CN110849971B - Structural modal parameter identification method based on double-exponential window function method - Google Patents

Structural modal parameter identification method based on double-exponential window function method Download PDF

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CN110849971B
CN110849971B CN201911149636.1A CN201911149636A CN110849971B CN 110849971 B CN110849971 B CN 110849971B CN 201911149636 A CN201911149636 A CN 201911149636A CN 110849971 B CN110849971 B CN 110849971B
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admittance
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damping
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圣小珍
张淑敏
杨世均
陈宗平
郎世伟
史佳伟
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Southwest Jiaotong University
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Abstract

The invention discloses a structural modal parameter identification method based on a double-exponential window function method, which comprises the steps of obtaining time domain signals of a plurality of measuring points on a structure by a hammering method; introducing an exponential window function with the attenuation rate b, windowing acceleration and force time domain signals, introducing a time length T to eliminate errors caused by Fourier transform after the finite length signal is cut off, and constructing a theoretical cut-off windowing admittance; constructing a truncated windowing admittance of the test by using the test acceleration and force time domain signals; obtaining the peak value of the test truncation windowing admittance averaged by all the test points of the structure as the natural frequency of the structure; given attenuation rate b1Attenuation ratio b2And taking a real part of the theoretical/test truncated windowed admittance to obtain an equation set related to the attenuation rate, the modal participation coefficient, the natural frequency and the damping ratio, and solving the equation set by adopting a nonlinear equation solver to obtain the damping ratio of each measuring point under the natural frequency. And then averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.

Description

Structural modal parameter identification method based on double-exponential window function method
Technical Field
The invention relates to a structure modal parameter identification technology, in particular to a structure modal parameter identification method based on a double-exponential window function method.
Background
Damping of a structure is an important parameter describing the energy dissipation of the structure, and is widely applied in the engineering field, and is generally obtained through experiments. The damping characteristic of the actual structure is very complex, and a complete and effective damping model is not established so far to describe the damping characteristic of the structure. Most of the existing damping models are proposed under the premise of empirical assumption.
Structural damping identification methods are numerous, and the existing method widely adopts a test modal analysis method to identify the natural frequency and the damping ratio, and mainly comprises a time domain analysis method and a frequency domain analysis method, such as an orthogonal polynomial fitting method, a least square complex exponential method, a least square complex frequency domain method and the like. Currently, various methods of damping identification are still under development, such as LMS PolyMAX, which has been widely recognized in recent years. The method mainly carries out windowing processing on the admittance of the structure, further solves the modal parameters of the structure by solving the nonlinear equation set containing the modal parameters, has simple and convenient process, high realization degree and flexible selection of attenuation rate aiming at different structures, and is beneficial to engineering application.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a structural modal parameter identification method based on a double-exponential window function method, which is mainly used for large-scale complex structures.
In order to achieve the purpose of the invention, the invention adopts the technical scheme that:
the structural modal parameter identification method based on the double-exponential window function method is provided, and comprises the following steps:
s1, acquiring time domain signals of acceleration and force of a plurality of measuring points on the structure by a hammering method;
s2, introducing an exponential window function with the attenuation rate b, windowing force and acceleration, and introducing a theoretical cutoff windowing admittance of a time length T construction structure
Figure BDA0002283184320000021
w(t)＝e-bt，(t≥0)
Figure BDA0002283184320000022
Wherein w (t) is an exponential window function; t is time; e pairs of natural logarithms; r is a modal order; alpha is alphasIs the participation coefficient of the mode of the s order; omega is frequency; omegasAnd
Figure BDA0002283184320000026
respectively the modal frequency and the initial value of the damping ratio of the s-th order;
Figure BDA0002283184320000027
the damping ratio is increased after the window function is introduced; i is an imaginary unit;
s3, constructing a test truncation windowing admittance by using the test acceleration and force time domain signals
Figure BDA0002283184320000028
Figure BDA0002283184320000023
Wherein the content of the first and second substances,
Figure BDA0002283184320000024
to cut off the acceleration frequency domain signal for windowing,
Figure BDA0002283184320000025
windowing and intercepting a force frequency domain signal;
s4, obtaining the peak value of the test truncation windowing admittance of the structure after the average of all the test points as the natural frequency of the structure;
s5, setting attenuation rate b1Attenuation ratio b2Taking the real part of the theoretical truncated windowed admittance and the test truncated windowed admittance to obtain the attenuation ratio b1Attenuation ratio b2Modal participation coefficient alphasNatural frequency omegasDamping ratio of
Figure BDA0002283184320000029
OfA program group; solving an equation set by adopting a nonlinear equation solver to obtain the damping ratio of each measuring point under the natural frequency; and then averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.
The invention has the beneficial effects that: (1) the method can realize the identification of modal parameters only by the original point admittance data of a plurality of measuring points on the structure, and compared with the cross-point admittance of the structure, the method has the advantages of no influence of the space between the excitation point and the response point and small noise interference; (2) by introducing the time length T, the error caused by Fourier transform after the finite length signal is cut off can be eliminated; (3) attenuation ratio b1Attenuation ratio b2The method can be flexibly selected according to different structures, can select a negative attenuation rate to highlight a peak value for a structure with large damping, and can select a positive attenuation rate to eliminate test noise for a structure with small damping, so that the method can accurately identify the damping ratio of the structure and has strong robustness for signals with strong noise interference.
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Fig. 1 is a flowchart of a structural modal parameter identification method based on a dual-exponential window function method.
FIG. 2 is a velocity time plot of a certain impeller of a turbocharger introducing a 3dB signal-to-noise ratio when an impact force is applied;
fig. 3 is the true damping ratio of the impeller, the damping ratio identified using this scheme, the damping ratio identified using PolyMAX, and the relative error of the damping ratios identified by the two methods with respect to the true damping ratio.
FIG. 4 is a schematic diagram of a finite element model of a floor aluminum profile for a high-speed train.
Fig. 5 is a schematic view of upper and lower panel measuring points of an aluminum profile hammering test.
FIG. 6 shows the attenuation b of the original admittance at a certain measuring point of the aluminum profile10.1dB and b1And processing the exponential window function of-20 dB to obtain an origin admittance real part, wherein the solid line is 0.1dB attenuation rate, and the dotted line is-20 dB attenuation rate.
Fig. 7 is a comparison of damping ratios identified by the aluminum profile through the scheme and PloyMAX.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.
Referring to fig. 1, fig. 1 shows a flow chart of a structural modal parameter identification method based on a bi-exponential window function method; as shown in fig. 1, the method S includes steps S1 to S5.
In step S1, acquiring time domain signals of acceleration and force of a plurality of measuring points on the structure by a hammering method; specifically, N measuring points are randomly selected on the structure, time domain signal data of acceleration and force of the N measuring points are respectively measured by an acceleration sensor, a force hammer and a data acquisition module, and each measuring point is measured at least five times for averaging.
According to the scheme, the time domain signals of the structure are collected through the plurality of measuring points, and the plurality of measuring points can reflect the energy dissipation conditions of different positions of the structure, so that the modal frequency and the damping ratio obtained subsequently can be closer to the actual real value of the structure than the initial value.
In step S2, an exponential window function with an attenuation rate b is introduced, force and acceleration are windowed, a time length T is introduced to eliminate errors caused by Fourier transform after finite signal truncation, and the theoretical truncation windowed admittance of the structure is constructed
Figure BDA0002283184320000041
w(t)＝e-bt，(t≥0)
Figure BDA0002283184320000042
Wherein w (t) is an exponential window function; t is time; e pairs of natural logarithms; r is a modal order; alpha is alphasIs the participation coefficient of the mode of the s order; omega is frequency; omegasAnd
Figure BDA0002283184320000043
respectively the modal frequency and the initial value of the damping ratio of the s-th order;
Figure BDA0002283184320000044
the damping ratio is increased after the window function is introduced; i is an imaginary unit;
the theoretical truncation windowing admittance constructed by the scheme eliminates errors caused by Fourier transformation after a finite-length signal is truncated, the natural frequency and the damping ratio are solved through the constructed model, the calculation accuracy of modal parameters (the modal parameters comprise at least the natural frequency and the damping ratio) is guaranteed to be higher, and only the original point admittance data of the structure are needed.
In one embodiment of the invention, an exponential window function is applied to the force and acceleration, introducing a theoretical truncated windowed admittance of a time-length-of-time T build structure
Figure BDA0002283184320000051
Further comprising:
s21 construction of theoretical truncation and windowing admittance
Figure BDA0002283184320000052
Comprises the following steps:
Figure BDA0002283184320000053
wherein the content of the first and second substances,
Figure BDA0002283184320000054
is derived for the displacement impulse response function;
s22, Fourier transform is carried out on the displacement frequency response function to obtain a displacement time response function h (t) with damping smaller than a set threshold:
Figure BDA0002283184320000055
s23, introducing the displacement time response function h (t) into a theoretical truncation windowing admittance model, and constructing a theoretical truncation windowing admittance
Figure BDA0002283184320000056
Figure BDA0002283184320000057
The scheme is mainly used for a complex structure with small damping, in particular to a structure with a damping ratio less than 0.01, wherein the set threshold is 0.01.
In step S3, a test truncated windowed admittance is constructed using the test acceleration and force time domain signals
Figure BDA0002283184320000058
Figure BDA0002283184320000059
Wherein the content of the first and second substances,
Figure BDA0002283184320000061
to cut off the acceleration frequency domain signal for windowing,
Figure BDA0002283184320000062
and (5) windowing and cutting off the force frequency domain signal.
In this embodiment, step S3 preferably further includes:
s31, carrying out finite-length windowed Fourier transform on the acceleration time interval signal:
Figure BDA0002283184320000063
wherein the content of the first and second substances,
Figure BDA0002283184320000064
windowing the acceleration for the cutoff at frequency ω; e pairs of natural logarithms;t is the time length; a (t) is the acceleration value tested at the time t; i is an imaginary unit;
Figure BDA0002283184320000065
windowing the truncation at frequency ω;
s32, cutting off the windowed acceleration
Figure BDA0002283184320000066
Substitution test cut-off windowed admittance
Figure BDA0002283184320000067
Figure BDA0002283184320000068
In step S4, the peak value of the test truncated windowed admittance after averaging all the test points of the structure is obtained as the natural frequency of the structure;
in this embodiment, step S4 preferably further includes:
acquiring all peak values of the structural windowed admittance of the measuring points and wave troughs on two sides of each peak value;
selecting a smaller trough in two sides of the peak value, and calculating the distance between the peak value and the selected trough;
and judging whether the distance is larger than a set distance, if so, keeping, and otherwise, deleting the corresponding peak value.
According to the scheme, the peak value is removed in the mode, and partial invalid peak values can be removed, so that the accuracy of the acquired modal frequency is improved.
In step S5, attenuation rate b is specified1Attenuation ratio b2Attenuation ratio b2＝1.005b1(ii) a Taking the real part of the windowed admittance of the structure to obtain the attenuation factor b1Attenuation ratio b2Modal participation coefficient alphasNatural frequency omegasDamping ratio of
Figure BDA0002283184320000069
Using a system of equations ofAnd solving the equation set by the nonlinear equation solver to obtain the damping ratio of each measuring point under the natural frequency, and averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.
Wherein, the step S5 further includes:
s51, setting attenuation rate b1Attenuation ratio b2And taking the real part of the theoretical truncated windowing admittance and the test truncated windowing admittance:
Figure BDA0002283184320000076
Figure BDA0002283184320000071
wherein the content of the first and second substances,
Figure BDA0002283184320000072
taking a real part for theoretical truncation and windowing admittance;
Figure BDA0002283184320000077
and
Figure BDA0002283184320000078
respectively corresponding to the attenuation ratio b1Attenuation ratio b2With respect to the time of flight with respect to omega,
Figure BDA0002283184320000079
and T;
Figure BDA0002283184320000073
Figure BDA0002283184320000074
respectively corresponding to the attenuation ratio b1Attenuation ratio b2Time-of-flight test cut-off windowing admittance at natural frequency omegasThe real part of (c).
S52, constructing the damping ratio of the mode in the S-th order mode
Figure BDA00022831843200000710
Equation for initial values:
Figure BDA0002283184320000075
s53, solving the damping of the equation set in the S31 by using the modal damping ratio initial value obtained in the S32 as the initial value of the equation set in the S31;
and S54, averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.
The following describes the accuracy of the modal parameters obtained by the identification method provided by the present embodiment with reference to specific examples:
the first embodiment is as follows: turbocharger impeller (30 vanes) model
Taking a turbocharger with 30 impellers as an example, by solving a differential equation containing 10% of blade detuning, a speed time domain response signal of 30 blades when each blade is acted by impact force is obtained, the signal duration is 1s, and the time step is 1 multiplied by 10, wherein the time step is delta t-5s; table 1 gives the true natural frequency and damping ratio of the impeller by solving the eigen equation composed of the mass matrix and stiffness matrix of the impeller.
TABLE 1 true natural frequency and damping ratio of the impeller
Figure BDA0002283184320000081
In order to verify the robustness of the identification method of the scheme, a signal-to-noise ratio of 3dB is added to each group of signals, and it can be seen from FIG. 2 that the signals are seriously polluted by noise at the moment. Based on the force and velocity time courses, a 30 × 30 structural admittance matrix may be generated. And sequentially selecting the data of the 1 st, 5 th, 16 th and 23 th columns of the structure admittance matrix, importing the data into LMS-PolyMAX for modal analysis, and averaging the identified damping ratios to obtain the damping ratio of the structure.
According to the steps of the embodiment of the scheme, 30 original point admittance data in the admittance matrix are selected, and the inherent frequency and the damping ratio are identified. The identified damping ratios are shown in fig. 3, and the relative errors of the damping ratios in the 1 st and 20 th order of the 30 damping ratios identified by PolyMAX are each greater than 20% compared to the damping ratio identified using this scheme. In contrast, the damping ratio recognized by the recognition method provided by the scheme is closer to the true value. The average relative error of the identification method of the scheme is 1.96%, while the average relative error of the PolyMAX method is 4.05%, so that the identification method of the scheme has strong robustness.
The second embodiment: floor aluminum section for high-speed train
The aluminum profile is a typical dynamic complex structure, a finite element model of the aluminum profile is schematically shown in fig. 4, and 19 points are randomly selected on the upper panel and the lower panel, as shown in fig. 5. Respectively carrying out a hammering test on each measuring point, collecting acceleration time-course signals of 19 measuring points, wherein the signal duration is 2s, and the time step length is 1.2207 multiplied by 10-4. Based on the force and acceleration time course signals, a 19 × 19 admittance matrix may be obtained according to the steps of the present solution.
To illustrate that the scheme can flexibly select the attenuation rate, the attenuation rate b is respectively given10.1dB and b1The force and acceleration time-course signals are truncated and windowed as an exponential window function of-20 dB to obtain real values for the theoretical truncated windowed admittance and the test truncated windowed admittance as shown in fig. 6, where the solid line is the 0.1dB attenuation rate and the dashed line is the-20 dB attenuation rate. By processing the origin admittance with a negative decay rate, the peak values of some modes become more obvious, which is beneficial to the identification of the natural frequency of the structure.
The structures are respectively given attenuation rates b1＝-20dB，b2＝1.005b1Taking the real part of the 19 truncated windowed origin admittances of the structure to obtain the attenuation ratio b1Attenuation ratio b2Modal participation coefficient alphasNatural frequency omegasDamping ratio of
Figure BDA0002283184320000091
The damping ratio of each measuring point under the natural frequency is obtained by solving the equation system by adopting a nonlinear equation solver. Then, the damping ratio of all measuring points is calculatedAveraged as the damping ratio of the structure. Meanwhile, each column of data of the admittance matrix is imported into the PolyMAX for damping ratio identification, and the identification results are averaged, and the result is shown in fig. 7. It can be seen that the recognition result of the scheme is similar to that of the PolyMAX.
It can be seen that the method of the present invention has the advantages of: (1) only the original point admittance data of the structure are needed, and compared with cross-point admittance, the signal to noise ratio is better, the test difficulty is reduced, and the working efficiency is improved; (2) fourier transformation errors caused by truncation of finite length signals are eliminated; (3) the selection of the attenuation rate is flexible, and different values and even negative attenuation rates can be selected according to the damping sizes of different structures; (4) the method has stronger robustness.

Claims (7)

1. The structural modal parameter identification method based on the double-exponential window function method is characterized by comprising the following steps:
s1, acquiring time domain signals of acceleration and force of a plurality of measuring points on the structure by a hammering method;
s2, introducing an exponential window function with the attenuation rate b, windowing force and acceleration, and introducing a theoretical cutoff windowing admittance of a time length T construction structure
Figure FDA0003020763560000011
w(t)＝e-bt，(t≥0)
Figure FDA0003020763560000012
Wherein w (t) is an exponential window function; t is time; e is the base number of the natural logarithm; r is a modal order; alpha is alphasIs the participation coefficient of the mode of the s order; omega is frequency; omegasAnd
Figure FDA0003020763560000013
respectively the modal frequency and the initial value of the damping ratio of the s-th order;
Figure FDA0003020763560000014
the damping ratio is increased after the window function is introduced; i is an imaginary unit;
s3, constructing a test truncation windowing admittance by using the test acceleration and force time domain signals
Figure FDA0003020763560000015
Figure FDA0003020763560000016
Wherein the content of the first and second substances,
Figure FDA0003020763560000017
is a windowed truncated acceleration frequency domain signal at frequency omega,
Figure FDA0003020763560000018
cutting off a force frequency domain signal for windowing;
s4, obtaining the peak value of the test truncation windowing admittance of the structure after the average of all the test points as the natural frequency of the structure;
s5, setting attenuation rate b1Attenuation ratio b2Taking the real part of the theoretical truncated windowed admittance and the test truncated windowed admittance to obtain the attenuation ratio b1Attenuation ratio b2Modal participation coefficient alphasModal frequency omegasInitial value of damping ratio
Figure FDA0003020763560000019
The system of equations (1); solving an equation set by adopting a nonlinear equation solver to obtain the damping ratio of each measuring point under the natural frequency; and then averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.
2. The method for identifying structural modal parameters based on the bi-exponential window function method of claim 1, characterized in that force and acceleration are windowed, introducing a theoretical truncated windowed admittance of a time length T-constructed structure
Figure FDA0003020763560000021
Further comprising:
s21 construction of theoretical truncation and windowing admittance
Figure FDA0003020763560000022
Comprises the following steps:
Figure FDA0003020763560000023
wherein the content of the first and second substances,
Figure FDA0003020763560000024
is derived for the displacement impulse response function;
s22, Fourier transform is carried out on the displacement frequency response function to obtain a displacement time response function h (t) with damping smaller than a set threshold:
Figure FDA0003020763560000025
s23, introducing the displacement time response function h (t) into the theoretical truncation windowing admittance model to obtain the theoretical truncation windowing admittance
Figure FDA0003020763560000026
Figure FDA0003020763560000027
3. The structural modal parameter identification method based on the bi-exponential window function method of claim 1, characterized in that a test truncated windowing admittance is constructed using test acceleration and force time domain signals
Figure FDA0003020763560000028
Further comprising:
s31, carrying out finite-length windowed Fourier transform on the acceleration time interval signal:
Figure FDA0003020763560000031
wherein T is a time length; a (t) is the acceleration value tested at the time t;
Figure FDA0003020763560000032
windowing the truncation at frequency ω;
s32, cutting the acceleration frequency domain signal by windowing
Figure FDA0003020763560000033
Substitution test cut-off windowed admittance
Figure FDA0003020763560000034
Figure FDA0003020763560000035
4. The method for identifying structural modal parameters based on the bi-exponential window function method of claim 1, wherein obtaining the peak value of the windowed admittance averaged over all the measured points of the structure as the natural frequency of the structure further comprises:
acquiring all peak values of the structural windowed admittance of the measuring points and wave troughs on two sides of each peak value;
selecting a smaller trough in two sides of the peak value, and calculating the distance between the peak value and the selected trough;
and judging whether the distance is larger than a set distance, if so, keeping, and otherwise, deleting the corresponding peak value.
5. The structural modal parameter identification method based on the dual exponential window function method according to claim 1 or 2, wherein the step S5 further comprises:
s51, setting attenuation rate b1Attenuation ratio b2And taking the real part of the theoretical truncated windowing admittance and the test truncated windowing admittance:
Figure FDA0003020763560000041
Figure FDA0003020763560000042
wherein the content of the first and second substances,
Figure FDA0003020763560000043
taking a real part for theoretical truncation and windowing admittance;
Figure FDA0003020763560000044
and
Figure FDA0003020763560000045
respectively corresponding to the attenuation ratio b1Attenuation ratio b2About of time
Figure FDA0003020763560000046
And T;
Figure FDA0003020763560000047
Figure FDA0003020763560000048
respectively corresponding to the attenuation ratio b1Attenuation ratio b2Time-of-flight test cut-off windowing admittance at modal frequency omegasThe real part of (c);
s52, constructing an initial value of the damping ratio in the S-th order mode
Figure FDA0003020763560000049
Equation for initial values:
Figure FDA00030207635600000410
solving the damping of the equation set by using the initial value of the modal damping ratio obtained in the step S52 as the initial value of the nonlinear equation set in the step S51;
and S54, averaging the damping ratios of all the measuring points to obtain the damping ratio of the structure.
6. The method according to claim 3, wherein the attenuation rate b is2＝1.005b1。
7. The structural modal parameter identification method based on the bi-exponential window function method according to claim 1, wherein the obtaining of the time domain signals of the acceleration and the force of the plurality of measuring points on the structure by the hammering method comprises:
the method comprises the steps of randomly selecting N measuring points on the structure, respectively measuring time domain signal data of acceleration and force of the N measuring points by adopting an acceleration sensor, a force hammer and a data acquisition module, and averaging at least five times of measurement of each measuring point.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102375120A (en) * 2010-08-16 2012-03-14 包米勒公司 Device and method for identifying mechanical parameters of an alternating current asynchronous motor
EP2749067A1 (en) * 2011-08-25 2014-07-02 Telefonaktiebolaget LM Ericsson (PUBL) Procedure latency based admission control node and method
CN104792450A (en) * 2015-04-09 2015-07-22 哈尔滨工程大学 Method for indirectly measuring exciting force of equipment acting on mounting base
CN104965023A (en) * 2015-05-21 2015-10-07 江苏大学 Multi-modal guided-wave industrial pipeline diagnostic method
CN105701278A (en) * 2016-01-05 2016-06-22 东华大学 Modal parameter acquisition method
EP3176784A1 (en) * 2013-01-08 2017-06-07 Dolby International AB Model based prediction in a filterbank
CN106844935A (en) * 2017-01-18 2017-06-13 大连理工大学 A kind of big damping engineering structure Modal Parameters Identification
CN106960068A (en) * 2016-09-30 2017-07-18 中国人民解放军海军工程大学 A kind of damping ratios quick calculation method based on pulse excitation response spectrum
CN107250777A (en) * 2014-11-30 2017-10-13 南方创新国际股份有限公司 Apparatus and method for substance characterization
CN109635334A (en) * 2018-11-12 2019-04-16 武汉科技大学 Fault Diagnosis of Roller Bearings, system and medium based on particle group optimizing
CN110118638A (en) * 2019-03-18 2019-08-13 东北大学 Civil engineering structure Modal Parameters Identification based on narrowband mode decomposition in short-term

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8904027B2 (en) * 2010-06-30 2014-12-02 Cable Television Laboratories, Inc. Adaptive bit rate for data transmission
US9698665B2 (en) * 2012-09-14 2017-07-04 Sparq Systems, Inc. Digital controller for a power converter
US20140091887A1 (en) * 2012-10-02 2014-04-03 Correlated Magnetics Research, Llc Method for isolation of vibration

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102375120A (en) * 2010-08-16 2012-03-14 包米勒公司 Device and method for identifying mechanical parameters of an alternating current asynchronous motor
EP2749067A1 (en) * 2011-08-25 2014-07-02 Telefonaktiebolaget LM Ericsson (PUBL) Procedure latency based admission control node and method
EP3176784A1 (en) * 2013-01-08 2017-06-07 Dolby International AB Model based prediction in a filterbank
CN107250777A (en) * 2014-11-30 2017-10-13 南方创新国际股份有限公司 Apparatus and method for substance characterization
CN104792450A (en) * 2015-04-09 2015-07-22 哈尔滨工程大学 Method for indirectly measuring exciting force of equipment acting on mounting base
CN104965023A (en) * 2015-05-21 2015-10-07 江苏大学 Multi-modal guided-wave industrial pipeline diagnostic method
CN105701278A (en) * 2016-01-05 2016-06-22 东华大学 Modal parameter acquisition method
CN106960068A (en) * 2016-09-30 2017-07-18 中国人民解放军海军工程大学 A kind of damping ratios quick calculation method based on pulse excitation response spectrum
CN106844935A (en) * 2017-01-18 2017-06-13 大连理工大学 A kind of big damping engineering structure Modal Parameters Identification
CN109635334A (en) * 2018-11-12 2019-04-16 武汉科技大学 Fault Diagnosis of Roller Bearings, system and medium based on particle group optimizing
CN110118638A (en) * 2019-03-18 2019-08-13 东北大学 Civil engineering structure Modal Parameters Identification based on narrowband mode decomposition in short-term

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Nonviscous Modes of Nonproportionally Damped Viscoelastic Systems;Mario Lazaro et al.;《Journal of Applied Mechanics》;20151231;全文 *
基于加窗插值FFT的加速度传感器信号处理方法;张浩;《仪表技术与传感器》;20160215;全文 *

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