A prediction method for the force sub-wave response under the vibrator coupling medium

Abstract

The present invention relates to a method for predicting the force sub-wave response under a controllable seismic source coupling medium, and belongs to the field of scanning signal design technology. The present invention first obtains the plate acceleration and weight acceleration information of any controllable seismic source under the near surface, and then calculates the medium property parameters, resonance frequency and damping ratio of the near surface by fitting the amplitude ratio curve and the phase difference curve; then establishes the transfer function of the force under the coupling medium, and calculates the frequency spectrum response of the force sub-wave under the controllable seismic source coupling medium corresponding to the near surface; finally, the force sub-wave distribution under the corresponding near-surface coupling medium is drawn according to the spatial positions corresponding to the different near-surface resonance frequencies and damping ratios, so as to realize the prediction of the force sub-wave response under the controllable seismic source coupling medium. The present invention can effectively predict the dominant frequency band of the downlink wave energy, provide a reliable basis for the optimal design of the controllable seismic source scanning signal, and realize the optimal transmission of the limited energy of the controllable seismic source.

Description

Technical Field

[0001] The invention relates to a method for predicting a force sub-wave response under a controllable seismic source coupling medium, and belongs to the technical field of scanning signal design. Background Art

[0002] The controllable vibrator is a safe, efficient and highly controllable seismic exploration equipment, and has gradually become one of the main excitation sources for seismic exploration. Before the controllable vibrator works, the controllable vibrator body must first be lifted up by the lifting cylinder so that the weight of the controllable vibrator acts entirely on the vibrator plate, thereby ensuring that the vibrator plate is tightly coupled with the ground. During the working process, the high-pressure hydraulic oil generated by the hydraulic system of the controllable vibrator vibrator alternately enters the upper and lower chambers of the heavy hammer, pushing the heavy hammer up and down. At the same time, the hydraulic pressure generated by the hydraulic oil is transmitted to the plate through the piston rod, the upper plate and the column structure, and finally transmitted to the earth through the contact between the plate and the earth, thereby exciting seismic waves. Therefore, the near-surface physical properties of the contact surface between the vibrator plate and the earth will directly affect the accuracy of the output signal of the controllable vibrator vibrator and the energy transfer of the vibrator, which plays an important role in the exploration accuracy.

[0003] In order to achieve the best energy transmission, improve the quality of downlink signals, and enhance the exploration capability of controllable vibrators, researchers have conducted a lot of research on vibrator-earth contact systems, but the current research is still mainly focused on controllable vibrator structures or some simple applications. For example, the Chinese patent document with announcement number CN203688810U discloses a device for reinforcing the center stiffness of a controllable vibrator plate, which is mainly composed of a piston rod base and a reinforcement plate. This solution can strengthen the stiffness of the vibrator plate without changing the original controllable vibrator structure, reduce the deformation of the center of the plate, improve the consistency of the directional deformation of the plate in the length and width directions, and enhance the uniformity of the energy distribution of the controllable vibrator excitation signal in the earth's space. For another example, the Chinese patent application document with application publication number CN110907992A discloses a near-surface physical property differentiation method based on vibrating induction of controllable seismic sources. The method first collects the induced stiffness and induced viscosity of each typical surface vibration point in the work area; then the induced stiffness and induced viscosity of the different vibration points are plotted in the same plane coordinate system to obtain a physical property differentiation map; finally, the work area is divided into different physical property surface types or the same physical property surface type is further divided into different physical property areas according to the physical property differentiation map. This scheme can determine the type of physical property of a certain surface according to the position characteristics of its physical property on the physical property map, thereby quantitatively dividing the types of surface earthquake conditions.

[0004] In summary, the current research on vibrators mainly stays on the contact surface between the plate and the ground. By analyzing the movement characteristics of the plate and the change of the contact force (ground force), the vibration response and energy transfer between the vibrator plate and the ground under different near-surface conditions are studied. The amplitude-frequency response of the force signal under the vibrator coupling medium can characterize the energy transmission of the vibrator. Therefore, studying the force signal under the vibrator coupling medium can provide a reliable basis for the optimization design of the vibrator scanning signal and improve the application effect of the vibrator in seismic exploration. However, there is a lack of research on the force signal under the vibrator coupling medium, which may reduce the use effect of the vibrator in seismic exploration. Summary of the invention

[0005] The purpose of the present invention is to provide a method for predicting the force wave response under a controllable vibrator coupling medium, so as to solve the problem of poor application effect of controllable vibrators caused by the lack of research on force signals under the controllable vibrator coupling medium.

[0006] In order to solve the above technical problems, the present invention provides a method for predicting the force sub-wave response under a vibrator-coupled medium, and the prediction method comprises the following steps:

[0007] 1) Obtain reference signals, force signals, weight acceleration signals and plate acceleration signals during the construction of any vibrator near the surface;

[0008] 2) Determine the amplitude ratio curve and phase difference curve according to the plate acceleration and the weight acceleration signals;

[0009] 3) Fitting the obtained amplitude ratio curve and phase difference curve respectively, solving the amplitude ratio function and the phase difference function, calculating the medium property parameters of the near surface, and thereby obtaining the resonance frequency and damping ratio of the near surface;

[0010] 4) establishing a transfer function of the force below the coupling medium based on the dynamic equilibrium relationship between the plate and the coupling medium, obtaining the relationship between the amplitude spectrum of the force below the coupling medium and the near-surface medium attribute parameters, and calculating the frequency spectrum response of the sub-wave of the force below the vibroseis coupling medium corresponding to the near-surface according to the near-surface medium attribute parameters of step 3);

[0011] 5) Repeat steps 1)-4) to obtain the frequency spectrum response of the force sub-wave under different near-surface controllable source coupling media and the corresponding resonance frequency and damping ratio, and plot the amplitude-frequency response of the force sub-wave under different near-surface controllable source coupling media according to the spatial positions corresponding to their resonance frequencies and damping ratios, and then obtain the force sub-wave distribution under different near-surface coupling media, so as to realize the prediction of the force sub-wave response under the controllable source coupling medium.

[0012] The present invention first obtains an amplitude ratio curve and a phase difference curve according to relevant signals in the construction process of any near-surface controllable source, and respectively performs fitting to solve the amplitude ratio function and the phase difference function, and then calculates the medium property parameters, resonance frequency and damping ratio of the near-surface; then establishes a transfer function of the force under the coupling medium, obtains the relationship between the amplitude spectrum of the force under the coupling medium and the near-surface medium property parameters, and calculates the frequency spectrum response of the force sub-wave under the controllable source coupling medium corresponding to the near-surface; finally, the amplitude-frequency response of the force sub-wave under different near-surface controllable source coupling media is plotted according to the spatial positions corresponding to their resonance frequencies and damping ratios, and then the force sub-wave distribution under different near-surface coupling media is obtained, and the prediction of the force sub-wave response under the controllable source coupling medium is realized. By analyzing the influence of different near-surface physical conditions on the amplitude-frequency characteristics of the force sub-wave under the controllable source coupling medium, the present invention can effectively predict the dominant frequency band of the downlink wave energy, provide a reliable basis for the optimal design of the controllable source scanning signal, realize the optimal transmission of the limited energy of the controllable source, and improve the application effect of the controllable source in seismic exploration.

[0013] Furthermore, the transfer function of the force below the coupling medium established in step 4) is:

[0014]

[0015] Where K g is the elastic coefficient of the near-surface coupling medium, D g is the viscosity coefficient of the near-surface coupling medium, M g is the mass of the captured body, F dg (jω) is the frequency spectrum function of the force below the coupling medium, F g (jω) is the frequency spectrum function of the force on the near-surface capture body, and ω is the vibration angular frequency.

[0016] The present invention analyzes the near-surface capture body as a force-bearing object, establishes a corresponding force equation by analyzing the force of the near-surface coupling medium, and derives the transfer function of the force under the coupling medium. The force transfer function under the coupling medium obtained by the present invention conforms to the force condition of the coupling medium, and provides a reliable data source for the forward simulation of the force sub-wave under the controllable seismic source coupling medium.

[0017] Furthermore, the near-surface medium property parameters include the elastic coefficient K of the near-surface coupling medium. g , viscosity coefficient of near-surface coupling medium D g and the captured mass M g .

[0018] Furthermore, the calculation formulas for the resonance frequency and damping ratio near the surface in step 3) are respectively:

[0019] ω n 2 =K g / (M b +M g )

[0020] 2ξω n =D g / (M b +M g )

[0021] where ω n is the resonant frequency, ξ is the damping ratio, K g is the elastic coefficient of the near-surface coupling medium, D g is the viscosity coefficient of the near-surface coupling medium, M g is the captured volume mass.

[0022] Furthermore, the process of obtaining the amplitude ratio curve in step 2) is as follows:

[0023] The acceleration information of the plate and the weight are converted into the frequency domain by Fourier transform respectively;

[0024] Calculate the ratio of the plate amplitude to the hammer amplitude in the frequency domain, and select the amplitude ratio data of the target frequency range;

[0025] The amplitude ratio data of the selected target frequency band is smoothed and converted into logarithmic decibel values.

[0026] Through the above process, the amplitude ratio data can be obtained conveniently and quickly. At the same time, the logarithmic decibel value can better reflect the change of the amplitude ratio with frequency, which is convenient for subsequent fitting processing.

[0027] Furthermore, the process of obtaining the phase difference curve in step 2) is as follows:

[0028] The plate acceleration and the hammer acceleration information are converted to the frequency domain through Fourier transform, and the corresponding phase-frequency response is calculated;

[0029] Calculate the difference between the plate phase and the hammer phase in the frequency domain, and select the phase difference data of the target frequency band;

[0030] The phase difference data of the selected target frequency band is smoothed and converted into logarithmic decibel values.

[0031] Through the above process, the phase difference data can be obtained conveniently and quickly. At the same time, the logarithmic decibel value can better reflect the change of the phase difference with the frequency, which is convenient for subsequent fitting processing.

[0032] Furthermore, the amplitude ratio function and phase difference function solved in step 3) are respectively:

[0033]

[0034]

[0035] Where K g is the elastic coefficient of the near-surface coupling medium, D g is the viscosity coefficient of the near-surface coupling medium, M g is the mass of the captured body, A(ω) is the amplitude ratio function obtained by fitting, is the phase difference function obtained by fitting, ω is the vibration angular frequency, M r is the mass of the weight, M b It is tablet quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of the structure of a controllable source vibrator;

[0037] Figure 2 It is a schematic diagram of the vibrator-earth coupled vibration model of the controllable source;

[0038] Figure 3 is a forced vibration amplitude-frequency curve diagram obtained in an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of vibroseis data collected in an embodiment of the present invention;

[0040] Figure 5-a is a flat panel amplitude-frequency response diagram obtained in an embodiment of the present invention;

[0041] Figure 5-b is a diagram of the amplitude-frequency response of a heavy hammer obtained in an embodiment of the present invention;

[0042] Figure 6 is the logarithmic spectrum of the amplitude ratio of the plate acceleration and the weight acceleration obtained in the embodiment of the present invention;

[0043] Figure 7-a is a flat panel phase-frequency response diagram obtained in an embodiment of the present invention;

[0044] Figure 7-b is a phase-frequency response diagram of a heavy hammer obtained in an embodiment of the present invention;

[0045] Figure 8 is a logarithmic spectrum of the phase difference between the plate acceleration and the weight acceleration obtained in the embodiment of the present invention;

[0046] Figure 9-a is a fitting result diagram of the hard grass ground surface amplitude ratio obtained in an embodiment of the present invention;

[0047] Figure 9-bis a graph of the phase difference fitting result of the hard grass surface obtained in an embodiment of the present invention;

[0048] Fig.10 is a spectrum diagram of the force sub-wave below the vibroseis coupling medium on the hard grass surface obtained in an embodiment of the present invention;

[0049] Fig.11 is a distribution diagram of force sub-waves under different near-surface coupling media obtained in an embodiment of the present invention;

[0050] Among them: 1 is a flat plate; 2 is a hydraulic oil chamber; 3 is a heavy hammer; 4 is an upper plate; 5 is a piston rod; 6 is a column; 7 is a hydraulic pipeline; 8 is an air spring; and 9 is the ground. DETAILED DESCRIPTION

[0051] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0052] Method Embodiment

[0053] The present invention firstly fits the amplitude ratio curve and the phase difference curve obtained from the relevant signals in the construction process of any near-surface controllable source, solves the amplitude ratio function and the phase difference function, and then calculates the medium property parameters, resonance frequency and damping ratio of the near-surface; then establishes the transfer function of the force under the coupling medium, obtains the relationship between the amplitude spectrum of the force under the coupling medium and the near-surface medium property parameters, and calculates the frequency spectrum response of the force sub-wave under the controllable source coupling medium corresponding to the near-surface; finally, the amplitude-frequency response of the force sub-wave under different near-surface controllable source coupling media is plotted according to the spatial positions corresponding to their resonance frequencies and damping ratios, and then the force sub-wave distribution under different near-surface coupling media is obtained, so as to realize the prediction of the force sub-wave response under the controllable source coupling medium.

[0054] Before describing the method of the present invention, the controllable vibrator is first introduced. The controllable vibrator is an excitation source with low energy density. The accumulation of excitation energy requires long-term vibration. The vibrator is the core of the controllable vibrator and the source of the seismic signal. Figure 1 As shown, the controllable source vibrator is composed of an upper plate 4, a column 6, a piston rod 5, a plate 1, a weight 3, a hydraulic oil chamber 2, a hydraulic pipeline 7 and an air spring 8. The weight is connected to the plate 1 through two air springs 8, and the air spring 8 is used to balance the weight of the weight. During operation, the high-pressure hydraulic oil generated by the hydraulic system of the controllable source vibrator alternately enters the upper and lower chambers of the weight, pushing the weight up and down. At the same time, the hydraulic pressure generated by the hydraulic oil is transmitted to the plate through the piston rod, the upper plate and the column structure, and finally transmitted to the ground 9 through the contact between the plate and the ground, thereby exciting seismic waves.

[0055] The vibrator-ground coupled vibration model of the controllable source can be simulated by the forced vibration of the mass-spring-damper. The vibrator plate of the controllable source and the ground form a non-perfectly elastic system, such as Figure 2 As shown, where M r is the mass of the weight, M b is the mass of the plate, M g is the mass of the near-surface coupling medium (mass of the captured body), H s and H v are the elastic and viscosity coefficients of the hydraulic oil, K g and D g are the elastic coefficient and viscosity coefficient of the near-surface coupling medium, X r is the displacement of the weight, X b is the displacement of the plate, F a is the force of the hydraulic oil, F g is the ground force, F dg is the force below the coupling medium.

[0056] According to the above model, the dynamic equilibrium equation of the plate and the coupling medium can be established, and the amplitude ratio and phase difference function can be obtained through mathematical transformation. According to the amplitude ratio and phase difference function, the weight mass M r And plate quality M b Determine the near-surface medium property parameters under certain conditions: elastic coefficient K g , viscosity coefficient D g and the captured mass M g From the amplitude-frequency curve of the forced vibration of the model (such as Figure 3 As shown in the figure, it can be seen that the smaller the damping ratio, the steeper the peak. The frequency corresponding to the peak is called the resonant frequency of the system. The damping ratio ξ and the resonant frequency ω n Determines the shape of the amplitude-frequency curve, the damping ratio ξ and the resonant frequency ω n The calculation formula is as follows:

[0057] ω n 2 =K g / (M b +M g )

[0058] 2ξω n =D g / (M b +M g )

[0059] Taking the captured body near the surface as the force analysis, we can get:

[0060]

[0061] like Figure 2As shown, the force below the coupling medium can be approximately expressed as:

[0062]

[0063] Thus, the transfer function of the force under the coupling medium can be obtained:

[0064]

[0065] Then the frequency spectrum of the force transfer function under the coupling medium is:

[0066]

[0067] According to the above spectrum equation, the forward simulation of the force sub-wave under the controllable seismic source coupling medium can be realized.

[0068] In view of the above analysis, a method for predicting the force sub-wave response under a controllable seismic source coupled medium of the present invention is proposed, and the implementation process of the method is as follows.

[0069] 1. Obtain reference signals, force signals, weight and plate acceleration signals during vibrator construction.

[0070] This embodiment uses the Nomad 65Neo low-frequency controllable vibrator produced by Sercel Company. The weight of the controllable vibrator is M r is 4082Kg, the mass of the plate is M b The weight is 1560 kg, and the plate area S is 2.634 m 2 . The up and down movement of the weight is controlled according to the reference signal given by the user, and is transmitted to the earth through the contact between the plate and the earth, thereby exciting seismic waves. The present invention installs a vibration signal detection device (accelerometer) on the weight and the vibrating plate, and detects the vibration signals of the weight and the vibrating plate through the accelerometer. During the scanning process, the two accelerometers respectively record the movement information of the weight and the plate, and feed them back to the electronic control system. The vector sum of the vibration output of the weight and the vibrating plate is called the force signal. The electronic control system corrects the phase and output of the force signal, thereby ensuring the synchronization accuracy and vibration accuracy of the controllable seismic source vibration. After each vibration is completed during the construction process of the controllable seismic source, the corresponding reference signal, force signal, weight and plate acceleration signal are collected for subsequent analysis. For example, the controllable seismic source data collected in this embodiment is as follows Figure 4 As shown, it includes a reference signal, a force signal, a weight acceleration signal and a plate acceleration signal.

[0071] 2. Based on the collected vibroseis data, determine the amplitude ratio and phase difference curves of the plate and the hammer.

[0072] The amplitude ratio curve is obtained by converting the plate acceleration signal and the weight acceleration signal into the frequency domain, such as Figure 5-a and Figure 5-b As shown, the ratio between the plate amplitude and the hammer amplitude is calculated in the frequency domain. In order to better express the relationship between the amplitude ratio and the frequency, the present invention also performs logarithmic processing on the ratio to obtain the corresponding amplitude ratio logarithmic spectrum. This embodiment intercepts the 10-90Hz target frequency range for display, as shown in FIG. Figure 6 shown.

[0073] The phase difference curve is obtained by converting the plate acceleration signal and the weight acceleration signal into the frequency domain, such as Figure 7-a and Figure 7-b As shown, the difference between the plate phase and the hammer phase is calculated in the frequency domain. In order to better express the relationship between the phase difference and the frequency, the present invention also performs logarithmic processing on the comparison value to obtain the corresponding phase difference logarithmic spectrum. This embodiment intercepts the 10-90Hz target frequency range for display, as shown in FIG. Figure 8 shown.

[0074] 3. Based on the obtained amplitude ratio and phase difference curves, the property parameters of the near-surface coupling medium are calculated, and then the resonant frequency and damping ratio of the forced vibration system are calculated.

[0075] The obtained amplitude ratio and phase difference curves are fitted respectively, and the solved amplitude ratio function and phase difference function are:

[0076]

[0077]

[0078] For the vibrator selected in this embodiment, the mass of the hammer M r And plate quality M b These are all known quantities. By fitting the obtained curve, we can solve the amplitude ratio function and phase difference function. r And plate quality M b Under certain conditions, the near-surface medium property parameters can be calculated: the elastic coefficient K of the near-surface coupling medium g , viscosity coefficient of near-surface coupling medium D g and the captured mass M g .

[0079] Assuming that the near surface in this embodiment is a hard grass surface, by fitting the amplitude ratio and phase difference curves, the curve fitting results are as follows: Figure 9-a and Figure 9-b As shown in the figure, the average stiffness coefficient of the hard grass surface is calculated to be 8.15×10 7 N / m, the average viscosity coefficient is 3.04×10 5 N*s / m, the average mass of the captured body is 515Kg.

[0080] According to the calculation results of the near-surface medium property parameters, the vibrator plate mass M b If the resonant frequency ω is known, the formula is used to calculate n and damping ratio ξ.

[0081] ω n 2 =K g / (M b +M g )

[0082] 2ξω n =D g / (M b +M g )

[0083] Therefore, the above formula can be used to calculate the resonance frequency ω when the near surface is hard grass. n is 198 (radians per second), converted to frequency ω n / 2π is 31.5Hz, and the damping ratio ξ is 0.37.

[0084] 4. Forward modeling of the force sub-wave under the controllable seismic source coupling medium.

[0085] According to the previous derivation, the frequency spectrum of the force transfer function under the coupling medium is:

[0086]

[0087] Then the amplitude spectrum of the force under the coupling medium can be expressed as:

[0088]

[0089] According to the above spectrum equation, the forward simulation of the force under the vibrator coupling medium can be realized. The input parameter of the equation is the force signal F g (jω) and near-surface medium property parameters: average stiffness coefficient K g , average viscosity coefficient D g and the average mass of the captured body M g By substituting the amplitude spectrum equation of the force under the coupling medium, the spectrum response of the force wavelet under the coupling medium of the controllable vibrator in the case of a single near-surface medium is obtained. The result is as follows: Fig.10 shown.

[0090] 5. Forward modeling of the force sub-waves under the controllable seismic source coupling medium under different near-surface conditions is carried out to obtain the distribution diagram of the force sub-waves under different near-surface coupling media.

[0091] Repeating steps 1 to 4 under different near-surface conditions, we can obtain the corresponding near-surface physical parameters, the resonant frequency of the forced vibration system, the damping ratio, and the spectrum response of the force sub-wave under the controlled vibrator coupling medium. The damping ratio and resonant frequency of the forced vibration system determine the shape of the amplitude-frequency curve. n / 2π is the abscissa, the damping ratio ξ is the ordinate, and the frequency spectrum responses of the force sub-waves under different near-surface coupling media are placed in the corresponding spatial positions to obtain the distribution diagrams of the force sub-waves under different near-surface coupling media.

[0092] This embodiment uses the vibrator of Nomad 65Neo, collects reference signals, force signals, heavy hammer and plate acceleration signals of the vibrator vibration under different near-surface conditions such as beach, cement road, hard grass, saline crust, hard sand, soft grass, gravel, rock, mud-covered rock, weathered rock, wet soil, etc., to simulate the spectrum of the force sub-wave under the vibrator coupling medium, and plots the amplitude-frequency responses of the force sub-wave under different near-surface vibrator coupling media on a graph according to the spatial positions corresponding to the resonance frequency and damping ratio, as shown in FIG. Fig.11 As shown, the force sub-wave response of different vibrator coupling media near the surface can be obtained.

[0093] The present invention analyzes the influence of different near-surface physical conditions on the amplitude-frequency characteristics of the force sub-wave under the controllable source coupling medium, grasps the dominant frequency band of the effective downlink wave energy, provides a reliable basis for the optimal design of the controllable source scanning signal, realizes the optimal transmission of the limited energy of the controllable source, thereby reducing distortion, improving the sub-wave quality, and fully tapping the excitation potential of the controllable source equipment, which is of great significance to improving the exploration effect of the controllable source.

Claims

1. A method for predicting the force sub-wave response under a vibrator-coupled medium, characterized in that: The prediction method includes the following steps: 1) Obtain reference signals, force signals, weight acceleration signals and plate acceleration signals during the construction of any near-surface vibrator; 2) Determine the amplitude ratio curve and phase difference curve according to the plate acceleration and the weight acceleration signals; 3) Fit the obtained amplitude ratio curve and phase difference curve respectively, solve the amplitude ratio function and phase difference function, calculate the medium property parameters of the near surface, and obtain the resonance frequency and damping ratio of the near surface. The medium property parameters of the near surface include the elastic coefficient K of the near surface coupling medium. g , viscosity coefficient of near-surface coupling medium D g and the captured mass M g ; 4) establishing a transfer function of the force below the coupling medium based on the dynamic equilibrium relationship between the plate and the coupling medium, obtaining the relationship between the amplitude spectrum of the force below the coupling medium and the near-surface medium attribute parameters, and calculating the frequency spectrum response of the sub-wave of the force below the vibroseis coupling medium corresponding to the near-surface according to the near-surface medium attribute parameters of step 3); 5) Repeat steps 1)-4) to obtain the spectrum response of the force sub-wave under different near-surface controllable source coupling media and the corresponding resonance frequency and damping ratio, and plot the spectrum response of the force sub-wave under different near-surface controllable source coupling media according to the spatial positions corresponding to their resonance frequencies and damping ratios, and then obtain the force sub-wave distribution under different near-surface coupling media, so as to realize the prediction of the force sub-wave response under the controllable source coupling medium; The transfer function of the force under the coupling medium established in step 4) is: where F dg (jω) is the frequency spectrum function of the force below the coupling medium, F g (jω) is the frequency spectrum function of the force on the near-surface capture body, and ω is the vibration angular frequency; The calculation formulas for the resonance frequency and damping ratio near the surface in step 3) are: ω n 2 =K g / (M b +M g ) 2ξω n =D g / (M b +M g ) where ω n is the resonant frequency, ξ is the damping ratio, M b It is the quality of the plate; The amplitude ratio function and phase difference function solved in step 3) are: Where A(ω) is the amplitude ratio function obtained by fitting, is the phase difference function obtained by fitting, M r It is the mass of the heavy hammer.

2. The method for predicting the force sub-wave response under a vibrator-coupled medium according to claim 1, characterized in that: The process of obtaining the amplitude ratio curve in step 2) is as follows: The acceleration information of the plate and the weight are converted into the frequency domain by Fourier transform respectively; Calculate the ratio of the plate amplitude to the hammer amplitude in the frequency domain, and select the amplitude ratio data of the target frequency range; The amplitude ratio data of the selected target frequency band is smoothed and converted into logarithmic decibel values.

3. The method for predicting the force sub-wave response under a vibrator-coupled medium according to claim 1, characterized in that: The process of obtaining the phase difference curve in step 2) is as follows: The plate acceleration and the hammer acceleration information are converted to the frequency domain through Fourier transform, and the corresponding phase-frequency response is calculated; Calculate the difference between the plate phase and the hammer phase in the frequency domain, and select the phase difference data of the target frequency band; The phase difference data of the selected target frequency band is smoothed and converted into logarithmic decibel values.

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