Name: blast quantification using hopkinson pressure bars
Uploaded: 2016-07-05T14:00:00
Description: Watch this Scientific Journal Video about Blast Quantification Using Hopkinson Pressure Bars at JoVE.com

The authors wish to thank the Defence Science and Technology Laboratory for funding the published work.

1. Stijve Reaction Frame <ol><li> Bepaal geschaalde distance waarvan tests gebruikt Vergelijking 1, waarbij R de afstand van het centrum van het explosief te nemen, en W de lading massa uitgedrukt als equivalente massa TNT. Z = R / W 1/3 (1) </li><li> Bereken bij benadering maximale impuls deze regeling zal via numerieke modellering te genereren (zie bijlage A) of specifieke instrumenten zoals ConWep 3. Opmerking: Het gebruik van ConWep 3 is all...

<ol>
	<li>Esparza, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blast+measurements+and+equivalency+for+spherical+charges+at+small+scaled+distances.">Blast measurements and equivalency for spherical charges at small scaled distances.</a> Int. J. Impact Eng. 4 (1), 23-40 (1986).</li><li>Kingery, C. N., Bulmash, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ARBRL-TR-02555.">ARBRL-TR-02555.</a> Airblast parameters from TNT spherical air burst and hemispherical surface burst. , (1984).</li><li>Hyde, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Conventional weapons program (ConWep). , (1991).</li><li>Randers-Pehrson, G., Bannister, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ARL-TR-1310.">ARL-TR-1310.</a> Airblast loading model for DYNA2D and DYNA3D. , (1997).</li><li>Neuberger, A., Peles, S., Rittel, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scaling+the+response+of+circular+plates+subjected+to+large+and+close-range+spherical+explosions.+Part+II:+Buried+charges.">Scaling the response of circular plates subjected to large and close-range spherical explosions. Part II: Buried charges.</a> Int. J. Impact Eng. 34 (5), 874-882 (2007).</li><li>Xu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+inverse+approach+for+pressure+load+identification.">An inverse approach for pressure load identification.</a> Int. J. Impact Eng. 37 (7), 865-877 (2010).</li><li>Pickering, E. G., Chung Kim Yuen, S., Nurick, G. N., Haw, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+response+of+quadrangular+plates+to+buried+charges.">The response of quadrangular plates to buried charges.</a> Int. J. Impact Eng. 49, 103-114 (2012).</li><li>Bergeron, D. M., Trembley, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Canadian+research+to+characterize+mine+blast+output.">Canadian research to characterize mine blast output.</a> , (2000).</li><li>Hlady, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+soil+parameters+on+landmine+blast.">Effect of soil parameters on landmine blast.</a> , (2004).</li><li>Fourney, W. L., Leiste, U., Bonenberger, R., Goodings, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+loading+on+plates+due+to+explosive+detonation.">Mechanism of loading on plates due to explosive detonation.</a> Int. J. on Blasting and Fragmentation. 9 (4), 205-217 (2005).</li><li>Anderson, C. E., Behner, T., Weiss, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mine+blast+loading+experiments.">Mine blast loading experiments.</a> Int. J. Impact Eng. 38 (8-9), 697-706 (2011).</li><li>Fox, D. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+response+of+small+scale+rigid+targets+to+shallow+buried+explosive+detonations.">The response of small scale rigid targets to shallow buried explosive detonations.</a> Int. J. Impact Eng. 38 (11), 882-891 (2011).</li><li>Ehrgott, J. Q., Rhett, R. G., Akers, S. A., Rickman, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+fabrication+of+an+impulse+measurement+device+to+quantify+the+blast+environment+from+a+near-surface+detonation+in+soil.">Design and fabrication of an impulse measurement device to quantify the blast environment from a near-surface detonation in soil.</a> Experimental Techniques. 35 (3), 51-62 (2011).</li><li>Pope, D. J., Tyas, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+hydrocode+modelling+techniques+to+predict+loading+parameters+from+free+air+hemispherical+explosive+charges.">Use of hydrocode modelling techniques to predict loading parameters from free air hemispherical explosive charges.</a> , (2002).</li><li>Clarke, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repeatability+of+buried+charge+testing.">Repeatability of buried charge testing.</a> , (2014).</li><li>Clarke, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+large+scale+experimental+approach+to+the+measurement+of+spatially+and+temporally+localised+loading+from+the+detonation+of+shallow-buried+explosives.">A large scale experimental approach to the measurement of spatially and temporally localised loading from the detonation of shallow-buried explosives.</a> Meas Sci Technol. 26, 015001 (2015).</li><li>Hopkinson, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Method+of+Measuring+the+Pressure+Produced+in+the+Detonation+of+High+Explosives+or+by+the+Impact+of+Bullets.">A Method of Measuring the Pressure Produced in the Detonation of High Explosives or by the Impact of Bullets.</a> Philos. Trans. R. Soc. (London) A. 213, 437-456 (1914).</li><li>Rigby, S. E., Tyas, A., Fay, S. D., Clarke, S. D., Warren, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+semi-empirical+blast+pressure+predictions+for+far+field+explosions+-+is+there+inherent+variability+in+blast+wave+parameters?.">Validation of semi-empirical blast pressure predictions for far field explosions - is there inherent variability in blast wave parameters?.</a> , (2014).</li><li>Rigby, S. E., Tyas, A., Bennett, T., Clarke, S. D., Fay, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+negative+phase+of+the+blast+load.">The negative phase of the blast load.</a> Int. J. of Protective Structures. 5 (1), 1-20 (2014).</li><li>Rigby, S. E., Fay, S. D., Tyas, A., Warren, J. A., Clarke, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angle+of+incidence+effects+on+far-field+positive+and+negative+phase+blast+parameters.">Angle of incidence effects on far-field positive and negative phase blast parameters.</a> Int. J. of Protective Structures. 6 (1), 23-42 (2015).</li><li>Tyas, A., Warren, J., Bennett, T., Fay, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prediction+of+clearing+effects+in+far-field+blast+loading+of+finite+targets.">Prediction of clearing effects in far-field blast loading of finite targets.</a> Shock Waves. 21 (2), 111-119 (2011).</li><li>Tyas, A., Watson, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+the+effect+of+spatial+variation+of+load+in+the+pressure+bar.">A study of the effect of spatial variation of load in the pressure bar.</a> Meas Sci Technol. 11 (11), 1539-1551 (2000).</li><li>Tyas, A., Watson, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+investigation+of+frequency+domain+dispersion+correction+of+pressure+bar+signals.">An investigation of frequency domain dispersion correction of pressure bar signals.</a> Int. J. Impact Eng. 25 (1), 87-101 (2001).</li><li>NATO Standardisation Agency. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Procedures+for+evaluating+the+protection+level+of+logistic+and+light+armoured+vehicles.">Procedures for evaluating the protection level of logistic and light armoured vehicles.</a> Allied Engineering Publication (AEP) 55. 2, (2011).</li><li>Elgy, I. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> UK ministry of defence technical authority instructions for testing the protection level of vehicles against buried blast mines. , (2014).</li><li>Clarke, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finite+element+simulation+of+plates+under+non-uniform+blast+loads+using+a+point-load+method:+Buried+explosives.">Finite element simulation of plates under non-uniform blast loads using a point-load method: Buried explosives.</a> , (2015).</li><li>Rigby, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finite+element+simulation+of+plates+under+non-uniform+blast+loads+using+a+point-load+method:+Blast+wave+clearing.">Finite element simulation of plates under non-uniform blast loads using a point-load method: Blast wave clearing.</a> , (2015).</li><li>Hallquist, J. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> LS-DYNA theory manual. , (2006).</li><li>Fay, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capturing+the+spatial+and+temporal+variations+in+impulse+from+shallow+buried+charges.">Capturing the spatial and temporal variations in impulse from shallow buried charges.</a> , (2013).</li><li>Fay, S. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+the+spatial+and+temporal+pressure+variation+from+buried+charges.">Measuring the spatial and temporal pressure variation from buried charges.</a> , (2014).</li></ol>

Gebruik van het protocol hierboven beschreven de auteurs hebben aangetoond dat het mogelijk is om zeer betrouwbare metingen van de sterk wisselende belasting krijgen van een explosieve lading, onder toepassing van een reeks Hopkinson drukstaven. Met de interpolatieroutine zet de discrete druk in de tijd kan worden omgezet in een continue schokgolf die direct bruikbaar als het laden functie in numerieke modellering of validatiegegevens voor de output van dergelijke modellen. Bij het gebruik v...

Karakteriseren van de output van explosieve ladingen heeft vele voordelen, zowel militaire (verdediging tegen begraven geïmproviseerde explosieven in de huidige conflictgebieden) en civiel (het ontwerpen van structurele componenten). In de afgelopen tijd heeft dit onderwerp veel aandacht gekregen. Veel van de kennis die is gericht op het kwantificeren van de output van kosten voor het ontwerpen van doeltreffende veiligheidsvoorzieningen structuren mogelijk. Het belangrijkste punt hier is dat als de metingen zijn niet van high fidelity dan de mechanismen van de belasting overdracht in deze explosieve gebeurtenissen onduidelijk blijven. Dit leidt tot problemen valideren numerieke modellen die gebaseerd zijn op deze metingen voor validatie. De term nabije-veld wordt gebruikt voor ontploffing met geschaalde afstanden, Z, minder dan ~ 1 m / kg 1/3, waarbij Z = R / W 1/3, R de afstand van het centrum van het explosief en W beschrijven wordt de lading massa geuiteen equivalente massa van TNT. In deze regeling wordt de laad- doorgaans gekenmerkt door een zeer grote omvang, zeer ruimtelijk en in tijd niet-uniforme belastingen. Robuuste instrumentatie is dus nodig om de extreme druk in verband met near-field lading te meten. Bij geschaalde afstanden Z &lt;0,4 m / kg 1/3, directe metingen van de ontploffing parameters zijn ofwel onbestaande of zeer weinig 1 en de semi-empirische voorspellende data voor deze serie is vrijwel volledig gebaseerd op parametrische studies. Dit gaat met behulp van de semi-empirische voorspellingen gegeven door Kingery en Bulmash 2, die zich buiten het toepassingsgebied van de auteur. Terwijl hulpmiddelen op basis van deze voorspellingen 3,4 zorgen voor een uitstekende eerste orde schattingen van het laden ze niet volledig vastleggen van de mechanica van near-field gebeurtenissen, die de focus van het huidige onderzoek. Near-field ontploffing metingen hebben in de afgelopen tijd gericht op het kwantificeren van de output van begraven kosten. De methodieken gebruikt variëren van het beoordelen van de vervorming veroorzaakt aan een structureel doel 5-7 aan de wereldwijde impuls meting 8-13 richten. Deze methoden leveren waardevolle informatie voor de validatie van beschermende systeemontwerpen maar kunnen geen volledig onderzoek naar de mechanismen van lastenoverdracht. Testen kan op laboratorium- schaal (1/10 volledige schaal), of nabij volle schaal (&gt; 1/4), met praktische redenen zoals het controleren of ingraafdiepte zodat er geen inherente vorm van de schokgolf wordt opgewekt door de gebruik van ontstekers in plaats van kale kosten 14. Met begraven lasten hebben de bodemgesteldheid in hoge mate worden gecontroleerd om de herhaalbaarheid van de test 15 te garanderen. Onafhankelijk van de vraag of de lading wordt geplaatst in de vrije lucht of is begraven, de meest fundamentele probleem in het meten van de resulterende explosie is het waarborgen van de geldigheid van de metingen die door de instrumentatie deployed. In het ontworpen testapparaat 16 vaste &#39;rigide&#39; target plaat wordt gebruikt om de Hopkinson druk bars 17 (HPbs), terwijl schermen tegelijkertijd ervoor te zorgen dat de uiteinden van de balken alleen het volledig tot uiting druk kan opnemen. De auteurs hebben eerder aangetoond dat de meting van gereflecteerd druk uit een rigide doel meer nauwkeurige en herhaalbare dan incident, of &quot;vrije-field&quot; metingen 18-20. De geometrie van deze plaat is zodanig dat elke drukverlaging gegenereerd door het opruimen of stroming rond het doel rand 21 verwaarloosbaar zou zijn. Deze nieuwe testapparatuur is gebouwd op 1/4 schaal. Op deze schaal strakke controle over de begrafenis omstandigheden en de explosieven kan worden gewaarborgd, met de volle schaal lading grootte van 5 kg verkleind tot 78 g, bij een begrafenis diepte van 25 mm.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Load Cell</td>
			<td style="width:71px;">RDP</td>
			<td style="width:119px;">RSL0960</td>
			<td style="width:167px;">This is only indicative, the exact load cell should be able to resolve the required loading</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Steel target plate / HPBs</td>
			<td style="width:71px;">Garratts&#160;</td>
			<td style="width:119px;">N/A</td>
			<td>Fabricated to order</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Strain gauge</td>
			<td style="width:71px;">Kyowa</td>
			<td>KSP-2-120-E4</td>
			<td>To use with steel HPBs</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cyanoacrylate</td>
			<td style="width:71px;">Kyowa</td>
			<td>CC-33-A</td>
			<td>Check with manufacturer depending on mar material to be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Digital Oscilloscope</td>
			<td style="width:71px;">TiePie</td>
			<td>HS4 16-bit Handyscopes&#160;</td>
			<td>6 used in parallel in current testing</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Leighton Buzzard sand</td>
			<td style="width:71px;">Garside sands</td>
			<td style="width:119px;">Garside 14/25</td>
			<td>Uniform silica sand&#160;</td>
		</tr>
	</tbody>
</table>

blast quantification using hopkinson pressure bars

Nabije veld blast belastingsmeting geeft een probleem bij vele typen sensoren mocht zeer agressieve milieus moeten ondergaan en in staat om druk te meten tot vele honderden Mpa. In dit opzicht is de eenvoud van de Hopkinson drukstang heeft een groot voordeel, dat terwijl de eindwaarde van de Hopkinson bar kan verdragen en worden blootgesteld aan zware omstandigheden, de spanningsmeter bevestigd aan de staaf kan op enige afstand aangebracht. Hiermee beschermende behuizingen worden gebruikt waarop de spanningsmeter te beschermen, maar niet interfereren met de meting acquisitie. Het gebruik van een array van drukstaven kan de druk in de tijd in discrete bekende punten te meten. Dit artikel beschrijft ook de interpolatie routine gebruikt om de druk in de tijd af te leiden at-un geïnstrumenteerde locaties op het vlak van belang. Momenteel de techniek is gebruikt voor het laden van hoge explosieven in vrije lucht meten en ondiep begraven in verschillende bodems.

Een effectief stijf reactie kader moet worden verstrekt. In de huidige testen totaal meegedeelde impuls van enkele honderden Newton-seconden moet worden tegengegaan met minimale vervorming. Een illustratie van de stijve reactiemengsel lijst is vervat in figuur 1. In elk frame een 50 mm staal &quot;acceptor&quot; plaat is in de basis van de dwarsbalken geworpen. Hoewel niet expliciet vereist, dit maakt een eenvoudige bevestiging van de weegcellen / richtplaat en biedt ext...

Watch this Scientific Journal Video about Blast Quantification Using Hopkinson Pressure Bars at JoVE.com

Blast Quantification Using Hopkinson Pressure Bars

This protocol details the use of Hopkinson pressure bars to measure reflected blast loading from near-field explosive events. It is capable of interpolating a pressure-time history at any point on a reflective boundary and as such can be used to fully characterize the spatial and temporal variations in loading produced.

Blast Kwantificering Met behulp van Hopkinson Pressure Bars

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures ...

The overall goal of this experiment is to accurately measure the spatial and temporal distribution of pressure in the extremely aggressive environment generated close to an explosive charge. This method can help answer the key questions in the field of blast protection engineering such as the exact form of the imparted load and how factors such as explosive type and shape influence the imparted load. The main advantage of this technique is that it allows us to record pressures that are beyond the limits of traditional measuring approaches.Though this method can provide insights into free air explosions, it can also be applied to other events, such as buried or underwater charges. We first trialed the idea for this method using a single Hopkinson pressure bar, and soon realized a large array is needed to accurately capture the data. To begin, calculate the approximate maximum impulse the test frame arrangement will generate using software analysis, such as with ConWep.For buried charges, this process is less straightforward, cause it requires more advanced numerical techniques to model the interaction between the soil, explosives, and the target plate. Details on the production of the test frame and the load cells are each provided in the text protocol. Choose the position on the Hopkinson pressure bars that the strain gauge will be positioned, being as close as possible to the loaded face to minimize dispersion.In this setup, the thickness of the target plate and the maneuverability required to fit the bars results in the gauges being installed 250 millimeters from the loaded face. The calculated bar radius required to capture the event is in this case five millimeters. Use the tightest spatial resolution for the bars that does not compromise structural integrity.In this case, the distance is 25 millimeters. Further details are provided in the text protocol. To begin, using cyanoacrylate, attach semiconductor strain gauge to the Hopkinson pressure bars, then to the load cells.Fit the target plate to the rigid reaction frame using the load cells if needed. Make certain that all of the cabling is well grounded for improved signal quality. The wiring must also be long enough to connect to an oscilloscope outside the blast area.Any shielded wire should carry enough signal. Now, hang Hopkinson pressure bars from the bar assembly receiver. Pass the loaded end through the correct hole in the target plate, and hang the Hopkinson pressure bars freely from the nut screwed onto their distal ends.Using a level, adjust the nuts to position the bars vertically and to make their faces level with the target plate. Now, use trial and error to set the trim on the variable resistor in the conditioning circuit to keep the voltage within the limits of the oscilloscope. Zero the out of balance reading on each channel as reported by the amplifier boxes.Next, connect the amplified gauge output to a suitable digital oscilloscope. Configure the oscilloscope to a 1.56 megahertz sampling frequency with a 28.7 millisecond recording duration and set the pre-trigger duration to 3.3 milliseconds. 22 total gauges should be connected, 17 from Hopkinson pressure bars, four from load cells, and the one break wire.Record the voltage and time from each gauge. Set the recording to trigger when the voltage in the break wire exceeds an out-window value, such as plus or minus 100 millivolts. In the case of a free air charge test, use a thin strip of wood to suspend the charge below the target plate at the correct stand-off, in this case 200 millimeters.Position the charge co-axially with the measurement array to ensure valid readings. The critical element in the buried charge test is in the preparation of the soil bed and the burial process. Precision is required to ensure repeatable results are attained.Next, close the range. Deploy sentries to ensure the range is clear during the firing. Now, just before firing a free air charge, attach the break wire to the detonator and insert an electrical detonator halfway into the charge from the base.Now, move to the firing point and confirm that the instrumentation is operative. Then, supply power to the break wire. Now, make certain to check with the sentries that it is safe to proceed with the firing.Then, initiate the explosives. After the detonation, make the test area safe and download and back up the data. Whilst a protocol is being written to describe the steps required in this stage, a developed Matlab script is also being made available to allow the data processing to be done quickly using the exact methodology.Import the data from the raw data files into Matlab by double clicking on the file name and then clicking Finish in the Import Wizard. Next, open the interpolation Matlab script. In the meshing section of the code, define a regular grid over which the interpolation will run by changing the mesh.Use the same resolution in any future numerical modeling. This crucial step transforms the discreet data into a 2D map. The script will time shift all Hopkinson pressure bar pressure traces.The time shift is required to allow the interpolation routine to successfully locate the shock front at any given time. Now, align the data from each radial array so all the maximum pressures are synced. Next, calculate the radius, r, and angle, beta, for a given point of interest on the grid.Apply the 1D interpolation to the two Hopkinson pressure bar arrays closest to the point of interest of the current radius. For example, at 45 degrees, the interpolation would use the X, X and Y, Y arrays. Now, interpolate the linearity between the two pressures based on the angle.For example, at 45 degrees, use 50%X, X and 50%Y, Y.Then, time shift the pressure time history for each location based on cubic interpolation of the shock arrival time. Ultimately, the result is a fully interpolated pressure time history. An effectively rigid reaction frame capable of resisting several hundred Newton-seconds with minimal deflection was conceived using a 100 millimeter mild steel target plate.This frame withstood tests up to 500 Newton-seconds. A single test was made with 17 Hopkinson pressure bars configured in a 2D array utilizing 3.25 meter long bars with five millimeter radii. Spacing was set to 25 millimeters.For this test, the strain gauge was attached 0.25 meters from the loaded face. A charge buried in saturated soil was detonated. Data from each of the four radial arrays with a central Hopkinson pressure bar common to all the plots shows the very clear shock front, with the pressure decaying slowly with radial distance.The recorded pressure time histories were then run through the 2D interpolation routine. The interpolated pressure acting on the target plate shows a 20 millisecond delay in the arrival of the shock front. The shock front is the time taken for the shock wave to cover the distance between the charge and the target plate.The asymmetric nature of the loading is especially clear at 0.22 milliseconds. By 0.3 milliseconds after detonation, the shock front was almost symmetric along all axes. Once the apparatus is commissioned, up to six free air tests per day can be conducted.This number is greatly reduced with a test using buried charges due to the added complexity of preparing the soil. This is the first time that such high resolution measurements have been possible. As a result, we're now able to measure the difference in the form of the loading caused by variations in test geometry.The numerical routine developed offers a very powerful way to visualize the loading and then to apply this loading directly in numerical models to act as a first step in modeling the response of structures to explosive detonations. The data produced from the current test has provided unique validation data to enhance the next generation of numerical models, improving our understanding of the problem and our ability to protect ourselves against explosive blasts.

Research

JoVE Journal

Engineering

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

Synthese en microdiffraction bij extreme drukken en temperaturen

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

Hoe maak je een atmosferische druk Magnetron Plasma Torch Ignite zonder extra vonkonststekers

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

The Measurement of Unsteady Surface Pressure Using a Remote Microphone Probe

De meting van Unsteady Surface Pressure Met behulp van een Remote Microphone Probe

Microphones are widely applied to measure pressure fluctuations at the walls of solid bodies immersed in turbulent flows. Turbulent motions with various ...

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

Een atmosferische druk Plasma Setup om de reactieve species Formatie Onderzoek

Non-thermal atmospheric pressure (&#39;cold&#39;) plasmas have received increased attention in recent years due to their significant biomedical potential. ...

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

Twee-weg Valorisatie van hoogovenslakken: Synthese van neergeslagen calciumcarbonaat en Zeolitische Heavy Metal Adsorbent

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with ...

Precision Milling of Carbon Nanotube Forests Using Low Pressure Scanning Electron Microscopy

Precisie Frezen van koolstof nanobuis Bossen Met behulp van Low Pressure Scanning Electron Microscopy

A nanoscale fabrication technique appropriate for milling carbon nanotube (CNT) forests is described. The technique utilizes an environmental scanning ...

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Luchtdruk fabricage van grote en middelgrote enkellaags rechthoekig SnSe vlokken

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Applicability Analysis of Assessment Methods for Morphological Parameters of Corroded Steel Bars

Analyse van de toepasbaarheid van de beoordelingsmethoden voor morfologische Parameters van gecorrodeerde Steel Bars

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly ...

Using Flexible Gold-Titanium Reaction Cells to Simulate Pressure-Dependent Microbial Activity in the Context of Subsurface Biomining

Met behulp van flexibele goud-Titanium reactie cellen om druk afhankelijke microbiële activiteit te simuleren in de context van suboppervlakte Biomining

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging ...

Fabrication of Compressed Hosiery and Measurement of its Pressure Characteristic Exerted on the Lower Limbs

Fabricage van gecomprimeerde kousen en meting van de drukkarakteristiek uitgeoefend op de onderste ledematen

This article reports the pressure characteristic measurement of compressed hosiery via direct and indirect methods. In the direct method, an interface ...