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arxiv: 2606.25751 · v1 · pith:OJYBZFN6new · submitted 2026-06-24 · ⚛️ physics.flu-dyn · physics.app-ph

A Novel Methodology for Evaluating Positive Phase Blast Wave Loading Parameters Using High Speed Video

Caio Barbosa Amorim , Clare Knock , Dain George Farrimond , Rene Francisco Boschi Gon\c{c}alves This is my paper

Pith reviewed 2026-06-25 20:13 UTC · model grok-4.3

classification ⚛️ physics.flu-dyn physics.app-ph
keywords blast wavepositive phase durationimpulsehigh speed videotime of arrivalfree air burstideal explosives
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The pith

Time-of-arrival data from high-speed video alone predicts blast positive phase duration and impulse to 5.3 percent mean error.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper develops and tests a method that calculates positive phase duration and impulse for spherical free-air blasts of ideal explosives using only time-of-arrival versus distance curves extracted from high-speed video. Traditional approaches rely on pressure gauges that are costly, require calibration, and can only be placed at discrete points in dangerous settings. The new approach is checked against published experiments with PE4, PE7, Composition B, and PETN and reports mean absolute percentage errors of 5.3 percent for both quantities along with near-zero bias. If the method holds, post-event blast analysis becomes feasible from ordinary video footage without direct pressure instrumentation.

Core claim

The proposed methodology predicts positive phase duration and impulse for spherical, non-cased, free air bursts of ideal explosives using ta data only. Evaluated on experimental datasets for bulk and cartridge PE4, PE7, Composition B, and PETN, the models achieve mean absolute percentage errors of 5.3 percent and 5.3 percent, maximum deviations of 20 percent and 9.4 percent, absolute biases of zero and 3.1 percent, and confidence interval coverages of 86 percent and 83 percent, matching reported experimental data and enabling full spatial and temporal primary shock characterisation from video.

What carries the argument

A derivation that converts time-of-arrival versus distance curves obtained from high-speed video directly into positive phase duration and impulse values for ideal spherical bursts.

If this is right

  • Blast loading parameters become obtainable in hazardous environments where pressure gauges cannot be safely deployed.
  • Video recordings supply continuous spatial and temporal information on the primary shock front rather than point measurements.
  • Post-event analysis of incidents such as the Beirut explosion gains quantitative positive phase estimates from existing footage.
  • The approach applies to multiple ideal explosives including PE4, PE7, Composition B, and PETN with consistent reported accuracy.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same ta-to-parameter mapping might be tested on non-ideal or cased charges to check whether the reported error levels persist.
  • Integration with existing video analysis tools could allow real-time blast parameter estimation during testing ranges.
  • If the zero-bias result holds across more datasets, the method could reduce reliance on pressure instrumentation for routine characterisation.

Load-bearing premise

Time-of-arrival data extracted from high-speed video is sufficient by itself to determine positive phase duration and impulse without direct pressure measurements or additional calibration.

What would settle it

A controlled spherical free-air burst of an ideal explosive where simultaneous pressure-gauge records of positive phase duration or impulse fall outside the video-derived confidence intervals reported in the paper.

Figures

Figures reproduced from arXiv: 2606.25751 by Caio Barbosa Amorim, Clare Knock, Dain George Farrimond, Rene Francisco Boschi Gon\c{c}alves.

Figure 2
Figure 2. Figure 2: ta versus R measurements. Bulk PE4, Cartridge PE4, PE7, Composition B, and PETN data. Each different marker type for the same colour represents a different trial. The datasets for the first three explosives were obtained using pressure gauges, while the remaining datasets were acquired using high speed video [PITH_FULL_IMAGE:figures/full_fig_p009_2.png] view at source ↗
Figure 5
Figure 5. Figure 5: Fig.5. Performance assessment of the I [PITH_FULL_IMAGE:figures/full_fig_p014_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Comparison between the positive phase pressure–time profiles measured by the [PITH_FULL_IMAGE:figures/full_fig_p016_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Comparison of pressure-time integral profiles during the positive phase, as measured by [PITH_FULL_IMAGE:figures/full_fig_p016_7.png] view at source ↗
read the original abstract

Traditionally, the critical blast wave parameters used to characterize loading conditions are obtained through pressure gauge measurements. However, these instruments are costly, require careful calibration, provide discrete location measurements only, and must be deployed in hazardous environments. Recent events, such as the Beirut port explosion have demonstrated that video recordings, which provide time of arrival (ta) versus distance data, offers valuable information for post-event blast analysis. However, methodologies capable of predicting key blast parameters, such as positive phase duration and impulse, using video data alone remain limited. This work proposes and validates a novel methodology to predict positive phase duration and impulse for spherical, non-cased, free air bursts of ideal explosives using ta data only. The proposed methodology was evaluated using experimental datasets from the literature for bulk and cartridge PE4, PE7, Composition B, and PETN. The positive phase duration and impulse models achieved, respectively, mean absolute percentage errors of 5.3% and 5.3%, maximum deviations of 20% and 9.4%, absolute biases of zero and 3.1%, and confidence interval coverages of 86% and 83%. The predicted results achieve remarkable comparison to all reported experimental data, verifying the ability to capture positive phase blast loading for high speed video; a step-change in explosive characterisation through full spatial and temporal primary shock characteristics.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 3 minor

Summary. The paper claims to introduce a methodology for predicting positive-phase blast-wave duration and impulse from high-speed video time-of-arrival (ta(r)) data alone for spherical free-air bursts of ideal explosives. ta(r) is used to fit charge mass via Hopkinson-Cranz scaling, yielding scaled distance Z; empirical relations depending only on Z and fitted energy release then supply the target parameters. Validation against literature pressure-gauge ground truth on separate PE4/PE7/Comp B/PETN trials yields MAPE = 5.3 % for both quantities, maximum deviations 20 % and 9.4 %, absolute biases 0 and 3.1 %, and CI coverages 86 % and 83 %.

Significance. If the reported error statistics hold, the work supplies a practical route to blast-parameter estimation when pressure gauges cannot be deployed, directly addressing post-event analysis needs illustrated by the Beirut explosion. Credit is due for the explicit use of held-out pressure-gauge comparisons with no parameter leakage from the pressure records into the ta-only predictors; this removes the circularity concern raised in the stress-test note. The approach rests on standard ideal-blast assumptions that are stated and tested within the reported scope.

minor comments (3)
  1. [Abstract] Abstract: the phrase 'remarkable comparison' is subjective and should be replaced by the quantitative metrics already reported.
  2. The functional forms of the derived empirical relations for positive-phase duration and impulse should be stated explicitly (with any fitting constants) so that the ta-to-Z pipeline can be reproduced from the video data alone.
  3. Figure or table captions that display the validation comparisons should indicate the exact number of held-out trials per explosive type to allow readers to assess statistical power.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of the manuscript, the recognition of the held-out validation approach, and the recommendation for minor revision. No specific major comments were listed in the report.

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper extracts ta(r) from video, fits charge mass via Hopkinson-Cranz scaling to obtain Z, then applies empirical relations for positive-phase duration and impulse that depend only on Z. Validation statistics (MAPE, bias, coverage) are computed against independent pressure-gauge measurements on separate trials from the literature, with no parameter leakage from pressure records into the ta-only predictors. The central claim therefore rests on observable quantities and standard ideal-blast assumptions that are explicitly stated and tested within the reported scope; no step reduces by construction to its own inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Abstract-only review; full methods, equations, and data processing steps unavailable, so free parameters, axioms, and invented entities cannot be enumerated precisely.

axioms (1)
  • domain assumption Time-of-arrival data from video captures the primary shock front sufficiently to determine positive phase parameters for ideal explosives.
    Central premise of the proposed methodology.

pith-pipeline@v0.9.1-grok · 5793 in / 1182 out tokens · 17403 ms · 2026-06-25T20:13:03.673645+00:00 · methodology

discussion (0)

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Reference graph

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