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. الصلبة إطار رد الفعل <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> تحديد المسافة تحجيمها الذي اختبار ستجري باستخدام المعادلة 1، حيث R هي المسافة من مركز الانفجار، وW هو المسؤول أعرب الجماهيري باعتبارها يعادل كتلة من مادة تي ان تي. Z = R / W 1/3...

<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>

باستخدام بروتوكول المذكورة أعلاه المؤلفين أظهرت أنه من الممكن الحصول على قياسات عالية الدقة للتحميل متفاوتة للغاية من عبوة ناسفة، وذلك باستخدام مجموعة واسعة من الحانات الضغط هوبكنسون. باستخدام روتين الاستيفاء أوجز تاريخها لمرة والضغط المنفصلة يمكن أن تتحول إلى جب...

تميز انتاج عبوات ناسفة له فوائد عديدة، سواء العسكرية (الدفاع ضد دفن عبوات ناسفة في مناطق الصراع الحالية) ومدني (تصميم المكونات الهيكلية). في الآونة الأخيرة قد تلقى هذا الموضوع اهتماما كبيرا. وتهدف الكثير من المعرفة التي تم جمعها في تقدير حجم الانتاج من الرسوم لتمكين تصميم هياكل الحماية أكثر فعالية. القضية الرئيسية هنا هي أنه إذا القياسات التي أجريت ليست ذات الدقة العالية ثم آليات نقل حمولة في هذه الأحداث المتفجرة لا تزال غير واضحة. وهذا بدوره يؤدي إلى مشاكل التحقق من صحة النماذج العددية التي تعتمد على هذه القياسات للمصادقة. يستخدم مصطلح قرب الميدان لوصف التفجيرات مع مسافات تحجيمها، Z، أقل من ~ 1 م / كغ 1/3، حيث Z = R / W 1/3، R هي المسافة من مركز الانفجار، وW هو المسؤول أعربت كتلةباعتبارها يعادل كتلة من مادة تي ان تي. في هذا النظام عادة يتميز التحميل من قبل حجم مرتفع للغاية، المكاني للغاية وزمانيا الأحمال غير موحدة. وبالتالي مطلوب أجهزة قوية لقياس الضغوط الشديدة المرتبطة تحميل قرب الميدان. على مسافات تحجيم Z &lt;0.4 م / كغ 1/3، القياسات المباشرة من المعلمات الانفجار إما غير موجودة أو قليلة جدا 1، ويستند البيانات التنبؤية شبه تجريبية لهذا النطاق بشكل كامل تقريبا على دراسات حدودي. هذا ينطوي على استخدام التنبؤات شبه التجريبية التي قدمها Kingery وBulmash 2، والتي هي خارج نطاق البلاغ المقصود. بينما أدوات بناء على هذه التوقعات 3،4 تسمح للتقديرات من الدرجة الأولى الممتازة للتحميل فهي لا تلتقط تماما اليات الأحداث قرب الميدان، والتي هي محور البحث الحالي. بالقرب من ميدان قياسات الانفجار لها في الآونة الأخيرة تركز على قياس OUTPحزب التحرير من رسوم دفن. تختلف المنهجيات المستخدمة من تقييم تشوه تسبب في هدف الهيكلي 07/05 لتوجيه قياس الدافع العالمي 8-13. وتوفر هذه الأساليب معلومات قيمة للتحقق من صحة التصاميم نظام الحماية ولكنها ليست قادرة على إجراء تحقيق كامل واليات نقل الحمولة. ويمكن أن يتم الاختبار في كل المقاييس مختبر (1/10 شاملة)، أو على قرب واسعة النطاق (&gt; 1/4)، مع أسباب براغماتية مثل التحكم في عمق الدفن أو ضمان عدم الشكل الأصيل للجبهة صدمة تم إنشاؤه بواسطة استخدام صواعق بدلا من الاتهامات العارية 14. مع رسوم دفن هناك حاجة إلى رقابة شديدة لضمان تكرار الاختبار 15 ظروف التربة. مستقلة عن ما إذا كان يتم وضع هذه التهمة في الهواء الحر أو دفن، فإن القضية الأساسية في قياس الانفجار الناتج هو ضمان صحة القياسات التي أجريت من قبل deplo الأجهزةYED. في جهاز اختبار تصميم 16 يتم استخدام لوحة ثابتة &#39;جامدة&#39; الهدف لحماية القضبان ضغط هوبكنسون 17 (HPBs)، وفي الوقت نفسه ضمان أن الغاية من القضبان يمكن تسجيل فقط الضغوط تنعكس بشكل كامل. وقد أظهرت المؤلفين في وقت سابق ان قياس الضغط المنعكسة من الهدف جامدة أكثر دقة وتكرار من الحادث، أو قياسات &quot;الميدان الحر&quot; 18-20. هندسة هذا الطبق هو من هذا القبيل أن أي تخفيف الضغط الناتجة عن إزالة أو تدفق نحو حافة الهدف 21 ستكون ضئيلة. وقد تم بناء هذا الجهاز اختبار جديد في 1/4 الحجم. في هذه رقابة مشددة على نطاق وحول شروط الدفن والمتفجرات يمكن أن يكون مضمونا، مع الحجم الكامل تهمة حجم 5 كجم تقليصها إلى 78 غ، على عمق دفن 25 مم.

<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

بالقرب من ميدان يعرض قياس حمولة انفجار قضية لكثير من أنواع أجهزة الاستشعار لأنها يجب أن تحمل بيئات عدوانية جدا وتكون قادرة على قياس ضغوط تصل إلى عدة مئات من megapascals. وفي هذا الصدد بساطة شريط الضغط هوبكنسون لديه ميزة كبيرة في أنه في حين أن نهاية القياس شريط هوبكنسون يمكن أن يدوم ويكون عرضة لظروف قاسية، شنت قياس الضغط إلى شريط ويمكن اضافته على مسافة بعيدة. وهذا يسمح العلب وقائية ليتم الاستفادة التي تحمي قياس الضغط ولكن لا تتداخل مع اكتساب القياس. استخدام مجموعة واسعة من الحانات ضغط يسمح تاريخها لمرة والضغط على نقاط المعروفة منفصلة إلى أن تقاس. توضح هذه المقالة أيضا الروتين الاستيفاء المستخدمة لاستخلاص تاريخها لمرة وضغط في مواقع-المجهزة للامم المتحدة على متن الطائرة من الفائدة. حاليا وقد استخدمت هذه التقنية لقياس التحميل من مواد شديدة الانفجار في الهواء الحر ودفن بسطحية في مختلف أنواع التربة.

يجب توفير إطار رد فعل صارم على نحو فعال. في التيار اختبار الدافع المنقولة الإجمالي لعدة مئات من نيوتن ثانية يحتاج إلى أن تقاوم مع الحد الأدنى من انحراف. وتعطى مثالا للإطار رد فعل صارم المستخدمة في الشكل 1. وفي كل إطار وقد يلقي الصلب &quot;متقبل&q...

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.

الانفجار الكمي عن طريق هوبكنسون البارات الضغط

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

التوليف وMicrodiffraction في الضغوط الشديدة ودرجات الحرارة

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

كيفية اشعال على الضغط الجوي البلازما الشعلة ميكروويف دون أي اشعال إضافية

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

وقياس الضغط متقلب السطحية باستخدام ميكروفون التحقيق عن بعد

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

لإعداد البلازما الضغط الجوي المعنية بالتحقيق في تشكيل أنواع رد الفعل

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

في اتجاهين تثمين انفجار فرن الخبث: توليف معجل كربونات الكالسيوم والأنظف الزيوليت المعادن الثقيلة الممتزات

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

الدقة طحن الأنابيب الجزيئية الكربونية الغابات عن طريق انخفاض الضغط الضوئي المجهر الإلكتروني

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

الضغط الجوي تصنيع رقائق سنسي مستطيلة طبقة واحدة كبيرة الحجم

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

تحليل تطبيق أساليب التقييم لمعلمات المورفولوجية لقضبان الصلب المتآكلة

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

استخدام خلايا تفاعل الذهب والتيتانيوم المرنة لمحاكاة النشاط الميكروبي المعتمد علي الضغط في سياق الحيوية تحت السطحية

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

تصنيع هوسيري مضغوط وقياس خصائص الضغط التي تمارس على الأطراف السفلية

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