Damping Ratio Identification Method, Device, Electronic Device and Storage Medium

Abstract

The present invention provides a damping ratio identification method, device, electronic device and storage medium, which are applied to the technical field of civil engineering structures. The method includes: acquiring a free decay signal generated by a target civil engineering structure; determining a pre-decay signal and a post-decay signal according to the free decay signal; calculating a pre-power spectrum by performing Fourier transform on the pre-decay signal, and calculating a post-power spectrum by performing Fourier transform on the post-decay signal; determining the natural vibration frequency and the pre-power spectrum amplitude according to the pre-power spectrum, and determining the natural vibration frequency and the post-power spectrum amplitude according to the post-power spectrum; identifying the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of pre-decay signal, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of post-decay signal. This application reduces the complexity of the calculation process and improves the accuracy and precision of the modal damping ratio identification result.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering structures, and in particular, to a method, device, electronic device, and storage medium for damping ratio identification. Background Art

[0002] Structural damping is an important characterization of structural energy dissipation and is crucial for the wind resistance and seismic design of large civil engineering structures. The identification of structural damping refers to estimating the modal damping ratio from the structural dynamic response.

[0003] Currently, the methods for calculating the modal damping ratio through the free vibration signal of the structure mainly include the logarithmic decrement method and the least square fitting method. However, time-domain methods such as the logarithmic decrement method and the least square fitting method are only applicable to single-mode vibration signals, while the free vibration signals of civil engineering structures are mostly multi-mode vibration signals. When applying the logarithmic decrement method and the least square fitting method, modal decomposition is still required. Due to the insufficient accuracy of the existing modal decomposition technology, the decomposed single-mode signal is distorted, which not only increases the complexity of the calculation process but also reduces the accuracy of modal damping ratio identification. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method, device, electronic device, and storage medium for damping ratio identification to solve the problem that the free vibration signals of civil engineering structures in the prior art are mostly multi-mode vibration signals. When applying the logarithmic decrement method and the least square fitting method, modal decomposition is still required. Due to the insufficient accuracy of the existing modal decomposition technology, the decomposed single-mode signal is distorted, which not only increases the complexity of the calculation process but also reduces the accuracy of modal damping ratio identification.

[0005] To solve the above technical problem, the technical solution proposed by the present invention is as follows:

[0006] In a first aspect, the present application provides a method for damping ratio identification, the method comprising:

[0007] Obtaining a free decay signal generated by a target civil engineering structure;

[0008] According to the time length of the free decay signal, taking a pre-decay signal and a post-decay signal with equal time lengths from the free decay signal;

[0009] Calculating a pre-power spectrum for the pre-decay signal according to Fourier transform and calculating a post-power spectrum for the post-decay signal according to Fourier transform;

[0010] Determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the peak value of each order of the pre-decay signal mode according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the peak value of each order of the post-decay signal mode according to the post-power spectrum;

[0011] Identify the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the peak value of each order of the pre-decay signal mode, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the peak value of each order of the post-decay signal mode.

[0012] In a second aspect, the present application provides a damping ratio identification device, and the device includes:

[0013] An acquisition module, configured to acquire a free decay signal generated by a target civil engineering structure;

[0014] A signal determination module, configured to extract a pre-decay signal and a post-decay signal with equal time lengths from the free decay signal according to the time length of the free decay signal;

[0015] A transformation module, configured to calculate a pre-power spectrum for the pre-decay signal according to Fourier transform, and calculate a post-power spectrum for the post-decay signal according to Fourier transform;

[0016] A peak determination module, configured to determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the peak value of each order of the pre-decay signal mode according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the peak value of each order of the post-decay signal mode according to the post-power spectrum;

[0017] A damping ratio identification module, configured to identify the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the peak value of each order of the pre-decay signal mode, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the peak value of each order of the post-decay signal mode.

[0018] In a third aspect, the present application provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the damping ratio identification method as described in any embodiment of the present application is implemented.

[0019] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the damping ratio identification method as described in any embodiment of the present application is implemented.

[0020] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, the damping ratio identification method as described in any embodiment of the present application is implemented.

[0021] Compared with the prior art, the advantages of the present invention are as follows: obtaining the free decay signal generated by the target civil engineering structure; according to the time length of the free decay signal, taking the front decay signal and the rear decay signal with equal time lengths from the free decay signal; calculating the front power spectrum according to the Fourier transform of the front decay signal, and calculating the rear power spectrum according to the Fourier transform of the rear decay signal; determining the natural vibration frequency and the front power spectrum amplitude corresponding to the modal peak of each order of the front decay signal according to the front power spectrum, and determining the natural vibration frequency and the rear power spectrum amplitude corresponding to the modal peak of each order of the rear decay signal according to the rear power spectrum; identifying the damping ratio corresponding to each order of mode according to the natural vibration frequency and the front power spectrum amplitude corresponding to the modal peak of each order of the front decay signal, and the natural vibration frequency and the rear power spectrum amplitude corresponding to the modal peak of each order of the rear decay signal. That is, in the solution of the present application, on the one hand, after the Fourier transform, the damping ratio identification is realized by combining the frequency domain analysis of the front and rear decay signals and the results of the frequency domain analysis of the two decay signals, without the need for modal decomposition, avoiding the distortion of the single-modal signal after modal decomposition, thereby reducing the complexity of the calculation process. On the other hand, the power spectrum is used for damping ratio identification, improving the anti-noise performance in the calculation process, reducing the influence of environmental vibration and measurement noise on the identification result, and improving the accuracy of the modal damping ratio identification result and the accuracy of the modal damping ratio identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, the present invention will be described in more detail based on embodiments and with reference to the drawings. Among them:

[0023] Figure 1 is a flowchart of a damping ratio identification method provided by the present application;

[0024] Figure 2a is another flowchart of a damping ratio identification method provided by the present application;

[0025] Figure 2b is an example diagram of a free decay signal of a damping ratio identification method provided by the present application;

[0026] Figure 2c is an exemplary identification result analysis diagram of a damping ratio identification method provided by the present application;

[0027] Figure 2d is an example diagram of a free vibration signal containing third-order modal information of a damping ratio identification method provided by the present application;

[0028] Figure 2e is another exemplary identification result analysis diagram of a damping ratio identification method provided by the present application;

[0029] Figure 2f is another exemplary identification result analysis diagram of a damping ratio identification method provided by the present application;

[0030] Figure 2g It is another exemplary analysis diagram of the identification result of the damping ratio identification method provided by the present application;

[0031] Figure 3 It is a schematic structural diagram of the damping ratio identification device provided by the present application;

[0032] Figure 4 It is a schematic structural diagram of the electronic device provided by the present application. Detailed implementation manners

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments, but the protection scope of the present invention is not limited thereby.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0035] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0036] In the present invention, unless otherwise clearly defined and limited, the terms "assembly", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] Before describing the present application, the background art of the present application is further introduced: Classical methods such as the logarithmic decrement method and the least squares fitting of free vibration time domain signals are used to calculate the modal damping ratio. However, affected by factors such as potential environmental vibration and measurement noise interference with signals, and damping amplitude dependence, there are large errors in calculating the modal damping ratio by the above methods. Especially for small damping structures, the calculation accuracy of the modal damping ratio often decreases significantly, unable to meet the requirements of engineering applications. On the other hand, both the logarithmic decrement method and the least squares fitting method are only applicable to single-mode vibration signals, while civil engineering structures are all multi-degree-of-freedom structures, and their free vibration signals are all multi-mode vibration signals. When applying the above methods, modal decomposition is also required. Due to the insufficient accuracy of existing modal decomposition techniques, it is not only easy to cause distortion of the single-mode signal after decomposition, but also makes the calculation process too complex. The current method of calculating the damping ratio of multi-mode free vibration signals using the decay characteristics of the Fourier amplitude spectrum over time cannot reflect all the vibration modes of the structure when the signal amplitude is low, and when the noise or environmental vibration signal component in the free vibration signal is large, the calculation accuracy of the Fourier amplitude spectrum is insufficient, resulting in large errors in the calculated modal damping ratio.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0039] Figure 1 is a schematic flowchart of a damping ratio identification method provided by the present application. This method can be executed by a damping ratio identification device, and the device can be implemented in a software and / or hardware manner. In a specific embodiment, the device can be applied in an electronic device, and the electronic device can be a computer. The following embodiments will be described by taking the application of the device in an electronic device as an example. Referring to Figure 1 , the method can specifically include the following steps:

[0040] Step 101, obtain the free decay signal generated by the target civil engineering structure.

[0041] Specifically, for large civil engineering structures, artificial excitation technology can be used to make the structure generate free vibration, and the obtained free vibration response is a free decay signal with a duration of T. .

[0042] Step 102, according to the time length of the free decay signal, take the pre-decay signal and the post-decay signal with equal time lengths from the free decay signal.

[0043] Specifically, according to the time length of the free decay signal, the free decay signal is divided into a pre-decay signal and a post-decay signal with equal time lengths, providing a data basis for subsequent calculation of the damping ratio, and thus increasing the accuracy of the identification result.

[0044] Step 103: Calculate the pre-power spectrum by performing Fourier transform on the pre-decay signal, and calculate the post-power spectrum by performing Fourier transform on the post-decay signal.

[0045] Exemplarily, the free decay signal has a duration of T. Denote the pre-decay signal and the post-decay signal as and respectively, and the time lengths of both signals are T / 2. Perform Fourier transform on both signals to obtain the pre-power spectrum and the post-power spectrum.

[0046] Optionally, after step 103, steps 31 to 32 can also be executed.

[0047] Step 31: Process the pre-power spectrum based on the power spectrum estimation method to determine multiple physical frequency points of the pre-decay signal and the pre-power spectrum density amplitude corresponding to each physical frequency point of the pre-decay signal.

[0048] Optionally, determine the pre-power spectrum density amplitude corresponding to multiple physical frequency points of the pre-decay signal according to the formula .

[0049] Where represents the Fourier transform of the pre-decay signal and the post-decay signal, represents dividing the pre-decay signal into M segments, r represents the index of the number of segments, and the subscript is the index of the th physical frequency point , where , represents the frequency resolution, T represents vector transpose, represents complex vector conjugate transpose, represents the power spectrum amplitude corresponding to the signal at the frequency point .

[0050] Specifically, the power spectrum estimation method can be the periodogram method. According to the periodogram method, process the pre-power spectrum according to the formula . Here represents the Fourier transform of the pre-decay signal , represents dividing the signal into M segments, r represents the index of the number of segments, and the subscript is the index of the th physical frequency point , , represents the frequency resolution, T represents vector transpose, Denotes the conjugate transpose of a complex vector, represents the signal at the frequency point corresponding power spectral amplitude. According to the formula, multiple physical frequency points of the pre-attenuation signal are obtained, as well as the pre-power spectral density amplitude corresponding to each physical frequency point of the pre-attenuation signal, thereby improving the determination efficiency and accuracy of the pre-power spectral density amplitude.

[0051] Step 32: Process the post-power spectrum based on the power spectrum estimation method to determine multiple physical frequency points of the post-attenuation signal and the post-power spectral density amplitude corresponding to each physical frequency point of the post-attenuation signal.

[0052] Specifically, the post-power spectrum can be processed according to the formula Here represents the post-attenuation signal Fourier transform of, represents dividing the signal into M segments, r represents the index of the number of segments, and the subscript is the th physical frequency point index of, , represents the frequency resolution, T represents vector transpose, denotes the conjugate transpose of a complex vector, represents the signal at the frequency point corresponding power spectral amplitude. According to the formula, multiple physical frequency points of the post-attenuation signal are obtained, as well as the post-power spectral density amplitude corresponding to each physical frequency point of the post-attenuation signal, thereby improving the determination efficiency and accuracy of the post-power spectral density amplitude.

[0053] Optionally, after performing Step 31 to Step 32, Step 33 to Step 34 can also be executed.

[0054] Step 33: Use the physical frequency points of the pre-attenuation signal as the abscissa and the pre-power spectral density amplitude corresponding to each physical frequency point of the pre-attenuation signal as the ordinate to plot the frequency spectrum diagram corresponding to the pre-attenuation signal.

[0055] Exemplarily, for , using as the abscissa, as the ordinate, plot the frequency spectrum diagram corresponding to the pre-attenuation signal.

[0056] Step 34: Use multiple physical frequency points of the post-attenuation signal as the abscissa and the post-power spectral density amplitude corresponding to each physical frequency point of the post-attenuation signal as the ordinate to plot the frequency spectrum diagram corresponding to the post-attenuation signal.

[0057] Exemplarily, for , with as the abscissa and as the ordinate, a spectrogram corresponding to the pre-attenuation signal is plotted.

[0058] Step 104: Determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-attenuation signal according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-attenuation signal according to the post-power spectrum.

[0059] Optionally, after performing Steps 31 to 34, Step 104 can be implemented through Steps 1041 to 1042.

[0060] Step 1041: Determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-attenuation signal according to the spectrogram corresponding to the pre-attenuation signal.

[0061] Optionally, in the spectrogram corresponding to the pre-attenuation signal, the abscissa corresponding to the modal peak of each order of the pre-attenuation signal is determined as the natural vibration frequency, and the ordinate of the spectrogram corresponding to the pre-attenuation signal is determined as the pre-power spectrum amplitude.

[0062] Exemplarily, according to the plotted spectrogram, obvious peak points will appear near the natural vibration frequency of the structure. Obtain the abscissa and ordinate values corresponding to the modal peak point of each order of the pre-attenuation signal, and record the abscissa corresponding to the th order modal peak point of the pre-attenuation signal, that is, the natural vibration frequency of the structure, as , and the corresponding ordinate, that is, the power spectral density amplitude corresponding to the natural vibration frequency, that is, the pre-power spectrum amplitude, is recorded as .

[0063] Step 1042: Determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-attenuation signal according to the spectrogram corresponding to the post-attenuation signal.

[0064] Optionally, in the spectrogram corresponding to the post-attenuation signal, the abscissa corresponding to the modal peak of each order of the pre-attenuation signal is determined as the natural vibration frequency, and the ordinate of the spectrogram corresponding to the post-attenuation signal is determined as the post-power spectrum amplitude.

[0065] Exemplarily, according to the plotted spectrogram, obvious peak points will appear near the natural vibration frequency of the structure. Obtain the abscissa and ordinate values corresponding to the modal peak point of each order of the post-attenuation signal, and record the abscissa corresponding to the th order modal peak point of the post-attenuation signal, that is, the natural vibration frequency of the structure, as , and the corresponding ordinate, that is, the power spectral density amplitude corresponding to the natural vibration frequency, that is, the post-power spectrum amplitude, is recorded as .

[0066] Step 105: Identify the damping ratio corresponding to each order of mode according to the natural vibration frequency and the front power spectrum amplitude corresponding to the modal peak of each order of the front decay signal, and the natural vibration frequency and the rear power spectrum amplitude corresponding to the modal peak of each order of the rear decay signal.

[0067] Optionally, for each order of mode, according to the ratio of the front power spectrum amplitude corresponding to the modal peak of the front decay signal to the rear power spectrum amplitude corresponding to the modal peak of the rear decay signal, the natural vibration frequency, and the formula Identify the damping ratio corresponding to the mode.

[0068] Wherein, is the damping ratio of the i-th order mode, is the natural vibration frequency of the i-th order mode, represents the front power spectrum amplitude corresponding to the modal peak of the front decay signal, represents the rear power spectrum amplitude corresponding to the modal peak of the rear decay signal, is the time length of the front decay signal and the rear decay signal.

[0069] Specifically, obtain and of the order modal peak point corresponding to the abscissa natural vibration frequency , , and the corresponding ordinate front power spectrum amplitude , rear power spectrum amplitude , and calculate the damping ratio of each order of mode using Formula 1.

[0070] Formula 1

[0071] Wherein, is the damping ratio of the i-th order mode, is the natural vibration frequency of the i-th order mode, is the power spectral density amplitude corresponding to the order mode of the signal, that is, the front power spectrum amplitude. is the power spectral density amplitude corresponding to the order mode of the signal, that is, the rear power spectrum amplitude.

[0072] The solution of this application is to obtain the free decay signal generated by the target civil engineering structure; according to the time length of the free decay signal, extract the pre-decay signal and the post-decay signal with equal time lengths from the free decay signal; calculate the pre-power spectrum based on the Fourier transform of the pre-decay signal, and calculate the post-power spectrum based on the Fourier transform of the post-decay signal; determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal according to the post-power spectrum; identify the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal. That is, the solution of this application, on the one hand, after the Fourier transform, combines the frequency-domain analysis of the two decay signals and the results of the frequency-domain analysis of the two decay signals to achieve damping ratio identification, without the need for modal decomposition, avoiding the distortion of the single-modal signal after modal decomposition, thereby reducing the complexity of the calculation process. On the other hand, the power spectrum is used for damping ratio identification, improving the anti-noise performance in the calculation process, reducing the influence of environmental vibration and measurement noise on the identification result, and improving the accuracy of the modal damping ratio identification result and the accuracy of the modal damping ratio identification.

[0073] Figure 2a is another schematic flow chart of the damping ratio identification method provided by this application. In this embodiment, based on the embodiment shown in Figure 1 and various optional implementation solutions, the step of obtaining the free decay signal of the target civil engineering structure is described in detail. As Figure 2a shown, the method may include the following steps:

[0074] Step 201, when the target civil engineering structure generates free vibration, obtain the free decay signal generated when the target civil engineering structure responds.

[0075] Specifically, when the target civil engineering structure generates free vibration, obtain the free decay signal generated when the target civil engineering structure responds, so that the free decay signal better fits the actual civil engineering structure, thereby improving the accuracy of the identification result.

[0076] Step 202, according to the time length of the free decay signal, extract the pre-decay signal and the post-decay signal with equal time lengths from the free decay signal.

[0077] Step 203, calculate the pre-power spectrum based on the Fourier transform of the pre-decay signal, and calculate the post-power spectrum based on the Fourier transform of the post-decay signal.

[0078] Step 204: Determine the natural vibration frequencies and the amplitudes of the pre-power spectra corresponding to the modal peaks of each order of the pre-decay signals according to the pre-power spectrum, and determine the natural vibration frequencies and the amplitudes of the post-power spectra corresponding to the modal peaks of each order of the post-decay signals according to the post-power spectrum.

[0079] Step 205: Identify the damping ratio corresponding to each order of the mode according to the natural vibration frequencies and the amplitudes of the pre-power spectra corresponding to the modal peaks of each order of the pre-decay signals, and the natural vibration frequencies and the amplitudes of the post-power spectra corresponding to the modal peaks of each order of the post-decay signals.

[0080] Exemplarily, Figure 2b is an example diagram of a free decay signal of the damping ratio identification method provided by the present application. The sampling frequency of this signal is 100 Hz, and the natural frequency is = 0.5 Hz, the damping ratio is = 0.02, the initial amplitude is = 1 m, and the initial phase is = 0.003. The noise level is to add four kinds of Gaussian distributed random noises with a mean of zero and standard deviations of 5%, 10%, 15%, and 20% of the root mean square value (Root Mean Square, RMS) of the free vibration signal respectively. According to the free vibration theory formula of the single-degree-of-freedom structure, a section of free decay signal is generated and Gaussian white noise with different noise levels is added to obtain Figure 2b the example diagram of the free decay signal shown. Figure 2c is an exemplary identification result analysis diagram of the damping ratio identification method provided by the present application. Under the interference of each noise level, 100 groups of signals are simulated, and the logarithmic decay method, the fast Fourier transform (Fast Fourier Transform, FFT) decay method, and the damping ratio identification method of the present application are respectively used to identify the damping ratio. Using obtains the average identification error value of different methods under each noise level, where is the damping ratio of the i-th order mode, and the result is as Figure 2c shown. From Figure 2c it can be seen that the identification error of the logarithmic decay method is relatively large and increases significantly with the increase of the noise level, and its identification error range is between 4.85% and 19.75%. The identification error range of the FFT decay method is between 2.80% and 5.96%, while the identification error of the damping ratio identification method of the present application is always less than 1%. Therefore, the identification accuracy of the damping ratio identification method of the present application is relatively high and the identification result is more accurate.

[0081] Figure 2d is an example diagram of a free vibration signal containing third-order mode information of the damping ratio identification method provided by the present application. The sampling frequency of this signal is 100 Hz, and the natural frequency is = 1 Hz, = 2 Hz, = 4 Hz, with an initial amplitude of = 1 m, = 0.2 m, = 0.1 m, with an initial phase of , and the noise level is to add four kinds of Gaussian distributed random noises with a mean of zero and standard deviations of 5%, 10%, 15%, and 20% of the RMS value of the free vibration signal respectively. Using MATLAB software, a free vibration signal containing third-order modal information is generated, and the generated signal is as Figure 2d shown. The logarithmic decrement method, the FFT decrement method, and the damping ratio identification method of the present application are used to identify the damping ratios of the third-order modes respectively. Figure 2e , Figure 2f and Figure 2g are all another exemplary identification result analysis diagrams of the damping ratio identification method provided by the present application. Among them, Figure 2e is the error analysis diagram of the logarithmic decrement method, the FFT decrement method, and the damping ratio identification method of the present application for identifying the damping ratio of the previous-order mode respectively, Figure 2f is the error analysis diagram of the logarithmic decrement method, the FFT decrement method, and the damping ratio identification method of the present application for identifying the damping ratio of the subsequent-order mode respectively, Figure 2g is the error analysis diagram of the logarithmic decrement method, the FFT decrement method, and the damping ratio identification method of the present application for identifying the damping ratio of the third-order mode respectively. From Figure 2e , Figure 2f and Figure 2g it can be seen that the errors of the three methods in identifying the damping ratio of the previous-order mode of the system are relatively small, basically remaining within 1%. However, the errors of the damping ratio identification results in the subsequent-order and third-order are relatively large, but among the three methods, the identification error of the damping ratio identification method of the present application is the smallest. Therefore, the damping ratio identification method of the present application enhances the anti-noise performance and robustness of the thread damping ratio identification. Therefore, compared with the logarithmic decrement method and the least squares fitting method, the method of the present application calculates the modal damping ratio in the frequency domain, does not require modal decomposition, and can effectively reduce the influence of environmental vibration and measurement noise on the identification result. On the other hand, due to the use of the power spectrum, compared with the Fourier amplitude spectrum, its anti-noise performance is stronger and the calculation result accuracy is higher. Since the calculation formula of the power spectrum decrement method is simple and easy to understand, it is convenient to use and also has good engineering adaptability.

[0082] In the solution of the present application, when the target civil engineering structure generates free vibration, the free decay signal of the response of the target civil engineering structure is obtained, so that the free decay signal is more in line with the actual civil engineering structure, thereby improving the accuracy of the identification result.

[0083] Figure 3This is a schematic structural diagram of the damping ratio identification device provided by the present application, and this device is applicable to execute the damping ratio identification method provided by the present application. As Figure 3 shown, this device may specifically include:

[0084] An acquisition module 301, configured to acquire a free decay signal generated by a target civil engineering structure.

[0085] A signal determination module 302, configured to take a pre-decay signal and a post-decay signal with equal time lengths from the free decay signal according to the time length of the free decay signal.

[0086] A transformation module 303, configured to calculate a pre-power spectrum by performing a Fourier transform on the pre-decay signal, and calculate a post-power spectrum by performing a Fourier transform on the post-decay signal.

[0087] A peak determination module 304, configured to determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to each order of pre-decay signal modal peak according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to each order of post-decay signal modal peak according to the post-power spectrum.

[0088] A damping ratio identification module 305, configured to identify the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to each order of pre-decay signal modal peak, and the natural vibration frequency and the post-power spectrum amplitude corresponding to each order of post-decay signal modal peak.

[0089] In one embodiment, the acquisition module 301 is specifically configured to: when the target civil engineering structure generates free vibration, acquire the free decay signal generated when the target civil engineering structure responds.

[0090] In one embodiment, the damping ratio identification module 305 is specifically configured to: for each order of mode, according to the ratio of the pre-power spectrum amplitude corresponding to the pre-decay signal modal peak to the post-power spectrum amplitude corresponding to the post-decay signal modal peak, the natural vibration frequency, and the formula identify the damping ratio corresponding to the mode; where is the damping ratio of the i-th order mode, is the natural vibration frequency of the i-th order mode, represents the pre-power spectrum amplitude corresponding to the pre-decay signal modal peak, represents the post-power spectrum amplitude corresponding to the post-decay signal modal peak, is the time length of the pre-decay signal and the post-decay signal.

[0091] In one embodiment, the device further includes: an amplitude determination module, configured to, after the transformation module 303, process the pre-power spectrum based on a power spectrum estimation method to determine a plurality of physical frequency points of the pre-attenuation signals and the pre-power spectrum density amplitude corresponding to each of the physical frequency points of the pre-attenuation signals; process the post-power spectrum based on the power spectrum estimation method to determine a plurality of physical frequency points of the post-attenuation signals and the post-power spectrum density amplitude corresponding to each of the physical frequency points of the post-attenuation signals.

[0092] In one embodiment, the amplitude determination module determines the pre-power spectrum density amplitude corresponding to a plurality of physical frequency points of the pre-attenuation signals according to the formula ; where represents the Fourier transform of the pre-attenuation signal and the post-attenuation signal, represents dividing the pre-attenuation signal into M segments, r represents the index of the number of segments, and the subscript is the th index of the physical frequency point where , represents the frequency resolution, T represents vector transpose, represents complex vector conjugate transpose, represents the power spectrum amplitude corresponding to the signal at the frequency point .

[0093] In one embodiment, after the amplitude determination module processes the post-power spectrum based on the power spectrum estimation method to determine a plurality of physical frequency points of the post-attenuation signals and the post-power spectrum density amplitude corresponding to each of the physical frequency points of the post-attenuation signals, it is further configured to: use the plurality of physical frequency points of the pre-attenuation signals as the abscissa and the pre-power spectrum density amplitude corresponding to each of the physical frequency points of the pre-attenuation signals as the ordinate to plot the spectrum diagram corresponding to the pre-attenuation signals; use the plurality of physical frequency points of the post-attenuation signals as the abscissa and the post-power spectrum density amplitude corresponding to each of the physical frequency points of the post-attenuation signals as the ordinate to plot the spectrum diagram corresponding to the post-attenuation signals; the peak determination module 304 is specifically configured to: determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-attenuation signals according to the spectrum diagram corresponding to the pre-attenuation signals; determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-attenuation signals according to the spectrum diagram corresponding to the post-attenuation signals.

[0094] In one embodiment, the peak determination module 304 is specifically configured to determine the natural vibration frequency and the pre-power spectral amplitude corresponding to each order of the pre-attenuation signal mode peak according to the spectrogram corresponding to the pre-attenuation signal: in the spectrogram corresponding to the pre-attenuation signal, determine the abscissa corresponding to each order of the pre-attenuation signal mode peak as the natural vibration frequency, and determine the ordinate of the spectrogram corresponding to the pre-attenuation signal as the pre-power spectral amplitude; the peak determination module 304 is specifically configured to determine the natural vibration frequency and the post-power spectral amplitude corresponding to each order of the post-attenuation signal mode peak according to the spectrogram corresponding to the post-attenuation signal: in the spectrogram corresponding to the post-attenuation signal, determine the abscissa corresponding to each order of the pre-attenuation signal mode peak as the natural vibration frequency, and determine the ordinate of the spectrogram corresponding to the post-attenuation signal as the post-power spectral amplitude.

[0095] The device of the present application acquires the free decay signal generated by the target civil engineering structure; takes the pre-attenuation signal and the post-attenuation signal with equal time lengths from the free decay signal according to the time length of the free decay signal; calculates the pre-power spectrum according to the Fourier transform of the pre-attenuation signal and calculates the post-power spectrum according to the Fourier transform of the post-attenuation signal; determines the natural vibration frequency and the pre-power spectral amplitude corresponding to each order of the pre-attenuation signal mode peak according to the pre-power spectrum, and determines the natural vibration frequency and the post-power spectral amplitude corresponding to each order of the post-attenuation signal mode peak according to the post-power spectrum; identifies the damping ratio corresponding to each order of mode according to the natural vibration frequency and the pre-power spectral amplitude corresponding to each order of the pre-attenuation signal mode peak, and the natural vibration frequency and the post-power spectral amplitude corresponding to each order of the post-attenuation signal mode peak. That is, in the solution of the present application, on the one hand, after the Fourier transform, the damping ratio identification is realized by combining the frequency domain analysis of the two decay signals and the results of the frequency domain analysis of the two decay signals, without the need for modal decomposition, avoiding the distortion of the single-modal signal after modal decomposition, thereby reducing the complexity of the calculation process. On the other hand, the power spectrum is used for damping ratio identification, improving the anti-noise performance in the calculation process, reducing the influence of environmental vibration and measurement noise on the identification result, and improving the accuracy of the modal damping ratio identification result and the accuracy of the modal damping ratio identification.

[0096] The present application also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the damping ratio identification method provided in any of the above embodiments.

[0097] The present application also provides a computer-readable medium, on which a computer program is stored. When the program is executed by a processor, it implements the damping ratio identification method provided in any of the above embodiments.

[0098] Next, refer to Figure 4, which shows a schematic structural diagram of an electronic device 400 suitable for implementing the present application. Figure 4 The shown electronic device is merely an example and should not impose any limitation on the functions and usage scope of the present application.

[0099] As Figure 4 shown, the electronic device 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 402 or the program loaded from the storage section 408 into the random access memory (RAM) 403. In the RAM 403, various programs and data required for the operation of the electronic device 400 are also stored. The CPU 401, ROM 402, and RAM 403 are connected to each other via a bus 404. The input / output (I / O) interface 405 is also connected to the bus 404.

[0100] The following components are connected to the I / O interface 405: an input section 406 including a keyboard, a mouse, etc.; an output section 407 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, a modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to the I / O interface 405 as required. A removable medium 411, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 410 as required so that a computer program read from it can be installed into the storage section 408 as required.

[0101] Specifically, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program codes for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from the network through the communication section 409, and / or installed from the removable medium 411. When the computer program is executed by the central processing unit (CPU) 401, the above functions defined in the system of the present application are executed.

[0102] It should be noted that the computer-readable medium shown in this application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of a computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this application, a computer-readable storage medium can be any tangible medium that contains or stores a program, which can be used by or in conjunction with an instruction execution system, apparatus, or device. And in this application, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0103] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks can occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0104] The modules and / or units involved in this application can be implemented in software or in hardware. The described modules and / or units can also be provided in a processor. For example, it can be described as: a processor includes an acquisition module, a signal determination module, a transformation module, a peak determination module, and a damping ratio identification module. Among them, the names of these modules do not constitute a limitation on the modules themselves in some cases.

[0105] As another aspect, this application also provides a computer-readable medium. The computer-readable medium can be included in the device described in the above embodiments; it can also exist alone without being assembled into the device. The above computer-readable medium carries one or more programs. When the above one or more programs are executed by the device, the device performs the following operations:

[0106] Obtain the free decay signal generated by the target civil engineering structure; according to the time length of the free decay signal, extract the pre-decay signal and the post-decay signal with equal time lengths from the free decay signal; calculate the pre-power spectrum for the pre-decay signal according to the Fourier transform, and calculate the post-power spectrum for the post-decay signal according to the Fourier transform; determine the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal according to the pre-power spectrum, and determine the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal according to the post-power spectrum; identify the damping ratio corresponding to each order of the mode according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal.

[0107] According to the technical solution of the present application, a free decay signal generated by a target civil engineering structure is obtained; according to the time length of the free decay signal, a pre-decay signal and a post-decay signal with equal time lengths are taken from the free decay signal; the pre-power spectrum is calculated for the pre-decay signal according to Fourier transform, and the post-power spectrum is calculated for the post-decay signal according to Fourier transform; the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal are determined according to the pre-power spectrum, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal are determined according to the post-power spectrum; the damping ratio corresponding to each order of mode is identified according to the natural vibration frequency and the pre-power spectrum amplitude corresponding to the modal peak of each order of the pre-decay signal, and the natural vibration frequency and the post-power spectrum amplitude corresponding to the modal peak of each order of the post-decay signal. That is, in the solution of the present application, on the one hand, after Fourier transform, the damping ratio identification is realized by combining the frequency-domain analysis of the two decay signals and the results of the frequency-domain analysis of the two decay signals, without the need for modal decomposition, avoiding the distortion of the single-modal signal after modal decomposition, thereby reducing the complexity of the calculation process. On the other hand, the power spectrum is used for damping ratio identification, improving the anti-noise performance in the calculation process, reducing the influence of environmental vibration and measurement noise on the identification result, and improving the accuracy of the modal damping ratio identification result and the accuracy of the modal damping ratio identification.

[0108] The embodiment of the present application further provides a computer program product, including a computer program, which implements the damping ratio identification method provided in any embodiment of the present application when executed by a processor.

[0109] In the process of implementing the computer program product, the computer program code for executing the operations of the present application can be written in one or more programming languages or combinations thereof. The programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed completely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or completely executed on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network - including a local area network (LAN) or a wide area network (WAN) - or can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0110] It should be understood that the various forms of processes shown above can be used, with steps reordered, added or deleted. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solution of this application can be achieved, and no limitations are imposed herein.

[0111] The above specific embodiments do not constitute a limitation on the protection scope of this application. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A damping ratio identification method, characterized in that: The method comprises: Obtain the free decay signal generated by the target civil engineering structure; According to the time length of the free decay signal, taking a front decay signal and a rear decay signal with equal time lengths from the free decay signal; Calculating the front attenuation signal according to Fourier transform to obtain a front power spectrum, and calculating the rear attenuation signal according to Fourier transform to obtain a rear power spectrum; Determine the natural frequency and the front power spectrum amplitude corresponding to each order of the front attenuation signal modal peak according to the front power spectrum, and determine the natural frequency and the rear power spectrum amplitude corresponding to each order of the rear attenuation signal modal peak according to the rear power spectrum; For each mode, according to the ratio of the front power spectrum amplitude corresponding to the front attenuation signal modal peak to the rear power spectrum amplitude corresponding to the rear attenuation signal modal peak, the natural frequency and the formula Identify the damping ratio corresponding to the mode; wherein, is the damping ratio of the i-th mode, is the natural frequency corresponding to the peak point of the i-th mode of the previous attenuation signal, represents the front power spectrum amplitude corresponding to the modal peak of the front attenuation signal, represents the post-power spectrum amplitude corresponding to the post-attenuation signal modal peak, is the time length of the front attenuation signal and the rear attenuation signal, is the natural frequency corresponding to the peak point of the i-th mode of the post-attenuation signal.

2. The damping ratio identification method according to claim 1, characterized in that: The step of obtaining a free attenuation signal generated by a target civil engineering structure comprises: When the target civil engineering structure generates free vibration, a free attenuation signal generated when the target civil engineering structure responds is obtained.

3. The damping ratio identification method according to claim 1, characterized in that: After calculating the front power spectrum by Fourier transforming the front attenuated signal and calculating the rear power spectrum by Fourier transforming the rear attenuated signal, the method further includes: Processing the front power spectrum based on a power spectrum estimation method to determine a plurality of front attenuation signal physical frequency points and a front power spectrum density amplitude corresponding to each of the front attenuation signal physical frequency points; The post-power spectrum is processed based on a power spectrum estimation method to determine a plurality of post-attenuation signal physical frequency points and a post-power spectrum density amplitude corresponding to each of the post-attenuation signal physical frequency points.

4. The damping ratio identification method according to claim 3, characterized in that: According to the formula Determine the front power spectrum density amplitude corresponding to multiple physical frequency points of the front attenuation signal; wherein, represents the Fourier transform of the pre-attenuation signal and the post-attenuation signal, represents dividing the pre-attenuated signal into M segments, r represents the index of the number of segments, and the subscript It is Physical frequency points The index of , represents the frequency resolution, T represents the vector transpose, represents the conjugate transpose of a complex vector, Represents the signal at the frequency point The corresponding power spectrum amplitude at .

5. The damping ratio identification method according to claim 3, characterized in that: After processing the post-power spectrum based on the power spectrum estimation method to determine a plurality of post-attenuation signal physical frequency points and a post-power spectrum density amplitude corresponding to each of the post-attenuation signal physical frequency points, the method further includes: With the multiple physical frequency points of the front attenuated signal as the abscissa and the front power spectrum density amplitude corresponding to each physical frequency point of the front attenuated signal as the ordinate, draw a frequency spectrum diagram corresponding to the front attenuated signal; Using the multiple post-attenuation signal physical frequency points as abscissas and the post-power spectrum density amplitude corresponding to each post-attenuation signal physical frequency point as a ordinate, plotting a frequency spectrum corresponding to the post-attenuation signal; The method of determining the natural frequency and the front power spectrum amplitude corresponding to each order front attenuation signal modal peak value according to the front power spectrum, and determining the natural frequency and the rear power spectrum amplitude corresponding to each order rear attenuation signal modal peak value according to the rear power spectrum, comprises: Determine the natural frequency and the front power spectrum amplitude corresponding to the modal peak of each order of the front attenuation signal according to the frequency spectrum corresponding to the front attenuation signal; The natural frequency and the post-power spectrum amplitude corresponding to the modal peak of each order post-attenuation signal are determined according to the frequency spectrum corresponding to the post-attenuation signal.

6. The damping ratio identification method according to claim 5, characterized in that: The determining, according to the frequency spectrum corresponding to the front attenuation signal, the natural frequency and the front power spectrum amplitude corresponding to the modal peak of each order of the front attenuation signal comprises: In the spectrum diagram corresponding to the front attenuation signal, the abscissa corresponding to the modal peak of each order of the front attenuation signal is determined as the natural frequency, and the ordinate of the spectrum diagram corresponding to the front attenuation signal is determined as the front power spectrum amplitude; The determining, according to the frequency spectrum corresponding to the post-attenuation signal, the natural frequency and the post-power spectrum amplitude corresponding to the modal peak of each order post-attenuation signal comprises: In the frequency spectrum diagram corresponding to the post-attenuation signal, the abscissa corresponding to the modal peak of each order of the pre-attenuation signal is determined as the natural frequency, and the ordinate of the frequency spectrum diagram corresponding to the post-attenuation signal is determined as the post-power spectrum amplitude.

7. A damping ratio identification device, characterized in that: The device comprises: An acquisition module, used for acquiring a free decay signal generated by a target civil engineering structure; A signal determination module, configured to extract a pre-decay signal and a post-decay signal of equal time length from the free decay signal according to the time length of the free decay signal; A transformation module, used for calculating the front attenuation signal according to Fourier transform to obtain a front power spectrum, and calculating the rear attenuation signal according to Fourier transform to obtain a rear power spectrum; A peak determination module, used to determine the natural frequency and the front power spectrum amplitude corresponding to each order of the front attenuation signal modal peak according to the front power spectrum, and to determine the natural frequency and the rear power spectrum amplitude corresponding to each order of the rear attenuation signal modal peak according to the rear power spectrum; The damping ratio identification module is used to identify the damping ratio for each mode according to the ratio of the front power spectrum amplitude corresponding to the front attenuation signal modal peak to the rear power spectrum amplitude corresponding to the rear attenuation signal modal peak, the natural frequency and the formula Identify the damping ratio corresponding to the mode; wherein, is the damping ratio of the i-th mode, is the natural frequency corresponding to the peak point of the i-th mode of the previous attenuation signal, represents the front power spectrum amplitude corresponding to the modal peak of the front attenuation signal, represents the post-power spectrum amplitude corresponding to the post-attenuation signal modal peak, is the time length of the front attenuation signal and the rear attenuation signal, is the natural frequency corresponding to the peak point of the i-th mode of the post-attenuation signal.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the damping ratio identification method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the damping ratio identification method according to any one of claims 1 to 6 is implemented.

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