相关技术在滚动轴承故障诊断中的应用

众所周知自相关技术能够有效地从随机嘈声中提取周期性信号.在滚动轴承元件的故障诊断中,由于信号图象不同,我们无法从原信号直接得到故障的情况,这种信号的显示就像宽频带随机嘈声在自相关函数的显示一样.本文中,信号经过了预处理,其结果证明是行之有效的.应用自相关技术我们还可以得到已测定的可比采样,这对于建立轴承运行条件的数据基础和进行故障诊断是十分重要的.     

圆薄膜中心部份受均布载荷产生的对称变形

本文给出了圆薄膜中心部份受均布载荷产生的对称弯曲变形的解,它的极限给出圆薄膜在中心集中载荷下的解.它们是Hencky圆薄膜解以后,第三种有关的圆薄膜解.     

Rolling bearing fault detection using correlation technique

It's known that auto-correlation technique is effective in extracting periodical signals from random noises. In the case of fault monitoring of rolling element bearing, we can't acquire the.fault information directly from the original signal because of the difference of signal phases. And the signal is shown as the wide band random signal in auto-correlation function. In this paper, the signal is pre-processed and the results are proved effctive. Moreow, by taking the auto-correlation fumction we can obtain the determined and comparable samples. This is very important for establishing the data base of running condition and for detecting the faults.     

厄密多项式在结构动力响应计算中的应用

本文利用正交多项式级数部分和的"最佳近似"性,推出了求解结构动力响应的付里叶-厄密多项式展开法.文中详细推导了振动系统的位移和速度响应的分步解析表达式,并讨论了计算格式的稳定性条件,通过了实例考核与精确度对比分析.     

THE FINITE DYNAMIC ANNULAR ELEMENT FOR THE VIBRATION ANALYSIS OF VARIABLE THICKNESS DISCS

According to the gyro-periodicity of dynamic displacements, the two-dimensional problems of circular plates with variable thickness are simplified into one-dimensional ones in this paper. Taking the expanded form of frequency power series of the dynamic displacement functions as the dynamic shape functions of the finite annular element, the mass and stiffness matrices as well as their one-order revised matrices are given succinctly. The dynamic method is used to analyse the vibration characteristics of a bladed disc assembly and is compared with conventional finite element method and experiment, and is proved to be superior to other numerical methods.     

THE USAGE OF HERMITE POLYNOMIAL IN THE CALCULATION OF STRUCTUBAL DYNAMIC RESPONSES

This paper employs the best approximation of part series sum of normal polynomials, and proposes a new method with the Fourier-Hermite polynomial expansion expressing structural dynamic responses. Analytic expressions of displacement and velocity responses of vibrational systems are established in this paper, and stability condition of the step-by-step algorithm is discussed. Finally, a computational example is demonstrated, and the precision of its results is compared with conventional methods.     

The application of pattern recognition techniques in fault diagnosis of machinery equipment

In this paper,the characteristics of vibration signal of machinery in different runningconditions are statistically analysed,and some moments of statistical distribution of signalsare selected as the eigenvector to condense the state information.Here,we divide the statesof machinery into two:‘good’and‘aulty’,and the pattern recognition techniques are usedto classify the running conditions of machinery.At the end of this paper,the authors presentsome test data,and from the results obtained,it’s verified that the eigenvector selected isreliable and sensible to faults.And the results also show the effectiveness of classificationrule.     

用于变厚度圆盘振动分析的动态环形元

本文利用动态位移的回转周期变化规律,将变厚度圆板弯曲振动的二维问题化为一维形式.并将环形单元的位移函数以频率的升幂形式展开,作为动态形状函数,进而推导了动态环形元的质量和刚度矩阵及其一次动态修正矩阵,并以简洁的形式给出.最后作为本文方法的直接应用,计算了叶盘组合件的固有特性与实验值及其它方法进行了比较,说明动态的变厚度环板元的优越性.     

旋转机械故障诊断中的哈尔谱研究

本文将哈尔变换应用于旋转机械故障诊断之中,并提出了用于诊断的“脉冲锐度”指标.基于付立叶分析的频谱分析是目前广泛采用的方法,与快速付立叶变换相比,哈尔变换具有实时性,逼近效果好,适用于对脉冲的提取等优点.而不足之处是受样本始点选取及样本长的影响大.对此,本文提出了控制各次样本的等效性的方法,改善了哈尔谱的稳定性与比较性.最后,通过对滚珠轴承故障模拟试验台进行试验得到的结果证实了哈尔谱及脉冲锐度指标对故障的敏感性.     

模式识别技术在机械设备故障诊断中的应用

本文从统计意义上分析了机械设备在不同运行状态下振动信号的特征;选择信号幅值的概率分布的前n阶矩作为特征向量来进行状态信息凝聚.在此,将设备的状态分为“完好”和“故障”两种,应用模式识别技术进行状态分类.最后通过对试验数据的分析,证实了特征参数的稳定性和对故障的敏感性.结果表明,分类判据是有效的.