爆炸冲击波在钢管混凝土柱表面压力分布试验研究及数值模拟

为了解决爆炸荷载下钢管混凝土柱表面冲击波压力实际分布和数值模拟存在偏差的问题,通过开展钢管混凝土柱爆炸试验,研究冲击波在钢管混凝土柱表面的压力分布,并结合试验建立爆炸荷载下钢管混凝土柱有限元模型,分析不同空气和炸药网格尺寸对冲击波传播及数值分析结果的影响.结果表明:在折合距离为1.1 m/kg1/3试验条件的爆炸荷载作用下,柱顶与柱底的约束条件良好,柱产生的变形属于弹性变形;考察冲击波对构件的损伤程度,应综合考量峰值压力与正压冲量两者的作用效应;不同空气和炸药网格尺寸对爆炸冲击波的压力峰值及压力时程曲线均有较大影响;数值模拟值与试验实测值的误差随着网格尺寸的减小而降低.综合考察数值分析结果与实测值吻合程度,最终确定:空气和炸药网格尺寸为20 mm,符合折合距离不小于1.1 m/kg1/3试验条件下的爆炸数值模拟要求.     

挡墙对冲击波削弱作用的数值分析

基于任意拉格朗日-欧拉(Arbitrary Lagrange-Euler,ALE)算法,采用有限元软件AutoDyn对TNT炸药地面起爆后,爆炸冲击波遇到挡墙时的传播及挡墙对冲击波的削弱作用进行了三维数值分析.分析了爆炸冲击波遇到挡墙后的反射、绕射及绕射后汇聚的全过程,并通过改变炸药比距离、挡墙尺寸分析了其对冲击波的削弱作用.结果表明:在挡墙作用下,挡墙背面冲击波峰值到达时间将被延长,相对于自由空气中挡墙背面的压力峰值将大大减小;在挡墙高度一定的情况下,其宽度越宽,对冲击波的削弱作用越强,但当挡墙高宽比H/B≤0.25时,挡墙宽度的影响将会很小.     

钢管混凝土柱对爆炸冲击波影响的数值模拟研究

通过LS-DYNA软件对两种截面的钢管混凝土柱在爆炸荷载下爆炸冲击波的传播过程进行了三维数值模拟。混凝土采用HJC模型,钢管采用了考虑应变率的随动硬化塑形模型,炸药采用TNT炸药,使用LS-DYNA程序中的高能炸药爆轰产物压力-体积关系的JWL状态方程分析了爆炸冲击波的传播过程,得到了在不同比例距离下爆炸冲击波在通过两种截面柱子时超压峰值的衰减及增大规律。     

防护堤对爆炸空气冲击波防护效果的数值分析

根据美国国防部相关标准设计了不同坡度的防护堤,采用任意拉格朗日-欧拉算法(arbitrary Lagrangian-Eulerian,ALE),仿真了凝聚炸药的爆炸及其产生的空气冲击波的传播过程,重点分析了不同坡度的防护堤对空气冲击波的防护能力。仿真结果表明:防护堤的设置在空气冲击波的防护过程中起着显著作用,其能够有效地减弱空气冲击波峰值超压对被防护对象的危害,防护能力由防护堤正后方向两边呈减弱趋势,同时防护堤坡度明显影响其对爆炸空气冲击波的防护能力。     

地下建筑内爆炸冲击波荷载分布规律研究

针对地下建筑结构或高层建筑地下室对爆炸灾害防护设计的需要,研究了建筑内爆炸冲击波在房间墙体开口及通道中的传播过程。通过与相关内爆炸模型试验数据对比,确定了合理的有限元内爆炸数值模型和计算参数,在此基础上模拟分析了内爆炸空气冲击波流场及爆炸荷载分布规律,重点研究了装药量与爆室容积比(W/V)、爆室墙面开口面积与房间容积参数V2/3比(A/V2/3)等因素对建筑内外空气冲击波及壁面反射冲击波的影响,根据大量计算结果,拟合给出了由爆炸间开口向外泄露的空气冲击波压力峰值衰减公式。     

网格划分影响二维爆炸冲击波数值模拟精度的研究

使用ANSYS／LS—DYNA建立了TNT炸药在空气中爆炸传播的二维计算模型,比较了相同网格划分比例时,三种不同当量TNT爆炸后在各自比例距离上测得的超压峰值．结果表明：各峰值基本相同,差别小于10^4Pa．在此基础上,改变网格划分比例,模拟计算5kg当量TNT的超压峰值,并与美国常规武器防护设计规范（TM5～855—1）进行对比,提出了与不同比例距离区间相适应的网格划分比例．     

燃料空气炸药的爆炸特性研究

利用一次起爆方式进行了镁粉和硝酸异丙酯组成的液固燃料空气炸药(Fuel-Air Explosive,FAE)的静爆试验,在获取试验数据的基础上,通过计算分析研究了FAE爆轰后冲击波的作用特点和超压场的变化规律,并与常规炸药TNT,RDX和钝黑铝进行了对比分析,得出了冲击波超压和冲量随距离变化的关系式.结果表明,燃料空气炸药装药爆轰特点与常规炸药不同,其爆轰反应区远比常规炸药大得多.在距离爆心一定的距离内,FAE爆轰时比常规炸药的正压作用时间长,比冲量大.     

爆炸冲击波数值计算网格划分方法研究

在爆炸冲击波数值计算过程中,计算精度很大程度上取决于空气和炸药的有限元网格尺寸.现在常用的爆炸冲击波数值计算网格划分方法大多是针对某一当量炸药的,在使用中存在一定的局限性.针对这一问题,本文提出了一种与炸药当量相关的网格划分方法,并应用有限元软件LS-DYNA进行了计算对比,结果表明:该方法适用性很好,而且在计算精度与计算效率上取得了很好的平衡.     

炸药驱动铜管加速能力试验研究

选用TNT、JH-16及CL20基含铝炸药进行Φ50mm标准圆筒试验,获得3种炸药加载条件下圆筒壁膨胀过程及最大膨胀速度,分析给出三种炸药的Gurney系数。结果表明:三种炸药驱动铜管做功能力CL20基含铝炸药最大,JH16次之;CL20基含铝炸药和JH16爆炸加载的破片初速比TNT爆炸加载的破片分别高36.3%和23.0%;用炸药爆速计算炸药Gurney系数的公式同样适用于含铝炸药。     

内爆炸作用下钢网壳结构动力响应的数值模拟

应用LS-DYNA有限元程序,建立了大空间钢网壳结构在内爆炸作用下进行动力响应分析的计算模型.通过提取结构表面有限测点的冲击波超压并将其进行本征正交分解(POD),解决了冲击波荷载的时空差异性及结构表面压力场分布问题.采用Ritz-POD法对大空间单层钢网壳结构在内爆炸荷载下的动力响应进行了数值模拟计算,分析了结构高度、矢跨比、炸药TNT当量及爆炸点位置等参数对结构动力响应的影响.结果表明:大空间钢网壳结构的最大位移和应力响应随炸药TNT当量的增加成非线性增大,其中应力响应近似成比例增大,而位移响应则急速增加.偏心爆炸冲击波比中心爆炸对大空间钢网壳构件的损害大,对结构的边跨构件最为不利.所得结论对于大空间钢网壳结构的防爆设计有参考价值.     

乳化炸药乳化器温度智能控制

文章在深入分析乳化炸药生产工艺的基础上,考虑乳化炸药生产工艺的非线性、大惯性、大滞后等特点,采用了专家控制策略来实现乳化器温度的智能控制。从而实现了工业炸药生产的连续化自动化技术,提升了我国民爆行业的国际地位。     

二级煤矿许用乳化炸药热安全性研究

为了研究乳化炸药在热作用下的反应特性，利用差示扫描量热仪研究了二级煤矿许用乳化炸药热分解过程。并利用Kissinger法与F1ynn—Wall-Ozawa法计算了其表观活化能和指前因子。并比较了二级煤矿许用乳化炸药的热分解特征温度与乳化炸药实际生产过程中的乳化温度、敏化温度及其使用温度。测试和分析结果表明二级煤矿许用乳化炸药具有良好的热安全性。     

Rheology of typical emulsifiers and effects on stability of emulsion explosives

Structure of emulsifiers or functionality and molecular weight determines its rheology,emulsification and stability of emulsion explosives.Rheology of typical emulsifiers was studied by automatic rheometer.Relations between rheology and structural properties of typical emulsifiers were analyzed.Experimental results show that viscosity of emulsifiers didn’t change with shear rate at room temperature and appeared properties of Newtonian fluid.Viscosity of different component emulsifiers declines with temperature in different modes.The change of strain doesn’t affect modulus of emulsifiers.Loss modulus increases linearly with the increase of frequency in oscillation and storage modulus does non-linearly.The higher the temperature is,the lower change amplitude of loss modulus with frequency will be.The emulsifiers with imide and amide functionality for emulsion explosives have better shear properties at high temperature and better shapingness and stability at room temperature than other emulsifiers with ester and Sorbin Monoleate(SMO)functionality.     

Floor dust erosion during early stages of coal dust explosion development

An ignition of methane and air can generate enough air flow to raise mixtures of combustible coal and rock dust. The expanding high temperature combustion products ignite the suspended dust mixture and will continue to propagate following the available combustible fuel supply. If the concentration of the dispersed rock dust is sufficient, the flame will stop propagating. Large-scale explosion tests were conducted within the National Institute for Occupational Safety and Health (NIOSH) Lake Lynn Experimental Mine (LLEM) to measure the dynamic pressure history and the post-explosion dust scour depth. The aim of this effort is to provide quantitative data on depth of dust removal during the early stages of explosion development and its relationship to the depth of floor dust collected for assessing the incombustible content most likely to participate in the combustion process. This experimental work on dust removal on is not only important for coal mine safety but also for industrial dust explosions.     

岩体巷道光面爆破参数比较分析与应用

光面爆破效果主要取决于岩石条件、炸药性质及光爆参数,岩石条件不同,则光面爆破参数应作相应调整.为将光面爆破更合理地应用于不同条件下的岩石,基于爆炸应力波和爆生气体共同作用理论,提出了普通光面爆破及计入损伤光面爆破参数计算公式.实例及分析说明：基于爆炸应力波和爆生气体综合作用理论的光面爆破计算公式是合理的,适用于不同岩石条件光面爆破参数的确定;在孔深、孔径和装药相同的条件下,岩石越完整,稳定程度越高,其光面爆破的周边眼间距越小;计入损伤时,光面爆破的周边眼间距可适当增大;岩石单轴抗压强度较大,则装药不耦合系数可取较小值,以提高炸药爆炸能量利用率,单轴抗拉强度越高,则光面爆破的周边眼间距值越小.     

Influence of an emulsifier on the pressure desensitization of emulsion explosives

The desensitization degree of emulsion explosives （EE） was calculated with the peak pressure of explosion shock waves tested in water. To an explosive, the less the desensitization degree, the better the compression resistance, so the compression resistance of an explosive can be compared and analyzed quantificationally with the desensitization degree. The influence of an emulsifier on the pressure desensitization of EE was studied, including the content and category of emulsifiers. Three kinds of emulsifiers （Span-80, compound emulsifier, and T-152） were used in the tests. The experimental results show that both the content and category of emulsifiers make a great effect on the pressure desensitization of EE. The desensitization degree of EE reduces with the emulsifier content being increased, but there is an optimal content of an emulsifier for the compression resistance of EE. While the content of Span-80 reaches 4wt%, the desensitization degree of EE becomes a minimal value, and augments somewhat if the emulsifier content is increased more. That is to say, the compression resistance of EE becomes the highest while the content of Span-80 is 4wt%, and the compression resistance will decline if the content of Span-80 is increased more. The compression resistance of the explosive emulsified by compound emulsifier is the highest among all the explosives, when the content of the whole components and manufacturing engineering are kept invariable.     

爆破对地表混凝土结构物影响的数值模拟研究

利用LS_DYNA程序,从岩土本身的力学性能、目标与炸药的位置、空气稀疏波的影响等多个角度出发,研究了岩土爆破中应力波的压力衰减以及爆破对地表混凝土结构物的影响,得到了其中的规律,为建筑结构的防护提供了一些思路与依据．     

Air-Decking Technique in Bench Blasting

1 Introduction The air-decking technique (Fig.1) has been ap- plied in mining industry abroad. Melniokov and other experts[1–5]* thought that the existence of the air layer causes the second loading waves and a series of sub- sequent loading waves stirred up in the process of the explosion, and also causes further breakage of the fractured rock mass resulting from the previous pres- sure wave. Although the average pressure on the borehole resulting from the air-decking structure is lower than…     

综放开采顶板冒落撞击摩擦火花引爆瓦斯研究

针对康家滩煤矿8^#煤层综放开采条件，采用专门设计的实验装置对其顶板冒落撞击摩擦火花引爆瓦斯的可能性进行了实验研究．结果表明：冒落岩石的质量、冒落岩石撞击高度与角度、岩石性质及砂岩中的石英含量、岩石的潮湿度等是影响岩石撞击摩擦火花温度及其能否引爆瓦斯的重要因素．当石英砂岩间在接触压力迭171．2N以上、以10m／s的速度摩擦，在2～30s内可引起瓦斯爆炸．康家滩煤矿8^#煤层局部区域的石英砂岩冒落撞击高度最大达6．76m，撞击速度可达11．51m／s，具有引爆瓦斯的可能性．     

Experimental Study on Methane Explosion Ignited by Sparks of Cable Bolt Breakage

An experimental device was designed for studying methane explosion ignited by sparks of cable bolt breakage. With the methane concentration being in explosion range, a series of experiments were conducted to study the law of spark generation during cable bolt breakage and the probability of methane explosion caused by the spark. The results show that the probability of generating sparks during cable bolt breakage is 50%. The spark generated by the breakage of steel cable bolt strand can‘t ignite a methane explosion. A detection was carried out using infrared-ray imaging apparatus (IRIA) to measure temperature of the spark generated by cable bolt breakage. It is indicated that the maximum temperature of the spark generated by cable bolt breakage is far less than the required ignition temperature for a methane explosion.