实验技术与管理2025，Vol.42Issue(11)：60-66,7.DOI:10.16791/j.cnki.sjg.2025.11.006
转子系统的弯扭振动信号解调及实验方法
Demodulation and experimental methods for bending and torsional vibration signals of rotor systems
摘要
Abstract
[Objective]This study aims to obtain vibration responses with synchronized bending and torsional timing at consistent cross-sectional positions under rotor operating conditions,improve the measurement accuracy of rotor torsional vibration using the zebra tape method with low keyphasor counts,reduce the influence of sensors and other attachments on rotor dynamic characteristics,and address the bending-torsional coupled measurement problem in complex rotor systems.To achieve these goals,we propose a trend-term method for demodulating bending vibration signals and a peak method for demodulating torsional vibration signals,both based on ultra-high-frequency data acquisition.[Methods]A rotor test bench was designed to study bending,torsional,and bending-torsional coupled vibrations.Thin metal zebra tapes(0.1 mm)were evenly bonded circumferentially to the outer diameters of disks at the reference and measurement sections.The radial vibration signals modulated by the zebra tapes were measured using eddy current displacement sensors.The amplitude demodulation of the sensors'raw data provided the bending vibration signal,whereas the phase demodulation provided the torsional vibration signal.The trend term method was first applied to demodulate the bending vibration signals at the reference and measurement sections.Subsequently,the disk bending vibration signals were removed from the raw data to obtain zebra tape signals containing torsional information.The peak method was then used to demodulate the torsional vibration signal at the measurement section.Simulation verifications of bending-torsional vibration signal demodulation were conducted under 1X,fractional-order,and harmonic torsional vibration orders.The demodulated bending and torsional vibration results under these three conditions showed excellent agreement with the true values,validating the accuracy of the proposed methods.The measurement accuracy of the torsional angular displacement decreased with the rotational speed but improved with the sensor sampling frequency.[Results]Three-dimensional waterfall plots and chromatograms of bending/torsional for speed,order,and amplitudes were obtained through Jeffcott rotor acceleration experiments.These identified the bending critical speed,the first two torsional resonance speeds,and the bending-torsional coupled resonance speed.Torsional vibration measurements under steady-state speed and non-uniform acceleration conditions demonstrate that combining 40 MHz ultra-high-frequency data acquisition with the trend term and peak methods resolves the low-accuracy issue in rotor torsional vibration measurement.Even with only 26 keyphasor counts,the measurement accuracy can reach 1.05×10-30° at 7 000 r/min.[Conclusions]This study reveals that bending and torsional vibrations exhibit distinct spectral and order characteristics.The torsional resonance shows broad-spectrum characteristics,but is primarily dominated by the 1X component within the resonance region,and shows a strong correlation with the rotor speed outside this zone.This indicates the distinct features of bending and torsional vibrations for rotor fault diagnosis.Pure torsional resonance has almost no effect on the rotor bending vibration;however,before the rotor passes through the bending critical speed,the bending vibration significantly influences the torsional vibration,leading to bending-torsional coupled resonance.The proposed methods can be applied to rotor bending-torsional coupled vibration experiments under unbalance,misalignment,rub-impact,crack,and bearing fault conditions.The proposed methods are also suitable for vibration characteristic experiments on co-rotating and counter-rotating dual-rotor systems.This study provides support for high-precision,low-cost torsional vibration measurement of complex rotor systems and establishes groundbreaking measurement techniques for rotor bending-torsional coupled vibration studies.关键词
转子/扭转振动/弯扭耦合/信号解调/实验Key words
rotor/torsional vibration/bending-torsional coupled vibration/signal demodulation/experiment分类
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陈茉莉,吴辰炫..转子系统的弯扭振动信号解调及实验方法[J].实验技术与管理,2025,42(11):60-66,7.基金项目
国家自然科学基金项目(52475106) （52475106）
"两机专项"项目(2017-Ⅳ-0008-0045-JX,J2019-Ⅳ-0004-0071) （2017-Ⅳ-0008-0045-JX,J2019-Ⅳ-0004-0071）
