非线性指标-3微分-代数系统的波形松弛算法的实现

本文探讨非线性指标-3微分-代数系统的波形松弛算法所涉及的理论模型和具体算例的求解。对于收敛性问题,我们利用谱半径条件证明该理论模型的收敛性,所得结论的收敛性条件相对较弱,并利用算例测试了收敛定理的正确性。结果显示:在求解非线性微分-代数系统时,波形松弛类算法是具有内在并行性的有效算法。     

液体除湿空调系统溶液再生性能的理论研究与实验分析

建立了液体除湿空调系统再生塔数学模型,对再生塔内溶液再生性能进行理论研究和模拟计算;并利用液体除湿空调系统实验台,进行再生实验,与理论计算进行对比分析,研究影响溶液再生性能的主要因素,以提高再生性能。     

换相过程对变抽头六相整流电路的影响

在变抽头六相整流系统中，整流换相和变抽头换相对有效抑制交流侧电流波形畸变起到了重要作用，采用分段解析法给出了考虑换相过程时变抽头六相整流系一统的数学模型，得出了交流侧电流波形，并对交流电流进行了傅氏级数分解，通过实验研究，查明了电流正弦性畸变率的变化规律和影响因素，给出了抽头换接器的匝数匹配优化值，为该系统的工程设计提供了重要指导。     

摄象机参数高精度求解方法

提出了一种新的高精度的摄象机参数的求解方法，文章利用透视变换理论建立了摄象机数学模型，模型中考虑了摄象机镜头的径向畸变和切向畸变，首先利用牛顿－高斯非线性搜索方法求争摄象机畸变系数和一个中间矩阵，然后再从中间矩阵中分离出其它模型参数；     

交流变频调速系统仿真建模及谐波特性分析

随着电力电子技术的发展,交流变频调速系统以其强大的优势逐渐取代传统的直流调速传动,其在给人们生产生活带来方便和效率的同时,也造成了电力系统谐波污染加重的问题。因此,设计了一种开环正弦脉宽调制（sinusoidal pulse width modulation,SPWM）控制的交流变频调速系统并搭建仿真模型,实现了对系统中变频器输出电压频率和幅值及电机转速的灵活控制。对系统网侧电压和电流进行了谐波特性分析,结果表明：网侧电压的波形比较理想、畸变很小,而电流波形畸变严重;且随着变频器输出频率的增加,电压波形畸变程度有所加剧,电流畸变程度有所减轻。     

滚珠丝杠进给系统的仿真建模

为了在设计阶段获得滚珠丝杠进给系统相对精确的二阶数学模型,提出了一种基于Lyapunov稳定性理论建立模型参考自适应系统,以二阶系统作为参考模型,以理论模型作为控制对象的仿真建模方法。结合实例,建立了考虑粘性摩擦和传动刚度的滚珠丝杠进给系统理论模型,运用MATLAB/Simulink建立了模型参考自适应系统的仿真模型,并利用仿真结果推导出了进给系统的二阶数学模型。结果表明：二阶模型的输出能够很好地跟踪理论模型的输出;同时对两模型输入1毫秒的单位脉冲信号时,相对误差在0.314%以内。     

斜盘式轴向柱塞泵后壳体机械振动传递路径研究

轴向柱塞泵振动产生后,会按照某种规律沿着一定路径向外传递。以斜盘式轴向柱塞泵为研究对象,分析其机械振动产生机理及传递规律,建立振动传递路径模型;以泵后壳体作为振动传递的最终受体,建立了泵机械振动向后壳体传递的路径模型;通过数值模拟和实验确定模型参数,利用MATLAB对数学模型进行求解,得到了机械振动向后壳体传递的规律;基于路径传递率的概念,对振动传递路径系统进行了路径贡献度分析,并辨识出主要传递路径;搭建了轴向柱塞泵振动测试实验台,进行了实验研究。结果表明:所建立的轴向柱塞泵振动传递路径模型和求解方法较为准确,分析误差小于5%。该研究方法为轴向柱塞泵振动传递、能量耗散规律研究,以及参数灵敏度分析奠定理论基础。     

变质量提升系统钢丝绳轴向-扭转耦合振动特性

为了掌握变质量提升系统的振动特性,考虑提升钢丝绳的扭转运动并根据变质量非完整系统的Ham ilton原理建立了钢丝绳轴向和扭转耦合振动数学模型,并推导了变质量提升系统振型函数及确定轴向与扭转耦合振动频率的超越方程,给出了基于振型函数随系统质量变化及固定不变两种情况下变质量提升系统钢丝绳振动位移、张力和扭矩响应的求解方法。以矿井提升箕斗装载为工况进行应用分析,结果表明:两种求解方法得到的响应基本接近;提升容器装载过程是一个质量增大振动频率减小的过程,钢丝绳的动位移、张力和扭矩以波动形式逐渐增加。装载量较大时可采用振型函数固定的方法计算装载提升系统的频率和响应,冲击较大的载荷建议考虑提升容器的波动载荷,从而有助于提高计算效率和增强提升系统的安全可靠性。     

同轴圆筒式磁力耦合器启动特性研究

磁力耦合器是在真空、化工等领域广泛使用的一种传动机构,当磁力耦合器负载突然增大而过载时,会产生滑脱而结束扭矩传递的现象.为解决这一问题,经过理论推导,建立了磁力耦合器启动过程的扭矩传递数学模型,推导了单纯性启动脱耦的判定条件.在此基础上,应用MATLAB软件模拟了磁力耦合器的启动及脱耦过程,并用扭矩与转角差实验台进行了试验,验证了单纯性启动脱耦的判定条件.提出了采用延时启动的方法可以解决磁力耦合器的脱耦问题,对磁力耦合器的推广应用具有重要意义.     

《波形和频谱分析与随机数据处理》一书再版

由应怀樵编著的《波形和频谱分析与随机数据处理》一书已经再版,该书较系统地介绍了波形、频谱与随机数据处理概述;波形分析(包括相关分析)的原理和方法;波形的畸变反演和基线修正;波形的微积分变换,频     

A three dimensional photoelastic study of the stress distributions in double helical epicyclic gears

This paper reports on part of a research programme which was carried out using two- and three-dimensional photoelastic model techniques in order to analyse the stress distributions in a double-helical epicyclic gear design incorporating typical features of production gear units.
The paper describes the testing of two three-dimensional models, one subjected to torque loading, i.e. tooth forces; the other to combined rotational and torque loading. Note is made of some of the problems inherent in the design and loading of complex models such as those used in the tests and of the solutions developed to overcome the difficulties.
Attention is devoted to the analysis of contact loads and load distribution, maximum sub-surface stresses, maximum root fillet bending stresses and the geometry of the lines of contact. General conclusions are drawn and an indication given of the subsequent extensive two-dimensional test programme which was carried out.     

Development of an Instantaneous Electromagnetic Torque Measuring System

The following paper describes a technique for measuring torques developed by various transducers. The technique was used to measure the instantaneous electromagnetic torque of a two-phase servomotor, and some test data are included. This measuring technique was developed for the purpose of obtaining test data to correlate with the analysis portion of the author's Ph.D. thesis on Phase Plane Solution for Systems Using Nonlinear Two-Phase Servomotor. The measuring technique performed satisfactorily in its prototype form and was further used to determine the characteristics of the 120-c/s alternating torque in relation to average torque for a 60-cycle two-phase servomotor. The principle of operation, test stand, arrangement circuitry, calibration procedure, test data, and a discussion of the performance of the instrument are presented.     

Magnetorheological fluid durability test—Iron analysis

This report describes chemical changes and the methodology to detect such changes in iron particles from extracts of certain magnetorheological fluids (MRFs) which had been subjected to durability testing in an MRF fan clutch. Samples of MRF subjected to 540 and 108 h of service in a MRF fan clutch on a test stand were characterized along with neat and unused materials for comparison. The results indicated that: the iron subjected to durability testing had oxidized; a portion of the iron oxides were crystalline magnetite; and the oxides were concentrated at the perimeter of the smaller iron particles although both large and small particles were oxidized. This oxidation may explain the gradual loss of fan clutch torque capacity observed during the 540 h durability test.     

卡环式扭矩测试系统在抽油机上的应用

由于抽油机输出轴的不可拆卸性,目前对于其功率的测试还没有合适手段,本文介绍的方法是采用卡环式扭矩测试系统来实现对抽油机功率的测试,介绍了抽油机的工作原理、卡环式传感器的结构、测试系统的软硬件结构以及此方法的应用领域.     

Analytical study of the thermal shock problem of a half-space with various thermoelastic models

Summary The thermal shock problem of a half-space is frequently used as a test example for checking computer programs which are suitable for solving thermoelastic problems. As there are no exact solutions for the problem formulated on the basis of complicated models, authors have compared their own results to previous numerical results in their publications so far. In the present paper six thermoelastic models are investigated. Curves of temperature, displacement and stress fields arising as a result of sudden and ramp-type surface heating are given in a very handy form for program testing. A thorough analysis of elastic and thermal waves is also included.     

Neural classification of Lamb wave ultrasonic weld testing signalsusing wavelet coefficients

This paper presents an ultrasonic nondestructive weld testing method based on the wavelet transform (WT) of inspection signals and their classification by a neural network (NN). The use of Lamb waves generated by an electromagnetic acoustic transducer (EMAT) as a probe allows us to test metallic welds. In this work, the case of an aluminum weld is treated. The feature extraction is made by using a method of analysis based on the WT of the ultrasonic testing signals; a classification process of the features based on a neural classifier to interpret the results in terms of weld quality concludes the process. The aim of this complete process of analysis and classification of the testing ultrasonic signals is to lead to an automated system of weld or structure testing. Results of real-world ultrasonic Lamb wave signal analysis and classifications for an aluminum weld are presented; these demonstrate the feasibility and efficiency of the proposed method     

Automated Torque Sensing Equipment for Cosmetics and Pharmaceuticals

Abstract

The limited accuracy of existing closure torque testers and the subjectivity of the measurements imparted by human operators has led to the development of an automated closure testing machine, the Auto-Torque.

As packaging requirements become more stringent in order to provide Improved consumer safety and product integrity, improved quality control techniques become necessary. Torque testing of closures has relied for years on a manually operated spring scale with a claimed accuracy of plus or minus four percent (4%) full scale. The closure testing process becomes more inaccurate when you add to this error the inconsistencies due to reading errors, data entry/analysis errors, and operator technique (1). Automation of the closure torque testing process narrows the range of errors down to those of the machine itself which are easily quantified by a calibration procedure.

Currently available spring scale closure testers have no provision for measuring downward force needed to engage child-resistant (CR) closures, requiring the user to develop their own apparatus (2). Currently, the Auto-Torque is being used for university research and by major pharmaceutical companies in both the package development and quality assurance test area to support the productivity of multiple lines.

This paper describes the Auto-Torque's ability to provide the quality assurance needed In the closure torque testing process. Technical problems encountered and their solutions are viewed from a general systems automation perspective.     

光电反射式动态扭矩测试方法研究

针对等直径转轴动态扭矩测试方法计算模型和测量装置复杂以及测试范围受限等问题,提出了一种基于DASP的光电反射式动态扭矩测试方法。建立由光电反射式传感器和DASP系统等组成的动态扭矩测试系统,利用传感器光电脉冲信号的时差和相对转角,来实现动态扭矩测量。实测结果表明,通过调整传感器的位置,就可以实时、精确地实现扭矩的非接触式测量。这种测试方法为转轴的扭矩测试提供了一种新的技术途径。     

纤维增强复合材料薄壁圆管扭转失效分析

对碳纤维增强树脂基复合材料（CFRP）薄壁圆管的扭转屈曲、失效载荷和失效模式进行了试验和数值模拟。试验观察圆管在扭矩作用下的3种失效模式,分析了不同失效模式的特征和机理。考虑圆柱壳的初始缺陷和非线性屈曲等因素,利用ABAQUS建立了圆管屈曲和损伤的有限元模型。结果表明:屈曲诱发圆管表面微裂纹的产生和扩展,对圆管的失效有着加速作用;扭转失效过程中圆管层间应力较低,层间分层主要由管壁突然的破坏产生;圆柱壳的初始缺陷对屈曲和失效载荷的模拟影响较大,本文通过对比计算结果和试验数据确定了圆管的初始缺陷系数;损伤模型的数值模拟结果与试验数据相一致,验证了有限元模型的有效性。