Numerical Simulation of the Flat Ribbon Wound Explosion Containment Vessels Subjected to Internal Blast Loading

In order to constitute engineering design methods of the flat ribbon wound explosion containment vessels, the dynamic response of such vessels subjected to internal explosion loading is simulated using LS-DYNA3D. Three winding angles, 10°, 15°and 20°, are considered. It is shown that among ribbon vessels investigated, the center displacement of outermost ribbons of the vessel with 10°winding angle is the smallest under the same blast loading. The response of vessels loaded in inner core is local. From the center of the cylindrical shell to the bottom cover, the maximum strain gradually decreases. The ribbons are subjected to tension in the length direction and compression in the width direction. Blasting shock energy concentrates on where is close to center section of blasting. For comparison, numerical simulation of a monobloc thick-walled explosion containment vessel is also investigated. It can be found that the biggest deformation of the flat ribbon wound explosion containment vessels is bigger than that of the monobloc thick-walled explosion containment vessel in the center section of blasting under the same TNT. Numerical results are approximately in agreement with experimental ones. It is proved that the ribbon vessels have the valuable properties of " leak before burst at worst" compared with the monobloc vessels through numerical simulation.     

Numerical and Experimental Investigation into Plane Charge Explosion Technique

Plane charge explosion technique （PCET） is one of the major techniques frequently used in large-scale blast-resistant structure tests. An FEM model was established, which can simulate the process of air releasing from the blast cavity. The effects of the charge density, the interval of the charge strip, the distance of the charges from the structure, and the mass of backfill soil on the overpressures applied on the tested structures were analyzed by the FEM model. The quantitative relationships between the peak value and the duration of the overpressure and the above-mentioned affecting parameters were established. Agreement between numerical results and the test data was obtained.     

我国优秀女子铁饼运动员最后用力技术的运动学分析

运用文献资料、图像解析和数理统计等方法对我国第11届全运会女子铁饼前8名运动员最后用力投掷技术的运动学特征以及产生这些运动特征的主要原因进行研究.结果表明,李艳凤右脚着地瞬间躯干扭紧效果与超越器械效果比较好;我国优秀女子铁饼运动员在转旋阶段用时较短,具有短时的转旋技术特点;李艳凤与宋爱民在转旋阶段的技术动作连贯性比较好,而且是在铁饼加速的过程中完成最后用力超越器械动作的;我国优秀女子铁饼运动员的最后出手速度明显低于世界优秀运动员.但是,李艳凤的出手速度已经达到了世界优秀运动员的水平.     

Experimental investigation of external explosion in the venting process

INTRODUCTION Venting technology provides possible protectivemeasures against the effect of explosions. The essen-tial point is to release the high pressure throughproper venting to ensure pressure vessel safety. In acombustion system, when abnormal pressure occursand the venting orifice is opened, a lot of combustiblemixtures venting from the vessel lead to a series ofchanges inside and outside the vessel, and may resultin serious explosion disasters. During the venting proc…     

In-Tunnel Blast Pressure Empirical Formulas for Detonations External, Internal and at the Tunnel Entrance

In order to define the loading on protective doors of an underground tunnel, the exact knowledge of the blast propagation through tunnels is needed. Thirty-three scale high-explosive tests are conducted to obtain in-tunnel blast pressure for detonations external, internal and at the tunnel entrance. The cross section of the concrete model tunnel is 0.67 m^2. Explosive charges of TNT, ranging in mass from 400 g to 4 600 g, are detonated at various positions along the central axis of the model tunnel. Blast gages are flush-installed in the interior surface of the tunnel to record side-on blast pressure as it propagates down the tunnel. The engineering empirical formulas for predicting blast peak pressure are evaluated, and are found to be reasonably accurate for in-tunnel pressure prediction.     

半掺杂锰氧化物的轨道序

基于两个轨道的双交换模型，加上超交换相互作用和格点库仑相互作用，利用Hartree-Fock平均场近似，得到半掺杂锰氧化物F相、A相、CE相和C相的轨道序。计算结果表明不同相有不同的轨道序，从而得出不同相呈现不同的电荷序。     

层次分析法在焦炉火灾爆炸事故中的应用

采用层次分析法对某焦化厂炼焦车间的焦炉设备进行了危险评价,得到焦炉设备发生火灾爆炸事故的主要原因事件,并提出对焦炉设备采取防护措施和规范工人操作的消防安全建议.     

爆炸冲击波在城市地下通道内传播规律的数值模拟

城市地下过街通道是城市重要的交通系统组成部分,也经常会成为恐怖分子爆炸袭击的对象。为了更好的了解爆炸冲击波在地下过街通道中的传播规律,本文通过数值模拟分析了13KG炸药在通道爆炸后冲击波的传播。分析过程中分别考虑了炸药起爆位置及通道顶盖对冲击波传播的影响。分析结果表明当TNT在通道内起爆后,通道顶部的角落将受到更大的冲击波压力作用,当冲击波从出口向外传播时将发生明显的射流现象;当通道出口有顶盖时,炸药在出口的起爆将明显加强通道内部及出口梯道的压力峰值。     

低压电气设备的火灾预防措施

本文分析了常用低压电气设备产生火灾的原因和预防措施。包括常见低压开关设备的防火,低压配电盘及电焊的防火防爆,插座的火灾及预防等。     

倒楔运动与汶川特大地震的成因

汶川特大地震的构造背景是＂两堑夹一垒＂.中生代以来,龙门山倒楔顺行,由地垒发展成横弯背斜;其东侧的正硬楔下降,仍然是地堑,形成了四川盆地;其西侧的正硬楔上部演化成软楔,软楔运动造山,形成了松潘-甘孜高原.伴随楔块运动,主要来自于四川盆地正硬楔底部的富含挥发组分的岩浆,在茶坪山、龙门山等背斜圈闭内大量聚集.当圈闭内的流体能够冲破盖层时,便发生隐爆,形成了5.12汶川特大地震和余震及其山崩地裂等地质现象.