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。     

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.     

长持时爆炸冲击波产生方法

不同持时的爆炸冲击波对建筑结构及防护工程的作用显著不同,在试验或数值模拟中常需要得到长持时爆炸冲击波,延长爆炸冲击波正压作用时间是研究长持时爆炸荷载下结构响应的难点。在AUTODYN中建立长筒爆室小当量炸药多点延时起爆模型,分析爆炸冲击波在长筒爆室中的传播规律,研究管道长度、延时起爆时差、起爆顺序对冲击波波形的影响。结果表明：距离增加,超压峰值减小、正压持续时间增加;根据炸药量和爆室长度合理地选择起爆时差可以获得波形丰满且连续衰减的超压时程曲线;爆室底部起爆、合理控制延时间隔,可以形成类似于大当量远距离爆炸下产生的连续衰减的长持时冲击波。分别给出100、200 ms爆炸持时起爆方案,为长持时爆炸模拟装置的设计提供技术支持。     

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.     

同步爆炸成型地下仓及混凝土仓壁的爆扩过程

运用爆炸冲击动力学理论,从理论上系统地分析了土中同步爆炸成型地下仓及混凝土仓壁过程中空腔的运动特征．在基本假设基础上结合冲击波传播规律,提出了反映空腔爆扩速度、时间和最终爆腔尺寸的理论计算式．     

CE／SE方法在障碍物对爆炸冲击波干扰流场计算中的应用

应用高精度的CE／SE方法对厂房中爆炸冲击波扫过障碍物挡墙形成的流场进行了二维数值模拟，具体分析了障碍物、厂房内壁与冲击波相互作用的规律，得到了能够反映障碍物作用前后波系结构变化的压力等值线图．数值结果显示了冲击波遇障碍物发生反射、绕流等现象，形成复杂波系；通过与尤障碍物存在的爆炸流场对比，分析了相对于爆点不同位置的障碍物对爆炸流场的影响；最后改变爆点个数，对爆炸流场的变化做了进一步分析．数值模拟结果符合相关物理规律．     

Numerical simulation of the parabolic shell surface under blast wave loading

Deformation of parabolic shell surface under explosion shock waves is a complex dynamic problem. Because of reflection and interference of blast wave, it’s hard to analytically delineate the dynamic responds of radar parabolic shell surface on blast wave. To gain the characteristics of thin shell deformation under impulsive loading of blast wave, numerical simulation methods for blast load on the shell structure was studied and analyzed. Euler-Lagrange numerical simulation was implemented by AUTODYN code to simulate the problem. Through analysis on deflection feature of radial position under different explosive mass and detonation height, an equation was founded by fitting the deflection results from numerical simulation results of shockwave loading. Experiments were arranged to confirm the validity of the formula. The results gained by simulation are consistent with experiments, and the formula can be used to delineate the deflection of aluminum alloy parabolic shell under blast loading.     

薄板在接触爆炸载荷作用下的破坏分析

对薄板在接触爆炸载荷作用下的塑性动力响应问题进行了理论研究.根据板受接触爆炸压力载荷的大小和应变率的不同将板划分为不同的区域,应用不同的本构关系进行研究,得到爆炸的破坏范围.通过算例进行验证,并与经验公式进行了比较,结果基本上是合理的.可应用于舰船结构在爆炸冲击波作用下的毁伤或防护方面的预测,从而为舰船的安全防护设计提供理论依据.     

岩体中软弱夹层影响爆炸波传播规律的数值分析

为了模拟岩体中软弱夹层对爆炸波传播衰减的影响,在块体离散元的基础上改进了数值计算方法（包括基本方程、求解步骤、能量耗散等效模式）,使其适合模拟爆源的特点、岩体中软弱夹层的性质以及应力波的传播衰减规律.用该方法建立了含软弱夹层岩体和爆源的数值模型,对岩体中软弱夹层影响爆炸波的传播衰减规律进行了数值试验.结果表明：软弱夹层前后爆炸波的振动速度峰值差别很大,存在量级上的差别;软弱夹层与爆源的距离对应力波衰减的影响很大,而夹层厚度影响较小;在两组软弱夹层之间的质点振动持续时间明显延长.数值模拟不仅给出了爆炸波经过软弱夹层的透反射关系,而且描述了不同情况下质点振动的基本形式,可为实际工程提供参考.     

意外撞击和冲击波作用下气瓶的动态响应分析

基于任意拉格朗日多物质流一固耦合算法,对空气采用ALE网格,对炸药采用JWL状态方程,分析了爆炸冲击波单独作用和高速子弹与冲击渡联合作用下高压气瓶的动态响应。结果表明,在冲击波作用下气瓶应力急剧上升,气瓶出现屈服并发生屈曲,爆心距瓶体越近,气瓶受冲击渡的影响越大;联合作用时应力相互叠加使得气瓶应力值比单独作用时有明显增大,变形相对于高速撞击和爆炸波单独作用显著增加,塑性变形区域变大,破坏程度更加明显。     

Study on Property of Desensitized Explosive Film

The mechanical sensitivity, the critical thickness of detonation wave propagation and detonation velocity of desensitized PETN film were studied by experiments. The relationship between the mass of desensitizer paraffin wax and the friction sensitivity of desensitized PETN film was tested. According to the microstructure of film, the function of desensitizer was explained. It was proved that the explosive film could make explosive element micromation and kept its inherence properties by the result of testing the propagating critical dimension of the desensitized PETN film detonation wave. The explosive velocity of confined desensitized PETN film was tested by the multiplex optical fibre.     

爆炸式催泪弹安全性研究

爆炸式催泪弹的安全性和可靠性设计是新型防暴弹的重要研究方向.本文针对爆炸式催泪弹的安全设计,利用最小自由能法获得了装药配方中炸药爆炸后的平衡组成,计算了爆炸式催泪弹反应过程释放的总能量、装药爆速、爆压.对弹体零件强度、爆炸冲击波、破片及残骸杀伤性进行了理论分析和计算.通过试验,证明了研发的爆炸式催泪弹产品具有极高的安全性和可靠性.     

Detonation Propagation Characteristics of Superposition Explosive Materials

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Numerical Simulation of the Protective Effect of Complex Boundaries Toward Shock Waves in a 3D Explosive Field

A numerical method is presented that simulates 3D explosive field problems.A code MMIC3D using this method can be used to simulate the propagation and reflected effects of all kinds of rigid boundaries to shock waves produced by an explosive source.These numerical results indicate that the code MMIC3Dhas the ability in computing cases such as 3D shock waves produced by air explosion,vortex region of the shock wave,the Mach wave,and ceflected waves behind rigid boundaties.     

新型钝感炸药组分配比对安全性影响的研究

新概念反应装甲的出现对传爆系统所用炸药提出了新的使用要求,即同时满足高威力、高安全性.充分考虑了钝感机理、粘结机理和组分配比对安全性的影响特性,研制了一种以PETN为主体,蜡、石墨、聚异丁烯为钝感剂与粘结剂的新型钝感炸药,进行了冲击波感度、机械感度以及火烤特性试验.试验结果表明:该新型钝感炸药具有理想能量和感度性能满足技术要求,为解决安全传爆技术奠定了基础.     

Destruction mechanism of gas explosion to ventilation facilities and automatic recovery technology

In order to overcome the heavy casualties caused by gas explosion, we verified the propagation law of shock wave in pipeline and the overpressure distribution of gas explosion by similar experiments according to the analyses of reasons for casualty and ventilation system model destroyed by gas explosion in the mining face. We summarized the gas composition after the explosion and its danger, analyzed the effects of the gas explosion shock wave to ventilation system and facilities and the laws of toxic gas spread and diffusion in the ventilation network after the explosion. We presented a technical proposal to control the smoke and recover the ventilation system after a gas explosion and developed a reserve air door and control system that were embed in the lane, and could close automatically in conditions of no pressure and electricity. The results showed that the reserve air door normally opened and could close automatically controlling the smoke flow and resuming the ventilation system when the gas explosion shock wave destroyed the original shutting air door which resulted in the air short circuit.     

Numerical Analysis of Effect of Water on Explosive Wave Propagation in Tunnels and Surrounding Rock

Based on the application of practical engineering, propagation processes of explosive waves in rock with water well and tunnel are simulated by ANSYS/LS-DYNA software. The evolution of damage in rock is presented. The effect of water on the damage of the concrete slab in a tunnel is compared with damage inflicted without water. The numerical simulation illustrates that water plays an important role in the evolution of damage of the concrete slab in a mine tunnel. In the presence of water in the rock the concrete slab is damaged more severely than without water in rock. The effect of water location in the rock is also considered. It is found that the concrete slab in the tunnel shows various degrees of damage as a function of the different locations of water. Attenuation laws of stress waves over time-space in rock with water are also obtained. Numerical results indicate that, under blast loading, there are three zones in the rock： a crushed zone nearby the explosive charge, a damaged zone and an elastic zone. The conclusions of numerical analysis may provide references for blasting designs and structure protection.     

移动通信中电波传播损耗的预测模型

在自由空间电波传播损耗模型基础上，基于微小区内电波传播新特点，给出了电波传播损耗的一般预测模型，其特点是用最小拐点距离D来统一反映天线高度和系统工作频率对电波传播损耗的影响，同时对电波在传播过程中经过的不同环境，分别用不同的路径衰减指数n来反映。     

Numerical simulation for explosion wave propagation of combustible mixture gas

A two-dimensional multi-material code was indigenously developed to investigate the effects of duct boundary conditions and ignition positions on the propagation law of explosion wave for hydrogen and methane-based combustible mixture gas. In the code,Young’s technique was employed to track the interface between the explosion products and air,and combustible function model was adopted to simulate ignition process. The code was employed to study explosion flow field inside and outside the duct and to obtain peak pressures in different boundary conditions and ignition positions. Numerical results suggest that during the propagation in a duct,for point initiation,the curvature of spherical wave front gradually decreases and evolves into plane wave. Due to the multiple reflections on the duct wall,multi-peak values appear on pressure—time curve,and peak pressure strongly relies on the duct boundary conditions and ignition position. When explosive wave reaches the exit of the duct,explosion products expand outward and forms shock wave in air. Multiple rarefaction waves also occur and propagate upstream along the duct to decrease the pressure in the duct. The results are in agreement with one-dimensional isentropic gas flow theory of the explosion products,and indicate that the ignition model and multi-material interface treatment method are feasible.     

动态光弹性应用的初步研究

爆破与高速冲去载荷所产生的应力波在弹性结构物中的传播,在理论分析上极为困难,但这类问题可以用动态光弹性法进行分析。本文仅涉及地震波传播及爆破方法选择两个课题,研究表明:在这类课题中,利用动态光弹性法有其优越性。