某球形雷体结构的毁伤特性数值研究

为合理设计反水雷武器的尺寸及重量、提高作战效率,对某球形雷体结构的毁伤特性数值进行研究。运用LS-DYNA软件开展水下静爆仿真,采用3维模型求解;分析裸药柱与某球形雷的作用距离、裸药柱装药量对雷体壳体毁伤的影响特性。结果表明：当裸药柱外端面与雷体壳体外缘的距离从210 mm增加到400 mm时,壳体变形量从3.9%降低到2.2%;裸药柱装药量从0.5 kg增加至2.5 kg,壳体变形量从0.58%降到3.4%;增大裸药柱装药量更能使雷体壳体结构加大塑性变形;确定造成雷体壳体毁伤的临界装药量为3 kg,临界距离为20 mm。     

浅析伺服液位计在乙烯丙烯球罐的应用

本文以E+H公司生产的NMS 5型伺服液位计为例,介绍了伺服液位计的工作原理、特点及故障处理方法。对伺服液位计在乙烯丙烯球罐维护过程中所出现的故障和发现的问题进行了详细阐述,提出了储存乙烯丙烯球罐使用伺服液位计在安装、选型和维护过程中的注意事项,通过在乙烯丙烯球罐应用实践,证明伺服液位计的稳定性和可靠性。     

基于节理产状不确定性的边坡稳定性及敏感度分析

用Monte Carlo法对服从Fisher分布的节理产状进行模拟,计算每个模拟产状的安全系数,并统计拟合安全系数的分布规律及边坡的可靠度。为同时考虑安全系数对节理倾角和倾向的敏感度,提出了以安全系数对节理面法向矢量球面距离的敏感度来反映其对产状敏感度的分析方法,并建议用平均值和最大值两个指标来反映任意产状的敏感度。用赤平投影方法在赤平图上绘制安全系数等值线图和敏感度等值线图,实现了计算结果的可视化展示。算例分析表明：此方法实现了对节理产状不确定性的全面直观分析,消除了产状测量数据离散化可能造成的安全隐患,解决了以往产状敏感度分析中需单独对倾角或倾向分析的不足。     

单层球壳模型结构振动台试验研究

通过对单层球壳结构模型的振动台试验,分析了结构在地震作用下的破坏模式。为使模型呈现不同的倒塌模式,设计了3个缩尺比为1/10的试验模型：模型1与模型3以期发生承载力破坏倒塌模式;模型2设置6个薄弱区,以期发生动力失稳。采用多次加载方案,水平向输入地震波,逐级提高峰值加速度,完成振动台试验。采用基线调整法对原始试验数据进行校正;采用有限元软件ANSYS中的大质量法对试验模型进行考虑双非线性的多点输入时程分析,获得结构动力响应;采用自编程序对模型结构进行有限元塑性分析。结果表明：试验模型的倒塌模式与试验预期结果吻合良好,验证了振动台试验的完备性;有限元分析结果与实测结果吻合较好,验证了数值计算方法的正确性。     

基于遗传-模拟退火算法的单层球面网壳结构破坏模式优化

将遗传算法和模拟退火算法相结合,以遗传算法作为基础,将模拟退火机制融入其中,提出遗传-模拟退火算法(GASA)。通过三个经典函数最小值求解,表明混合算法在优化行为、优化效率及稳定性方面均具有明显优势。以构件截面为优化变量,应用构形易损性理论,以结构集簇过程中自由簇构形度Q标准差最小为优化目标,建立单层球面网壳结构倒塌破坏模式优化模型。以一个原型跨度75m、相似比1∶10的单层球壳振动台试验模型为例,采用GASA算法对此试验模型进行倒塌模式优化分析,通过优化前后自由簇构形度变化规律和加速度时程分析结果的对比,表明提出的优化方法及优化模型能够实现单层球面网壳在地震作用下的倒塌模式从无征兆的动力失稳破坏转化为承载力强度破坏。     

向心关节轴承撑杆上节点试验研究及有限元分析

将向心关节轴承引入弦支穹顶结构的索杆体系,作为撑杆上节点的刚性转动核心,形成了向心关节轴承撑杆上节点。对该节点进行轴向加载试验,得到其承载力以及全过程应力发展情况。试验结果表明,即使在节点耳板屈服后,刚性转动核心转动性能仍然良好,能够保证该节点在轴压作用下仍然具有较好的转动能力。采用ANSYS软件对该节点试验进行了考虑接触的非线性有限元分析,得到各部件应力状态,补充节点试验数据。试验和数值分析结果表明,该类型节点力学性能良好。最后根据分析结果提出了铰节点刚性转动核心的概念,并给出了该类型撑杆上节点承载力及转动能力的建议设计计算式。     

球面棱锥式玻璃幕墙设计与施工技术

广州亚运工程之一——广州从化温泉养生谷流溪广场景观工程首次应用了球面棱锥式玻璃幕墙结构.结合工程实际,从设计理念、幕墙造型、节点设计和幕墙安装等方面,全面分析了球面棱锥式玻璃幕墙在设计和施工中的创新点和技术难点.三维活动节点使球面棱锥式玻璃幕墙具有三维变形的特点,使球面棱锥式玻璃幕墙变形和球面网壳主体结构变形相协调,有效消除了主体结构变形引起的附加内力和变形,使幕墙结构处在简单的受力状态,延长了玻璃幕墙使用寿命和防水维修周期.     

An artificial neural network model for the prediction of critical submergence for intake in a stratified fluid medium

Density differences may occur because of temperature differentials, suspended sediments, dissolved salts or other chemicals. Most of the large surface reservoirs are stably stratified throughout most, or all, of the year. One of the means of assisting the management is to allow a selective withdrawal from the reservoir. And while an intake is used for withdrawal (from the lower layer), a maximum discharge is required not allowing the uptake of the upper layer fluids. The value of the intake's vertical distance from the upper layer elevation (submergence) when the upper layer fluids begin to be drawn into the intake is known as ‘critical submergence’. In this study, the critical submergence for a circular intake pipe in a stratified body (which has different layer thickness) is investigated. Experiments were conducted on a vertically flowing downward intake pipe in a still-water reservoir. Artificial neural network (ANN) models and formulas, which are found by the theoretical analysis of critical spherical sink surface (CSSS), are used for the analysis of experimental results. The CSSS has the same centre and discharge as the intake. The ANN model and CSSS results are compared with the experimental results.     

Mechanics unloading analysis and experimentation of a new type of parallel biomimetic shoulder complex

The structure design for high ratio of carrying capacity to deadweight is one of the challenges for the bionic mechanism, while the problem concerning high carrying capacity has not yet be solved for the existing shoulder complex. A new type biomimetic shoulder complex, which adopts 3-PSS/S(P for prismatic pair, S for spherical pair) spherical parallel mechanism (SPM), is proposed. The static equilibrium equations of each component are established by using the vector method and the equations for constrain forces with certain load are solved. Then the constrain force on the middle limb and that on the side limbs are compared in order to verify the unloading performance of the mechanism. In addition, the prototype mechanism of the shoulder complex is developed, and the force feedback experiment is conducted to verify the static analysis, which indicates that the middle limb suffers most of the external force and the effect of mechanics unloading is achieved. The 3-PSS/S spherical parallel mechanism is presented for the shoulder complex, and the realization of mechanics unloading is benefit for the improvement of the carrying capacity of the shoulder complex.     

基于SolidWorks的直齿锥齿轮三维建模方法

从直齿锥齿轮齿面形成原理出发,研究了直齿锥齿轮大小端齿廓的数字化建模方法,提出一种基于Solid Works三维模型建立方法——边界曲面法。基于Solid Works中相应的功能,生成直齿锥齿轮一个齿不同侧的大小端球面渐开线,通过与大小端齿顶处所在圆锥截面圆弧剪裁得到大小端齿形,然后通过边界曲面功能形成一个齿并转换成实体,最后通过圆周阵列形成最终的直齿锥齿轮,实现直齿锥齿轮的三维精确建模。