Medium-high frequency radiation sound power prediction method based on transfer function

Abstract

The invention provides a medium-high frequency radiation sound power prediction method based on a transfer function. According to the method, on the basis of a transfer function method, an acoustic model about medium-high frequency radiation sound power prediction is established according to finite element software simulation calculation and a mean square vibration velocity obtained through an experiment, the acoustic model is a model capable of being predicted, transfer efficiency obtained through simulation and the mean square vibration velocity measured through the experiment are input, and the medium-high frequency radiation sound power is obtained through model calculation. The prediction performance of the model is evaluated, and the medium-high frequency radiation sound power can be accurately predicted.

Description

Technical Field

[0001] This invention relates to the field of mid-to-high frequency acoustic radiation power prediction technology, and in particular to a method for predicting mid-to-high frequency radiated acoustic power based on transfer function. Background Technology

[0002] In today's complex international environment, mastering advanced acoustic detection technology has become a focal point of competition among nations. Various equipment and ships in the ocean generate radiated noise due to vibration during operation. Accurate measurement and prediction of this noise are crucial indicators for understanding their operational status and for precise positioning and monitoring. Traditional acoustic measurement methods are often limited by background noise, requiring not only complex deployments and high-precision equipment but also relatively quiet and stable environments. However, predicting acoustic radiation power using structural vibration data can reduce the impact of background noise on acoustic measurements and provide a reference for acoustic prediction of other complex structures, thus promoting technological advancements and widespread application in this field.

[0003] Many scholars have studied the vibration and acoustic radiation of underwater structures and proposed numerous methods, the most common being theoretical analysis and numerical simulation. However, both methods have limitations and complexities. Generally, when the excitation force is not particularly strong, the acoustic radiation process of underwater structure vibration is a linear system. Therefore, when the model and excitation force are determined, the mean square velocity of the structure's vibration is linearly proportional to its underwater radiated acoustic power. Based on the excitation location and model structure, the transfer efficiency from mean square velocity to radiated acoustic power can be theoretically calculated in advance. Combined with the measurement of the actual mean square velocity of the structure, the mid-to-high frequency radiated acoustic power can be predicted. This is the acoustic radiation prediction model based on the transfer function method for predicting mid-to-high frequencies. Since the transfer function method does not require direct measurement of the structure's radiated acoustic power, and the vibration data obtained through accelerometers is unaffected by environmental background noise and the cutoff frequency of the experimental anechoic tank, this method has received increasing attention from scholars. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art and to propose a method for predicting mid-to-high frequency radiated acoustic power based on transfer function.

[0005] This invention is achieved through the following technical solution: This invention proposes a method for predicting mid-to-high frequency radiated acoustic power based on transfer function, the method comprising: Step 1: First, establish a sound radiation prediction model of the underwater structure and the underwater free field using finite element software. Obtain the vibration data of the underwater structure surface and the radiated sound power of the envelope surface by applying excitation. After the simulation calculation is completed, the transmission efficiency between the radiated sound power of the underwater structure and the mean square vibration velocity of the surface can be obtained through data processing. Step 2: In the water tank experiment, measure the radiated acoustic power and mean square velocity of the underwater structure under a given excitation; calculate the actual transmission efficiency of the underwater structure surface under the experimental environment according to the formula for transmission efficiency. Step 3: Compare and analyze the transmission efficiency obtained from experiments and simulation calculations to verify the correctness and reliability of underwater structure modeling and simulation; Step 4: Based on the transmission efficiency obtained from finite element software simulation calculations and the mean square vibration velocity data measured in the water tank experiment, the radiated acoustic power of the underwater structure is predicted using the acoustic radiation prediction model. The prediction results are then compared with the experimental results to verify the effectiveness of the acoustic radiation prediction model.

[0006] Furthermore, mean square velocity (MSV) refers to the time average of the squares of the vibration velocities at various points on the surface of an object, used to describe the energy characteristics of vibration; the definition formula for mean square velocity is: (1) in, Let be the normal velocity of the structural surface. The mean square velocity is the normal direction.

[0007] Furthermore, radiated sound power W refers to the sound energy radiated into the surrounding medium when an object vibrates; the expression for calculating radiated sound power is: (2) in Sound intensity, or simply sound strength, represents the time-averaged sound energy density at a point in a sound field.

[0008] Furthermore, transmission efficiency represents the ratio of the surface mean square vibration velocity to the radiated sound power of a structure; it characterizes the efficiency of vibration energy to sound energy conversion. The formula for calculating transmission efficiency is: (3) (4) The radiated acoustic power of the vibrating structure. The mean square vibration velocity is extracted from the surface of the vibrating structure. Characteristic impedance is the product of the density of the fluid medium surrounding the structure and the velocity of sound. The surface area of ​​the vibrating structure; The expression for transmission efficiency in decibels; Assuming the transmission efficiency of the underwater structure surface is calculated through simulation, it is... The mean square vibration velocity of the structural surface measured in the actual environment is Then the radiated acoustic power of the structure can be predicted. for (5).

[0009] Furthermore, in the modeling process, for sections of the structure that contain both thick and thin layers, a layered theory is applied in critical areas, while an equivalent single-layer theory is used in secondary areas; the layer width-to-thickness ratio is... The calculation formula is as follows: (6) in Indicates the maximum width of the structure. The thickness of the multilayer material.

[0010] Furthermore, after modeling is completed, the sound intensity at the envelope surface is calculated using the following formula: (7) in, This represents the instantaneous sound pressure value in the sound field, indicating the change of sound pressure with time and space. yes The conjugate of the complex number is used to ensure that the complex part is processed in the subsequent product calculation; the sound pressure Conjugate complex number of velocity component The sound pressure and velocity are multiplied to calculate the inner product in the direction of the normal vector; finally, the real part is taken and divided by 2 to obtain the average energy density; according to the calculation of radiated sound power in equation (2), after obtaining the average sound intensity through equation (7), the sound intensity is multiplied by the surface area of ​​the envelope to obtain the radiated sound power of the underwater structure vibration.

[0011] Furthermore, the radiated sound power level is calculated by performing a leveling operation on the data according to the following formula: (8) Mean square velocity level: (9) The mean square acceleration level is: (10) in, , , .

[0012] Furthermore, in step two, the radiated acoustic power is measured using the surface-wrapping method, specifically: the expression for the model's radiated acoustic power is as follows: (11) In the formula, The radiated sound power of the sound source. The distance between the hydrophone array and the radial distance to the target being measured is denoted as . For the depth of the water, For compensation coefficient, The distance from the equivalent sound center is The average sound intensity The distance from the equivalent sound center is The acoustic energy flux envelope area at the vertical array measurement position. Measuring the surface of the bag The average mean square sound pressure level in the space of the hydrophone; taking the logarithm of both sides of the above equation, we can obtain (12) In the formula, The radiated sound power level of the model, To measure the surface of the bag Spatial mean sound pressure level of the hydrophone; correction parameters (13) Based on the above formula, the formula for calculating the equivalent sound source level can be obtained as follows: (14) In the formula, This is the equivalent sound source level.

[0013] The present invention also proposes an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method for predicting mid-to-high frequency radiated acoustic power based on a transfer function.

[0014] The present invention also proposes a computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the steps of the method for predicting mid-to-high frequency radiated acoustic power based on a transfer function.

[0015] The beneficial effects of this invention are: This invention is based on the transfer function method. It establishes an acoustic model for predicting mid-to-high frequency radiated sound power by combining the mean square velocity obtained from finite element software simulation calculations with experimental results. This is a predictive model. By inputting the transfer efficiency obtained from simulation and the mean square velocity measured in experiments, the corresponding radiated sound power can be predicted through model calculation. The predictive performance of this model has been evaluated and it can predict mid-to-high frequency radiated sound power with relatively high accuracy. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1This is a simulation diagram of the underwater structure. Figure 2 A spectrum of the magnitude of the excitation force applied to the center of an underwater structure as a function of frequency; Figure 3 The following diagram shows the results of the data level calculation for underwater structures: (a) simulated radiated acoustic power level of the laminate, (b) simulated mean square vibration velocity level of the laminate, and (c) simulated mean square acceleration level of the laminate. Figure 4 The diagram shows the transmission efficiency results of the underwater structure simulation; where (a) is the transmission efficiency of the laminated plate simulation, and (b) is the transmission efficiency level of the laminated plate simulation. Figure 5 A schematic diagram showing the measurement results of the equivalent sound source level of an underwater structure; Figure 6 Schematic diagram of the radiated acoustic power level of the underwater structure in the experiment; Figure 7 The diagram shows the measurement results of the accelerometer on the underwater structure; where (a) is the mean square acceleration level of the laminate white noise excitation, (b) is the acceleration of the laminate white noise excitation, and (c) is the one-third octave band of the mean square acceleration of the laminate white noise excitation. Figure 8 The diagram shows the surface velocity and mean square vibration level of an underwater structure; where (a) is the surface velocity and (b) is the mean square vibration level. Figure 9 The diagram shows the radiated acoustic power and mean square vibration velocity of the underwater structure in the experiment; where (a) is the radiated acoustic power of the laminate in the experiment, and (b) is the mean square vibration velocity of the laminate surface in the experiment. Figure 10 This is a schematic diagram comparing simulation data and experimental data; where (a) is the comparison data of radiated sound power, (b) is the comparison data of mean square vibration velocity level, and (c) is the comparison data of mean square acceleration level. Figure 11 The comparison charts show the predicted results, simulation results, and experimental results; (a) is a comparison chart, and (b) is a comparison chart of one-third octave bands. Figure 12 This is a schematic diagram showing the error results between the predicted values ​​and the experimental measurements. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention provides a method for predicting mid-to-high frequency radiated acoustic power based on transfer function. By simply obtaining the transfer efficiency between the radiated acoustic power of an underwater structure and the mean square velocity of its surface through simulation calculation, and combining the mean square velocity value obtained from actual experimental measurements with the acoustic radiation prediction model based on the transfer function method for predicting mid-to-high frequencies, the corresponding radiated acoustic power can be predicted with relatively high accuracy. This reflects the characteristic that, under normal circumstances, once the model and excitation force are determined, the mean square velocity of structural vibration is linearly proportional to its underwater radiated acoustic power.

[0020] Combination Figures 1-12 This invention proposes a method for predicting mid-to-high frequency radiated acoustic power based on transfer function, the method comprising: Step 1: First, establish a sound radiation prediction model of the underwater structure and the underwater free field using finite element software. Obtain the vibration data of the underwater structure surface and the radiated sound power of the envelope surface by applying excitation. After the simulation calculation is completed, the transmission efficiency between the radiated sound power of the underwater structure and the mean square vibration velocity of the surface can be obtained through data processing. Step 2: In the water tank experiment, measure the radiated acoustic power and mean square velocity of the underwater structure under a given excitation; calculate the actual transmission efficiency of the underwater structure surface under the experimental environment according to the formula for transmission efficiency. Step 3: Compare and analyze the transmission efficiency obtained from experiments and simulation calculations to verify the correctness and reliability of underwater structure modeling and simulation; Step 4: Based on the transmission efficiency obtained from finite element software simulation calculations and the mean square vibration velocity data measured in the water tank experiment, the radiated acoustic power of the underwater structure is predicted using the acoustic radiation prediction model. The prediction results are then compared with the experimental results to verify the effectiveness of the acoustic radiation prediction model.

[0021] Furthermore, mean square velocity (MSV) refers to the time average of the squares of the vibration velocities at various points on the surface of an object. It is an important parameter in vibration analysis, used to describe the energy characteristics of vibration; the definition formula for mean square velocity is... (1) in, Let be the normal velocity of the structural surface. The mean square velocity is the normal direction.

[0022] Furthermore, in underwater acoustics, radiated sound power W refers to the sound energy radiated into the surrounding medium when an object vibrates; its unit is . The expression for calculating radiated sound power is: (2) in Sound intensity, or simply sound strength, represents the time-averaged sound energy density at a point in a sound field, and its unit is 1000 kJ / m². .

[0023] Furthermore, transmission efficiency represents the ratio of the surface mean square vibration velocity to the radiated sound power of a structure; it characterizes the efficiency of vibration energy to sound energy conversion. The formula for calculating transmission efficiency is: (3) (4) The radiated acoustic power of the vibrating structure. The mean square vibration velocity is extracted from the surface of the vibrating structure. Characteristic impedance is the product of the density of the fluid medium surrounding the structure and the velocity of sound. The surface area of ​​the vibrating structure; The expression for transmission efficiency in decibels; Based on dimensional calculations, the transmission efficiency The unit is 1, which represents the ratio of the radiated energy of an underwater structure to the vibrational energy of its surface when it is excited to vibrate. This theory treats the excited vibration of an elastic body and the radiated sound field as a linear system.

[0024] Assuming the transmission efficiency of the underwater structure surface is calculated through simulation, it is... The mean square vibration velocity of the structural surface measured in the actual environment is Then the radiated acoustic power of the structure can be predicted. for (5).

[0025] Furthermore, in finite element method (FE) software for multi-layer material modeling, lamination theories can be categorized based on their underlying principles: Equivalent Single-Layer Theory (ESL), Layered Theory (LW), and multi-model methods. However, computational accuracy and speed are often mutually exclusive in these two methods. Therefore, to appropriately select a modeling method, the concept of lamination width-to-thickness ratio is proposed. During model building, to address the issue of combining Equivalent Single-Layer Theory and Layered Theory, for structures containing both thick and thin laminations, Layered Theory is applied in critical regions, while Equivalent Single-Layer Theory is used in secondary regions. This approach improves the accuracy of local analysis while maintaining computational efficiency. The lamination width-to-thickness ratio is used... The calculation formula is as follows: (6) in Indicates the maximum width of the structure. The thickness of the multilayer material.

[0026] Furthermore, after modeling is completed, the sound intensity at the envelope surface is calculated using the following formula: (7) in, This represents the instantaneous sound pressure value in the sound field, usually a complex number, indicating the change of sound pressure with time and space; yes The conjugate of the complex number is used to ensure that the complex part is processed in the subsequent product calculation; the sound pressure Conjugate complex number of velocity component The sound pressure and velocity are multiplied to calculate the inner product in the direction of the normal vector; finally, the real part is taken and divided by 2 to obtain the average energy density; according to the calculation of radiated sound power in equation (2), the average sound intensity is obtained through equation (7), and the sound intensity is multiplied by the surface area of ​​the envelope to obtain the radiated sound power of the underwater structure vibration. Based on the above formulas, the sound intensity, mean square velocity, and mean square acceleration can be calculated in the finite element software.

[0027] Furthermore, the radiated sound power level is calculated by performing a leveling operation on the data according to the following formula: (8) Mean square velocity level: (9) The mean square acceleration level is: (10) in, , , .

[0028] Furthermore, in step two, the radiated sound power is measured using the envelope method. Specifically, in water at a depth of m, at different azimuth positions at appropriate distances from the equivalent sound center of the target, a hydrophone array consisting of high-gain hydrophones spaced at certain distances from the water surface to the bottom is used. The radiated sound power is measured by vertical averaging and azimuth averaging (reducing all vertical averaging results to the same distance). This method (spatial averaging) measures the radiated acoustic power of the model by spatially averaging all hydrophones on the measurement surface. The expression for the model's radiated acoustic power is: (11) In the formula, The radiated sound power of the sound source. The distance between the hydrophone array and the radial distance to the target being measured is denoted as . For the depth of the water, The compensation factor (to make up for the leaked energy through compensation), ), The distance from the equivalent sound center is The average sound intensity The distance from the equivalent sound center is The acoustic energy flux envelope area at the vertical array measurement position. Measuring the surface of the bag The average mean square sound pressure level in the space of the hydrophone; taking the logarithm of both sides of the above equation, we can obtain (12) In the formula, The radiated sound power level of the model, To measure the surface of the bag Spatial mean sound pressure level of the hydrophone; correction parameters (13) Based on the above formula, the formula for calculating the equivalent sound source level can be obtained as follows: (14) In the formula, This is the equivalent sound source level.

[0029] Example First, a structural model of the underwater structure and a model of the underwater free field are established using finite element method (FEM) software. Vibration data of the underwater structure's surface and radiated acoustic power of its envelope are obtained by applying excitation. After the simulation is completed, the transmission efficiency between the radiated acoustic power and the mean square vibration velocity of the surface of the underwater structure can be obtained through data processing.

[0030] Underwater structure simulation Suppose an underwater structure with geometric dimensions of 1m × 1m, composed of two types of glass fibers with different material properties laid in a specific manner. One material is chopped strand mat with a thickness of 0.2981mm; the other material is unidirectional fabric with a thickness of 0.4482mm. The mechanical properties of both the chopped strand mat and the unidirectional fabric are obtained experimentally. The chopped strand mat is isotropic, while the unidirectional fabric is anisotropic.

[0031] Based on the above, two different materials were created in the finite element method (FEM) software. When modeling the materials, the properties of the multiple layers need to be configured according to the stacking order. This process is performed within the multi-layer shell interface of the FEM software to ensure that the characteristics of each layer are accurately reflected.

[0032] Free field simulation After completing the structural modeling of the underwater structure, a two-dimensional working plane is established using the "multilayer material linking" function in the finite element software. On this working plane, a square with a side length of 1 meter is created, and the properties of the multilayer material are assigned to this square. This two-dimensional plane is used to simulate the actual underwater structure. Outside the working plane, a circle with a radius of 2 meters is established with the center of the underwater structure as its center, serving as an envelope for calculating the radiated acoustic power. This envelope will encompass the entire underwater structure, and its size is large enough to minimize boundary effects in the acoustic analysis. Simultaneously, another circle with a radius of 3 meters is established on the outer side, with a perfectly matched layer placed between the two circles to achieve an infinitely far free-field condition. Figure 1 This refers to the simulation modeling structure of underwater structures under free field conditions.

[0033] Apply excitation to obtain vibration data at the excitation point and radiated acoustic power at the envelope surface. After the model was constructed, the vibration and radiation of the underwater structure's surface in the frequency range of 20 Hz to 10 kHz were studied by applying excitation to the center of the underwater structure. The spectrum of the excitation force as a function of frequency is shown in the figure below. Figure 2 As shown, the direction of the excitation force is perpendicular to the surface of the underwater structure and downwards. The mesh properties of the structure are set based on a maximum frequency of 10kHz.

[0034] Simulation calculations yielded the transmission efficiency between radiated acoustic power and mean square surface vibration velocity of the underwater structure. Add the excitation spectrum to the finite element software. After confirming that the parameters of the underwater structure model are correct, add the study frequency domain. In the frequency domain solver, set the study frequency range to 20Hz to 10kHz, with a frequency interval of 5Hz, and start the solution calculation.

[0035] Meanwhile, since the vibration data was obtained through accelerometer measurements in the experiment, only acceleration data was available. Therefore, it was necessary to integrate the acceleration data to obtain velocity data. To verify the data, the mean square acceleration of the structure was also exported from the finite element software.

[0036] Simultaneously, the data is exported and saved as a ".txt" file for subsequent data processing. Based on the fundamental principle of the transfer efficiency method, the radiated acoustic power of the underwater structure is calculated in MATLAB by reading the exported data from the finite element software.

[0037] Based on formulas (8), (9), and (10), the data was processed in MATLAB to calculate the radiated acoustic power level, mean square velocity level, and acceleration level under the simulation conditions of the underwater structure. The results are as follows: Figure 3 As shown.

[0038] Based on the formula for calculating transmission efficiency, the obtained radiated acoustic power data and mean square vibration velocity data are used for calculation. The transmission efficiency of the underwater structure under excited vibration simulation results is then obtained. and transmission efficiency level like Figure 4 As shown.

[0039] Combination Figure 2 The excitation spectrum in the data shows that the energy of radiation and vibration is mainly concentrated in the frequency range of 0-3 kHz, which is highly consistent with the frequency range of energy concentration in the excitation data. This indicates that the main energy of the excitation source is between 0-3 kHz, which has a significant impact on the vibration and sound radiation of the system. In the high-frequency part, the trends of radiated sound power and mean square velocity also show consistency, further reflecting that under the condition of weak excitation force, the relationship between radiated sound power and mean square velocity can be regarded as linear.

[0040] In the water tank experiment, the radiated acoustic power and mean square velocity of the underwater structure were measured under a given excitation. Based on the formula for transmission efficiency, the actual transmission efficiency of the underwater structure surface under experimental conditions was calculated.

[0041] This experiment was conducted in an anechoic pool. The radiated acoustic power was measured using the surface wrapping method. The final vibration data of the underwater structure surface was obtained by accelerometer measurement. The measurement results are acceleration levels. In subsequent processing, the velocity data needs to be obtained by inverting the levels and performing integration.

[0042] To obtain more comprehensive sound source characteristic data, the measurement results from each direction were averaged. The process was as follows: first, the sound pressure level was inversely calculated to obtain the sound pressure data from each direction; then, the sound pressure from each direction was averaged to obtain the average sound pressure; finally, the average sound pressure was calculated to obtain the average sound source level from each direction. The final average equivalent sound source level obtained through averaging is shown below. Figure 5 As shown. Then, based on the sound source level, the final radiated sound power level of the underwater structure is calculated as follows: Figure 6 As shown.

[0043] The excitation used in the experiment was a white noise signal, and the excitation location was at the center of the underwater structure. The magnitude and location of the excitation were the same as those used in the simulation. The acceleration and mean square velocity level results measured by the accelerometer are as follows: Figure 7 As shown, the variable relationship between the two satisfies equation (10).

[0044] By comparing and analyzing the radiated acoustic power level and mean square vibration velocity level obtained from experiments and simulation calculations, the correctness and reliability of underwater structure modeling and simulation are verified.

[0045] The transmission efficiency and transmission efficiency level of the underwater structure in this experiment were calculated according to formulas (3) and (4). First, the transmission efficiency of the underwater structure was calculated. Figure 7The acceleration data is processed. Its velocity is calculated through integration. Based on the properties of the Fourier transform, time-domain integration of the acceleration is equivalent to frequency-domain division. Therefore, the acceleration spectrum obtained from the experiment is divided by the angular frequency. This allows us to obtain the velocity spectrum of the underwater structure's vibration. The obtained velocity data is as follows: Figure 8 As shown in (a).

[0046] According to equation (9), Figure 8 The mean square velocity level data obtained from the data in (a) are as follows: Figure 8 As shown in (b).

[0047] At this point, mean square vibration velocity data and radiated acoustic power data of the underwater structure surface under experimental conditions have been obtained, such as... Figure 9 As shown.

[0048] Based on the underwater structure simulation and free-field modeling, the mean square velocity, mean square acceleration, and radiated acoustic power of the envelope surface of the underwater structure under excitation were calculated. To verify the accuracy of the simulation, the simulation data were compared with experimental measurement data. By observing the overall trend and magnitude of the two sets of data, the correctness of the simulation results was determined. The comparison graph of the two sets of data is shown below. Figure 10 As shown.

[0049] Overall, the simulated and experimental data show a generally consistent trend, with similar peak positions across multiple frequency bands. For example, both simulated and experimental values ​​exhibit significant peaks in the 0-1kHz, 2kHz-3kHz, 4kHz-5kHz, and 7kHz-8kHz frequency ranges. The spectrum plots show a multi-peak-valley structure with relatively consistent peak and valley distribution. However, numerically, despite the similar overall trend, differences exist between simulated and experimental values ​​in some frequency bands. For instance, the simulated peak is higher than the experimental peak around 1kHz and 3kHz, while the experimental peak is higher around 5kHz. Furthermore, the simulated curve shows significantly more peaks than the experimental curve. In general, the two curves demonstrate high similarity in trend and peak positions, indicating that the simulation model effectively reflects the overall trend of the experimental data. However, certain numerical differences exist between simulated and experimental values ​​in some frequency bands, particularly at higher frequencies. These differences may be due to model simplification, inaccurate parameters, or experimental errors. Further research and model improvement may help reduce these discrepancies.

[0050] Based on the transmission efficiency calculated by finite element method (FEM) software and the mean square vibration velocity data measured in the water tank, the radiated acoustic power of the underwater structure is predicted. The predicted results are then compared with the experimental results to verify the effectiveness of the model.

[0051] Based on the modeling and simulation of the underwater free field of the underwater structure using finite element method software, its surface transfer efficiency was obtained. In the water tank experiment, the actual mean square vibration velocity data of the underwater structure under excited vibration were obtained through accelerometers and data processing. According to equation (5), the radiated acoustic power of the underwater structure can be predicted based on the transfer method. The comparison between the predicted results and the experimental results is shown in the figure below. Figure 11 As shown.

[0052] The prediction results show that the overall trend is consistent with the experimental and simulated values. The error between the predicted and experimentally measured radiated acoustic power by one-third is as follows: Figure 12 As shown, the error between the predicted and experimental measurements can be controlled within 4 dB. Despite some error, within an acceptable range, the predicted values ​​can still accurately reflect the radiated acoustic power of underwater structures under underwater excited vibration.

[0053] This invention belongs to the field of mid-to-high frequency acoustic radiation power prediction technology, specifically involving a method for predicting mid-to-high frequency radiated acoustic power based on the transfer function. The method combines the transfer function approach with simulation calculations to obtain the transfer efficiency between the radiated acoustic power and the mean square vibration velocity of an underwater structure. It then combines this with the mean square vibration velocity value obtained from actual experimental measurements to predict the mid-to-high frequency acoustic radiation power. Compared with existing methods, this model has superior performance and avoids the problem of environmental background noise and the cutoff frequency of the experimental anechoic pool affecting vibration data obtained from accelerometers, thus improving the model's generalization ability. The modeling-computation-measurement method system proposed in this invention, using the transfer function method to predict radiated acoustic power, improves the accuracy and reliability of marine monitoring. Research on the method described in this invention not only deepens the understanding of the vibration characteristics of laminated plate structures but also provides a reference for acoustic prediction of other complex structures.

[0054] The present invention also proposes an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method for predicting mid-to-high frequency radiated acoustic power based on a transfer function.

[0055] The present invention also proposes a computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the steps of the method for predicting mid-to-high frequency radiated acoustic power based on a transfer function.

[0056] The memory in this application embodiment can be volatile memory or non-volatile memory, or it can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the methods described in this invention is intended to include, but is not limited to, these and any other suitable types of memory.

[0057] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0058] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0059] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuitry in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as execution by a hardware decoding processor, or as a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0060] The above provides a detailed description of the mid-to-high frequency radiated acoustic power prediction method based on transfer function proposed in this invention. Specific examples have been used to illustrate the principle and implementation of this invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for predicting mid-to-high frequency radiated acoustic power based on transfer function, characterized in that, The method includes: Step 1: First, establish a sound radiation prediction model of the underwater structure and the underwater free field using finite element software. Obtain the vibration data of the underwater structure surface and the radiated sound power of the envelope surface by applying excitation. After the simulation calculation is completed, the transmission efficiency between the radiated sound power of the underwater structure and the mean square vibration velocity of the surface can be obtained through data processing. Step 2: In the water tank experiment, measure the radiated acoustic power and mean square velocity of the underwater structure under a given excitation; calculate the actual transmission efficiency of the underwater structure surface under the experimental environment according to the formula for transmission efficiency. Step 3: Compare and analyze the transmission efficiency obtained from experiments and simulation calculations to verify the correctness and reliability of underwater structure modeling and simulation; Step 4: Based on the transmission efficiency obtained from finite element software simulation calculations and the mean square vibration velocity data measured in the water tank experiment, the radiated acoustic power of the underwater structure is predicted using the acoustic radiation prediction model. The prediction results are then compared with the experimental results to verify the effectiveness of the acoustic radiation prediction model.

2. The method according to claim 1, characterized in that, Mean square velocity (MSV) is the time average of the squares of the vibration velocities at various points on the surface of an object, used to describe the energy characteristics of vibration; the formula for the mean square velocity is... （1） in, Let be the normal velocity of the structural surface. The mean square velocity is the normal direction.

3. The method according to claim 2, characterized in that, Radiated sound power W refers to the sound energy radiated into the surrounding medium when an object vibrates; the expression for calculating radiated sound power is: （2） in Sound intensity, or simply sound strength, represents the time-averaged sound energy density at a point in a sound field.

4. The method according to claim 3, characterized in that, Transmission efficiency represents the ratio of the surface mean square vibration velocity to the radiated sound power of a structure; it characterizes the efficiency of vibration energy to sound energy conversion. The formula for calculating transmission efficiency is: （3） （4） The radiated acoustic power of the vibrating structure. The mean square vibration velocity is extracted from the surface of the vibrating structure. Characteristic impedance is the product of the density of the fluid medium surrounding the structure and the velocity of sound. The surface area of ​​the vibrating structure; The expression for transmission efficiency in decibels; Assuming the transmission efficiency of the underwater structure surface is calculated through simulation, it is... The mean square vibration velocity of the structural surface measured in the actual environment is Then the radiated acoustic power of the structure can be predicted. for （5）。 5. The method according to claim 4, characterized in that, In the modeling process, for sections of the structure that contain both thick and thin layers, a layered theory is applied to critical areas, while an equivalent single-layer theory is used to address less critical areas; the layer width-to-thickness ratio is... The calculation formula is as follows: （6） in Indicates the maximum width of the structure. The thickness of the multilayer material.

6. The method according to claim 5, characterized in that, After modeling is completed, the sound intensity at the envelope surface is calculated using the following formula: （7） in, This represents the instantaneous sound pressure value in the sound field, indicating the change of sound pressure with time and space. yes The conjugate of the complex number is used to ensure that the complex part is processed in the subsequent product calculation; the sound pressure Conjugate complex number of velocity component The sound pressure and velocity are multiplied to calculate the inner product in the direction of the normal vector; finally, the real part is taken and divided by 2 to obtain the average energy density; according to the calculation of radiated sound power in equation (2), after obtaining the average sound intensity through equation (7), the sound intensity is multiplied by the surface area of ​​the envelope to obtain the radiated sound power of the underwater structure vibration.

7. The method according to claim 6, characterized in that, The radiated sound power level is calculated by subdividing the data using the following formula: （8） Mean square velocity level: （9） The mean square acceleration level is: （10） in, , , .

8. The method according to claim 7, characterized in that, In step two, the radiated acoustic power is measured using the surface-wrapping method. Specifically, the expression for the model's radiated acoustic power is: （11） In the formula, The radiated sound power of the sound source. The distance between the hydrophone array and the radial distance to the target being measured is denoted as . For the depth of the water, For compensation coefficient, The distance from the equivalent sound center is The average sound intensity The distance from the equivalent sound center is The acoustic energy flux envelope area at the vertical array measurement position. Measuring the surface of the bag Average mean square sound pressure level in the space of the hydrophone; Taking the logarithm of both sides of the above equation, we get （12） In the formula, The radiated sound power level of the model, To measure the surface of the bag Spatial mean sound pressure level of the hydrophone; correction parameters （13） Based on the above formula, the formula for calculating the equivalent sound source level can be obtained as follows: （14） In the formula, This is the equivalent sound source level.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-8.

10. A computer-readable storage medium for storing computer instructions, characterized in that, When the computer instructions are executed by the processor, they implement the steps of the method according to any one of claims 1-8.

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