CL-20基混合炸药的冲击起爆特征

为了研究CL-20基混合炸药的冲击起爆特征,深入分析冲击波作用下CL-20基混合炸药的爆轰成长规律,采用炸药驱动飞片冲击起爆实验方法,对CL-20、CL-20/NTO和CL-20/FOX-7三种压装混合炸药进行了冲击起爆实验,通过嵌入在炸药内部不同位置处的锰铜压力传感器,获得了炸药内部压力的变化历程。依据实验结果标定了混合炸药的点火增长模型参数,其中,利用反应速率方程中的两个增长项,分别模拟CL-20/NTO和CL-20/FOX-7混合炸药中两种组分的反应增长过程,得到这两种混合炸药的反应速率方程参数。并通过数值模拟的方法得到了三种炸药的临界起爆阈值和POP关系。研究结果表明:三种CL-20基混合炸药中,CL-20/NTO混合炸药具有更高的临界起爆阈值,而CL-20/FOX-7混合炸药具有更长的爆轰成长距离;此外,利用此套拟合双组分混合炸药反应速率方程的方法,可以对新型配方炸药的冲击起爆过程进行预测性计算     

Secondary shock features for large surface explosions: results from the Sayarim Military Range,Israel and other experiments

A series of surface explosions was designed and conducted by the Geophysical Institute of Israel at the Sayarim Military Range in the Negev desert, including two large-scale explosions: approx. 82 tons of high explosives in 2009, and approx. 100 tons of low-grade ANFO explosives in 2011. The main goal of the explosions was to provide large controlled sources for calibration of global infrasound stations designated for monitoring nuclear tests; however, the geophysical experiment also provided valuable observations for shock wave research. High-pressure gauges were deployed at distances between 100 and 600 m to record air blast properties and to provide reliable estimation of the true charge yield compared to the design value. Secondary shock phenomena were clearly observed at all near-source gauges as characteristic shock wave shapes. Secondary shocks were also observed at numerous seismic and acoustic sensors deployed in the range 0.3–20 km as acoustic phases. Empirical relationships for standard air blast parameters (peak pressure and impulse) and for a new parameter called secondary shock time delay, as a function of distance, were established and analyzed. The standard parameters, scaled by the cubic root of the estimated TNT yield, were found to be consistent for all analyzed explosions. However, the scaled secondary shock delays were clearly separated for the 2009 and 2011 explosions, thus demonstrating dependence on the explosive type. Additionally, air blast records from other experiments were used to extend the charge and distance ranges for the secondary shock observation, and showed consistency with the Sayarim data. Analysis and interpretation of observed features of the secondary shock phenomenon are proposed and a new empirical relationship of scaled secondary shock delay versus scaled distance is established. The results suggest that the secondary shock delay can be used as a new additional waveform feature for simple and cost-effective explosive yield estimation.     

RDX基铝纤维炸药空中爆炸性能

将铝纤维炸药与传统铝粉炸药和RDX炸药进行空中爆炸实验并得到压力时程曲线,经过分析计算得到3种炸药的压力峰值、二次击波、正相持续时间以及冲量。结果表明:铝纤维炸药的压力峰值相对于RDX没有明显提高,但其压力时程曲线衰减速度慢于RDX的,使铝纤维炸药的正相持续时间大于RDX,铝纤维炸药的冲击波冲量相对于RDX的平均提高了18%,与铝粉炸药的相当。铝纤维炸药的二次击波超压幅值与到达时间与铝粉炸药的接近,而铝纤维炸药的二次击波到达时间早于RDX,说明二次击波的超压幅值与到达时间与炸药类型有关。     

侧向稀疏波对非均质凝聚炸药冲击波起爆过程的影响

以压装TNT为例,开展二维拉氏实验,利用二维锰铜-康铜组合拉氏量计测量了轴对称位置和径向位置的压力时程曲线和径向位移曲线.同时利用二维拉格朗日分析计算程序RFLA对压装TNT的冲击波起爆过程进行了计算,分别得到了在2个不同径向位置上各个Lagrange位置上的质点速度、相对比容、比内能等时程曲线.研究结果展现了侧向稀疏...     

TATB基钝感炸药JB-9014的冲击起爆反应增长规律

采用铝基组合式电磁粒子速度计技术，通过一维平面冲击实验研究了JB-9014炸药的冲击起爆反应增长规律，获得了11.33～14.18 GPa不同初始入射冲击压力下JB-9014炸药撞击界面及其内部不同深度处冲击前沿的波后粒子速度，进而得到粒子速度-时间波剖面图，并拟合得到未反应JB-9014炸药的Hugoniot关系。此外，根据冲击波跟踪器所测波形获得了不同冲击压力下的到爆轰时间及距离。     

Experimental technique for generating fast high-density shock waves with phased linear explosive shock tubes

The sequential detonation of a layer of explosive surrounding a pressurized tube can be used to generate fast, high-density shock waves by means of a piston-like implosive pinch travelling at the detonation velocity of the explosive. A novel technique has been developed to extend the regime of operation to piston velocities greater than the detonation velocity of known explosives. This technique consists of cutting a slit in the tamper of a conventional explosive shock tube and introducing a phased detonation wave into the explosive cladding. Preliminary results indicate that quasi-steady shocks can be generated in helium with velocities between 13–17 km/s for initial fill pressures of 6.9 MPa.     

炸药水中爆炸的冲击波性能

采用PCB138压力传感器测量了TNT、RS211、HLZY-1和HLZY-3等几种炸药水中爆炸冲击波远场的压力时间历程,计算得到了这几种炸药水中爆炸冲击波性能参数及其相似常数。研究表明,含铝炸药水中爆炸冲击波远场的传播服从指数变化的相似律,其冲击波性能比标准炸药TNT优越。含铝炸药HLZY-1具有较好的水中爆炸冲击波性能。     

Decay of a plane shock wave in a two-parameter medium with arbitrary equation of state

Special curves, called shock polars, are frequently used to determine the state of the gas behind an oblique shock wave from known parameters of the oncoming flow. For a perfect gas, these curves have been constructed and investigated in detail [1]. However, for the solution of problems associated with gas flow at high velocities and high temperatures it is necessary to use models of gases with complicated equations of state. It is therefore of interest to study the properties of oblique shocks in such media. In the present paper, a study is made of the form of the shock polars for two-parameter media with arbitrary equation of state, these satisfying the conditions of Cemplen's theorem. Some properties of oblique shocks in such media that are new compared with a perfect gas are established. On the basis of the obtained results, the existence of triple configurations in steady supersonic flows obtained by the decay of plane shock waves is considered. It is shown that D'yakov-unstable discontinuities decompose into an oblique shock and a centered rarefaction wave, while spontaneously radiating discontinuities decompose into two shocks or into a shock and a rarefaction wave.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 147–153, November–December, 1982.     

爆炸驱动典型活性材料能量释放特性研究

为了研究活性材料爆炸驱动反应特性，基于粉末压制成型工艺，制备了Al/PTFE、Al/Ni两种典型的活性材料及Al₂O₃/PTFE、Al₂O₃/PTFE/W惰性材料。通过爆炸驱动试验，并结合高速摄影、远红外热像仪以及峰值超压测试技术，分析了不同活性材料壳体装药爆炸火球、温度场分布及空气冲击波峰值超压等特性。同时，在炸药爆炸空气冲击波峰值超压经验计算模型中考虑了活性材料释放的化学能，分析了反应释放能量对空气冲击波的影响规律。结果表明:活性材料在爆炸驱动过程中经历了强加载条件下反应、产生碎片并向四周飞散、撞击钢板及后续反应等阶段。活性材料对炸药爆炸产生的空气冲击波具有强化作用，爆炸加载瞬间材料仅发生了部分化学反应。     

双驱动激波管稀疏波破膜技术研究

本文介绍了在双驱动激波管中运用稀疏波破膜的技术。在以压缩空气和氮气作实验气体的情形下,实验研究了中间段长度、稀疏波强度及中间段B膜的破膜压力（压差）对第二激波追韩第一激波的影响。实验结果表明：中间段的长短,显著地制约着前后两道激波的间隔;稀疏波强度及中间段B膜的破膜压力对稀疏波破膜时间及第二激小对反射稀疏波的追赶有重要影响。     

On the effect of grain size on shock sensitivity of heterogeneous high explosives

Analysis of available data on dependence of the critical detonation diameter of various heterogeneous condensed explosives on mean size of grains and voids demonstrated that in many cases surprising correlations between and the initial specific surface area of heterogeneous explosives exist, namely, or . The run distance to detonation in wedge test with sustained strong shock of constant amplitude also linearly correlates with , i.e. . At the same time, the shock sensitivity reversal effect is often observed when grain size of HE is reduced. Apart from that Moulard (1989) found that detonation critical diameter of plastic bonded explosive with mono- and bimodal RDX grain size distribution depends nonmonotonously on mean grain size. Complicated dependence of shock sensitivity of heterogeneous explosives on their specific surface area can be explained based on comparison of the critical hot spot size at given characteristic pressure behind shock wave with the mean heterogeneity size . At high characteristic pressure (relative to the critical ignition pressure) is small compared with and all specific surface area of heterogeneous explosive is available for the hot spot growth process in accordance with the grain burn concept. However, when characteristic pressure of shock wave decreases, increases and can become comparable with . In this case only relatively large potential hot spots with size can result in self-supported hot spot growth process and shock sensitivity is controlled by the specific surface area which corresponds to only larger heterogeneities and can be significantly smaller than initial specific surface area. Received 18 July 1996 / Accepted 6 November 1996     

Comparison of different methods of measurement of pressure of underwater shock waves generated by electrical discharge

Different methods for measurement of strong underwater shock waves pressure pulses with peak pressures of up to 200 MPa and rise time of tens to hundreds of nanoseconds are described and compared. The experimental techniques include direct methods of pressure measurement using various electromechanical gauges such as quartz, carbon-based, and commercially available PCB gauges, and nondirect methods based on measurement of the velocity of the shock wave such as time-of-flight and fast-streak photography. Advantages and disadvantages of the used gauges and methods are discussed. The shock waves were produced by underwater electrical discharge (discharge current amplitude ≤100 kA, pulse duration ≤5 μs) initiated by an exploding wire. A good correspondence between the pressure amplitudes measured by the various gauges and methods was observed. The obtained dependence of the shock wave pressure on the distance from the discharge channel was found to be best fitted by a r ^−0.7 law. It is also shown that none of these methods can be used to determine the time evolution of the pressure behind the front of the shock wave.     

基于PVDF复合压电效应的低强度冲击波柔性测量

为探索低强度冲击波的柔性测量技术,对PVDF(polyvinylidene fluoride)压力传感器开展冲击波加载和灵敏度标定实验,评估其低强度冲击波压力测量的可靠性。基于微结构设计改进薄膜传感器,获得适用于低强度冲击波压力测量的高灵敏柔性传感器,结果表明:单一压电工作模式的薄膜传感器测量低强度冲击波时有效输出电荷量和信噪比较低,测量结果容易受压电膜力电响应非线性、结构表面变形振动以及封装因素的影响,灵敏度系数不稳定、个体差异性大。采用周向固支的微结构设计能够将作用于薄膜传感器表面幅值较低的冲击波转换为幅值较高的面内拉应力,产生的复合压电效应可大幅提高传感器名义灵敏度系数、降低个体差异性。研制的柔性传感器在0.2～0.7 MPa压力范围内名义灵敏度约900～1 350 pC/N,相对测量误差不大于±13%。     

Hot spot formation from shock reflections

Heterogeneities sensitize an explosive to shock initiation. This is due to hot-spot formation and the sensitivity of chemical reaction rates to temperature. Here, we describe a numerical experiment aimed at elucidating a mechanism for hot-spot formation that occurs when a shock wave passes over a high-density impurity. The simulation performed is motivated by a physical experiment in which glass beads are added to liquid nitromethane. The impedance mismatch between the beads and the nitromethane results in shock reflections. These, in turn, give rise to transverse waves along the lead shock front. Hot spots arise on local portions of the lead front with a higher shock strength, rather than on the reflected shocks behind the beads. Moreover, the interactions generated by reflected waves from neighboring beads can significantly increase the peak hot-spot temperature when the beads are suitably spaced.     

Experimental Study on the Dynamic Mechanical Properties of Reinforced Concrete under Shock Loading

A simple experimental method was introduced to study the mechanical properties of reinforced concrete under shock loading. The one-stage light gas gun was used to test the mechanical properties of reinforced concrete with different reinforcement ratios under various impact velocities. Three Mn-Cu piezoresistive pressure gauges embedded in the target were used to record the voltage-time signals, from which the stress-strain curves of reinforced concrete were obtained using Lagrangian analysis. Experimental results indicated that the load-bearing capacities of reinforced concrete increased greatly with the impact velocity and the reinforcement ratio. The peak stress of the shock wave decreased exponentially with the propagation distance.     

钛基纤维炸药水下爆炸性能的初步分析

通过爆炸压力时程曲线分析含钛纤维炸药的压力峰值、水下比冲击波能、比气泡能、质量能量及能量密度变化趋势,通过对所得能量结果分析钛纤维炸药的化学反应过程。结果表明:含钛纤维炸药的压力峰值、比冲击波能随钛纤维含量的提高而降低,比气泡能随钛纤维含量的提高而增大,质量能量及能量密度都随钛纤维含量的提高而增大。随距离的增大,钛纤维炸药压力峰值衰减比RDX的慢,而不同钛纤维含量的钛纤维炸药的比冲击波能、比气泡能在不同距离处随钛纤维含量变化趋势基本一致。根据炸药反应释放的总比能量进行理论分析,得出钛纤维炸药爆炸反应方程式。     

接触爆炸荷载作用下带孔防护结构内冲击波的传播规律

采用有限元分析软件ATUODYN,对接触爆炸荷载作用下带孔防护结构内冲击波的传播进行了数值模拟,得到了防护结构孔口和内部中心处冲击波超压－时间曲线;分析了炸药量和爆心距孔口距离对防护结构内部超压、正压冲量的影响;以数值计算结果为基础,结合量纲分析,拟合得到了结构内部中心处爆炸冲击波特征参数的预估公式。     

PVDF压电薄膜在应力波测量中的应用

综合介绍了PVDF压力传感器的测试原理、动态标定实验，并采用定制的PVDF压力传感器测量了不同类型分层介质在冲击载荷作用下的压力衰减，说明了PVDF压力传感器在压力测量中有着很好的前景．     

Modeling Damage Induced Initiation of Explosives

Sandia National Laboratories developed the DaMaGe Initiated Reaction (DMGIR) model to numerically predict weakly supported shock waves that generate an initiation at energy levels below the shock-to-detonation transition (SDT) of an explosive. The DMGIR model couples the strain energy fluence contribution from damage to the initiation process. It does not attempt to include all possible specific initiation mechanisms at the mesoscale, but instead looks at cumulative damage incurred in the explosive through experimental calibration of a small number of material constants. Both shock pressure (hydrostatic) and shear stress (deviatoric) are accounted for in the summation. The model was designed to be robust and relatively simple to calibrate. The DMGIR model is implemented into the Sandia National Laboratories’ CTH shock wave and large deformation code. The model runs concurrently with the existing History Variable Reactive Burn (HVRB) model currently used for shock initiation.     

Spallation of polycarbonate under laser-driven shocks

Laser driven shocks have been used to investigate dynamic failure (spallation) of polycarbonate under uniaxial tensile loading at very high strain rate, of the order of 10 s. First, uninstrumented recovery shots have been performed, post-test examination of the fracture damage has been carried out, and the influences of the experimental parameters (loading conditions and target thickness) have been analyzed. Then, an attempt to model the response of polycarbonate to plane shock loading has been made. On one hand, in-situ measurements have been performed in polycarbonate samples submitted to the plane detonation wave of a strong explosive, and the results have led to content with simple constitutive relations. On the other hand, piezoelectric measurements under laser shocks have provided a characterization of the loading pressure pulse, and comparisons of the measured and computed signals have confirmed the ability of the model to describe wave propagation in polycarbonate. Finally, the spallation experiments have been simulated. A spall strength has been estimated, on the basis of the experimental data, and the predictive capability of the model has been tested. Received: 18 February 1997 / Accepted 1 April 1997