共查询到20条相似文献,搜索用时 187 毫秒
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针对已有的时频分析方法在转子非平稳特征提取方面的不足,提出采用同步压缩小波包变换(SSWPT)方法进行转子油膜失稳故障分析.首先将采集的振动信号进行小波包变换得到小波包变换系数,然后求取信号的瞬时频率,最后对小波包变换系数沿信号瞬时频率方向进行压缩,从而将各频率成分清晰呈现于时频图中.分别利用仿真、实验信号及油膜涡动现... 相似文献
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根据希尔伯特黄变换(Hilbert-Huang Transform,HHT)原理对虚拟仪器设计软件—LabVIEW进行二次开发,实现HHT方法,并设计基于HHT的虚拟信号分析仪。利用Bently RK-4转子试验台模拟汽轮机转子局部碰摩及油膜涡动故障,并将虚拟信号分析仪运用到对该转子的故障诊断中。通过对转子局部碰摩及油膜涡动故障特征的分析并结合虚拟信号分析仪的分析结果,验证了基于HHT的虚拟信号分析仪可以有效地提取旋转机械故障信息。 相似文献
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针对变转速工况下滚动轴承的故障诊断问题,提出一种基于阶次解调谱的故障诊断方法。该方法先利用线调频小波路径追踪算法提取转速信号,并根据转速信号对轴承振动信号进行角域重采样,将时域非平稳信号转化为角域平稳信号。然后对角域平稳信号进行变分模态分解(variational mode decomposition,VMD)得到若干本征模态函数分量(intrinsic mode function,IMF),并利用峭度指标筛选出敏感IMF分量,最后对敏感IMF进行Hilbert变换获得其阶次解调谱,通过提取阶次解调谱中的故障特征阶次来识别轴承故障。仿真和实验分析结果表明,该方法成功提取出故障特征阶次,可实现变转速工况下滚动轴承故障的有效诊断。 相似文献
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由于变工况条件下存在非平稳、多元耦合振动、传递路径具有时变特性等特点,导致故障振动信号的复杂性以及响应更加微弱,其故障诊断特别是太阳轮故障是研究重点以及难点。针对该问题,提出一种适合变工况及弱特征信号解调的包络阶比分析方法。首先利用Tukey窗函数对振动信号进行加窗处理,其次利用谱峭度自适应地确定优化共振解调带通滤波中心频率和滤波带宽,获取复包络加窗信号,最后利用计算阶比跟踪对复包络加窗信号进行等角度重采样,转换为角域准平稳信号,进而获取阶比谱信息。通过太阳轮故障实验验证包络阶比分析方法的有效性。 相似文献
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《International Journal of Hydrogen Energy》2019,44(44):24301-24311
Costly and time-consuming maintenance of the hydrogen compressors due to their frequent breakdown severely hinders the deployment and promotion of hydrogen refueling station (HRS), and effective condition monitoring and fault diagnosis is the key to reduce the unscheduled downtime of the compressor. This paper proposes a non-destructive method for fault diagnosis of diaphragm compressors for HRSs based on the acoustic emission (AE) signal. The AE signals in the time domain are segmented into angle-domain signals correspond to a working cycle. The feature events of the moving components are determined through the measured AE signal in both angle-domain and angle-frequency domain based on short-term Fourier transform (STFT). Those feature events signals are innovatively applied to identify the typical abnormal conditions of excessively high oil pressure, slightly inadequate oil pressure and seriously inadequate oil pressure, replacing the traditional and destructive pressure measuring method. The results show that this method can be used to effectively diagnose abnormal working conditions and indicate that this method can be utilized as a powerful tool in the non-destructive condition monitoring and fault diagnosis of the diaphragm compressors. 相似文献
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通过对磁场作用下旋转火焰涡量变化特性影响的研究,得到在不同的磁场作用时旋转火焰的旋转特性.研究结果表明:磁场的作用会改变旋转火焰的旋转强度,使火焰的旋转强度降低;对于相同旋转速度的旋转火焰,使火焰停止旋转的时间随磁场强度的增加而减小;在一定的火焰旋转强度(<95r/min)、磁场强度(一般>0.357T)和足够长的时间下,能使旋转火焰的旋转速度降低到零. 相似文献
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基于声信号小波分解的转子碰磨故障特征分析 总被引:2,自引:0,他引:2
研究了基于声信号小波分解的转子碰磨故障特征,通过人为条件使转子产生碰磨故障,记录现场信号分析故障特征。转子碰磨信号具有较强的奇异性,而奇异信号往往载有重要的故障信号特征,利用小波分析理论在时域和频域上可同时对信号实现局部化处理的“变焦距”性质,分别对不同试件碰磨故障的声音信号进行了分析,将结果进行了对比,研究了碰磨声信号在小波包变换下的特征。结果表明:声音信号用于旋转机械故障诊断具有其特有的优越性。基于声音信号的小波分解可以识别碰磨故障特征。 相似文献
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Planetary gearbox fault diagnosis under nonstationary conditions is important for many engineering applications in general and for wind turbines in particular because of their time-varying operating conditions. This paper focuses on the identification of time-varying characteristic frequencies from complex nonstationary vibration signals for fault diagnosis of wind turbines under nonstationary conditions. We propose a time–frequency analysis method based on the Vold-Kalman filter and higher order energy separation (HOES) to extract fault symptoms. The Vold-Kalman filter is improved such that it is encoders/tachometers-free. It can decompose an arbitrarily complex signal into mono-components without resorting to speed inputs, thus satisfying the mono-component requirement by the HOES algorithm. The HOES is then used to accurately estimate the instantaneous frequency because of its high adaptability to local signal changes. The derived time–frequency distribution features fine resolution without cross-term interferences and thus facilitates extracting time-varying frequency components from highly complex and nonstationary signals. The method is illustrated and validated by analyzing simulated and experimental signals of a planetary gearbox in a wind turbine test rig under nonstationary running conditions. The results have shown that the method is effective in detecting both distributed (wear on every tooth) and localized (chipping on one tooth) gear faults. 相似文献
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基于MATLAB的噪声信号采集与分析系统研究 总被引:4,自引:0,他引:4
基于MATLAB的数据采集工具箱(DAQ)和信号处理工具箱开发了一套声音信号采集分析系统,该系统不仅能够实现低成本、高精度的实时采集,还能将声音信号资料导入系统进行时域和频域分析。利用另外一个工具Compiler使编制的MATLAB程序能够独立运行从而提高了运行速度;配备了友好的图形用户界面(GUI),方便用户操作。最后给出了系统在内燃机噪声诊断方面的应用实例。 相似文献
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柴油机运行时因激振力的作用会产生一定方向和频率的冲击振动,构件的裂纹或松动等故障会影响到其响应成分的频率能量特性.针对柴油机运行时的冲击响应振动信号,利用小波分析快速进行信噪分离,频域范围内采用功率谱分析结合小波包分解对各频段能量谱分析.根据振动信号时域峰值和时刻,频域能量的变化和分布,给出故障诊断层使用的状态特征向量... 相似文献
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