Cavitation damage incubation with typical fluids applied to a scroll expander system

During the operation of a scroll expander system overpressure may occur resulting in cavitation damage. Impacts due to implosion of cavitation bubbles near to suction ports can result in damage to the scroll plate in the expander. The accumulation of cavitation pits across the scroll plate leads to cavitation erosion hence efficiency drop. An experimental analysis to identify the mechanical damage of the cavitation on various steel surfaces with different liquid environments was conducted.Three liquid environments and four steel grades were utilised experimentally. The liquids used for the tests were distilled water, used as a reference liquid, and the two working fluids of the scroll expander a synthetic lubricant and a high molecular refrigerant. The steel grades were a high carbon (AISI 1085) and low carbon (AISI 1010) martensitic steel with retained austenite, a chromium martensitic steel (AISI 52100) and a martensitic scroll plate (SP) sample. An ultrasonic transducer was utilised to produce cavitation conditions using a 5 mm diameter probe. The comparison of the results revealed the most hostile liquid environment according to the morphology evaluation of the incubation pits. The cavitation mechanisms are discussed and the cavitation resistance of the steel grades is evaluated. The best performing steel material against cavitation is determined for the conditions described.     

几种数据协调方法在浆纸平衡系统中的应用

若信息管理系统直接利用带误差的现场数据,将造成管理失误和决策偏差。因此,必须根据浆平衡,对各类浆池与纸机的原始数据进行过失误差处理和数据协调计算。该文比较了浆纸平衡模型中,不确定模型的数据协调法,基于统计检验的协调法及用Matlab优化工具协调的应用结果,其中不确定模型的数据协调方法具有良好的适应性及数据协调能力。     

应用于门禁通道系统的红外线算法

为了完善目前国内的门禁通道系统,加强门禁系统对人的监控作用,研究了如何在传统的基于无线射频识别（RFID）技术的门禁通道系统中应用红外线技术,分析了红外线识别的基本原理,提出了一种能准确判断人通过的红外算法,并已成功地将该红外算法应用于红外通道系统中。研究结果表明,该算法具有判断准确、响应速度快等优点,并且能与传统的只利用RFID技术的读卡式通道系统完美结合。     

传递横向载荷的螺栓联接系统强度可靠性设计

对传递横向载荷的螺栓联接系统的失效模式作了详细分析。并根据载荷均分、k/ n表决系统力学模型作了有关分析计算 ,为该系统的强度可靠性设计作了初步探讨     

Screw system algebra applied to special linkage configurations

Much has been published on special positions of planar linkages, as a prelude to synthesis. There have also appeared several papers on stationary configurations of spatial linkages, and a variety of techniques is available for isolating them. One of the methods employs screw system algebra, which is demonstrably a direct and wide-ranging technique for kinematic analysis of spatial chains. It is shown here that the theory may be applied with equal ease in determining the conditions for uncertainty configurations to be reached in 3-dimensional loops.     

An adaptive optimization system applied to machine synthesis

The paper presents the foundations of an optimization system for medium size computers. The system may be used to solve technical or economic problems with nonlinear objective functions and constraints. The system contains five algorithms of the deterministic and stochastic category. The master algorithm, based on works of Bush and Mosteller, randomly seeks one of these five. It performs computations for a certain time and examines its effectiveness. This experience is then taken as the basis for modification of the probability vector used in the choice of algorithm.The technical examples solved by different algorithms are presented. The results needed for definition of the initial vector illustrate difficulties met by an engineer in the proper choice of algorithm. These difficulties, which occur often in practical cases, prove the demand for further studies on optimization systems.     

Cohesive and continuum damage models applied to fracture characterization of bonded joints

In this work, two different methods for simulating damage propagation are presented and applied to fracture characterization of bonded joints in pure modes I and II. The cohesive damage model is based on a special developed interface finite element including a linear softening damage process. In the continuum damage model the softening process is performed by including a characteristic length associated with a given Gauss point. The models were applied to the simulation of “double cantilever beam” (DCB) and “end notched flexure” (ENF) tests used to obtain the critical strain release rates in mode I and II of bonded joints. In mode I it was observed, under certain conditions, a good agreement between the results obtained by the two models with the reference value of critical strain energy release rate in mode I (G_Ic), which is an inputted parameter. However, in mode II some discrepancies on the obtained G_IIc values were observed between the two models. These inaccuracies can be explained by the simplifying assumptions inherent to the cohesive model. Better results were achieved considering the crack equivalent concept.     

Composite indices applied to vibration data in rolling tires to detect bead area damage

The primary objective of this research was to identify an online indicator of tire bead area separation for use in tire durability testing. The dynamics of tires with asymmetric bead area damage and the transmission of vibrations to an axle housing were studied. Experimental results from online data collected on a 67-in diameter roadwheel and a 120-in diameter roadwheel are presented. Statistical measures, trends in frequency content and transient wavelet maps, and composite damage indices were all evaluated as online damage detection features. Trends in statistical measures and frequency content were both indicative of damage progression, but were also sensitive to changes in test conditions. Wavelet maps were indicative of damage progression and showed potential for locating damage circumferentially on a tire. Wavelet analysis of data from both roadwheels indicated that damage increased the amount of higher frequency content in the response signals measured at the spindle arm and axle housing. The increase in broadband content was thought to come from transient vibrations generated when the damaged bead area passed through the contact patch. Composite damage indices that combined frequency and spatial data provided very clear indicators of potential damage initiation events, even predicting the number of ruptures, by drawing out the relevant information in the signals from the ambient vibration. The most effective composite indices multiplied several data signals such that only when all data signals indicated a change would the composite indices also indicate that damage had occurred.     

A novel optical telemetry system applied to flowmeter networks

Recently developed transducers utilise the unique characteristics of Deformed Helix Ferroelectric Liquid Crystal (DHFLC) to linearly and passively transduce small voltage signals into the optical domain. These small optical transducers can be retrofitted to an existing flowmeter network where the true benefits of distributed sensing in the optical domain can be leveraged. Signals from multiple sensors can be multiplexed into a single optical fibre for measurement at a remote location. We demonstrate two methods of signal measurement based on a positive displacement oval gear flowmeter. Utilising a reed switch to produce short pulses, errorless flow rate transduction is possible across all flow rates including very low flows. Using a variable reluctance sensor, completely passive transduction of flow rates can be achieved. The same technique can be applied to any sensing network with an electrical signal output.     

无线通信技术在钢厂重量采集系统中的应用

设计了一种基于串行无线通信的钢厂转炉称重计量系统。针对钢厂恶劣生产环境以及称重数据传输高准确性等问题,设计了抗干扰能力强、性能可靠的硬件系统。进而设计了一种主从式的串行无线通信协议,基于该协议设计了主控计算机与车载计算机软件。系统在钢厂得到成功应用并获得了良好的效益。     

基于LonWorks技术的智能建筑楼宇自动化系统的研究

楼宇自动化系统作为智能建筑的一个重要组成部分,其系统构成与运行直接影响到整个智能建筑系统运行的成败.LonWorks总线因其很强的开放性、兼容性、灵活性、安全性、可靠性和可互操作性,已被广泛应用于智能建筑领域.本文介绍了智能建筑和现场总线的基本概念,在了解和掌握LonWorks现场总线技术的基础上,提出了一种基于LonWorks技术的空调系统设计方案.     

应用于电脑配色系统的凹面光栅光谱仪

介绍了一种应用于电脑配色系统的小型光谱仪。它根据分光测色的原理,使用 型凹面光栅作为其分光器件,石英光纤做测色探头,线阵CCD为探测器。详细介绍了实验仪器的硬件及软件系统,给出了波长标定方法,并进一步探讨了影响仪器准确性和重复性的因素以及解决办法。     

A novel representation of tandem systems with inter-stage storage applied to on-line system monitoring

One of the goals of operating a tandem manufacturing system with finite inter-stage storage and asynchronous operations is to meet the demand without over-producing, under-producing or carrying large quantities of material in storage. We believe that analysing the operation of such a system on a real-time basis helps achieve this goal. The first step in this real-time analysis would be to quantitatively associate the causes and effects of over-production or under-production as they occur. This requires determining the cumulative effect that the performance that any stage has on the system, based on its history, the current system state and the interrelationships between the stages. This paper proposes a method which first represents uniquely and completely each stage and surrounding storage as an element. While this system, which consists only of this simple type of element functions in exactly the same way as the original one, each element is put into an ideal world for decoupled measurement. Though an element behaves in exactly the same way whether it is in the ideal world or in the real world, the elapsed times in the two worlds since the beginning of production can be different, since the responses (occurrences and durations of the blockings and starvations) of the two worlds can be different. A phase parameter is introduced for each element to represent this difference. Once the formation of the phase parameter of the output element is formulated, quantitative relationships between causes and effects of over-producing or under-producing can be explained as they occur.     

交流伺服系统中PID参数模糊自整定控制器

为了改善以交流永磁同步电机为控制对象的伺服系统性能,在PID控制规律和模糊控制算法研究的基础上,提出了一种PID参数模糊自整定控制器。利用模糊推理方法建立了模糊控制规则,对交流伺服电机控制中的PID参数实现了自整定,并在Matlab中进行了仿真。仿真结果表明,该控制器改善了常规PID控制器的性能,使伺服系统具有良好的动、静态性能。     

啤酒糖化过程BITBUS计算机控制系统

本文对采用位总线和分布式计算机控制技术研制出的啤酒糖化过程计算机控制系统进行了介绍。     

用于无人机飞行控制系统的分布式测控系统设计

将复杂庞大的工程项目分解成多个功能单一的小模块实现，是COM组件设计思想的具体体现。在简要介绍分布式对象与对象服务后，本文设计了具有命名服务和事件服务两种对象服务功能的事件提供者和事件消费者COM组件以及其他诸如硬件驱动、图形显示等COM功能组件。这些组件提供的远程对象状态监控以及基于事件的对象间数据通信功能，使应用于无人机飞行控制系统的分布式测控系统的实现成为可能。最后，本文通过分布式传感器监测系统开发实例，说明本文所提出的组件设计方法能帮助系统设计者方便地扩展系统，加快系统开发速度，提高设计效率。     

耐泥沙磨蚀涂层研究

分析了热喷涂层试验室模拟及水轮机真机运行的试验结果。选择出耐磨性好的合金粉末和喷涂工艺,以提高水轮机和水泵的抗磨蚀性能,研究成果成功应用于引黄大泵生产,避免了腐蚀破坏。     

电液主动悬架控制系统设计与仿真

对一个电液主动悬架装置进行了研究.首先对该装置进行了分析并建立了该主动悬架系统的动力学模型,然后以装配该悬架装置的1/2车辆模型为控制对象,设计了一个力追踪控制系统.最后,采用MATLAB/SIMULINK对该控制系统进行仿真,结果表明,所设计的控制系统能够保证悬架具有良好的控制效果.