共查询到18条相似文献,搜索用时 171 毫秒
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航空发动机转子早期裂纹故障振动特征的维谱分析 总被引:1,自引:0,他引:1
针对航空发动机转子早期裂纹故障难以检测的特点首先,根据转子裂纹扩展机理,建立早期裂纹转子振动分析理论模型,提出利用112维谱对早期裂纹振动信号进行分析。然后,利用112维谱分析法对早期裂纹转子理论模型和早期裂纹转子故障实验数据进行了具体分析。理论模型和实验数据分析结果都表明:应用112维谱对实际发动机转子早期裂纹故障信号进行分析,不仅能够得到一般频谱分析法难以获得的故障特征频率,还能对混叠噪声信号进行降噪。因此,112维谱能够有效的诊断航空发动机转子裂纹故障,在航空发动机故障诊断中具有一定的应用价值。 相似文献
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为了研究复杂涡动引起的裂纹非线性呼吸行为对转子临界转速的影响,构建了带横向裂纹Jeffcott转子的通用运动方程,利用新建运动方程对临界转速附近裂纹转子的稳态响应进行了数值研究。发现裂纹的非线性呼吸行为对转子不但具有增强稳定性的作用(与开裂纹转子相比),而且在一定条件下具有降低振动响应的作用(与无裂纹转子相比)。与无裂纹转子相似,稳定的裂纹转子的临界转速等于响应振幅最大且重心转向约90°对应的转速。裂纹转子的临界转速值随不平衡量方位角在开裂纹和闭裂纹转子固有频率之间变化。在转子实验台上进行了裂纹转子通过临界转速的实验验证,观察数据支持理论研究结果。 相似文献
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针对反应堆主冷却剂泵经过长期运行后,可能会出现的转子裂纹故障,利用小波分析,能够实现对故障特征的识别。结合反应堆主冷却剂泵裂纹转子振动模型的仿真信号,运用连续小波变换的方法,从小波基库中选出不同小波基分别计算与故障信号的互相关系数,确定最大值,其对应的小波基即为转子裂纹故障信号的最优小波基,并使用该小波基对故障信号进行分析,将功率谱、变换尺度以及频率以三维图的形式刻画出来。仿真结果表明,最大互相关系数选出的小波基可以作为转子裂纹故障信号的最优小波基,并且能够很好的识别出转子裂纹故障特征。 相似文献
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Jeffcott裂纹转子动力特性的研究 总被引:16,自引:5,他引:11
本文采用适当的裂纹开闭模型,导出了固定坐标系中裂纹轴的刚矩阵,建立了水平Jeffcott裂纹转子的振动微分方程,并对其进行了仿真计算。数值仿真表明:裂纹转子的响应中出现2x、3x等倍频分量,并产生分数次共振现象。在超临界转速区,倍频分量很小,但在响应的相频特性图中2x、3x处相位变化很大。参数β和e^-主要影响1x谐波分量,对2x、3x等倍频分量影响很小。由于裂纹的存在,转子轨迹的中心也发生偏移。在临界速附近,转子运行过程中裂纹处于常开或常闭状态。一般情况,当转子的偏心e^-小于1时,裂纹在转子运行过程中总是时开时闭的。这些结论将有助于转子裂纹故障的监测和诊断。 相似文献
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《基于微分的经验模式方法在转子裂纹和碰摩故障诊断中的应用》 总被引:1,自引:0,他引:1
介绍了基于微分的经验模式方法(DEMD),在Jeffcott裂纹转子模型和碰摩转子模型基础上,对裂纹和碰摩信号进行时间响应分析。结果表明,DEMD比传统的EMD方法呈现出更好的检测效果。研究工作为裂纹和碰摩转子故障诊断提供了一种工具。 相似文献
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K. N. Akhurst T. C. Lindley K. J. Nix 《Fatigue & Fracture of Engineering Materials & Structures》1983,6(4):345-348
Abstract— Four particularly pronounced beachmarks have been identified on the fracture surface of a cracked rotor. A correlation has been made between these beachmarks and events in the operational record. Fatigue crack growth calculations have been performed for a chordally cracked shaft subject to alternating self-weight bend stresses. The shaft dimensions and loading used correspond to the position of the crack in the rotor and growth rates were calculated over a range of crack depths spanning the positions of the major beachmarks. The results of the calculations agree with the beachmark correlation if allowance is made for the effect of the torsional loading of the shaft. 相似文献
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针对含拉杆裂纹的转子非线性振动现象,基于Paris裂纹扩展规律,建立了裂纹拉杆刚度模型;以界面接触刚度表征拉杆预紧作用,建立了轮盘接触刚度模型;采用Capone短轴承模型,完成了含拉杆裂纹的转子连接界面非线性动力学建模。通过系统Poincare截面分析发现,在转速与偏心多因素影响下得到的e-n分岔集中,系统在倍周期分岔与拟周期分岔之间交替变化;在裂纹扩展与转速的η-n分岔集中,解的分岔点分布不连续;不同转速下,位移随裂纹扩展的分岔轨迹比较复杂,拉杆裂纹的存在会加速或减缓分岔点的出现。结果表明:拉杆裂纹对转子稳定性作用机理受系统参数集的影响。研究结论对拉杆转子的参数设计与故障识别有一定意义。 相似文献
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以拉杆转子为对象,对具有横向裂纹的拉杆转子非线性动力学响应特性进行研究。基于达朗贝尔原理建立考虑轮盘之间非线性接触特性的裂纹拉杆转子系统运动方程。采用数值积分方法对运动方程进行求解,得到轮盘振幅随转速变化的曲线。分析裂纹刚度减小量、轮盘质量偏心矢量夹角、接触面阻尼系数、裂纹角等系统参数对轮盘幅频特性的影响。同整体转子相比,裂纹拉杆转子除在1/2阶、1/3阶临界转速附近发生1/2阶、1/3阶亚谐共振外,在超临界转速区域存在超谐共振。系统参数对裂纹拉杆转子幅频特性曲线影响较大。分析结果可为认识裂纹转子系统的响应特性、开展裂纹转子的故障诊断提供理论指导。 相似文献
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The dynamics and diagnostics of a cracked rotor have been gaining importance in recent years. The early detection of faults
like fatigue cracks in rotor shafts are very important to prevent catastrophic failure of the rotor system. Vibration monitoring
during start up or shut-down is as important as during steady state operation to detect cracks especially for machines such
as aircraft engines which start and stop quite frequently and run at high speeds. So, the transient data of the cracked rotor
has been transformed using the wavelet transforms for crack detection. Most of the works quoted in the literature used 1D
wavelets or 2D wavelets (Continuous Wavelet Transform-CWT) for crack detection. The crack detectors in the signals are both
time as well as frequency dependent. So, the use of 2D wavelets is also not enough to detect the crack. In the present work
a 3D wavelet (CWT) has been utilized which clearly indicates both the time and frequency features of the crack. The presence
of sub-criticals in the CWT may be a best crack indicator but it is not always reliable. The addition of noise to the signal
may sometimes lead to inaccurate results. So, there is a need to identify a parameter in addition to the sub-criticals. The
phase angle between the two signals (cracked and un-cracked) or two transverse vibrations can be a better crack indicator
because it is very less sensitive to noise disturbance. So, to extract the above phase angle a new transform has been applied
called Cross Wavelet Transform (XWT). The XWT is exploited for the first time to a rotor fault detection system in the present
work. Some interesting results have been obtained using the same. The advantage of the XWT is that both, the phase angles
between the transverse signals and also the amplitudes of sub-criticals are viewed in a single plot. Parametric analysis is
also carried out by varying crack depth and crack position for diagnostic purposes. The inverse problem of crack identification
(i.e. determining the crack parameters through known vibration data) has also been carried out using Artificial Neural Network
(ANN). 相似文献