面向运行的绿色设计技术系统研究

通过振动测试系统的开发研究和理论建模，对理论振型计算和测试结果进行比较分析，提出了对变速器性能、振动与噪声的综合设计改进方案。     

虚拟仪器在水力机组振动和噪声测试中的应用

分析了传统仪器系统与虚拟仪器系统的特点，以水电机组振动、噪声为研究对象。提出了一种基于虚拟仪器技术的测试分析系统的设计思想及实现方法。将虚拟仪器引入水力机组振动、噪声测试分析系统，实现了对水力机组振动信号实时的数字化采集、测试、分析、控制。该系统具有人机界面友好、运行速度快、信息存储量大、开发周期短、易于维护和扩充等特点。     

基于高速数据采集和实时信号分析的结构实验分析系统的研究与应用

本文采用计算机多线程技术实现了实时信号数据采集分析,开发出了一种基于高速数据采集和实时信号分析的结构实验分析系统。该系统具有对给定结构进行振动噪声等信号的实时信号测试分析和进行实验模态分析等功能,具有广泛的适用性和良好的及时扩充功能、处理能力和性能价格比。     

摩擦噪声系统的振动特性研究

建立了一个往复滑动摩擦系统1∶1实体装配模型,采用有限元方法对该系统的振动特性进行研究,获得了系统的自然频率和振动模态。将得到的系统振动频率与系统的试验噪声的频率进行比较,发现它们的一些结果有很好的一致性。对系统的计算模态分析显示,发生噪声的模态同时具有切向和法向振动特征。     

电控制动助力系统NVH优化设计及试验方法研究

制动系统NVH性能是影响整车NVH表现的重要因素，对制动助力系统振动噪声进行优化研究具有重要意义。以某电控制动助力系统为研究对象，通过噪声产生机理研究、CAE仿真分析与试验虚实结合、电机控制优化等技术手段，实践验证了一种有效的制动助力系统NVH优化设计方法，为电控制动系统减振降噪开发提供助力。     

基于可靠性的混合不确定参数汽车盘式制动器振动稳定性分析

针对汽车盘式制动器的制动噪声抑制问题,基于可靠性分析理论,将响应面法与有限元复特征值技术相结合,提出一种混合不确定性参数下汽车盘式制动器系统振动稳定性的可靠性分析方法。该方法将参数不确定性引入到汽车盘式制动器的振动稳定性分析中,采用随机参数和区间参数对制动器系统进行描述,建立包含随机参数和区间参数的制动器系统不稳定特征值的响应面近似模型,实现分析模型的参数化,进而可对系统的振动稳定性进行参数灵敏度分析和可靠性分析。用该方法对某车的浮钳盘式制动器系统进行研究,采用蒙特卡洛方法分析系统振动稳定的可靠性和参数灵敏度。结果表明存在不确定性参数的情形下,通过提高制动器支撑背板的支撑刚度,能有效可靠地改善制动器系统的振动稳定性,减小制动噪声的产生,分析方法对抑制制动噪声具有一定的工程指导意义。     

滚动轴承振动噪声检测用驱动及测试装置

滚动轴承的振动及由此产生的噪声对设备运转的平稳性、舒适性造成较大的影响,而振动噪声检测仪器自身振动对轴承振动、噪声真实值的评价也造成一定影响。因此,开发了用于静音室内轴承振动和噪声测量的驱动装置,其包括主轴变频驱动系统、芯轴、轴向/径向加载装置、振动测量系统等,具有测量范围大,加载灵活,无级变速等功能,可满足各类型滚动轴承振动、噪声检测的需要。     

汽车振动噪声性能开发浅析

对国内外汽车振动噪声研究设计的现状进行了分析,并给出了汽车振动噪声性能开发流程,还分析了开发流程中的对标分析、目标分解和设定、方案设计、模态规划、仿真分析、试验分析等环节的工作内容和存在的问题,提出了提高汽车振动噪声性能开发能力的若干建议.     

汽车主减速器噪声振动检测系统研究

为测试汽车主减速器性能,采用计算机测控系统实现了对主减速器噪声、振动等指标的综合检测。介绍了该系统的检测原理及相应的软硬件设计方案,并对噪声和振动因素进行了初步的分析。     

核电用行星减速箱计算机建模及动态仿真研究

用于泵海水对核电系统进行冷却的行星减速系统,具有输入功率大,体积重量大,要求振动噪声小,使用时间长(二十年连续运行)等特点.国内某企业为开发核电用立式行星齿轮减速箱系统新产品,对该系统进行了充分的前期技术设计和分析,用ProE软件进行了系统的三维建模和装配,加载动态仿真运行,用ProE自带的Mechanica分析软件对关键零部件的受力情况进行了有限元分析计算,并用SimulationX软件对系统的振动特性进行了分析.前期的仿真分析研究对整个系统的成功设计、制造起到了关键的作用.     

采煤机摇臂齿轮传动系统振源定位分析方法

为了研究采煤机摇臂传动齿轮的振动分析方法并进行实机振源定位验证,首先,采用小波分析对采煤机摇臂振动信号进行降噪处理和频谱分析,依据特征频率下的振幅结果确定故障齿轮的啮合频率;然后,通过Morlet小波包络解调分析获取边频带信号频谱特征,依据边频带特征频率下的振幅结果确定故障齿轮的转动频率;最后,对频谱分析和Morlet小波包络解调分析的结果进行综合分析,锁定故障齿轮的准确位置。对一台国产采煤机摇臂齿轮传动系统进行了振动测试与信号分析,结果表明,基于小波分析、频谱分析和Morlet小波包络解调分析相结合的振动分析方法可以实现对采煤机摇臂故障齿轮的准确定位,为强噪声环境下复杂齿轮传动系统的故障快速定位和现场定点维修提供了方法支持。     

Principal component analysis and blind source separation of modulated sources for electro-mechanical systems diagnostic

Under the only hypothesis of independent sources, blind source separation (BSS) consists of recovering these sources from several observed mixtures of them. As it extracts the contributions of the sources independently of the propagation medium, this approach is usually used when it is too difficult to modelise the transfer from the sources to the sensors. In that way, BSS is a promising tool for non-destructive machine condition monitoring by vibration analysis. Principal component analysis (PCA) is applied as a first step in the separation procedure to filter out the noise and whiten the observations. The crucial point in PCA and BSS methods remains that the observations are generally assumed to be noise-free or corrupted with spatially white noises. However, vibration signals issued from electro-mechanical systems as rotating machine vibration may be severely corrupted with spatially correlated noises and therefore the signal subspace will not be correctly estimated with PCA.This paper extends a robust-to-noise technique earlier developed for the separation of rotating machine signals. It exploited spectral matrices of delayed observations to eliminate the noise influence. In this paper, we focus on the modulated sources and prove that the proposed PCA is available to denoise such sources as well as sinusoidal ones. Finally, performance of the algorithm is investigated with experimental vibration data issued from a complex electro-mechanical system.     

Diagnostics and prognostics based on adaptive time-frequency feature discrimination

This paper presents a novel diagnostic technique for monitoring the system conditions and detecting failure modes and precursors based on wavelet-packet analysis of external noise/ vibration measurements. The capability is based on extracting relevant features of noise/ vibration data that best discriminate systems with different noise/vibration signatures by analyzing external measurements of noise/vibration in the time-frequency domain. By virtue of their localized nature both in time and frequency, the identified features help to reveal faults at the level of components in a mechanical system in addition to the existence of certain faults. A prima-facie case is made via application of the proposed approach to fault detection in scroll and rotary compressors, although the methods and algorithms are very general in nature. The proposed technique has successfully identified the existence of specific faults in the scroll and rotary compressors. In addition, its capability of tracking the severity of specific faults in the rotary compressors indicates that the technique has a potential to be used as a prognostic tool.     

超高压压缩机及管线系统的振动分析与控制

针对石化企业中超高压压缩机及管线系统普遍存在振动大、噪声污染严重的问题,根据振动特性方程,运用参数化的设计思路建立了在役超高压压缩机及管线系统一体化的有限元分析模型,并依据现场测试数据修正参数化模型,复原振动现场;同时进行了系统动力特性分析,提出了振动控制的优化方案。方案实施后管线振动能量分布趋于均匀,振动位移大幅减小,说明这种建立在一体化模型基础上的有限元分析方法是进行超高压压缩机及其管线系统振动控制改造的有效方法。     

汽车制动发抖振动测试与分析

针对某汽车在行驶过程中发生制动发抖问题进行振动测试与分析,首先介绍了汽车转鼓测试试验方法,紧接着利用PULSE数据采集分析系统,对制动鼓和仪表板在汽车行驶制动中进行了自谱分析和相干分析,分析结果确定了汽车在制动过程中异常振动的振源与各通道上零部件的振动水平,为正确识别仪表板异常振动的原因提供了理论依据,从而为采取相应措施来消除制动过程中仪表板的异常振动打下基础。     

THE INFLUENCE OF PERIOD VARIATION ON TIME–FREQUENCY ANALYSIS OF THE WESTLAND HELICOPTER DATA

In this work, we address the influence of period variation on the Westland CH-46E helicopter vibration data. The estimation of the time-varying shaft speed by using a newly developed constrained AR(2) estimator and the well-known EKF estimator will be discussed. The influence that the period variation captured by these two estimators have on the periodic time–frequency analysis will be illustrated via numerical simulation. This simulation clearly illustrates a potential spectral smearing if the period variation is not properly accommodated. A data resampling scheme will then be proposed to eliminate the spectral smearing effect. The potential of this scheme will be demonstrated via the analysis of the helicopter vibration data.     

基于试验的汽车手动变速器噪声源识别

手动变速器的噪声控制是汽车噪声控制的难点之一.基于低噪声变速器测试台,对某5档手动变速器的噪声特性进行了全面测试.综合利用频谱分析、阶次分析和相干分析等方法来识别变速器的主要噪声源.分析表明:变速器的振动主要是由挡位齿轮啮合过程以及主减速齿轮啮合过程共同引起;且高速时挡位齿轮啮合过程引发强烈振动的原因与齿轮轴弯曲和齿轮模态有关;5档高速工况时,变速器噪声的主要引发原因是变速器箱体表面某位置的振动,若要改善变速器的振动噪声特性,可从该位置处人手.分析结果为低噪声变速器的优化设计提供了试验支持.     

相关熵的降噪机理及其在轴承故障诊断中的应用

针对传统相关函数和谱相关密度难以有效处理强非高斯噪声干扰的问题,提出了一种基于循环平稳相关熵的故障诊断方法。以理论分析和几何图解等方式系统分析了相关熵的降噪机理,以余弦信号和仿真调幅信号为例解释了相关熵以及循环平稳相关熵的降噪机理并验证了其良好的噪声抑制能力;应用循环平稳相关熵方法对轴承内、外圈局部裂纹故障振动信号进行了分析和处理,试验结果表明,循环平稳相关熵谱密度具有解调功能,能准确刻画轴承局部裂纹故障的频谱特征,可有效提取淹没在强噪声环境中的微弱信号。     

The use of SESK as a trend parameter for localized bearing fault diagnosis in induction machines

A critical work of bearing fault diagnosis is locating the optimum frequency band that contains faulty bearing signal, which is usually buried in the noise background. Now, envelope analysis is commonly used to obtain the bearing defect harmonics from the envelope signal spectrum analysis and has shown fine results in identifying incipient failures occurring in the different parts of a bearing. However, the main step in implementing envelope analysis is to determine a frequency band that contains faulty bearing signal component with the highest signal noise level. Conventionally, the choice of the band is made by manual spectrum comparison via identifying the resonance frequency where the largest change occurred. In this paper, we present a squared envelope based spectral kurtosis method to determine optimum envelope analysis parameters including the filtering band and center frequency through a short time Fourier transform. We have verified the potential of the spectral kurtosis diagnostic strategy in performance improvements for single-defect diagnosis using real laboratory-collected vibration data sets.     

机床噪声分析与控制

本文论述了机床的噪声源以及噪声频谱分析的方法。齿轮是机床的主要噪壳源之一,但它绝不是唯一重要的因素。除了齿轮之外,影响机床噪声的因素还有很多,如电机、轴承、皮带、高速回转轴的不平衡以及结构振动等等。必须对机床进行噪声频谱分析才能确定它的主要噪声源。本文以YN-01φ400毫米车床和T649镗铣床为例,介绍了各种降低噪声的措施,其中包括：（1）用合理配置筋板的方法限制齿轮箱体的结构振动;（2）对高速回转轴和电机轴进行动平衡;（3）提高齿轮加工精度;（4）用齿顶修缘和阻尼的方法减小齿轮噪声;（5）改进结构设计;（6）提高装配质量。本文最后还论述了一些低噪声机床的设计原则,并且认为这是控制机床噪声的根本途径。