壳体对炸药水下爆炸近场特性的影响

为了研究壳体对炸药水下爆炸近场特性的影响,在水下进行了Φ25mm圆筒试验与Φ25mm裸药柱滑移爆轰试验,对比分析了带壳装药、裸装药的冲击波迹线与壳体、气泡的膨胀迹线。结果表明,壳体对炸药爆炸后冲击波的衰减作用较为明显,带壳装药水下爆炸冲击波波阵面压力与冲击波传播速度以相对较低的初始值(0.9GPa,0.78mm/μs)近似保持不变,而裸装药水下爆炸冲击波波阵面压力与冲击波传播速度从较高初始值(8.5GPa,0.92mm/μs)以指数形式快速衰减;不同膨胀时期壳体对膨胀过程的影响不同,导致水下爆炸初期(0～5μs)与后期(20μs以后)带壳装药壳体的膨胀速率低于裸装药气泡的膨胀速率,水下爆炸中期(5～20μs)带壳装药壳体的膨胀速率高于裸装药气泡的膨胀速率。     

壳体厚度和爆炸深度对水下爆炸冲击波的影响

根据Cole水下爆炸冲击波经验公式和C-J爆轰理论,用AUTODYN软件对带壳小药量装药水下爆炸进行数值模拟,计算了不同壳体厚度的TNT水下爆炸冲击波压力峰值,得到带壳装药水下爆炸冲击波峰值压力的拟合公式,分析了冲击波随装药壳厚与半径比以及爆炸深度的变化规律.结果表明,带壳装药水下爆炸的冲击波峰值压力随壳厚与装药半径比...     

不同壳体装药爆炸威力的数值模拟及试验研究

为研究装药壳体材料对爆炸威力的影响,对不同壳体装药在空气和混凝土靶中的爆炸破坏效应进行了数值模拟及试验研究.结果表明,在相同的装药情况下,碳纤维复合材料壳体装药爆炸产生的冲击波超压相对D6A钢壳体装药的高.因碳纤维复合材料壳体装药爆炸时不产生破片,所以对远距离目标不造成破坏,而D6A钢壳体装药爆炸时产生的破片对远距离目标具有一定的杀伤效应.从混凝土靶的爆炸破坏效应来看,碳纤维复合材料壳体装药在阻抗匹配方面要比D6A钢壳体装药好,更利于爆炸冲击波的传播.在同样装药的情况下,碳纤维复合材料壳体装药爆炸对靶体爆炸驱动有效能量大于D6A钢壳体装药.静爆试验证明了数值计算与试验结果相一致.     

装药壳体厚度对水激波管内压力波形的影响研究

为提高水下爆炸时水激波管对压力校准的精度,在原有的设计基础上,针对压力源起爆装置,探讨了装药壳体厚度对水激波管内爆炸产生的冲击波压力的影响;利用AUTODYN-2D软件,对壳体厚度分别为0.5、1.5、2.5、3.5和5.0mm下的小当量TNT装药起爆进行数值模拟,获得了不同壳体厚度下水激波管内多个距离处的压力时程曲线;将点火头起爆装置改为雷管起爆装置进行试验,对数值模拟进行验证。结果表明,壳体越厚,其对冲击波在水激波管内的约束作用越明显;相同的传播距离下,壳体越厚,冲击波压力峰值越小,脉宽越大;在端盖处,当填装比为2(壳厚为5mm)时,其压力峰值可达等条件下裸药的0.42倍;试验结果证明了模拟结果的准确性以及设计的起爆装置的可行性。     

约束方式和强度对HMX基压装含铝炸药慢烤响应特性的影响

为了获取不同约束方式和强度下HMX基压装含铝炸药慢速烤燃响应特性，以典型超音速钻地/侵爆战斗部为背景，设计了装药长径比为5∶1的缩比烤燃弹；开展了无约束和不同约束强度下HMX基压装含铝炸药慢速烤燃实验；获取了无约束条件下HMX基压装含铝炸药的反应过程，以及不同壳体壁厚(4、10、16和20mm)与端盖螺纹长度(10、12和14mm)时装药反应烈度的变化规律。结果表明，慢速烤燃条件下该HMX基压装含铝炸药反应包括生成气体、端面燃烧、火焰熄灭3个阶段；烤燃弹约束强度影响装药烤燃时间和点火温度，进而影响烤燃弹内部反应压力增长，最终导致不同的反应等级；当螺纹长度(L)为14mm时，壳体厚度(δ)由4mm增加至20mm,反应等级由爆燃发展为爆炸而后降低为燃烧；当壳体壁厚(δ)为10mm时，螺纹连接长度(L)由10mm增加至14mm,烤燃弹反应等级由燃烧转变为爆炸；当壳体壁厚(δ)与等效壳体壁厚(δ_e)相当时，烤燃弹约束强度较为均匀，有利于反应压力的不断增长，最终导致烤燃弹发生更为剧烈的爆炸反应。     

铝粉含量对梯铝炸药爆压和冲击波参数的影响

测试了以TNT为基不同含量含铝炸药的爆压和空中爆炸冲击波参数,通过分析铝粉对炸药爆压、空中爆炸参数和爆炸冲击波超压的影响,建立了爆压与铝氧比的关系曲线、5种TNT基含铝炸药的冲击波相似律方程和TNT/Al炸药的爆压与空中爆炸冲击波超压的关系式.结果表明,随着铝粉含量的增加,炸药的爆压呈指数衰减,近距离的冲击波超压也快速减小,但爆炸场温度和爆炸火球的直径及持续时间会增大.     

LX-04炸药大隔板试验的数值模拟

为研究不同条件下LX--04（HMX／氟橡胶／85／15）大隔板试验（LSGT）的冲击波感度G。,运用ANSYS／LS．DYNA对整个爆炸冲击波传爆过程进行了数值模拟,观察了LSGT中爆轰冲击波的传播过程,分别讨论了主发炸药PE4、TNT、B炸药产生的爆轰波经过有机玻璃隔板、铝隔板、钢隔板衰减后的冲击波压力变化情况,最终找出了3种不同主发炸药和3种隔板下LX-04冲击波感度G50。同时,定性地分析了3种隔板对爆炸冲击波的衰减系数。其中,铝隔板的衰减系数最大,有机玻璃隔板的衰减系数最小。     

小尺寸装药输出冲击波衰减规律的研究

采用锰铜压阻法对PBXN-5炸药于小尺寸装药情况下输出冲击波在有机玻璃中的衰减规律进行了实验研究,得出了各装药直径下的衰减系数a,并通过对比实验研究了不同装药直径和约束条件对小尺寸装药输出冲击波在有机玻璃中衰减系数的影响规律.结果表明,装药直径越小,a值越大,且这种变化越快.装药约束对衰减系数也有影响,较弱约束下a值较大.     

水下爆炸冲击波传播的近似计算

水下爆炸冲击波传播计算由能流密度一时间曲线经验表达式化简。用简单数值积分法解由拉格朗日形式流体动力学方程、Hugoniot方程和能流密度一时间关系式组成的偏微分方程组,不同距离处的冲击波峰值由单点初始数据计算。结果表明,由近似计算方法所得结果与实测数据和相似律结果一致。适当选取起算参数,在5倍装药半径以外的爆炸远场范围计算精度良好。5倍装药半径以内的爆炸近场,冲击波未充分形成,计算方法失效。计算了几种含铝炸药的冲击波传播,表明冲击波能显著影响冲击波传播特性,冲击波能有利于抑制超压衰减。     

FOX-7和RDX基含铝炸药的冲击起爆特性

为研究FOX-7和RDX基含铝炸药的冲击起爆特性,对其进行了冲击波感度试验和冲击起爆试验,结合冲击波在铝隔板中的衰减特性,确定了FOX-7和RDX基含铝炸药的临界隔板值和临界起爆压力,并通过锰铜压阻传感器记录了起爆至稳定爆轰过程压力历程的变化。结果表明,以Φ40mm×50mm的JH-14为主发装药时,FOX-7和RDX基含铝炸药临界隔板值分别为37.51和34.51mm,对应的临界起爆压力为10.91和11.94GPa;起爆压力为11.58GPa时,FOX-7炸药的到爆轰距离为25.49~30.46mm,稳定爆轰后的爆轰压力为27.68GPa,爆轰速度为8 063m/s;起爆压力为14.18GPa时,RDX基含铝炸药的到爆轰距离为17.27~23.53mm,稳定爆轰后的爆轰压力为17.16GPa,爆轰速度为6 261m/s。     

基于气固两相反应流的温压炸药能量释放规律数值模拟及实验验证

为研究气体环境、铝粉含量、空间体积对温压炸药能量释放的影响,基于气固两相反应流模型,建立有限差分-物质点耦合算法,对温压炸药密闭容器内爆炸流场演化进行数值模拟及实验验证。结果表明,温压炸药在空气环境中爆炸释放的能量高于氮气中,壁面冲击波峰值压力和空间准静态压力的增幅分别在20%和80%以上,空间准静态压力随空间体积的增大呈先增大后减小的趋势;铝粉含量越高,冲击波在传播过程中衰减得越慢,空间准静态压力越高;铝粉燃烧反应度随空间体积的增加而下降,当比空间体积超过100m³/kg时,反应度下降到90%以下,且铅粉含量越高,其反应程度越低。     

Semi‐Closed Investigations of New Aluminized Thermobaric and Enhanced Blast Composites

The investigations of new aluminum‐enriched RDX‐based composites belonging to the thermobaric and enhanced blast explosive formulations were undertaken. In a semi‐closed bunker, the blast wave and the thermal characteristics of pressed and layered charges made from the composites are determined. The study includes the blast wave history registrations as well as the determination of the overpressure peaks and the specific impulses of the incident blast wave. The total impulses have been estimated for a period of 60 ms. Since the composites are supposed to be volumetric, the explosion light outputs and the fireball temperatures were also investigated. The results obtained for the composite charges were compared with the blast performances and fireball temperatures of TNT and phlegmatized RDX charges of the same mass. Also differences between the pressed and the layered composite charges prepared from the same composites were observed and explained. The effect of the aluminum particle size was checked. Discussion of the results and conclusions about the aluminum combustions during the explosions of such charges were presented.     

TNT装药水中爆炸的数值模拟

采用AUTODYN软件对不同起爆方式下TNT装药水中爆炸模型进行了数值计算,并对计算结果进行了实验验证.根据计算结果分析了中心起爆、端面中心起爆和端面面起爆情况下,在装药不同方位的水中冲击波压力峰值随距离的变化趋势.计算结果表明,端面起爆状态下,装药径向的冲击波压力峰值均大于端部;中心起爆状态下,一定距离处,装药端面的压力峰值大于径向.改变起爆方式,可以实现水中爆炸冲击波能量的定向增益,提高特定方位爆炸能量利用率.     

Energy release of mixed explosives during propagation of a nonideal detonation under conditions similar to the operation conditions of a blasthole charge

Detonation experiments were performed in a specially developed explosive device simulating a blasthole using charges of fine-grained and coarse-grained (granular) 30/70 TNT/ammonium nitrate mixtures of identical density 0.89 g/cm³ in steel shells with an inner diameter of 28 mm and a wall thickness of 3 mm at detonation velocities of 4.13 and 2.13 km/sec, respectively. Despite significant differences in detonation velocity (pressure), identical expansion of the charge shells was observed. On the other hand, numerical simulations of detonation propagation in the explosive device with the corresponding velocities ignoring the possibility of energy release behind the shock front show that the expansion of the charge shell is always greater in the case of a high-velocity regime. It is concluded that under the conditions simulating detonation propagation and the work of explosion products in a blasthole, effective additional energy release occurs behind the low-velocity (nonideal) detonation front. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 111–120, July–August, 2007.     

A Model for the Collapse of Explosively Driven Liners in spinning warheads

An analytical model has been developed for the rapid collapse of explosively driven metal shells that includes the effects of material strength and shell spin. The model can be used to approximate the collapse process of shaped charges and EFPs. A closed form solution for shell velocity as a function of shell position is developed and compared to several two-dimensional and three-dimensional continuum mechanic numerical simulations. Comparisons with the simulations include a parametric evaluation of shell geometry, initial conditions, and material strengths. The analytical model compares well with the numerical simulations for very thin shells. It shows that spin can significantly affect the final collapse velocity, and may even result in hollow penetrators. The model also shows that strength has a similar effect, and can greatly reduce the final collapse velocity.     

Quantitative Schlieren Measurement of Explosively‐Driven Shock Wave Density,Temperature, and Pressure Profiles

Shock waves produced from the detonation of laboratory‐scale explosive charges are characterized using high‐speed, quantitative schlieren imaging. This imaging allows the refractive index gradient field to be measured and converted to a density field using an Abel deconvolution. The density field is used in conjunction with simultaneous piezoelectric pressure measurements to determine the shock wave temperature decay profile. Alternatively, the shock wave pressure decay profile can be estimated by assuming the shape of the temperature decay. Results are presented for two explosive sources. The results demonstrate the ability to measure both temperature and pressure decay profiles optically for spherical shock waves that have detached from the driving explosion product gases.     

On the Use of Composite Charges to Determine Insensitive Explosive Material Properties at the Laboratory Scale

Laboratory‐scale air‐blast experiments an gram‐range composite explosive charges are presented. The composite charges consist of a spherical booster charge surrounded by a concentric, spherical “candidate material” shell charge. By way of composite charge explosive characterization, the candidate explosive material is able to be characterized through the “removal” of the known booster effects. Using peak shock wave pressures, a method is developed to remove the booster effects from the composite charge’s signature to yield the sole effects of the candidate explosive material, permitting its characterization. Air‐blast explosive tests are conducted using digital high‐speed shadowgraph visualization to measure the resulting shock wave radial position as a function of time. Booster and composite charge data are converted to Mach number versus shock wave radius profiles and subsequently to peak shock wave pressure versus shock wave radius profiles for characterization of the shell material. Explosives tested include: PETN, RDX, HMX, and Alliant Bullseye® SP.     

Underwater detonation performance of the aluminum film explosive

A new aluminized explosive is proposed, and the approach is to replace the aluminum powder in the traditional aluminized explosive with an aluminum film. The purpose is not only to improve mechanical properties and lower the impact sensitivity of traditional aluminized explosives, but also to reduce environmental pollution in the aluminum particle production process. The pressure-time curves of the aluminum film explosive and RDX are measured in underwater explosion experiments. The peak pressure, impulse, shock wave energy, and bubble energy are obtained by analyzing the curves. The results of the study indicate that the peak pressure of the aluminum film explosive is lower than that of RDX. However, the aluminum film explosive maintains a high pressure for a longer period of time. The large amount of energy is found to liberate by subsequent reactions of the Al film with the primary detonation products. The increase in the explosion energy of the aluminum film explosive is based mainly on the increase in the bubble energy.     

Influence of the tunnel wall surface condition on the methane-air explosion

Based on numerical methods and theoretical analysis, the influence of the tunnel wall surface conditions on the methane-air explosion is evaluated. A rough tunnel wall causes stronger turbulence in the methane-air explosion. In a straight tunnel where some part of the space is filled with the methane-air mixture, the turbulence intensity varies with distance along the tunnel axis: it is higher in the methane-air premixing region and also in the far region of air shock wave propagation; between these regions, the turbulence intensity is lower. In the methane-air premixing region, the effect of turbulence is manifested as a significant increase in the explosion pressure. In the far region of air shock wave propagation, turbulence makes the shock wave strength decrease, but its effect is indistinctive among others. In the original methane-air premixing region, the explosion pressure of the methane-air mixture in a tunnel with rough walls is higher than that in a tunnel with smooth walls. However, the air shock wave beyond the premixing region in a tunnel with rough walls is weaker than that in a tunnel with smooth walls.