Investigation on the temperature distribution and strength of flat steel ribbon wound cryogenic high-pressure vessel

INTRODUCTION Cryogenic high-pressure vessels are used to store liquid hydrogen and liquid oxygen, and are necessary equipments in the fields of chemical engineering, astronautic engineering and nuclear power plant, and so on. Safe operation of the vessel is always a concern of environmental protection. The inner pressure of the vessel can reach 40 MPa at temperature of 20 K; Therefore, the vessel requires high-performance wall material excellent in mechanical strength, plastic property,…     

Strain Growth in Containment Vessels

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.     

Research on reasonable winding angle of ribbons of Flat Steel Ribbon Wound Pressure Vessel

INTRODUCTION Axial strength is viewed as the most important parameter in the failure analysis of a pressure vessel. As axial damage is destructive, special attention should be paid to it. The axial strength of an FSRWPV has close relationship with the winding angle α as shown in Fig.1 (Zhu et al., 1995). ASME CODE (1996-1997) stipulates that winding angle of 15°~30° should be used, with nothing said about how the range was determined. In fact, 15°~30° winding angle is not suita…     

基于FLAC3D不同倾角结构面剪切特性研究

为了分析不同倾角结构面对裂隙岩体强度及变形性质的影响,本文通过数值模拟的方法,分析了0°、15°、30°、45°、60°、75°、90°7种典型倾角结构面岩体在三轴压缩条件下的应力应变响应,并从微观角度分析了结构面的变形性质.研究结果表明：在相同围压条件下,随着结构面倾角的增大,不同倾角结构面岩石试件抗压强度呈先减小后增大趋势;含有90°倾角结构面的岩石试件的抗压强度与含有0°倾角结构面岩石试件的相等;随着结构面倾角的增大,结构面上的剪应力的变化趋势是由中部向结构面倾向方向的两侧扩展,并且逐渐趋于集中.     

福州市住宅建筑合理日照间距

利用棒影日照图研究福州市建筑日照间距系数,按建筑朝向正南、南偏东及南偏西各5°、10°、15°、20°、30°、40°等方位,分别计算福州市冬至日的建筑日照间距系数,并与城市居住区规划设计规范进行比较。提出福州市达到既改善居住的生态环境又有效节约土地资源的合理朝向与间距的科学建议。     

大断面台阶式光面爆破技术的应用

台阶式爆破主要针对大断面掘进巷道而使用的爆破工艺,可以很好地解决大药量同时起爆产生的强冲击波致使巷道成型变差以及瓦斯释放量的增加的问题;通过实践对比,台阶式爆破很好地解决了超挖和欠挖的现象,提高了爆破效果和巷道成型质量,降低了围岩和瓦斯的危害。     

不同加载角T形钢管混凝土压弯承载力研究

采用有限元软件ABAQUS建立了不同加载角T形带肋和多室钢管混凝土压弯构件的计算模型,数值计算结果与试验结果吻合良好。对影响T形钢管混凝土柱水平荷载P-水平位移Δ关系曲线的参数进行分析,结果表明:加载角为0°时,T形钢管混凝土构件的承载力最低,在67.5°负向加载时,构件的承载力最大,比0°加载角构件大13%左右,加载角为45°~90°间承载力总体上差别不大。随着钢管屈服强度、混凝土抗压强度、钢管长厚比、带肋和多室T形钢管混凝土构件在斜向加载的承载力增加,在传统钢管混凝土基础上,提出了适用于不同加载角带肋和多室T形钢管混凝土压弯构件的承载力设计方法,简化计算公式与有限元结果、试验结果均吻合较好。     

Numerical analysis of dynamic behavior of RC slabs under blast loading

In Order to reduce economic and life losses due to terrorism or accidental explosion threats,reinforced concrete(RC)slabs of buildings need to be designed or retrofitted to resist blast loading.In this paper the dynamic behavior Of RC slabs under blast loading and its influencing factors are studied.The numerical model of an RC slab subjected to blast loading is established using the explicit dynamic analysis software.Both the strain rate effect and the damage accumulation are taken into account in the material model.The dynamic responses of the RC slab subiected to blast loading are analyzed,and the influence of concrete strength,thickness and reinforcement ratio on the behavior of the RC slab under blast loading iS numerically investigated.Based on the numerical results.some principles for blast-resistant design and retrofitting are proposed to improve the behavior of the RC slab subjected to blast loading.     

AZ91D变形镁合金板温热拉伸性能研究

在应变速率为10-3～10-1S-1、温度为150℃～400℃的条件下,在万能试验机上对AZ91D镁合金板材进行了在线加热拉伸试验,获得了各成形条件下0°、45°、90°三个方向的应力应变曲线。试验结果表明,当拉伸温度增加或拉伸速率降低时,板料的屈服强度和抗拉强度降低,而其塑性变形能力提高;板材具有明显的各向异性,45°方向塑性变形能力最高,90°方向时最低。     

如何确定带式输送机传动装置的合理布局方案

在带式输送机传动装置中,V带对一级直齿圆柱齿轮减速器主动轴拉力方向不同,则主动轴的抗弯刚度和抗弯扭强度不一样。合理的布局方案应该使V带对主动轴的拉力方向有利于减少主动轴的总弯曲变形以提高它的抗弯刚度,有利于减少主动轴在水平面上的弯矩以提高它的抗弯扭强度。     

Test and Analysis of an Existing Tunnel Vibration Induced by Blasting Construction of Diaphragm Wall

According to the blasting construction of the diaphragm wall of Puxi approaching section of East Fuxing Road river-crossing tunnel,the monitoring project of the vibration of the existing tunnel induced by the blasting construction is put forward,which includes the sensors' location,monitor method and the vibration monitoring system.Based on the monitoring data of the explosion vibration,the vibration wave forms,velocities,acceleration responses,main frequencies and fields of measure points are analyzed under the conditions of three locations and different charge quantities.According to the safety-judging standard of explosion vibration,the conclusion that the existing tunnel is safe under the explosion vibration is then drawn.Furthermore,the spectrum characteristics of three explosion vibrations and the spectrum changing properties of explosion vibration wave transmitting in different directions are concluded,which can provide reference to similar projects.     

模拟高原水下爆炸特征参数的实验研究

高原地区进行的水下爆破工程,因水体表面气压随海拔的升高而线性降低,其装药爆炸后的特征参数是否发生变化,对爆破施工有重要意义;采用密闭的高压爆炸容器,模拟高原气压条件,对雷管水下爆炸参数进行了实验研究,研究结果表明：在海拔0---4500m范围内随着气压降低,冲击波峰值压力大小与气压无关。冲击波衰减时间却有一定增长,导致比冲击波能微小增大;气泡脉动周期按二阶多项式规律显著增大,仍由于气压随海拔升高丽变小,装药深度处的总静水压力随之降低,使比气泡能微量减小,而爆炸总能量基本不变。     

太阳双带耀斑的分离运动与纵向磁场的关系

文章通过一个典型的太阳双带耀斑事件（2001年4月10日,NOAAAPt9415）研究耀斑带分离速度和纵向磁场强度的关系。这个耀斑事件具有很清晰的双带结构而且沿耀斑带的磁场变化很大,有利于研究耀斑带的分离速度和磁场分布的关系。结果表明：耀斑带的分离速度负相关于纵向磁场,而且这种负相关在耀斑峰值的时候最弱。     

椭圆截面容器的应力计算及分析

该文利用无限长和有限长容器模型,对椭圆截面容器的应力进行了理论分析,并与实验结果进行对比,得出了有限长椭圆截面容器的应力分布规律,找出了危险截面的位置,对实践中椭圆截面容器的设计提出了一些建议。     

Assessment of Containment Structures Against Missile Impact Threats

In order to ensure the highest safety requirements, nuclear power plant structures (the containment structures, the fuel storages and transportation systems) should be assessed against all possible internal and external impact threats. The internal impact threats include kinetic missiles generated by the failure of high pressure vessels and pipes, the failure of high speed rotating machineries and accidental drops. The external impact threats may come from airborne missiles, aircraft impact, explosion blast and fragments. The impact effects of these threats on concrete and steel structures in a nuclear power plant are discussed. Methods and procedures for the impact assessment of nuclear power plants are introduced. Recent studies on penetration and perforation mechanics as well as progresses on dynamic properties of concrete-like materials are presented to increase the understanding of the impact effects on concrete containment structures.     

定西市城区居民饮用水硬度分析

水是人类赖以生存的重要条件,也是人体的重要组成部分,因此饮用水的硬度与人体的健康关系极为密切.水的硬度是指溶解在水中的盐类物质的含量,即钙盐与镁盐含量的多少,它是表示水质的一个重要指标.钙、镁离子的质量总和相当于10mgCaO或7.19mgMgO称之为1"度(°)".8度(°)以下为软水,8~16度(°)为中水,16度(°)以上为硬水,30度(°)以上为极硬水.硬度又可分为暂时性硬度和永久性硬度,暂时性和永久性硬度之和称为总硬度.本工作采用EDTA法对定西市城区居民饮用水的硬度进行了测定分析.经测定,定西市城区居民饮用水的总硬度为10.40度,永久硬度为7.00度(°),暂时硬度为3.40度(°).按照水的硬度标准(钙、镁离子的质量总和相当于10mgCaO称之为1"度(°)")划分,定西市城区居民饮用水属于中硬水.     

高校涉爆实验室及爆炸物品安全管理

高校涉爆实验室是开展工程爆破理论与技术、爆炸物品性能及新型爆炸物品研究开发与实验教学的必备场所。这类实验室的安全管理对高校甚至当地社会安全和稳定都是非常重要的。2006年开始实施的新《民用爆炸物品安全管理条例》没有对高校涉爆实验室及爆炸物品安全管理作出具体规定。根据其精神,探讨高校涉爆实验室及爆炸物品的安全管理问题,具有一定的参考作用。     

高耸构筑物定向爆破切口长度理论分析

爆破拆除高耸构筑物时,爆破切口长度的合理选取是爆破成功的关键.针对爆破拆除高耸构筑物安全事故时有发生的实际情况,建立了高耸构筑物定向倒塌的数学—力学模型,推导了爆破切口长度计算公式,并计入被炸裸露钢筋的支撑力.     

竞技武术套路侧空翻转体360°腾空阶段动作分析

对陕西省武术队和西安体育学院院队现役竞技武术套路优秀运动员的B级跳跃难度动作侧空翻转体360°进行三维高速摄影,在西安体育学院实验中心用美国艾里尔三维运动图像解析系统对所截取图像进行解析,研究表明：腾空瞬间到腾空最高点,男子运动员重心高度变化的相对值为27.48±4.99%,女子运动员重心高度变化的相对值为23.55±2.90%;运动员身体腾空侧翻过垂直面瞬间,所有受试运动员在空中都有屈膝、屈髋、分腿的动作,尤其是过垂直面时身体与地面远远不足垂直角度。男子运动员左右腿的夹角为29.93±14.48°,女子运动员左右腿的夹角为4.96±3.91°。男子运动员躯干倾角为54.09±10.93°,女子运动员躯干倾角为49.65±1.89°运动员身体腾空侧翻过垂直面后,左、右腿通过屈髋等姿势调整,提高了身体的侧翻速度。     

Simulation methodology development for rotating blade containment analysis

An experimental and numerical investigation on the aeroengine blade/case containment analysis is presented. Blade out containment capability analysis is an essential step in the new aeroengine design, but containment tests are time-consuming and incur significant costs; thus, developing a short-period and low-cost numerical method is warranted. Using explicit nonlinear dynamic finite element analysis software, the present study numerically investigated the high-speed impact process for simulated blade containment tests which were carried out on high-speed spin testing facility. A number of simulations were conducted using finite element models with different mesh sizes and different values of both the contact penalty factor and the friction coefficient. Detailed comparisons between the experimental and numerical results reveal that the mesh size and the friction coefficient have a considerable impact on the results produced. It is shown that a finer mesh will predict lower containment capability of the case, which is closer to the test data. A larger value of the friction coefficient also predicts lower containment capability. However, the contact penalty factor has little effect on the simulation results if it is large enough to avoid false penetration.