中小跨径梁桥地震易损性研究

为对桥梁系统地震易损性进行准确评估,结合Copula函数技术,提出基于串-并联组合体系的桥梁系统易损性分析方法。桥墩是桥梁抗震中的控制构件且较难修复,采用串联体系将多个桥墩进行组合,对于修复难度较低的桥台及支座构件,采用并联体系进行模拟。在此基础上,将桥墩、桥台及支座三类构件体系进行串联,构成桥梁系统的串-并联组合体系。以三跨连续箱梁桥为例,阐明了基于串-并联体系的桥梁系统易损性分析方法,并将分析结果与基于串联体系的桥梁系统易损性进行对比。结果表明:对于中小跨径的连续梁桥,基于单一串联体系会明显高估桥梁系统的易损性,相对于串-并联体系,在轻微、中等、严重及完全四种破坏状态下,其中位值偏差在纵桥向分别为22.2%、20.7%、20.5%及24.6%;在横桥向分别为30.0%、16.1%、9.8%及11.3%,基于串-并联组合体系建立桥梁系统地震易损性更切实合理。     

多源不确定性条件下气动弹性系统颤振可靠性分析方法

传统的气动弹性系统颤振分析模型大多是在确定性参数条件下建立的,当系统中存在不确定因素时,按确定性方法设计的气动弹性系统存在颤振失效风险.以概率和非概率区间模型为基础,建立了单源不确定性条件下颤振可靠性分析模型;在此基础上,针对含随机和区间多源不确定参数的气动弹性系统颤振可靠性分析问题,提出一种基于分步求解策略的新型混合...     

基于可视化的事故树分析系统研究与开发

事故树分析是安全系统工程最重要的分析方法之一，它能对各种系统的危险性进行辨识和评价，不仅能分析出事故的直接原因，而且能深入地揭示出事故的潜在原因。用它描述事故的因果关系直观、明了，思路清晰，逻辑性强，既可定性分析，又可定量分析。基于可视化理论和技术，建立了事故树可视化模型，确定了系统功能目标，完成了系统结构设计，构造了事故树图形生成与事故树动态分析于一体的集成分析环境，开发出事故树计算机分析系统，为事故分析和安全评价提供高效、准确的技术和方法。     

Reliability Analysis Method on Repairable System with Standby Structure Based on Goal Oriented Methodology

This paper presents a reliability analysis method on repairable system with standby structure based on goal oriented (GO) methodology. Firstly, a new combination of GO operator, which is composed of a new logical GO operator named Type 18A operator and a new auxiliary GO operator named Type 20 operator, is created to represent standby mode. The availability formula of standby equipment with translation exception is deduced based on Markov process theory. Then, the application method of combination of GO operator for standby mode and the analysis process of repairable system with standby structure based on GO method are proposed. Thirdly, this new combination of GO operator is applied in availability analysis of the hydraulic oil supply system of power‐shift steering transmission. Finally, the results obtained by the new GO method are compared with the results of fault tree analysis, Monte Carlo simulation, GO methods using Type 2 operator and Type 18 operator to represent the standby mode, respectively. And the comparison results show that this new GO method is applicable and reasonable for reliability analysis of repairable system with standby structure. All in all, this paper provides guidance for reliability analysis of repairable systems with standby structure. Copyright © 2015 John Wiley & Sons, Ltd.     

Assembly system design principles and tradeoffs

This paper develops an analytical model to evaluate serial and parallel designs for an assembly system. The purpose is to identify when each design is cost-effective, using minimal data. The analysis shows that the design alternatives are based on a trade-off between labour and equipment utilization. Equations are derived for a simple system to illustrate this trade-off. Results indicate that the optimal trade-off depends simply on the ratio of labour to equipment costs. The trade-off analysis provides a first step towards establishing basic principles for assembly system design.     

地震作用下隧道-列车系统动力响应及安全性分析

针对土体-隧道-列车动力相互作用的特点,建立地震作用下隧道-列车系统的三维有限元模型,运用基于接触负载均衡的显式并行计算方法求解计算。研究了地震作用下隧道-列车系统的动力响应,并对地铁列车运行安全性进行了评价,分析了行车速度及地震强度对地铁运行安全性的影响。数值分析结果表明:地震作用对隧道-列车系统动力响应影响显著,地震作用使系统动力响应明显增大,并使地铁运行安全性及平稳性大大降低;列车动载荷对地震作用下的隧道系统动力响应影响较小;无震工况下,地铁运行安全指标对车速变化并不敏感;地震工况下,随着地震强度的增大,车速对地铁运行安全性的影响逐渐增大。     

投影机镜头的MTF实时检测系统

目前还没有标准的方法来检测投影机镜头的MTF,为此我们提出了一种基于图像分析的投影机镜头MTF实时测试系统.本系统使用CCD作为成像接收器,采用基于图像分析的方法,通过分析单个像素成像同时获得投影镜头子午和弧矢两个方向上的调制传递函数(MTF).阐述了整个测试系统的构造及理论框架,着重分析了系统参数标定的重要性以及如何正确地进行系统参数标定;全面分析了影响测试结果的因素以及如何正确快速地修正噪声的影响.检测了质量合格与质量不合格的投影机镜头,并将结果同设计值的进行比较,实验结果表明了本系统及其处理方法的有效性.     

基于cv-FDM法的铸件凝固过程热应力数值模拟

为了实现铸件凝固过程多物理场的无缝耦合数值模拟,开展基于有限差分法的铸件凝固过程热应力分析.建立了热弹塑性的三维控制体积有限差分(cv-FDM)算法,开发了相应的铸件凝固过程热应力分析三维仿真软件.将该软件应用于典型的应力框试件和轧钢机机架铸件,计算得到了铸件凝固过程产生的应力和位移,并将结果与采用有限元分析软件ANSYS的计算结果进行了对比验证,吻合较好,表明模拟结果基于cv-FDM的铸件热应力分析达到了有限元法的精度水平.     

多齿轮耦合复杂转子系统的振动特性分析

本文探讨了多对齿轮耦合对齿轮转子系统动力学特性的影响程度,以压缩机转子系统为例,对整个耦合系统进行了安全校核。首先,基于有限元法,建立了通用的弯—扭—轴—摆斜齿轮耦合动力学分析模型,此模型中考虑了啮合刚度、方位角、啮合角、螺旋角以及主动轴转动方向对齿轮啮合刚度矩阵的影响;接着,对系统进行了固有特性分析,得到了系统的临界转速和安全裕度表;然后,基于模态叠加法,对系统进行了不平衡响应分析,对比了考虑齿轮啮合前后系统各位置处的不平衡响应变化曲线。研究结果表明,对于多对齿轮啮合的系统,齿轮间的耦合使系统之间的振动强烈,必须考虑齿轮耦合的影响,并且要结合固有特性以及瞬态响应分析来判断临界转速和振动峰值的大小。     

基于GIS的潮流场POM模式计算分析系统

为实现潮流场计算与基于GIS的分析的整体集成,提出了基于GIS的潮流场计算分析系统的总体框架结构,设计了潮流场计算模块、基于GIS的空间分析模块、用户端接口模块与数据库的组织,建立了一个具有基本应用功能的集成系统.选取南海为例进行了潮流计算和基于GIS的结果分析,分析结果验证了该系统的有效性.     

主动转动惯量驱动系统用于悬吊结构摆振控制的方法研究（Ⅰ）：理论建模和试验验证

提出了主动转动惯量驱动控制系统(Active Rotary Inertia Driver,ARID),该系统通过伺服电机驱动转动惯性质量的回转运动,从而产生抑制结构摆振的力矩。首先针对ARID控制系统,基于拉格朗日原理建立了平面内悬吊结构在吊点激励下运动控制的分析模型,基于分析模型进行主动控制LQR算法系统匹配推导,然后利用Simulink对ARID系统控制效果进行了数值模拟计算,并通过与TRID装置对比,对ARID系统的有效性进行了分析。最后设计了ARID振动台试验系统,对结构的控制效果进行了试验验证。试验结果验证了理论建模和主动控制LQR算法与系统匹配的合理性,表明ARID系统对悬吊结构摆振控制具有很好的控制作用,理论建模和试验验证为ARID系统的深入研究和应用奠定了理论基础。     

FASEA: A FPGA Acquisition System and Software Event Analysis for liquid scintillation counting

The FASEA (FPGA based Acquisition and Software Event Analysis) system has been developed to replace the MAC3 for coincidence pulse processing. The system uses a National Instruments Virtex 5 FPGA card (PXI-7842R) for data acquisition and a purpose developed data analysis software for data analysis. Initial comparisons to the MAC3 unit are included based on measurements of ⁸⁹Sr and ³H, confirming that the system is able to accurately emulate the behaviour of the MAC3 unit.     

Approximate analysis of a conveyor system

An approximate method for the performance analysis of a particular flexible manufacturing system with unreliable machines and a circular conveyor consisting of a fixed number of cells is presented. Workpieces are transported among the machines on the conveyor. We assume that the time to failure and the time to repair are exponentially distributed. Our analysis is based on the service completion time of the workstations, which leads us to find the system time. We have developed a decomposition method that analyses each workstation in isolation. The performance measures of our interest include the mean system time, the mean number of workpieces in the system, the probability that a cell is occupied by a workpiece and the conveyor's throughput. Experimental results show that the approximate method is highly accurate.     

Reliability assessment of passive isolation condenser system of AHWR using APSRA methodology

In this paper, a methodology known as APSRA (Assessment of Passive System ReliAbility) is used for evaluation of reliability of passive isolation condenser system of the Indian Advanced Heavy Water Reactor (AHWR). As per the APSRA methodology, the passive system reliability evaluation is based on the failure probability of the system to perform the design basis function. The methodology first determines the operational characteristics of the system and the failure conditions based on a predetermined failure criterion. The parameters that could degrade the system performance are identified and considered for analysis. Different modes of failure and their cause are identified. The failure surface is predicted using a best estimate code considering deviations of the operating parameters from their nominal states, which affect the isolation condenser system performance. Once the failure surface of the system is predicted, the causes of failure are examined through root diagnosis, which occur mainly due to failure of mechanical components. Reliability of the system is evaluated through a classical PSA treatment based on the failure probability of the components using generic data.     

基于DSP的紫外/红外复合告警系统的伺服设计

紫外告警虚警率和精度都较低,而红外告警则相反．基于此,提出一种将紫外告警与红外跟踪相结合的全新的告警/跟踪一体模式,并进行基于TMS320F2812的伺服系统设计．依据设计要求和实际机械结构参数建立了伺服控制模型,并对模型进行软硬件设计．最后对伺服系统进行基于Matlab软件的伺服控制仿真,并在仿真环境试验型样机上进行相关的实验验证,得到与设计要求基本符合的结果,为系统的实际装校提供了依据．通过对仿真结果的分析处理,得到了系统可行性结论．该控制系统可应用于其他光电伺服平台．     

A real-time system for power quality testing

This paper presents a real-time system that can be used for quick and reliable power quality testing. The system is based on a dual-processor architecture with a digital signal processor (DSP) interfaced to a personal computer (PC). Real-time tasks are delegated to run on the optimized hardware of the DSP board, while system-level requirements are handled by the PC. The real-time processing (RTP) kernel implemented on the DSP supports multitasking to handle tasks associated with data collection, data analysis, and interprocessor communication. The results of real-time analysis are presented in the PC through a menu-driven, graphical interface. Tests show that the system complies with IEC standards for power quality monitoring. This system offers many significant advantages. Real-time analysis of acquired data significantly reduces storage requirements. Data analysis algorithms can be modified to suit specific testing needs. Test results available in the PC can be exported to other computer analysis tools. The system is portable and holds promise as a powerful, low-cost tool for practising power quality engineers     

家庭远程医疗监护报警和咨询智能系统

介绍了家庭远程医疗监护和咨询智能系统，它综合运用数据融合、数据挖掘、小波分析、模式识别、人工智能等技术，能自动进行监护数据分析和异常情况识别及网络报警、远程实时诊断。给出了系统的硬件组成框图，家庭端软件结构组成框图、医疗监护中心端软件结构组成框图，介绍了系统的部分关键技术，基于小波变换的心电信号分析，结合数据挖掘和机器学习的自动建模方法，基于数据融合和识别推理的病人异常情况识别。该系统在微机Windows平台采用VC 实现，经仿真实验取得了满意的结果。     

Power Pinch Analysis supply side management: strategy on purchasing and selling of electricity

Pinch analysis concept has been recently stepped into the realm of design and optimisation of power systems. One well-established pinch analysis that has been used in power systems design and optimisation is called Power Pinch Analysis (PoPA). In PoPA, both graphical and numerical approaches have provided an insight on the systematic approach to target and design various power systems. By only visualising the minimum amount of outsource energy required by the power system, the graphical PoPA method as a whole does not show the purchasing of outsource energy based on the exact time intervals. Using graphical PoPA, the objective of this study is to determine a proper strategy to buy and sell outsource electricity to improve the overall performance of a hybrid power system comprising renewable power generators and energy storage system. The strategies are made based on three design parameters: energy-related capacity, power-related capacity of energy storage and maximum grid power rating between centralised grid and hybrid power system. While deciding on the best strategy and heuristics to be implemented, the effects on system operation and economy are indirectly analysed. It is experimented that the output can benefit electricity consumers or producers.     

刹车系统的摩擦自激振动和控制

研究刹车系统的摩擦自激振动和控制问题。采用LuGre 模型计算摩擦力,建立了两自由度盘式刹车系统的动力学模型。通过平衡点的稳定性分析,给出Hopf 分岔失稳的临界速度。应用基于微分几何法和线性二次型最优控制相结合的方法,设计单输入单输出的非线性系统控制器,以便通过推迟系统的分岔临界速度,减少减速型刹车过程中的摩擦颤振,避免刹车啸叫。最后分析了控制器和系统参数对控制效果的影响。仿真表明,该控制器能有效的抑制刹车系统中的摩擦自激振动。     

基于Web技术的IP网络性能测量系统的研究与实现

在分析了网络性能测量系统的功能和层次结构的基础上,设计并实现了一个利用Web技术测量IP网络性能的系统。系统基于分布式B／S架构,有效地简化了部署并增强了移植性,降低了开发和维护的成本。在模拟网络环境中的试验结果显示,系统测量结果准确可靠,测量速度快,代价低。