Study on blast loadings of cylindrical charges air explosion
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摘要: 受比例距离、装药长径比、起爆方式、方位角、冲击波入射角以及反射面相对位置等多种因素的影响,球形装药空中爆炸冲击波荷载的计算方法不适用于柱形装药。为探究柱形装药空中自由场爆炸冲击波入射和反射荷载,首先,开展柱形TNT装药单端起爆的空中爆炸试验,并基于显式动力学分析软件AUTODYN进行数值模拟,通过与试验和规范进行对比,验证了采用的有限元分析方法的适用性。进一步开展考虑比例距离、长径比、起爆方式、方位角和刚性反射等因素的1000余组柱形装药空中爆炸工况的数值模拟。基于模拟结果,揭示了柱形装药空中爆炸入射冲击波峰值超压和最大冲量及其形状因子的分布特征,提出峰值超压和最大冲量临界比例距离的判定准则和确定方法,阐明了刚性反射冲击波峰值超压和反射系数的变化规律。最后,提出柱形装药空中爆炸入射和反射冲击波荷载的计算方法,并得到360余组试验数据的验证。该方法可快速计算作用于建筑结构上的爆炸荷载,并为弹药毁伤效能评估、结构动态响应和破坏分析及其抗爆设计提供参考。Abstract: The existing specifications and studies mainly focus on the scenarios that the spherical charges are ignited at the central point and explosion is in free air, while the studies of the blast loadings of cylindrical charges air explosion, especially the reflected overpressure acting on the structure, are relatively limited. The blast loading calculation formula for spherical charge cannot be applied for cylindrical charge as attributed to the parametric influences such as scaled distance, length-to-diameter ratio, ignition method, azimuth angle, incident angle and relative location of reflected plane. To explore the incident and reflected blast loadings of cylindrical charges air explosion, firstly, three shots of explosion test of the single-end ignited cylindrical TNT charge were conducted. The corresponding numerical simulations are conducted based on the finite element program AUTODYN, and the applicability of the adopted finite element analysis method is verified by comparing with the experimental incident and reflected overpressure-time histories of spherical and cylindrical charges air explosion of tests, as well as the peak incident overpressure-scaled distance relationship of unified facilities criteria (UFC) 3-340-02 of spherical charges air explosion. Furthermore, the numerical simulations of more than 1000 sets of cylindrical charges air explosion scenarios considering the scaled distance, length-to-diameter ratio, ignition method, azimuth angle and rigid reflection are carried out based on validated finite element analysis method. The distribution characteristics of peak overpressure, maximal impulse of the incident blast wave and the corresponding shape factors are examined and discussed. The judging criteria and determination methods for the critical scaled distance of peak overpressure and maximal impulse are proposed by using data fitting, and the variation law of the reflected peak overpressure and the rigid reflection coefficient are revealed. Finally, a calculation method for the incident and reflected blast loadings of cylindrical charges air explosion is proposed and experimentally verified by 360 sets data. The method can rapidly predict the blast loadings on building structures, and provide reference for evaluating the ammunition damage efficiency, analyzing structural dynamic response and failure, as well as for the corresponding blast-resistant design.
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Key words:
- cylindrical charge /
- air explosion /
- peak overpressure /
- maximal impulse /
- critical scaled distance
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表 1
$L/D{\text{≥}}1 $ 柱形装药入射峰值超压拟合公式系数Table 1. Fitted formula coefficients for peak incident overpressure of central ignited cylindrical charges with
$L/D{\text{≥}}1 $ 起爆方式 α/(°) 0.3 m/kg1/3≤Z≤1 m/kg1/3 1 m/kg1/3<Z≤15 m/kg1/3 A B C R2 A B C R2 中心起爆 0 173 9 399 0.943 7 −211 390 31 0.612 6 30 −33 503 −166 0.904 5 −200 424 40 0.902 7 60 −103 958 −491 0.988 3 −202 644 −11 0.969 0 90 −242 1 352 −141 0.926 4 281 501 −11 0.986 3 单端起爆 0 −56 1 013 −900 0.884 5 −491 619 22 0.616 4 30 −39 365 −96 0.800 2 −284 546 1 0.880 1 60 60 −131 693 0.940 7 −114 509 9 0.961 8 90 −225 1 438 −244 0.941 8 306 512 −19 0.976 8 120 −205 1 732 −1 360 0.977 9 −238 721 −16 0.969 6 150 −27 580 −261 0.943 1 −171 431 43 0.915 8 180 77 1 246 −1 057 0.909 9 −531 574 34 0.775 3 双端起爆 0 −25 865 −796 0.875 3 −887 1 096 −56 0.733 9 30 −29 304 −24 0.793 5 −313 593 4 0.914 4 60 29 22 602 0.954 3 −69 505 18 0.968 2 90 −255 2 054 −1 068 0.923 7 187 694 −74 0.932 8 表 2 最大冲量临界比例距离拟合公式系数
Table 2. Coefficients of fitted formula for the maximal impulse critical scaled distance
起爆方式 拟合公式系数 k a b c R2 中心起爆 2.13 0.25 1.14 0.32 0.945 0 单端起爆 2.48 0.24 1.09 0.61 0.981 2 双端起爆 2.60 0.23 0.97 0.46 0.927 8 表 3 最大冲量拟合公式系数
Table 3. Coefficients of the fitted formula for the maximal impulse
起爆方式 公式拟合系数 A1,1 A1,2 A1,1,1 A1,1,2 A1,2,1 A1,2,2 A1,3,1 A1,3,2 A1,4,1 A1,4,2 中心 2 088 −2 044 1 222 −1 043 −4 422 4 503 2 583 −2 715 −971 1 101 单端 341 −110 276 −257 186 −163 247 −236 −27 105 双端 640 −384 1 304 −783 −2077 1 352 1 026 −620 85 −190 起爆方式 A2,1 A2,2 A2,1,1 A2,1,2 A2,2,1 A2,2,2 A2,3,1 A2,3,2 A2,4,1 A2,4,2 中心 −543 568 −550 459 1 321 −1 436 −677 824 173 −293 单端 −135 21 −127 101 −43 22 −106 95 −40 −23 双端 −88 −123 −516 225 528 16 −154 −126 −174 250 起爆方式 A3,1 A3,2 A3,1,1 A3,1,2 A3,2,1 A3,2,2 A3,3,1 A3,3,2 A3,4,1 A3,4,2 中心 45 −50 60 −49 −110 134 42 −73 3 21 单端 18 −1 17 −12 7 −2 13 −11 11 2 双端 15 28 57 −16 −63 −33 12 34 25 −38 -
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