高炉利用定量霍普金森杆
Summary
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.
Abstract
近场爆炸荷载的测量提供了一个问题的许多传感器类型，因为它们必须承受非常侵蚀性环境，并能够向上测量压力数百兆帕。在这方面，霍普金森压力棒的简单有，虽然Hopkinson杆的测定端可承受并暴露于恶劣的条件下，应变仪安装到杆可以一定距离被固定的一大优势。这允许利用防护罩用于保护所述应变计，但不与测量采集干扰。使用压力杆阵列的允许测量在离散已知点的压力 – 时间历史记录。本文还描述了用于在感兴趣的平面未仪表化的位置以得到压力 – 时间历史内插程序。目前，该技术已被用来测量在自由空气高能炸药装在各种土壤埋藏浅。
Introduction
表征炸药输出有很多好处，军事（抵御当前冲突地区埋简易爆炸装置）和民用（设计结构部件）。近来这个话题已经得到相当的重视。多收集的知识已经针对从电荷输出的量化，以便更有效地保护结构的设计。这里的主要问题在于，如果所取得的测量是高保真的不那么在这些炸药事件负荷转移的机制尚不清楚。这反过来又导致了验证数值模式依赖于这些测量结果进行验证的问题。
近场的术语是用来描述与缩放的距离，Z小于〜1米/公斤1/3，其中Z = R / W 1/3，R是从炸药的中心的距离，而W爆炸在电荷质量表示作为TNT的等效质量。在这种状态的负载量为典型特征是非常高的幅度，高空间和时间上的非均匀的负荷。强大的仪器，因此被要求测量与近场加载相关的极端压力。在缩放距离ž<0.4米/ kg的1/3，爆破参数的直接测量要么不存在或很少1和此范围内的半经验预测的数据几乎完全基于参数研究。这包括使用由Kingery和Bulmash 2，这是笔者的预期范围之外给出的半经验预测。虽然基于这些预测3,4工具允许装载的优秀一阶估计他们并不完全捕捉近场事件，这都是当前研究的重点的机制。
近场爆破的测量有近来集中量化OUTP从葬费UT斯达康。所采用的方法，从评估造成结构目标5-7全球直接冲击测量8-13变形而变化。这些方法提供了保护系统设计验证有价值的信息，但不能够完全调查负荷转移的机制。测试可以在两个实验室天平（1/10满刻度）进行，或在附近的满刻度（> 1/4），与实际的理由，例如控制埋藏深度或确保休克前的没有固有形状是由所生成的使用雷管，而不是裸露的费用14。埋电荷的土壤条件需要进行高度控制，以保证在测试15的可重复性。
独立的电荷是否被放置在自由空气或埋设，在测量产生爆炸的最根本的问题是确保测量由仪器deplo制成的有效性YED。在设计的测试装置16固定的'刚性'的目标板是用来屏蔽霍普金森杆17（HPBs），而在同一时间确保杆的末端，只能记录充分体现压力。笔者以前曾表明反射压力的该测量从一个硬指标更准确，比事件重复，或“自由场”三围18-20。该板的几 何形状是这样的，通过围绕目标边缘21清零或流动而产生的任何压力释放可以忽略不计。这个新的测试装置已在1/4比例被构造。在以上的埋藏条件和炸药这种规模紧密控制可以确保，与按比例缩小至78克5公斤满刻度充电的大小，在25毫米的埋藏深度。
Protocol
Representative Results
Discussion
使用提交上面概述的协议已经表明，有可能从炸药得到高度变负载的高保真测量，使用的霍普金森压力棒的阵列。使用插值例程概述的离散压力 – 时间历史记录可以转化成一个连续的冲击前它是直接使用如在数值模拟或作为这种模型的输出验证数据的加载功能。
当使用掩埋费用于制备在协议部分5中概述的土壤容器中的方法必须进行检查，以确保有足够的压实能量被提供以达?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors wish to thank the Defence Science and Technology Laboratory for funding the published work.
Materials
| Load Cell | RDP | RSL0960 | This is only indicative, the exact load cell should be able to resolve the required loading |
| Steel target plate / HPBs | Garratts | N/A | Fabricated to order |
| Strain gauge | Kyowa | KSP-2-120-E4 | To use with steel HPBs |
| Cyanoacrylate | Kyowa | CC-33-A | Check with manufacturer depending on mar material to be used |
| Digital Oscilloscope | TiePie | HS4 16-bit Handyscopes | 6 used in parallel in current testing |
| Leighton Buzzard sand | Garside sands | Garside 14/25 | Uniform silica sand |
References
- Esparza, E. Blast measurements and equivalency for spherical charges at small scaled distances. Int. J. Impact Eng. 4 (1), 23-40 (1986).
- Kingery, C. N., Bulmash, G. ARBRL-TR-02555. Airblast parameters from TNT spherical air burst and hemispherical surface burst. , (1984).
- Hyde, D. W. . Conventional weapons program (ConWep). , (1991).
- Randers-Pehrson, G., Bannister, K. A. ARL-TR-1310. Airblast loading model for DYNA2D and DYNA3D. , (1997).
- Neuberger, A., Peles, S., Rittel, D. Scaling the response of circular plates subjected to large and close-range spherical explosions. Part II: Buried charges. Int. J. Impact Eng. 34 (5), 874-882 (2007).
- Xu, S., et al. An inverse approach for pressure load identification. Int. J. Impact Eng. 37 (7), 865-877 (2010).
- Pickering, E. G., Chung Kim Yuen, S., Nurick, G. N., Haw, P. The response of quadrangular plates to buried charges. Int. J. Impact Eng. 49, 103-114 (2012).
- Bergeron, D. M., Trembley, J. E. Canadian research to characterize mine blast output. , (2000).
- Hlady, S. L. Effect of soil parameters on landmine blast. , (2004).
- Fourney, W. L., Leiste, U., Bonenberger, R., Goodings, D. J. Mechanism of loading on plates due to explosive detonation. Int. J. on Blasting and Fragmentation. 9 (4), 205-217 (2005).
- Anderson, C. E., Behner, T., Weiss, C. E. Mine blast loading experiments. Int. J. Impact Eng. 38 (8-9), 697-706 (2011).
- Fox, D. M., et al. The response of small scale rigid targets to shallow buried explosive detonations. Int. J. Impact Eng. 38 (11), 882-891 (2011).
- Ehrgott, J. Q., Rhett, R. G., Akers, S. A., Rickman, D. D. Design and fabrication of an impulse measurement device to quantify the blast environment from a near-surface detonation in soil. Experimental Techniques. 35 (3), 51-62 (2011).
- Pope, D. J., Tyas, A. Use of hydrocode modelling techniques to predict loading parameters from free air hemispherical explosive charges. , (2002).
- Clarke, S. D., et al. Repeatability of buried charge testing. , (2014).
- Clarke, S. D., et al. A large scale experimental approach to the measurement of spatially and temporally localised loading from the detonation of shallow-buried explosives. Meas Sci Technol. 26, 015001 (2015).
- Hopkinson, B. A Method of Measuring the Pressure Produced in the Detonation of High Explosives or by the Impact of Bullets. Philos. Trans. R. Soc. (London) A. 213, 437-456 (1914).
- Rigby, S. E., Tyas, A., Fay, S. D., Clarke, S. D., Warren, J. A. Validation of semi-empirical blast pressure predictions for far field explosions – is there inherent variability in blast wave parameters?. , (2014).
- Rigby, S. E., Tyas, A., Bennett, T., Clarke, S. D., Fay, S. D. The negative phase of the blast load. Int. J. of Protective Structures. 5 (1), 1-20 (2014).
- Rigby, S. E., Fay, S. D., Tyas, A., Warren, J. A., Clarke, S. D. Angle of incidence effects on far-field positive and negative phase blast parameters. Int. J. of Protective Structures. 6 (1), 23-42 (2015).
- Tyas, A., Warren, J., Bennett, T., Fay, S. Prediction of clearing effects in far-field blast loading of finite targets. Shock Waves. 21 (2), 111-119 (2011).
- Tyas, A., Watson, A. J. A study of the effect of spatial variation of load in the pressure bar. Meas Sci Technol. 11 (11), 1539-1551 (2000).
- Tyas, A., Watson, A. J. An investigation of frequency domain dispersion correction of pressure bar signals. Int. J. Impact Eng. 25 (1), 87-101 (2001).
- NATO Standardisation Agency. Procedures for evaluating the protection level of logistic and light armoured vehicles. Allied Engineering Publication (AEP) 55. 2, (2011).
- Elgy, I. D., et al. . UK ministry of defence technical authority instructions for testing the protection level of vehicles against buried blast mines. , (2014).
- Clarke, S. D., et al. Finite element simulation of plates under non-uniform blast loads using a point-load method: Buried explosives. , (2015).
- Rigby, S. E., et al. Finite element simulation of plates under non-uniform blast loads using a point-load method: Blast wave clearing. , (2015).
- Hallquist, J. O. . LS-DYNA theory manual. , (2006).
- Fay, S. D., et al. Capturing the spatial and temporal variations in impulse from shallow buried charges. , (2013).
- Fay, S. D., et al. Measuring the spatial and temporal pressure variation from buried charges. , (2014).
