老旧电梯制动器风险辨识与评价方法研究

为降低老旧电梯制动器运行风险,从老旧电梯制动器故障形式及原因分析出发,辨识老旧电梯制动器的机械、电气危险状态,建立老旧电梯制动器风险辨识指标体系·运用PHA-FMEA方法对老旧电梯制动危险状态进行了风险分析与评定,并根据指标特征与风险叠加原理构建制动器的风险评价模型。通过案例评估,划定老旧电梯制动器整体风险等级,并突出了制动器风险评价指标危险等级的影响,避免了关键状态指标在多指标体系中的湮没问题.     

电梯安全级别模糊综合评价方法及应用探究

本文对电梯安全级别模糊评价方法以及应用展开论述。综合评估电梯的安全级别,是降低事故风险概率的前提。采用该方法是从环境、管理、人员使用、机械运行等多角度对电梯进行多层次的安全指标评估,使用到包括区间估计分析和特征向量法等在内的权重计算方法,并从中筛选指标。模糊综合评价方法将数据进行随机和模糊的向量分值量化,综合分为5种安全级别,经过在电梯安全评估实际应用,得出的安全综合评价结合基本与实际情况吻合。     

基于风险评价的老旧电梯安全检测评价技术研究

运用GB/T 20900-2007规定的风险评价方法对老旧电梯可能存在的危险进行风险评价,将风险评价确定的主要风险转换成安全检查表的检查项目和内容,使老旧电梯的风险评价过程转变为安全检查表的对照检查过程.用该方法对1300多台老旧住宅电梯实施了安全检测评价,取得了很好的实用效果.     

福州市老旧电梯评估缺陷情况分析

介绍了福州市老旧电梯基本情况。通过对福州市老旧电梯安全性能评估,对评估结论及缺陷进行统计分析研究,以此提出老旧电梯安全监管的对策与措施,为老旧电梯监管提供数据支撑。     

老旧电梯安全评估方案及隐患对策研究

老旧电梯的安全评估是关乎生活质量的问题,电梯的监管及维护甚至大修也是热点问题,其安全问题也越来越受到关注。本文在分析电梯复杂的电气、机械系统的基础上,阐述了老旧电梯安全评估方案和具体实施方案,针对老旧电梯的评估和安全隐患提出了一些对策意见。     

基于层次分析法的老旧电梯安全评估方法

针对老旧电梯,采用层次分析原理的加权计算进行安全评估。首先建立了一种电梯评估模型,利用层次分析法来求得电梯各层次系统的权重,再对电梯整机系统进行加权计算,最后评估出电梯安全级别。为当前需迫切实施的老旧电梯评估提供了一种操作性较强的方法。     

老旧电梯安全风险评估与在线监测技术研究

基于电梯多层综合评价模型的综合评估,提出以数据库的方式集合电梯系统的参数、安全要求、缺陷严重程度和风险降低措施等信息,用数学语言对失效概率和严重程度后果进行描述和运算,以多层综合评价数学模型统计的方法为准则,实现电梯系统的综合安全评估。针对老旧电梯故障率与使用风险较高的问题,提出了基于物联网技术的故障实时监测与报警的安全监管对策。     

老旧电梯安全评估方法研究

针对老旧电梯日益凸显的安全问题,提出了基于电梯零部件的故障分析,采用层次分析法建立老旧电梯安全评估模型,实现了对电梯复杂系统的标准化、体系化、定量化的安全评估。建立安全评估指标体系不仅能够对电梯进行科学合理的安全评估,而且对现有的法规标准有一定的补充和完善意义。     

基于数据统计的老旧电梯安全评估分析

老旧电梯安全评估是综合判定老旧电梯安全状态的有效方法。本文通过数据统计分析影响老旧电梯运行安全的风险项,根据风险项产生的原因提出切实有效的工作建议,使老旧电梯的安全使用得到更好的保障。     

层次灰色理论在老旧电梯综合评价中的应用

将灰色系统理论应用到老旧电梯的整体评价中,结合电梯多层次的结构特点,建立了层次灰色评价模型。该模型充分利用专家经验和各个零部件的基础数据,将评价结果按等级进行划分,提供了一个计算简单、可行的综合评价方法,并为老旧电梯的安全管理提供参考依据。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.     

5083H111轧制铝合金的低周疲劳行为

在室温下对5083H111轧制铝合金板三个典型方向——轧制方向(RD方向)、与轧制方向成45°角方向(MD方向)、垂直于轧制方向(TD方向)的试样进行了单轴对称应变控制的低调疲劳试验,研究了不同方向试样的循环变形行为和疲劳寿命差异。结果表明:铝合金板在三个方向上都表现出了明显的循环硬化特性,即在恒定的应变幅下,三个方向的响应应力幅均随着循环次数的增加而增大,并且外加应变幅越大,响应应力幅也越大;三个方向的低周疲劳ε-Nf曲线差别不明显;三参数幂函数寿命模型可以很好地预测5083H111铝合金的低周疲劳寿命。