The experimental and numerical impacts of geometrical parameters of conical shock tube on the function,maximum pressure and generative impulses to expose equivalent mass and behavioral equation

One of the methods to investigate the phenomenon of explosion underwater and its impact on the structures is to use the conical shock tube. These tubes produce a lot of pressure using a tiny explosive charge. In this essay, the geometry of the established/manufactured explosive shock tube is demonstrated first and the results of the experiments operating the tube is presented. Then, the explosion of a given amount of explosive charge in the conical shock tube is studied by benefiting the LS‐DYNA code. The numerical simulation is done by Lagrange‐Oiler selected multi‐materials solutions. To ensure the authenticity of the selected method in the software, the results of the stimulated model is compared with the experimental outcomes accordingly, after accrediting the accuracy of the results, the stimulating and scrutinizing the effects of geometrical parameters on the function of explosive shock tubes is proceeded. In this research, the effect of the cone head angel on the produced pressure inside the shock tube is analyzed first. Then, the function of shock tubes with different lengths is checked. Moreover, after changing the scale of the explosive charge and studying the outcome, stating the reasons for changes in each parameter and examining the effect of the relation between the explosive proportion and the water volume inside the shock tube, an equation for the equivalent mass for all sock tubes with different angels is exhibited and the existing theoretical relation is revised. Finally, by examining the pressure and impulses changes in different intervals, an equation is presented to anticipate the pressure and impulses in different shock tubes.     

轴向打孔装药爆炸切断TC4钛合金板的研究

为了探究爆炸切断TC4钛合金板的最佳方式，设计了轴向单孔和轴向双孔两种装药结构。采用AUTODYN软件进行了数值模拟，并结合试验分别对单孔装药和双孔装药优劣性以及装药孔径对爆炸切断效果的影响进行了对比分析。通过计算装药量及运用Mises屈服准则，判断了两种装药结构下4组试验方案中TC4钛合金板的切断及损伤情况，且结合测点振速与加速度变化情况说明了应力波在板内的传播规律。结果表明:爆炸切断能力会随着装药直径的增大而增强，且钛合金板的损伤也随之增大；相较于单孔装药，双孔装药更适用于爆炸切断TC4钛合金板。     

两起钢管约束的工业炸药爆炸事故分析

介绍了两起装有工业炸药的钢管发生的爆炸事故。事故钢管来源为采石场违章用作爆破装药时捣实炮孔用的钢管，该钢管改作他用时，在实施电焊、锻造加工时发生了爆炸。用化学分析方法在爆炸后的钢管残余物中找到了工业炸药的成分。用4种典型的工业炸药模拟了事故钢管热爆炸的过程，试验结果表明工业炸药填充在钢管中能发生热爆炸，进一步证实了事故钢管爆炸的原因推断。建议工程爆破中严格禁止使用管状金属材料做装药时捣实炮孔之用。     

铝纤维炸药的土中爆炸成腔试验与工程应用

通过对铝纤维炸药在土中爆炸成腔效应进行研究,得到土中爆炸成腔的半经验公式。针对5m高水下爆炸塔的倾斜问题,结合塔底矩形钢板环绕支撑结构和地质情况,设计具体的单孔装药量与孔深,利用铝纤维炸药土中爆炸成腔技术重新调整塔底地基水平面,使塔在振动与重力作用下得以纠偏。实践证明,铝纤维炸药由于其能量密度高、成型效果好等特点可在一些特殊环境下应用并取得理想的效果。     

单个球形装药浅层水中爆炸冲击波特性的研究

通过对单个球形装药浅层水中爆炸的模拟试验研究,分析了在涉及边界影响条件下水中爆炸冲击波参数的分布和变化规律,拟合了相应的计算公式。试验数据能较好地反映浅层水中单个球形装药爆炸冲击波的传播规律     

Numerical simulation of explosive welding using the material point method

Explosive welding involves detonation of explosive, interactions of fluid-structure and plastic deformations of metal plates at the instant of the explosion. Conventional mesh-based methods such as the finite element method (FEM) and finite difference method (FDM), are limited in simulation of the explosive welding when mesh distortion and interaction of different materials occur. In order to describe process of the explosive welding and accurately predict physical parameters for the explosive welding, numerical simulation of the explosive welding which involves multi-physical phenomenon is performed by using material point method (MPM). Not only can major physical phenomena of explosion impact be well captured, but also some important technical parameters for the explosive welding can be attained based on the MPM simulation. Through the comparison with the experimental results, it is shown that the MPM is a robust tool in simulation of the explosive welding.     

Deformation and fracture behaviour of plate specimens subjected to underwater explosion—a review

Behaviour of plate specimens subjected to underwater explosion is of interest to metal forming community and ship designers. The break down of the original molecule of an explosive into product molecules associated with the evolution of large amount of heat generates a shock front in the water medium, followed by a gas bubble pulsation. The interaction of the shock wave with a plate imparts energy to it, which is dissipated in the form of deformation. The intensity of explosion determines whether a plate undergoes elastic deformation, yielding, plastic deformation or fracture. When the deformation is in the elastic range, the stress developed in the plate is given as a function of the material and shock wave parameters. As the intensity of explosion progressively increases, the elastic to plastic transition occurs over a specific shock factor. Plastic deformation is predicted as a function of geometric and material properties of the plate and shock pulse impulse. Deflection-time history reveals the reloading effects of the shock wave. As the deforming plate absorbs maximum energy, depending on its strength and ductility, it undergoes fracture. Terminal strain to fracture is considered as the criterion for explosive shock performance of ship materials.     

Damage prediction of concrete gravity dams subjected to underwater explosion shock loading

The damage prediction of concrete gravity dams under blast loads has gained importance in recent years due to the great number of accidental events and terrorist bombing attacks that affected engineering safety. It has long been known that an underwater explosion can cause significantly more damage to the targets in water than the same amount of explosive in air. While the physical processes during an underwater explosion and the subsequent response of structures are extremely complex, which involve lots of complex issues such as the explosion, shock wave propagation, shock wave-structure interaction and structural response. Hence a sophisticated numerical model for the loading and material responses would be required to enable more realistic reproduction of the underlying physical processes. In this paper, a fully coupled numerical approach with combined Lagrangian and Eulerian methods, incorporating the explosion processes, is performed. The RHT (Riedel–Hiermaier–Thoma) model including the strain rate effect is employed to model the concrete material behavior subjected to blast loading. Detailed numerical simulation and analysis of a typical concrete gravity dam subjected to underwater explosion are presented in this study. In terms of different TNT charge weights, the structural response and damage characteristics of the dam at different standoff distances are investigated. Based on the numerical results, critical curves related to different damage levels are derived.     

TNT炸药爆炸场中三波点的数值模拟

准确预测三波点的位置和揭示三波点的规律,对工程防护和实现弹药的高效损伤有着重要作用。基于LS-DYNA有限元软件,利用数值模拟方法研究了TNT炸药在混凝土地面上形成爆炸冲击波的三波点运动轨迹,并初步揭示了炸高、药量和炸药形状等因素对三波点高度的影响。研究表明:在爆炸场中,爆炸冲击波以炸药为中心向四周传播,三波点轨迹的高度均呈现逐渐增高的变化趋势。不论改变炸药的药量还是炸高,三波点高度的增速在中场(4.0⁷.0 m)都较缓,而进入远场(>7.0 m)增速骤增。当炸药的炸高和药量相同,炸药形状不同时,圆柱状炸药在中场爆炸形成的三波点高度比长方体炸药略高,且高度增速都较缓;而在远场三波点的高度基本相等,且增速急剧上升,趋于定值。与炸药形状的影响相比,炸高和药量对TNT炸药爆炸冲击波的三波点高度的影响较大。     

TNT炸药爆炸场中三波点的数值模拟

准确预测三波点的位置和揭示三波点的规律,对工程防护和实现弹药的高效损伤有着重要作用。基于LS-DYNA有限元软件,利用数值模拟方法研究了TNT炸药在混凝土地面上形成爆炸冲击波的三波点运动轨迹,并初步揭示了炸高、药量和炸药形状等因素对三波点高度的影响。研究表明:在爆炸场中,爆炸冲击波以炸药为中心向四周传播,三波点轨迹的高度均呈现逐渐增高的变化趋势。不论改变炸药的药量还是炸高,三波点高度的增速在中场(4.0~7.0 m)都较缓,而进入远场(7.0 m)增速骤增。当炸药的炸高和药量相同,炸药形状不同时,圆柱状炸药在中场爆炸形成的三波点高度比长方体炸药略高,且高度增速都较缓;而在远场三波点的高度基本相等,且增速急剧上升,趋于定值。与炸药形状的影响相比,炸高和药量对TNT炸药爆炸冲击波的三波点高度的影响较大。     

条形药包水下爆炸能量计算

文章根据流体动力学理论，采用当量药量处理方法，推导出无限长和有限长条形药包水下爆炸冲击波比能气泡波比能的计算公式，为条菜药包水下爆炸能量测试提供了理论依据。     

等效靶弹药空气中爆炸威力评估

针对传统的冲击波压力电测法操作复杂且易受干扰的问题,提出基于等效靶塑性变形的炸药爆炸威力评估方法.首先进行小当量立姿等效靶板变形试验,并基于实验结果确定适用于有限元数值模拟的模型;其次,使用量纲分析方法简化等效靶变形的理论模型,建立靶板中心最终变形挠度与爆炸当量、爆炸距离的关系;进一步结合实验数据与数值模拟结果,得出通...     

含铝炸药近场水下爆炸冲击波的实验及数值模拟

含铝炸药能改善能量的输出结构,增强爆轰产物的做功能力,将其应用于水下爆炸,能显著提高水中兵器的爆炸威力和毁伤能力。基于电测法采用PVDF压力传感器开展含铝炸药RL-F和TNT近场水下爆炸冲击波实验,并采用耦合欧拉-拉格朗日(CEL)法对其进行模拟;通过将仿真结果与实验值及经验值对比,结果表明采用合理的边界条件、计算参数和有限元模型,CEL方法能准确地模拟含铝炸药和TNT近场水下爆炸冲击波的传播过程;含铝炸药近场水下爆炸冲击波压力衰减速率相对于TNT较缓慢。在验证数值模型合理性的基础上,将数值结果拟合得到TNT近场水下爆炸冲击波峰值压力在6倍装药半径内以及含铝炸药峰值压力在一定比例距离范围内的近似回归公式。     

不同结构柱状药包径向破碎效应的实验研究

不同结构的柱状药包在有机玻璃板中爆炸后产主的民向破碎效应有明显的区别。本文介绍了实验情况,分析了产生不同破碎效应的原因,认为柱状中空药包爆炸产生的径向破碎效应有利于改善坚硬矿岩的破碎质量。     

大当量炸药齐爆远区安全性分析

炸药爆炸后的安全性问题是涉爆类试验研究的关注重点,文中分别从爆炸冲击波与爆破地震波的危害效应进行了研究,计算得出了某当量装药条件下爆炸远区的相关爆炸参数,总结出了其分布与衰减规律,为今后类似试验研究工作的顺利进行与安全组织管理奠定了科学基础.     

不同结构柱状药包径向破碎效应的实验研究

不同结构的柱状药包在有机玻璃板中爆炸后产主的民向破碎效应有明显的区别。本文介绍了实验情况，分析了产生不同破碎效应的原因，认为柱状中空药包爆炸产生的径向破碎效应有利于改善坚硬矿岩的破碎质量。     

高能炸药毁伤威力数值仿真实验研究

采用AUTODYN分别对2.0 kg球体裸装药TNT、H6、AL/AP-HE和PBX90104种常用爆炸材料建立数值仿真模型,对爆炸冲击波及热毁伤效应进行仿真分析,并对冲击波超压峰值和温度场温度进行对比分析.结果表明:不同爆炸材料爆炸产生的毁伤效应存在很大差别,在同等装药质量下,4种爆炸材料冲击波超压峰值PBX9010...     

添加物对改性岩石膨化硝铵炸药爆炸性能影响的实验研究

为了提高和改善膨化硝铵炸药的密度和殉爆距离,在实验的基础上,研究了没食子酸、对硝基苯甲酸、硫酸高铁铵以及金属矿粉等几种添加剂对岩石膨化硝铵炸药爆炸性能和装药密度的影响,分析它们在工业炸药中应用的可行性.实验结果表明,添加剂对膨化硝铵炸药的爆炸性能影响较大,寻求物美价廉的、可以满足不同爆破条件的添加剂是改善该类炸药性能的措施之一,而硫酸高铁铵是容易推广和工业化应用的膨化改性剂.     

轴向不耦合装药结构形式优化仿真研究

为了改变某隧道平导爆破效果差、爆炸能量利用率低的现状,采用ANSYS/LS-DYNA模拟不同轴向不耦合装药结构形式对爆破效果的影响,优化装药结构,以期达到增强爆破效果,降低粉尘量和岩石大块率的目的。合理的选择数值模拟中的材料模型和算法,是高效模拟分析轴向不耦合装药结构爆破的关键,因此采用ALE算法对孔口空气填塞不耦合,孔口炮泥填塞、上部空气间隔不耦合,孔口水介质填塞、底部水介质间隔不耦合,孔口炮泥填塞、上部水介质间隔不耦合,孔口水介质填塞、中部水介质间隔不耦合和孔口炮泥填塞与中、上部水介质间隔不耦合的装药结构进行数值模拟,并以爆炸应力波云图和最大拉应力来评价炸药爆破效果。数值模拟结果表明:水介质可以降低炮孔壁附近岩石的压力。装药长度1.25m时,孔口炮泥填塞、上部空气间隔不耦合装药结构较孔口空气填塞不耦合装药结构,能提高爆炸能量的利用率;孔口水介质填塞、底部水介质间隔不耦合装药结构和孔口炮泥填塞、上部水介质间隔不耦合装药结构,爆炸能量利用率基本相同;孔口水介质填塞、中部水介质间隔不耦合装药结构的炸药爆炸能量利用率较其余5种装药结构都大,能提高爆炸应力波对岩石的作用,使得爆炸应力波更加均匀作用于岩体,降低大块率产生。此数值模拟结果可为现场爆破方案设计与实施提供依据。     

柱状药包岩石中爆炸的数值模拟

利用ANSYS/LS-DYNA3D对柱状药包在半无限岩石介质中爆炸情况进行了数值模拟,对柱状药包的爆炸在岩石内产生的应力变化进行了分析。给出了岩石弹性区内一点的应力变化时程曲线;并借助球形装药的经验公式对柱状装药的情况进行了分析比较,结果表明,应力波的峰值基本一致。该时程曲线可以用于多孔爆破计算。