共查询到17条相似文献,搜索用时 125 毫秒
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准确计算口部内爆炸条件下坑道中冲击波传播速度的变化规律,是坑道工程中防护设施抗精确打击设计的前提。为此,在野外进行10次模型坑道内爆炸试验。模型坑道由可拼装式钢结构单元组成,净截面积为60cm×60cm,B炸药装药量范围为75g~500g。通过安装于坑道侧壁上的压力传感器实测冲击波波形,由实测数据拟合出坑道口部内爆炸条件下冲击波沿等截面直坑道传播的速度模型。算例分析表明,所拟合的坑道内冲击波传播速度的工程经验模型具有较高实用价值。 相似文献
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为弄清温压炸药爆炸冲击波在坑道内的传播特性,考虑实际坑道口部特征,使用厚壁钢管和钢板加工了模型试验坑道。利用安装在模型坑道侧壁的压力传感器,分别实测了HMX基温压炸药和TNT口外爆炸时坑道内不同距离处的冲击波波形。通过对比分析,研究了该温压炸药冲击波波形及其参数在坑道内的传播特征。试验结果表明:温压炸药波形具有冲击波的典型特征,该温压炸药爆炸冲击波传播速度、超压峰值、正压持时和正向冲量均大于TNT,坑道深处其平均超压峰值、正压持时和正向冲量分别为TNT的1.19、1.31和1.53倍。利用坑道内冲击波传播的经验公式反推,得到试验用温压炸药爆炸冲击波超压峰值和正向冲量的平均等效TNT当量系数分别为1.79和1.99。表明该温压炸药冲击波比TNT具有更大的威力。 相似文献
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坑道内爆炸冲击波传播规律的研究 总被引:3,自引:1,他引:2
摘 要:炸药在坑道内爆炸将产生沿坑道传播的空气冲击波,冲击波与坑道壁相互作用,使得坑道内冲击波的传播规律明显不同于自由大气中冲击波的传播规律。使用有限元计算软件LS-DYNA对已有的坑道试验进行了数值模拟,通过数值模拟结果与试验结果数据比较,验证了有限元计算中所使用的计算模型和参数取值的合理性。利用数值模拟的计算结果,使用量纲分析理论,拟合了距离爆炸中心点一定距离处爆炸冲击波超压峰值的计算公式,并与试验结果进行对比,分析了该公式的适用性,为坑道中爆炸冲击波的传播规律研究提供了参考。
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为研究坑道内爆炸冲击波相似律问题,进行了不同药量坑道堵口爆炸实验,并利用ANSYS/LSDYNA软件对原型坑道与模型坑道爆炸冲击波进行数值计算。结果表明:与自由大气中不同,同一坑道内不同药量爆炸产生的冲击波不符合爆炸相似律;若原型坑道与模型坑道几何相似,装药量之比为几何相似比的三次方,则原型坑道与模型坑道内爆炸冲击波符合爆炸相似律;坑道内爆炸冲击波数值模拟时,若原型坑道与模型坑道网格尺寸符合相应的几何相似比,则冲击波计算结果满足相似律,当坑道截面网格密度为1675~2977时可以达到计算精度要求。 相似文献
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温压炸药爆炸冲击波在坑道内的传播规律研究 总被引:1,自引:0,他引:1
温压炸药爆炸冲击波对坑道内的人员和设备构成严重威胁。在TNT爆炸试验数据验证的基础上,利用AUTODYN软件建立了炸药堵口爆炸的数值计算模型。基于JWL-Miller能量释放模型计算原理,通过与TNT冲击波的对比,研究了某型温压炸药爆炸冲击波在坑道内的传播特性;通过与空旷地面爆炸冲击波的对比,研究了坑道对温压炸药爆炸冲击波的约束作用。研究结果表明:温压炸药具有更大的破坏威力,温压炸药的超压峰值和正相冲量平均为TNT的1.91倍和1.82倍,其超压和冲量等效TNT当量系数分别为1.94和2.21;坑道对温压炸药冲击波的约束作用明显,其超压峰值和正相冲量平均值分别为空旷地面上的13.55倍和15.21倍。 相似文献
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Dynamic responses of a multi-storey building without or with a sliding base-isolation device to ground shock induced by an in-tunnel explosion are numerically analyzed in this paper. The effect of an adjacent tunnel in between the building and the explosion tunnel, which affects ground shock propagation, is also considered in the analysis. Different modeling methods, such as the eight-node iso-parametric finite element and mass-lumped system, are used to establish the coupling model consisting of the two adjacent tunnels, the surrounding soil medium with the Lysmer viscous boundary condition and the multi-storey building with or without the sliding base-isolation device. In numerical calculations, a continuous friction model, which is different from the traditional Coulomb friction model, is adopted to improve the computational efficiency and reduce the accumulated errors. Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock. The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated in the study. The final conclusions based on the numerical results will provide some guidance in engineering practice. 相似文献
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对双层柱面网壳结构在地下隧道内爆炸冲击作用下的动力响应进行了研究.借助ABAQUS有限元软件建立了考虑地基土、混凝土、钢材等材料非线性的隧道-土-网壳结构耦合体系的三维数值模型,并通过算例验证了所建体系模型的正确性和有效性.分别对单、双线隧道布局、网壳与爆炸隧道间距离的变化、爆炸点在隧道内沿其纵轴线移动等三组工况进行了... 相似文献
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《International Journal of Impact Engineering》2002,27(4):359-376
This study is concerned with the effect of confinement, provided by tall buildings which border straight city streets, on the positive and negative phase impulses of blast waves originating from explosive detonations. An approach to the problem is described which is based on a parametric study comprising numerical simulations validated by comparison with small-scale experiments. Results of the simulations are presented in graphs of peak scaled positive and negative phase impulse, measured at locations near to ground level on the building facades, plotted against scaled distance along the centreline of the city street. A range of scaled street widths and building heights are considered which covers most cases of practical interest. The nature of the variation of both positive and negative phase impulses is described, and the implications for the design and hazard assessment of urban landscapes are considered. 相似文献
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城市复杂环境中爆炸波的传播规律与超压荷载 总被引:1,自引:1,他引:0
该文利用LS-DYNA软件,采用ALE方法,对城市复杂环境中爆炸波的传播规律与超压荷载进行了数值模拟和分析。通过对两建筑物模型中爆炸波传播的数值模拟及其与单建筑物模型的对比分析,结果表明两建筑物模型中爆炸波由于在两建筑物之间多次反射而被增强,因此在计算建筑物所受到的爆炸波超压荷载时必须考虑相邻建筑物的影响。通过对一典型T型街道中爆炸波传播的数值模拟及其与简单环境的对比分析,结果表明在城市街道中爆炸波受到地面和周边建筑物的多次反射而增强,且在一定高宽比范围内,街道越窄、周边建筑物越高,爆炸波超压荷载的增大系数越大,因此在分析城市复杂环境中爆炸波的传播规律和超压荷载时必须考虑周边建筑物的影响。从而为制定城市大型及重要建筑的防爆措施提供依据。 相似文献
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Kessler DA Gamezo VN Oran ES 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2012,370(1960):567-596
The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that one-dimensional detonation properties of model low- and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon-air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuel-lean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient. 相似文献
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Blast damage assessment of buildings and structural elements requires an accurate prediction of the blast loads in terms of the peak pressures and impulses. Blast loadings on structures have typically been evaluated using empirical relationships. These relationships assume that there are no obstacles between the explosive device and the target. If a blast barrier is used to protect personnel or a structure behind it, the actual blast loading environment will be significantly reduced for some distance behind the barrier. This paper is concerned with an accurate prediction of the area of effectiveness behind the barrier using experimental data and a neural network-based model. To train and validate the neural network, a database is developed through a series of measurements of the blast environment behind the barrier. The principal parameters controlling the blast environment, such as wall height, distance behind the wall, height above ground, and standoff distance are used as the training input data. Peak overpressure and peak scaled impulse are used as the outputs in the neural network configuration. The trained and validated neural network is used to develop contour plots of overpressure and impulse adjustment factors to simplify the process of predicting the effectiveness of blast barriers. The developed model is also deployed in a stand-alone application that is used as a fast-running predictive tool for the blast overpressures and impulses behind the wall. 相似文献