CN102467654A - Structural modal parameter identification method - Google Patents
Structural modal parameter identification method Download PDFInfo
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- CN102467654A CN102467654A CN2010105315989A CN201010531598A CN102467654A CN 102467654 A CN102467654 A CN 102467654A CN 2010105315989 A CN2010105315989 A CN 2010105315989A CN 201010531598 A CN201010531598 A CN 201010531598A CN 102467654 A CN102467654 A CN 102467654A
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Abstract
The invention relates to a structural modal parameter identification method used for identification of modal frequency, damping and vibration mode of civil and space structures. The method comprises the following steps: carrying out experience mode decomposition on a noisy vibration testing signal of a structure, and carrying out power spectrum analysis on an obtained intrinsic mode function component after decomposition; according to a frequency structure of each intrinsic mode function component, selecting an intrinsic mode function component containing structural modal information, and carrying out linear superposition to obtain a reconstruction signal; utilizing the reconstruction signal to carry out Morlet wavelet transformation, carrying out least square linear fitting on instantaneous amplitude logarithm and phase of a wavelet transformation coefficient corresponding to each modal, and calculating modal frequency, modal damping and modal vibration mode of the structure.
Description
[technical field]
Patent of the present invention relates to a kind of modal parameters recognition methods; More particularly; Relate to a kind of modal parameters recognition methods based on empirical mode decomposition and Morlet wavelet transformation, it is used for the identification of model frequency, damping and the vibration shape of building, aerospace structure.
[background technology]
Be used to discern building, aerospace structure model frequency, damping and the vibration shape empirical mode decomposition and wavelet transformation technique be that prior art is known; But existing generally is the vibration monitoring of engineering structure signal to be carried out empirical mode decomposition obtain a series of intrinsic mode functions components with class methods; Then single intrinsic mode functions is carried out Hilbert transform or carried out wavelet transformation, carry out Modal Parameter Identification again.A great defective of these methods is to be to be directed against the reasonable shock response signal of signal to noise ratio (S/N ratio).Because than higher, the intrinsic mode functions component that has noise effect to decomposite slightly is just not ideal, loses clear and definite mode of oscillation meaning to the requirement of signal for empirical mode decomposition.Although alleviate this problem with using the way of bandpass filtering in the class methods; But the imagination of mode aliasing still takes place in intrinsic mode functions component easily that obtain; So the method for carrying out the mode of oscillation decoupling zero through empirical mode decomposition is often unsuccessful under the not high situation of signal to noise ratio (S/N ratio), modal parameter that can't recognition structure.
[summary of the invention]
Owing to receive under the situation of noise pollution at the vibration-testing signal; The method of carrying out the mode of oscillation decoupling zero through empirical mode decomposition is often unsuccessful under the not high situation of signal to noise ratio (S/N ratio); Modal parameter that can't recognition structure; Defective in view of above-mentioned prior art existence; An object of the present invention is to provide a kind of modal parameters recognition methods based on empirical mode decomposition and Morlet wavelet transformation; It utilizes empirical mode decomposition to carry out adopting the Morlet wavelet transformation to carry out the extraction of mode decoupling zero and modal parameter after mode screening and the signal reconstruction, and this method can obtain modal parameter more accurately under the vibration-testing signal receives the situation of noise pollution.
Particularly, the present invention adopts following technical scheme, a kind of modal parameters recognition methods: empirical mode decomposition is at first carried out to the noisy vibration-testing signal of structure in (1), and the intrinsic mode functions component that decomposes the back acquisition is carried out power spectrumanalysis; (2) select to comprise the intrinsic mode functions of structural modal information then according to the frequency structure of each intrinsic mode functions component, carry out linear superposition and obtain reconstruction signal; (3) utilize reconstruction signal to carry out the Morlet wavelet transformation, the instantaneous amplitude logarithm and the phase place of wavelet conversion coefficient are carried out least square linear fit, the model frequency of computation structure, modal damping and Mode Shape.Thereby through method of the present invention, under the unfavorable situation of signal to noise ratio (S/N ratio), Morlet wavelet transformation capable of using carries out parameter identification to the superposed signal of intrinsic mode functions and replaces single intrinsic mode functions is carried out parameter identification respectively.
Than prior art; Through method of the present invention; Under the prerequisite of the impact shock response signal that obtains structure, obtain modal parameters information more accurately thereby more can carry out the mode decoupling zero effectively, even if signal to noise ratio (S/N ratio) is not high; Also can obtain modal parameters accurately, can be widely used in the identification of model frequency, damping and the vibration shape of building, aerospace structure.
[description of drawings]
Fig. 1 illustrates the acceleration impact signal of many-degrees of freedom system, and SF is 20 hertz, 25 seconds sampling times, and sampling optimization 512, signal to noise ratio (S/N ratio) is 10.
Fig. 2 illustrates signal shown in Figure 1 is carried out the intrinsic mode functions component that obtains after the empirical mode decomposition.
Fig. 3 illustrates through the Morlet wavelet transformation spectrum of mode screening back to being done after the first five intrinsic mode functions component linear superposition; Last figure from left to right is respectively the real part and the imaginary part of wavelet conversion coefficient, and figure below from left to right is respectively the amplitude and the phase place of wavelet conversion coefficient.
Fig. 4 illustrates the instantaneous amplitude logarithm and the instantaneous phase least square fitting relation of the wavelet conversion coefficient of wavelet ridge (the high bright position) correspondence among Fig. 3, is respectively the first rank mode to the, three rank mode from top to bottom.
[embodiment]
To combine accompanying drawing that embodiments of the invention are further described below.
According to a preferred embodiment of the present invention, a kind of modal parameters recognition methods may further comprise the steps:
(1) power spectrum of vibration signal shown in Figure 1 is analyzed the probable ranges of confirming model frequency, and this signal is carried out preliminary bandpass filtering;
(the noisy vibration-testing signal of 2 pairs of structures carries out empirical mode decomposition, obtains a plurality of intrinsic mode functions components, and its result is with reference to Fig. 2;
(3) select to comprise the intrinsic mode functions of structural modal information then according to the frequency structure of each intrinsic mode functions component, carry out linear superposition and obtain reconstruction signal;
(4) utilize reconstruction signal to carry out the Morlet wavelet transformation, extract the pairing wavelet conversion coefficient of each rank mode according to the local maximum in the little wave spectrogram (wavelet ridge, i.e. high bright position in the spectrogram), its result is with reference to Fig. 3;
(5) the instantaneous amplitude logarithm and the instantaneous phase of the pairing wavelet conversion coefficient of each rank mode are carried out least square linear fit, obtain instantaneous amplitude logarithm and instantaneous phase linear relationship chart in time, calculate its corresponding slope and be respectively s
1, s
2, then by-ζ
iω
Ni=s
1,
Can calculate these rank model frequency ω
Ni, modal damping compares ζ
i, its result is with reference to Fig. 4 and table 1;
(6) the vibration-testing data that the measuring point of structure diverse location obtained repeat above-mentioned steps, and the instantaneous amplitude logarithm of the wavelet conversion coefficient that 2 same order mode are corresponding subtracts each other that to ask its index be exactly that this rank mode is at this vibration shape of 2 ratio; Symbol is by phase decision, if 2 phase differential is approximately zero, and jack per line then, if 2 phase differential is approximately 180 degree, opposite sign then, the result is with reference to table 2.
Table 1 is first three rank model frequency of structure and the recognition result of modal damping ratio and the comparison of discre value and theoretical value of this paper specific embodiment; And table 2 is recognition result and the comparison of discre value and theoretical value of first three rank Mode Shape of structure of this paper specific embodiment.
Table 1 model frequency and damping ratio recognition result
Table 2 recognition of vibration result
The theoretical value of first three the rank modal parameter of structure that provides through table 1 and table 2 can be found out with the comparison of using the discre value that method described herein obtains; Be under 10 the situation in signal to noise ratio (S/N ratio), decompose and the Morlet wavelet transformation carries out the mode decoupling zero and parameter recognition can be carried out the mode decoupling zero effectively and obtained modal parameters more accurately based on structure acceleration shock response signal use experience pattern.This method of present embodiment explanation can still can successfully be carried out the structural modal decoupling zero and obtain parameter recognition result accurately in the situation that the structural impact response signal receives noise pollution.
Specific embodiment described herein only is that patent spirit of the present invention is illustrated.Patent person of ordinary skill in the field of the present invention can make various modifications or replenishes or adopt similar mode to substitute described specific embodiment, but can't depart from the spirit of patent of the present invention or surmount the defined scope of appended claims.
Claims (1)
1. modal parameters recognition methods, the identification that it is used for model frequency, damping and the vibration shape of building, aerospace structure is characterized in that, said recognition methods comprises:
(1) at first the noisy vibration-testing signal of structure is carried out empirical mode decomposition, and carry out power spectrumanalysis, obtain the frequency structure of each intrinsic mode functions component decomposing the intrinsic mode functions component that the back obtains;
(2) select to comprise the intrinsic mode functions of structural modal information then according to the frequency structure of each intrinsic mode functions component of gained, it is carried out linear superposition obtain reconstruction signal;
(3) utilize said reconstruction signal to carry out the Morlet wavelet transformation at last, the instantaneous amplitude logarithm and the phase place of wavelet conversion coefficient are carried out least square linear fit, calculate model frequency, modal damping and the Mode Shape of said building, aerospace structure.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105787655A (en) * | 2016-02-24 | 2016-07-20 | 西安工业大学 | Superhigh-layer structure modal parameter identification method |
| CN106548031A (en) * | 2016-11-07 | 2017-03-29 | 浙江大学 | A kind of Identification of Modal Parameter |
| CN109100103A (en) * | 2018-07-06 | 2018-12-28 | 哈尔滨工业大学（深圳） | Based on blower 1p signal recognition method, device, terminal and the computer readable storage medium continuously monitored |
| CN111368642A (en) * | 2020-02-11 | 2020-07-03 | 北京交通大学 | Method for identifying modal frequency of railway ballastless track steel rail based on wheel-rail excitation |
| CN111368642B (en) * | 2020-02-11 | 2024-05-14 | 北京交通大学 | Railway track component modal identification method |
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| CN1869972A (en) * | 2006-06-15 | 2006-11-29 | 沈阳建筑大学 | Structural response analysing method of improving Hibert-Huang transform |
| CN101158623A (en) * | 2007-09-29 | 2008-04-09 | 南京航空航天大学 | Acquiring system eigenfunction and signal feature value method |
| CN101822548A (en) * | 2010-03-19 | 2010-09-08 | 哈尔滨工业大学（威海） | Ultrasound signal de-noising method based on correlation analysis and empirical mode decomposition |
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2010
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1869972A (en) * | 2006-06-15 | 2006-11-29 | 沈阳建筑大学 | Structural response analysing method of improving Hibert-Huang transform |
| CN101158623A (en) * | 2007-09-29 | 2008-04-09 | 南京航空航天大学 | Acquiring system eigenfunction and signal feature value method |
| CN101822548A (en) * | 2010-03-19 | 2010-09-08 | 哈尔滨工业大学（威海） | Ultrasound signal de-noising method based on correlation analysis and empirical mode decomposition |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105787655A (en) * | 2016-02-24 | 2016-07-20 | 西安工业大学 | Superhigh-layer structure modal parameter identification method |
| CN105787655B (en) * | 2016-02-24 | 2020-08-04 | 西安工业大学 | Method for identifying modal parameters of super high-rise structure |
| CN106548031A (en) * | 2016-11-07 | 2017-03-29 | 浙江大学 | A kind of Identification of Modal Parameter |
| CN109100103A (en) * | 2018-07-06 | 2018-12-28 | 哈尔滨工业大学（深圳） | Based on blower 1p signal recognition method, device, terminal and the computer readable storage medium continuously monitored |
| WO2020007375A1 (en) * | 2018-07-06 | 2020-01-09 | 哈尔滨工业大学（深圳） | Continuous monitoring-based method and device for identifying 1p signal of wind turbine, terminal, and computer readable storage medium |
| CN109100103B (en) * | 2018-07-06 | 2020-04-14 | 哈尔滨工业大学（深圳） | Fan 1p signal identification method, device, terminal and computer readable storage medium based on continuous monitoring |
| CN111368642A (en) * | 2020-02-11 | 2020-07-03 | 北京交通大学 | Method for identifying modal frequency of railway ballastless track steel rail based on wheel-rail excitation |
| CN111368642B (en) * | 2020-02-11 | 2024-05-14 | 北京交通大学 | Railway track component modal identification method |
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Application publication date: 20120523 |