducted in Ansys Autodyn. A comparison of the reduced scale model simulation with a full-scale blast simulation resulted in self-similar overpressure waveforms when employing the H-C scaling model. Experimental overpressure waveforms showed a high level of correlation between the reduced scale model and simulations. Additionally, peak overpressure, duration, and impulse values were found to match within tolerances that are highly promising for applying this methodology in future applications. Using this validated relationship, the simulated model and reduced scale tests were used to predict an overpressure waveform in a full-scale underground mine opening to within 2.12%, 2.91%, and 7.84% for peak overpressure, time of arrival, and impulse, respectively. This paper demonstrates the effectiveness of scaled, blast models when predicting blast wave parameters in a confined environment.

show abstract

An evaluation of measured and predicted air blast parameters from partially confined blast waves

Cited by 7 publications

References 38 publications

Evaluating blast wave overpressure from non‐spherical charges using time of arrival from high‐speed video

Evaluating blast wave overpressure from non‐spherical charges using time of arrival from high‐speed video

Blast loads and variability on cylindrical shells under different charge orientations

An experimental and simulated investigation into the validity of unrestricted blast wave scaling models when applied to transonic flow in complex tunnel environments

Contact Info

Product

Resources

About