Modal damping ratio identification method, system, device and computer readable storage medium

Abstract

A modal damping ratio identification method, system, device and computer readable storage medium, relating to the technical field of bridge engineering, specifically comprising: performing variational modal decomposition on the free vibration response of the target bridge to obtain a plurality of connotative modal components; determining the attributes of each connotative modal component based on the time domain and frequency domain characteristics of each connotative modal component, and taking the connotative modal component with the actual modal response attribute as the target connotative modal component; performing Hilbert transform on the target connotative modal component, and determining the target instantaneous amplitude and the target instantaneous frequency corresponding to the target connotative modal component based on the results of the Hilbert transform and the target connotative modal component; determining the instantaneous modal damping ratio corresponding to the target connotative modal component based on the target instantaneous amplitude and the target instantaneous frequency, so as to obtain the amplitude correlation of the modal damping ratio. The application improves the modal damping ratio identification precision.

Description

Technical Field

[0001] The present application relates to the field of bridge engineering technology, and in particular to a modal damping ratio identification method, system, device and computer-readable storage medium. Background Art

[0002] With the continuous development of bridge structural design and operation, the demand for refined analysis of bridge dynamic performance is increasing, especially in the identification of bridge modal damping ratios. The modal damping ratio is a key parameter in bridge structures, determining the energy dissipation characteristics of the structure during vibration. The modal damping ratio of a bridge is affected by various external factors, including environmental conditions (wind, temperature), vibration excitation method (vibrator excitation, vehicle jumping excitation), and vibration conditions (frequency, amplitude, etc.).

[0003] Currently, operational modal analysis technology has been widely used to identify the damping ratio of large bridges. Its advantage is that it does not require the magnitude of the input excitation and can identify the modal damping ratio based solely on the structural response. Common operational modal analysis techniques such as the random subspace method, peak picking method, and frequency domain decomposition method are all based on the linear structure assumption, that is, the modal damping ratio and frequency are assumed to be fixed during the measurement period. Therefore, these methods cannot reflect the instantaneous characteristics of the modal damping ratio and frequency and do not take into account the amplitude characteristics of the mode, resulting in low accuracy of the identified modal damping ratio.

[0004] Therefore, how to improve the accuracy of modal damping ratio identification is an urgent problem that needs to be solved. Summary of the Invention

[0005] The present application provides a modal damping ratio identification method, system, device and computer-readable storage, which can improve the modal damping ratio identification accuracy.

[0006] In a first aspect, an embodiment of the present application provides a modal damping ratio identification method, the modal damping ratio identification method comprising:

[0007] Perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components;

[0008] The attributes of each intrinsic modal component are determined based on the time domain and frequency domain characteristics of each intrinsic modal component, and the intrinsic modal component whose attribute is the actual modal response is used as the target intrinsic modal component;

[0009] Performing a Hilbert transform on the target intrinsic modal component, and determining a target instantaneous amplitude and a target instantaneous frequency corresponding to the target intrinsic modal component based on the result of the Hilbert transform and the target intrinsic modal component;

[0010] The instantaneous modal damping ratio corresponding to the target intrinsic modal component is determined based on the target instantaneous amplitude and the target instantaneous frequency to obtain the amplitude correlation of the modal damping ratio.

[0011] In conjunction with the first aspect, in one embodiment, determining the attributes of each intrinsic modal component based on the time domain and frequency domain characteristics of each intrinsic modal component includes:

[0012] For each intrinsic modal component, if the detected time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, then the attribute of the intrinsic modal component is determined to be an actual modal response;

[0013] If at least one of the following conditions is not met: the time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, the attribute of the intrinsic modal component is determined to be noise.

[0014] In conjunction with the first aspect, in one embodiment, taking the intrinsic modal component having the attribute of actual modal response as the target intrinsic modal component includes:

[0015] For each intrinsic modal component, the frequency corresponding to the spectrum peak of the intrinsic modal component is taken as the characteristic frequency;

[0016] Determine the modal order corresponding to the intrinsic modal component based on the characteristic frequency;

[0017] The intrinsic modal component whose modal order is the preset modal order and whose attribute is the actual modal response is taken as the target intrinsic modal component.

[0018] In conjunction with the first aspect, in one embodiment, determining the modal order corresponding to the intrinsic modal component based on the characteristic frequency includes:

[0019] Differences are obtained by subtracting the characteristic frequency from the theoretical frequency of each modal order;

[0020] The modal order corresponding to the difference value being less than the preset difference threshold is taken as the modal order corresponding to the intrinsic modal component.

[0021] In conjunction with the first aspect, in one embodiment, determining the target instantaneous amplitude and target instantaneous frequency corresponding to the target intrinsic modal component based on the Hilbert transform result and the target intrinsic modal component includes:

[0022] Substituting the Hilbert transform result and the target connotation modal component into the second calculation formula to obtain the target instantaneous amplitude corresponding to the target connotation modal component;

[0023] Substituting the Hilbert transform result and the target connotation modal component into the third calculation formula to obtain the target instantaneous frequency corresponding to the target connotation modal component;

[0024] The second calculation formula is as follows:

[0025]

[0026] The third calculation formula is as follows:

[0027]

[0028] Where, is the result of Hilbert transform; is the target connotation modal component; is the target instantaneous amplitude, is the target instantaneous frequency.

[0029] In conjunction with the first aspect, in one embodiment, determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency includes:

[0030] Calculate the first-order derivative of the target instantaneous amplitude and target instantaneous frequency respectively to obtain the instantaneous amplitude change rate and instantaneous frequency change rate;

[0031] The instantaneous modal damping ratio corresponding to the target intrinsic modal component is determined based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate and the instantaneous frequency change rate.

[0032] In conjunction with the first aspect, in one embodiment, determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate, and the instantaneous frequency change rate includes:

[0033] Substituting the target instantaneous amplitude, target instantaneous frequency, instantaneous amplitude change rate, and instantaneous frequency change rate into the first calculation formula, the instantaneous modal damping ratio corresponding to the target intrinsic modal component is obtained. The first calculation formula is:

[0034]

[0035] Where, is the instantaneous amplitude of the target; is the target instantaneous frequency; is the instantaneous amplitude change rate; is the instantaneous frequency change rate; is the instantaneous modal damping ratio corresponding to the target intrinsic modal component.

[0036] In a second aspect, an embodiment of the present application provides a modal damping ratio identification system, the modal damping ratio identification system comprising:

[0037] A first processing module is used to perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components;

[0038] The second processing module is used to determine the attributes of each intrinsic modal component based on the time domain and frequency domain characteristics of each intrinsic modal component, and use the intrinsic modal component whose attribute is the actual modal response as the target intrinsic modal component;

[0039] a third processing module, which is used to perform a Hilbert transform on the target connotation modal component, and determine a target instantaneous amplitude and a target instantaneous frequency corresponding to the target connotation modal component based on the result of the Hilbert transform and the target connotation modal component;

[0040] The fourth processing module is configured to determine an instantaneous modal damping ratio corresponding to a target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency, so as to obtain an amplitude correlation of the modal damping ratio.

[0041] In a third aspect, an embodiment of the present application provides a modal damping ratio identification device, which includes a processor, a memory, and a modal damping ratio identification program stored in the memory and executable by the processor, wherein when the modal damping ratio identification program is executed by the processor, the steps of the modal damping ratio identification method described in any of the foregoing items are implemented.

[0042] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a modal damping ratio identification program is stored, wherein when the modal damping ratio identification program is executed by a processor, the steps of the modal damping ratio identification method as described in any of the foregoing items are implemented.

[0043] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0044] By performing variational modal decomposition on the free vibration response of the target bridge, multiple intrinsic modal components are obtained. Unlike traditional modal analysis methods, variational modal decomposition does not rely on the preset linear structure assumption, but can extract different intrinsic modal components based on the characteristics of the free vibration response signal; based on the time domain and frequency domain characteristics of each intrinsic modal component, the attributes of each intrinsic modal component are determined to screen out the component most relevant to the structural response (i.e., the actual modal response) from multiple intrinsic modal components, and the intrinsic modal component with the attribute of the actual modal response is used as the target intrinsic modal components, thereby improving the accuracy of modal identification; performing a Hilbert transform on the target intrinsic modal components, and determining the target instantaneous amplitude and target instantaneous frequency corresponding to the target intrinsic modal components based on the results of the Hilbert transform and the target intrinsic modal components, so as to describe the dynamic characteristics of the mode during the measurement; combining the target instantaneous amplitude and the target instantaneous frequency to more accurately identify the instantaneous modal damping ratio. In other words, the present application improves the identification accuracy of the modal damping ratio by considering the instantaneous characteristics of the modal damping ratio and frequency and combining the target instantaneous amplitude characteristics of the modal. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a flow chart of an embodiment of the modal damping ratio identification method of the present application;

[0046] Figure 2 Schematic diagram of the free vibration displacement response of a certain point in the embodiment of the modal damping ratio identification method of the present application;

[0047] Figure 3 Schematic diagram of the intrinsic modal component of the free vibration displacement response in an embodiment of the modal damping ratio identification method of the present application;

[0048] Figure 4 This is a schematic diagram of the Hilbert transform of the target connotation modal component in the embodiment of the modal damping ratio identification method of the present application;

[0049] Figure 5 Schematic diagram showing the comparison between the modal damping ratio identification value and the theoretical value in the embodiment of the modal damping ratio identification method of the present application;

[0050] Figure 6 This is a functional module diagram of an embodiment of the modal damping ratio identification system of the present application;

[0051] Figure 7 This is a schematic diagram of the hardware structure of the modal damping ratio identification device involved in the embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0054] In a first aspect, an embodiment of the present application provides a method for identifying a modal damping ratio.

[0055] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of an embodiment of the modal damping ratio identification method of this application. Figure 1 As shown in Figure 2, the modal damping ratio identification method includes:

[0056] Step S10: Perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components.

[0057] For example, in the embodiment of the present application, the target bridge refers to the bridge used as the research object in the structural vibration analysis. The free vibration response x(t) refers to the vibration behavior of the bridge due to natural excitation without external force, which can reveal the vibration characteristics of the bridge under different excitation conditions. In the embodiment of the present application, the free vibration displacement response is preferably used as the analysis object. For details, please refer to Figure 2 As shown in the figure, variational mode decomposition (VMD) is a signal decomposition method based on the variational principle, which is used to decompose complex vibration signals into multiple intrinsic modal components. The intrinsic modal components are the signal components decomposed by the VMD algorithm, which can reflect the local time-frequency characteristics of the signal components.

[0058] Specifically, refer to Figure 3 As shown in FIG, the free vibration displacement response of the target bridge can be decomposed by VMD to obtain multiple intrinsic modal components (such as intrinsic modal component I1, intrinsic modal component I2, intrinsic modal component I3, etc.). These intrinsic modal components can then be analyzed to further understand the vibration characteristics of the bridge, thereby providing a basis for subsequent analysis of the target bridge structure. It should be noted that the principle and implementation process of the variational modal decomposition algorithm are common knowledge in this field and will not be repeated here for the sake of brevity.

[0059] Step S20: Determine the attributes of each intrinsic modal component based on the time domain and frequency domain characteristics of each intrinsic modal component, and use the intrinsic modal component with the attribute of the actual modal response as the target intrinsic modal component.

[0060] Exemplarily, in an embodiment of the present application, an attribute refers to a feature extracted from an intrinsic modal component, for example, the attribute of the intrinsic modal component is an actual modal response or noise; wherein, the actual modal response refers to the real vibration mode generated in the system due to the inherent characteristics of the structure and external excitation, which reflects the vibration response of the system under specific conditions; noise refers to a signal generated due to external interference or measurement error, which has no direct relationship with the modal vibration of the system and will interfere with the extraction and analysis of the actual modal response; the target intrinsic modal component refers to the intrinsic modal component that is subsequently used as the object of modal damping ratio identification, which can effectively reflect the real dynamic behavior and characteristics of the system.

[0061] Specifically, after decomposing a complex vibration signal into multiple intrinsic modal components through variational modal decomposition, the time domain and frequency domain characteristics of the intrinsic modal components can be used to determine whether their attributes are actual modal responses, that is, to determine whether the time history curve of the intrinsic modal component is in the form of oscillation attenuation and whether the frequency domain characteristics meet the preset conditions; then, based on the judgment results, it is determined which intrinsic modal components have the attributes of actual modal responses, and these intrinsic modal components with the attributes of actual modal responses are defined as target intrinsic modal components. This can avoid the influence of noise when the modal damping ratio is subsequently identified based on the target intrinsic modal components, thereby improving the accuracy of modal damping ratio identification.

[0062] Step S30: Performing a Hilbert transform on the target intrinsic modal component, and determining a target instantaneous amplitude and a target instantaneous frequency corresponding to the target intrinsic modal component based on the result of the Hilbert transform and the target intrinsic modal component.

[0063] Exemplarily, in an embodiment of the present application, the Hilbert transform is performed by transforming the original signal to generate a signal having the same frequency as the original signal but with a phase shift of 90 degrees. The signal contains the amplitude and phase information of the original signal, so that the instantaneous characteristics of the original signal can be effectively extracted based on the transformed signal. In other words, the Hilbert transform can provide a target instantaneous amplitude and a target instantaneous frequency for the target intrinsic modal component. The target instantaneous amplitude refers to the intensity or size of the target intrinsic modal component, and the target instantaneous frequency is a quantity that describes the change in the frequency of the target intrinsic modal component over time.

[0064] It should be understood that the purpose of performing Hilbert transform on the target intrinsic modal component is to extract its target instantaneous amplitude and target instantaneous frequency in order to further analyze its dynamic characteristics; specifically, refer to Figure 4As shown, the target intrinsic modal component can first be Hilbert transformed to obtain the transformed target intrinsic modal component; then, the target instantaneous frequency and target instantaneous amplitude of the target intrinsic modal component can be obtained based on the target intrinsic modal component and the transformed target intrinsic modal component. The Hilbert transform of the target intrinsic modal component can accurately capture the frequency and amplitude changes of the mode at different time points, that is, it takes into account the instantaneous characteristics of frequency and amplitude, providing a basis for the subsequent calculation of the modal damping ratio. It should be noted that the principle and implementation process of the Hilbert transform are common knowledge in this field and will not be repeated here for the sake of brevity.

[0065] Step S40: Determine the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency to obtain the amplitude correlation of the modal damping ratio.

[0066] Exemplarily, in an embodiment of the present application, the modal damping ratio is a dimensionless parameter that describes the energy attenuation rate of the system under a specific vibration mode, which reflects the ability of the system to dissipate energy during the vibration process; specifically, after the target instantaneous frequency and target instantaneous amplitude of the target intrinsic modal component are extracted through the Hilbert transform, the target instantaneous frequency and target instantaneous amplitude can be differentiated, and the modal damping ratio can be solved based on the result of the differentiation, the target instantaneous frequency and the target instantaneous amplitude, that is, the mathematical relationship between the target instantaneous amplitude change rate, the target instantaneous frequency and the target instantaneous amplitude and the damping ratio is used to accurately estimate the damping characteristics of the target bridge, thereby fully describing the dynamic dissipation characteristics of the target bridge under this mode; after the instantaneous modal damping ratio is calculated, the relationship between the modal damping ratio and the amplitude is determined, that is, the amplitude correlation of the modal damping ratio is obtained.

[0067] This application obtains multiple intrinsic modal components by performing variational modal decomposition on the free vibration response of the target bridge. Unlike traditional modal analysis methods, variational modal decomposition does not rely on a preset linear structure assumption, but can extract different intrinsic modal components based on the characteristics of the free vibration response signal; based on the time domain and frequency domain characteristics of each intrinsic modal component, the attributes of each intrinsic modal component are determined to screen out the component most relevant to the structural response (i.e., the actual modal response) from the multiple intrinsic modal components, and the intrinsic modal component with the attribute of the actual modal response is used as the target The target intrinsic modal component is subjected to a Hilbert transform, thereby improving the accuracy of modal identification, and based on the result of the Hilbert transform and the target intrinsic modal component, a target instantaneous amplitude and a target instantaneous frequency corresponding to the target intrinsic modal component are determined to describe the dynamic characteristics of the mode during the measurement; the instantaneous modal damping ratio is more accurately identified in combination with the target instantaneous amplitude and the target instantaneous frequency. In other words, the present application improves the identification accuracy of the modal damping ratio by considering the instantaneous characteristics of the modal damping ratio and the frequency and combining the target instantaneous amplitude characteristics of the modal.

[0068] Furthermore, in one embodiment, the attributes of each intrinsic modal component are determined based on the time domain and frequency domain characteristics of each intrinsic modal component, including:

[0069] For each intrinsic modal component, if the detected time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, then the attribute of the intrinsic modal component is determined to be an actual modal response;

[0070] If at least one of the following conditions is not met: the time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, the attribute of the intrinsic modal component is determined to be noise.

[0071] For example, in the embodiment of the present application, the target narrow frequency band and the target frequency point are used to characterize the frequency domain characteristics of the intrinsic modal component. For each intrinsic modal component, reference can be made to Figure 3As shown, first, it is necessary to analyze its oscillation characteristics, that is, to determine whether the time history curve presents an oscillation attenuation form by detecting the change form of its time domain signal; if it is detected that the time history curve of the intrinsic modal component is in an oscillation attenuation form, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the preset order modal frequency, then it means that the intrinsic modal component meets the actual modal response characteristics, and therefore it can be determined that its attribute is the actual modal response, and I1 and I2 are the actual modal response; on the contrary, if it is detected that at least one of the following conditions is not met: the time history curve is in an oscillation attenuation form, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, then it means that the intrinsic modal component is more likely to come from external interference or measurement error and is a noise component, and therefore it can be determined that its attribute is noise, and I3 is noise. In the embodiment of the present application, the intrinsic modal component belonging to noise is no longer further processed to reduce the subsequent calculation amount and thereby improve the calculation efficiency. The above determination process relies on the dynamic characteristics analysis of the intrinsic modal components, which can effectively distinguish the actual modal response from the noise components, thus providing a basis for the subsequent damping ratio identification.

[0072] Furthermore, in one embodiment, taking the intrinsic modal component having the attribute of actual modal response as the target intrinsic modal component includes:

[0073] For each intrinsic modal component, the frequency corresponding to the spectrum peak of the intrinsic modal component is taken as the characteristic frequency;

[0074] Determine the modal order corresponding to the intrinsic modal component based on the characteristic frequency;

[0075] The intrinsic modal component whose modal order is the preset modal order and whose attribute is the actual modal response is taken as the target intrinsic modal component.

[0076] For example, in an embodiment of the present application, the modal order reflects the order of the modes, and each mode corresponds to a specific frequency. For example, the frequency corresponding to the first-order mode is the lowest, and the frequency gradually increases with the increase of the order. The preset modal order can be determined according to actual needs and is not limited here. For example, the preset modal order can preferably be taken as the second order, and its corresponding frequency is 10.7 Hz. For each intrinsic modal component, the frequency corresponding to the spectrum peak of the intrinsic modal component can be used as the characteristic frequency. The extracted characteristic frequency is then compared with the specific frequency corresponding to each mode to further determine the modal order corresponding to the intrinsic modal component. When the modal order corresponding to the characteristic frequency of the intrinsic modal component is consistent with the preset modal order, and the attribute of the intrinsic modal component is determined to be an actual modal response (confirmed by the aforementioned oscillation attenuation detection), the intrinsic modal component can be used as the target intrinsic modal component for further modal damping ratio identification.

[0077] Furthermore, in one embodiment, determining the modal order corresponding to the intrinsic modal component based on the characteristic frequency includes:

[0078] Differences are obtained by subtracting the characteristic frequency from the theoretical frequency of each modal order;

[0079] The modal order corresponding to the difference value being less than the preset difference threshold is taken as the modal order corresponding to the intrinsic modal component.

[0080] For example, in the embodiment of the present application, the specific value of the preset difference threshold can be determined according to actual needs and is not limited here. The theoretical frequencies of different modal orders can be calculated through finite element analysis. After obtaining the characteristic frequency of the intrinsic modal component, the difference between the characteristic frequency and the theoretical frequency of each modal order is calculated respectively, and the modal order with a difference less than the threshold is regarded as the modal order corresponding to the intrinsic modal component. The above processing method relies on the principle of frequency matching, that is, by comparing the proximity between the characteristic frequency and the preset frequency, it determines which modal order best matches the modal order of the intrinsic modal component, thereby ensuring the accuracy of modal order identification.

[0081] Furthermore, in one embodiment, determining the target instantaneous amplitude and target instantaneous frequency corresponding to the target intrinsic modal component based on the Hilbert transform result and the target intrinsic modal component includes:

[0082] Substituting the Hilbert transform result and the target connotation modal component into the second calculation formula to obtain the target instantaneous amplitude corresponding to the target connotation modal component;

[0083] Substituting the Hilbert transform result and the target connotation modal component into the third calculation formula to obtain the target instantaneous frequency corresponding to the target connotation modal component;

[0084] The second calculation formula is as follows:

[0085]

[0086] The third calculation formula is as follows:

[0087]

[0088] Where, is the result of Hilbert transform; is the target connotation modal component; is the target instantaneous amplitude, is the target instantaneous frequency.

[0089] For example, in the embodiment of the present application, after the target connotation modal component is subjected to Hilbert transform, the target instantaneous amplitude and target instantaneous frequency of the target connotation modal component can be further calculated according to the result of Hilbert transform. Specifically, the result of Hilbert transform can be used to calculate the target instantaneous amplitude and target instantaneous frequency of the target connotation modal component. and the target connotation modal component Substitute the following calculation formula to obtain the target instantaneous amplitude corresponding to the target intrinsic modal component: , the calculation formula is:

[0090]

[0091] The result of Hilbert transform can be and the target connotation modal component Substitute the following calculation formula to obtain the target instantaneous frequency corresponding to the target intrinsic modal component: , the calculation formula is:

[0092] .

[0093] Furthermore, in one embodiment, determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency includes:

[0094] Calculate the first-order derivative of the target instantaneous amplitude and target instantaneous frequency respectively to obtain the instantaneous amplitude change rate and instantaneous frequency change rate;

[0095] The instantaneous modal damping ratio corresponding to the target intrinsic modal component is determined based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate and the instantaneous frequency change rate.

[0096] For example, in the embodiment of the present application, the instantaneous amplitude change rate is expressed as the rate of change of the target instantaneous amplitude over time, and the instantaneous frequency change rate is expressed as the rate of change of the frequency over time; the instantaneous amplitude change rate can be obtained by taking the first-order derivative of the target instantaneous amplitude, and the instantaneous frequency change rate can be obtained by taking the first-order derivative of the target instantaneous frequency. After determining the instantaneous amplitude change rate and the instantaneous frequency change rate, the target instantaneous amplitude can be obtained by taking the first-order derivative of the target instantaneous frequency. , target instantaneous frequency , instantaneous amplitude change rate and the instantaneous frequency change rate Substitute the following calculation formula to obtain the instantaneous modal damping ratio corresponding to the target intrinsic modal component: , the calculation formula is:

[0097] .

[0098] It should be noted that after determining the instantaneous modal damping ratio based on the above calculation formula, the instantaneous modal damping ratio corresponding to different target instantaneous amplitudes is obtained. The correlation curve between the target instantaneous amplitude and the identified instantaneous modal damping ratio can be plotted to more intuitively present the correlation between the modal damping ratio and the target instantaneous amplitude; refer to Figure 5 As shown, based on the above correlation curve, a correlation curve between the target instantaneous amplitude and the theoretical modal damping ratio can be drawn to intuitively present the accuracy of the damping ratio identified in the embodiment of the present application.

[0099] In a second aspect, an embodiment of the present application also provides a modal damping ratio identification system.

[0100] In one embodiment, referring to Figure 6 , Figure 6 This is a functional module diagram of the embodiment of the modal damping ratio identification system of this application. Figure 6 As shown in Figure 2, the modal damping ratio identification system includes:

[0101] A first processing module is used to perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components;

[0102] The second processing module is used to determine the attributes of each intrinsic modal component based on the time domain and frequency domain characteristics of each intrinsic modal component, and use the intrinsic modal component whose attribute is the actual modal response as the target intrinsic modal component;

[0103] a third processing module, which is used to perform a Hilbert transform on the target connotation modal component, and determine a target instantaneous amplitude and a target instantaneous frequency corresponding to the target connotation modal component based on the result of the Hilbert transform and the target connotation modal component;

[0104] The fourth processing module is configured to determine an instantaneous modal damping ratio corresponding to a target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency, so as to obtain an amplitude correlation of the modal damping ratio.

[0105] Furthermore, in one embodiment, the second processing module is specifically configured to:

[0106] For each intrinsic modal component, if the detected time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, then the attribute of the intrinsic modal component is determined to be an actual modal response;

[0107] If at least one of the following conditions is not met: the time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, the attribute of the intrinsic modal component is determined to be noise.

[0108] Furthermore, in one embodiment, the second processing module is further configured to:

[0109] For each intrinsic modal component, the frequency corresponding to the spectrum peak of the intrinsic modal component is taken as the characteristic frequency;

[0110] Determine the modal order corresponding to the intrinsic modal component based on the characteristic frequency;

[0111] The intrinsic modal component whose modal order is the preset modal order and whose attribute is the actual modal response is taken as the target intrinsic modal component.

[0112] Furthermore, in one embodiment, the second processing module is further configured to:

[0113] Differences are obtained by subtracting the characteristic frequency from the theoretical frequency of each modal order;

[0114] The modal order corresponding to the difference value being less than the preset difference threshold is taken as the modal order corresponding to the intrinsic modal component.

[0115] Furthermore, in one embodiment, the third processing module is specifically configured to:

[0116] Substituting the Hilbert transform result and the target connotation modal component into the second calculation formula to obtain the target instantaneous amplitude corresponding to the target connotation modal component;

[0117] Substituting the Hilbert transform result and the target connotation modal component into the third calculation formula to obtain the target instantaneous frequency corresponding to the target connotation modal component;

[0118] The second calculation formula is as follows:

[0119]

[0120] The third calculation formula is as follows:

[0121]

[0122] Where, is the result of Hilbert transform; is the target connotation modal component; is the target instantaneous amplitude, is the target instantaneous frequency.

[0123] Furthermore, in one embodiment, the fourth processing module is specifically configured to:

[0124] Calculate the first-order derivative of the target instantaneous amplitude and target instantaneous frequency respectively to obtain the instantaneous amplitude change rate and instantaneous frequency change rate;

[0125] The instantaneous modal damping ratio corresponding to the target intrinsic modal component is determined based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate and the instantaneous frequency change rate.

[0126] Furthermore, in one embodiment, the fourth processing module is further configured to:

[0127] Substituting the target instantaneous amplitude, target instantaneous frequency, instantaneous amplitude change rate, and instantaneous frequency change rate into the first calculation formula, the instantaneous modal damping ratio corresponding to the target intrinsic modal component is obtained. The first calculation formula is:

[0128]

[0129] Where, is the instantaneous amplitude of the target; is the target instantaneous frequency; is the instantaneous amplitude change rate; is the instantaneous frequency change rate; is the instantaneous modal damping ratio corresponding to the target intrinsic modal component.

[0130] This application obtains multiple intrinsic modal components by performing variational modal decomposition on the free vibration response of the target bridge. Unlike traditional modal analysis methods, variational modal decomposition does not rely on the preset linear structure assumption, but can extract different intrinsic modal components according to the characteristics of the free vibration response signal; based on the time domain and frequency domain characteristics of each intrinsic modal component, the attributes of each intrinsic modal component are determined to screen out the component most relevant to the structural response (i.e., the actual modal response) from the multiple intrinsic modal components, and the intrinsic modal component with the attribute of the actual modal response is used as Target intrinsic modal component; performing a Hilbert transform on the target intrinsic modal component to improve the accuracy of modal identification, and determining the target instantaneous amplitude and target instantaneous frequency corresponding to the target intrinsic modal component based on the result of the Hilbert transform and the target intrinsic modal component to describe the dynamic characteristics of the mode during the measurement; combining the target instantaneous amplitude and the target instantaneous frequency to more accurately identify the instantaneous modal damping ratio. In other words, the present application improves the identification accuracy of the modal damping ratio by considering the instantaneous characteristics of the modal damping ratio and frequency and combining the instantaneous amplitude characteristics of the mode.

[0131] Among them, the functional implementation of each module in the above-mentioned modal damping ratio identification system corresponds to the various steps in the above-mentioned modal damping ratio identification method embodiment, and their functions and implementation processes are no longer repeated here.

[0132] In a third aspect, an embodiment of the present application provides a modal damping ratio identification device, which may be a device with data processing capabilities, such as a personal computer (PC), a laptop computer, or a server.

[0133] Reference Figure 7 , Figure 7 Schematic diagram of the hardware structure of the modal damping ratio identification device involved in the embodiment of the present application. In the embodiment of the present application, the modal damping ratio identification device may include a processor, a memory, a communication interface and a communication bus.

[0134] The communication bus may be of any type and is used to interconnect the processor, memory, and communication interface.

[0135] Communication interfaces include input / output (I / O), physical, and logical interfaces, which interconnect components within the modal damping ratio identification device and other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet, fiber, or ATM; user equipment can include displays and keyboards.

[0136] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0137] The processor may be a general-purpose processor that can invoke a modal damping ratio identification program stored in a memory and execute the modal damping ratio identification method provided in the embodiments of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the modal damping ratio identification program is invoked can be described with reference to the various embodiments of the modal damping ratio identification method of the present application and will not be further described here.

[0138] Those skilled in the art will understand that Figure 7 The hardware structure shown in the figure does not constitute a limitation to the present application and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0139] In a fourth aspect, an embodiment of the present application also provides a readable storage medium.

[0140] The readable storage medium of the present application stores a modal damping ratio identification program, wherein when the modal damping ratio identification program is executed by a processor, the steps of the modal damping ratio identification method as described above are implemented.

[0141] Among them, the method implemented when the modal damping ratio identification program is executed can refer to the various embodiments of the modal damping ratio identification method of the present application, and will not be repeated here.

[0142] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0143] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0144] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0145] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0146] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0147] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0148] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A modal damping ratio identification method, characterized in that: The modal damping ratio identification method includes: Perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components; The attributes of each intrinsic modal component are determined based on the time domain and frequency domain characteristics of each intrinsic modal component, and the intrinsic modal component whose attribute is the actual modal response is used as the target intrinsic modal component; Performing a Hilbert transform on the target intrinsic modal component, and determining a target instantaneous amplitude and a target instantaneous frequency corresponding to the target intrinsic modal component based on the result of the Hilbert transform and the target intrinsic modal component; Determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency to obtain the amplitude correlation of the modal damping ratio; The step of determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency includes: Calculate the first-order derivative of the target instantaneous amplitude and target instantaneous frequency respectively to obtain the instantaneous amplitude change rate and instantaneous frequency change rate; Determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate, and the instantaneous frequency change rate; The step of determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate, and the instantaneous frequency change rate includes: Substituting the target instantaneous amplitude, target instantaneous frequency, instantaneous amplitude change rate, and instantaneous frequency change rate into the first calculation formula, the instantaneous modal damping ratio corresponding to the target intrinsic modal component is obtained. The first calculation formula is: Where, is the instantaneous amplitude of the target; is the target instantaneous frequency; is the instantaneous amplitude change rate; is the instantaneous frequency change rate; is the instantaneous modal damping ratio corresponding to the target intrinsic modal component.

2. The modal damping ratio identification method according to claim 1, wherein: The properties of each intrinsic modal component are determined based on its time domain and frequency domain characteristics, including: For each intrinsic modal component, if the detected time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, then the attribute of the intrinsic modal component is determined to be an actual modal response; If at least one of the following conditions is not met: the time history curve is in the form of oscillation attenuation, the frequency is concentrated in the target narrow frequency band or at the target frequency point, and the frequency is the same as the preset order modal frequency, the attribute of the intrinsic modal component is determined to be noise.

3. The modal damping ratio identification method according to claim 1, wherein: The step of taking the intrinsic modal component having the attribute of the actual modal response as the target intrinsic modal component includes: For each intrinsic modal component, the frequency corresponding to the spectrum peak of the intrinsic modal component is taken as the characteristic frequency; Determine the modal order corresponding to the intrinsic modal component based on the characteristic frequency; The intrinsic modal component whose modal order is the preset modal order and whose attribute is the actual modal response is taken as the target intrinsic modal component.

4. The modal damping ratio identification method according to claim 3, wherein: The determining of the modal order corresponding to the intrinsic modal component based on the characteristic frequency includes: Differences are obtained by subtracting the characteristic frequency from the theoretical frequency of each modal order; The modal order corresponding to the difference value being less than the preset difference threshold is taken as the modal order corresponding to the intrinsic modal component.

5. The modal damping ratio identification method according to claim 1, wherein: The step of determining the target instantaneous amplitude and target instantaneous frequency corresponding to the target intrinsic modal component based on the result of the Hilbert transform and the target intrinsic modal component includes: Substituting the Hilbert transform result and the target connotation modal component into the second calculation formula to obtain the target instantaneous amplitude corresponding to the target connotation modal component; Substituting the Hilbert transform result and the target connotation modal component into the third calculation formula to obtain the target instantaneous frequency corresponding to the target connotation modal component; The second calculation formula is as follows: The third calculation formula is as follows: Where, is the result of Hilbert transform; is the target connotation modal component; is the target instantaneous amplitude, is the target instantaneous frequency.

6. A modal damping ratio identification system, characterized in that: The modal damping ratio identification system includes: A first processing module is used to perform variational modal decomposition on the free vibration response of the target bridge to obtain multiple intrinsic modal components; The second processing module is used to determine the attributes of each intrinsic modal component based on the time domain and frequency domain characteristics of each intrinsic modal component, and use the intrinsic modal component whose attribute is the actual modal response as the target intrinsic modal component; a third processing module, which is used to perform a Hilbert transform on the target connotation modal component, and determine a target instantaneous amplitude and a target instantaneous frequency corresponding to the target connotation modal component based on the result of the Hilbert transform and the target connotation modal component; a fourth processing module, configured to determine an instantaneous modal damping ratio corresponding to a target intrinsic modal component based on the target instantaneous amplitude and the target instantaneous frequency, so as to obtain an amplitude correlation of the modal damping ratio; Wherein, the fourth processing module is further used for: Calculate the first-order derivative of the target instantaneous amplitude and target instantaneous frequency respectively to obtain the instantaneous amplitude change rate and instantaneous frequency change rate; Determining the instantaneous modal damping ratio corresponding to the target intrinsic modal component based on the target instantaneous amplitude, the target instantaneous frequency, the instantaneous amplitude change rate, and the instantaneous frequency change rate; The fourth processing module is further configured to: Substituting the target instantaneous amplitude, target instantaneous frequency, instantaneous amplitude change rate, and instantaneous frequency change rate into the first calculation formula, the instantaneous modal damping ratio corresponding to the target intrinsic modal component is obtained. The first calculation formula is: Where, is the instantaneous amplitude of the target; is the target instantaneous frequency; is the instantaneous amplitude change rate; is the instantaneous frequency change rate; is the instantaneous modal damping ratio corresponding to the target intrinsic modal component.

7. A modal damping ratio identification device, characterized in that: The modal damping ratio identification device includes a processor, a memory, and a modal damping ratio identification program stored in the memory and executable by the processor, wherein when the modal damping ratio identification program is executed by the processor, the steps of the modal damping ratio identification method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a modal damping ratio identification program, wherein when the modal damping ratio identification program is executed by a processor, the steps of the modal damping ratio identification method according to any one of claims 1 to 5 are implemented.

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