Method, device and storage medium for estimating random incidence sound transmission loss of small-sized samples

Abstract

The present invention relates to the technical field of measuring the acoustic transmission loss of materials, in particular to a method, device and storage medium for estimating the random-incidence acoustic transmission loss of small-sized samples. The method includes: obtaining a small-sized sample with a surface size meeting the measurement conditions; obtaining the normal-incidence acoustic transmission loss measurement result of the small-sized sample, and constructing an acoustic transmission loss difference calculation model according to the number of configuration layers of the small-sized sample, and obtaining the difference result of the normal-incidence and random-incidence acoustic transmission losses based on the acoustic transmission loss difference calculation model; obtaining the estimated value of the random-incidence acoustic transmission loss based on the normal-incidence acoustic transmission loss measurement result and the difference result of the normal-incidence and random-incidence acoustic transmission losses, and evaluating the sound insulation effect of the small-sized sample according to the estimated value of the random-incidence acoustic transmission loss. The present invention can realize the estimation of the random-incidence acoustic transmission loss of small-sized samples with different configurations, and has good accuracy and applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring the acoustic transmission loss of materials, in particular to a method, device and storage medium for estimating the random incidence acoustic transmission loss of small-sized samples. Background Art

[0002] The sound insulation performance of buildings is an important parameter for evaluating the quality of building projects. The reverberation room method and the impedance tube method are widely used in measuring the acoustic transmission loss of materials. At present, the reverberation room method is mostly used for detecting the sound insulation performance of building walls because the test structure size and installation boundary conditions are closer to the actual use situation of buildings, and its results are more authoritative. However, it requires a special sound insulation laboratory, installation of large-sized wall samples, and large and complex equipment, which is time-consuming, laborious and costly. If the random incidence sound insulation performance closer to the actual use situation can be estimated by applying the normal incidence sound insulation performance measurement results with simple operation, a large amount of cost can be saved.

[0003] Compared with traditional analytical methods such as the modal superposition method, the numerical calculation method based on the high-order deformation theory is more suitable for analyzing the sound insulation performance of plates with more complex configurations. The existing research on the relationship between the normal incidence and random incidence acoustic transmission losses mostly focuses on the mass control region of simple structures such as infinite plates, and rarely involves finite plates with more complex configurations and other sound insulation regions. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for estimating the random incidence acoustic transmission loss of small-sized samples, which aims to provide an efficient and accurate tool for predicting the random incidence acoustic transmission loss of small-sized samples (finite large rectangular plates) in the stiffness control region and the mass control region, and is of great significance for improving the quality and detection efficiency of building projects. The method includes the following steps:

[0005] S1: Obtain a small-sized sample with a surface size meeting the measurement conditions, and the surface area of the small-sized sample matches the inner cross-sectional size of the impedance tube used to place it;

[0006] S2: Within the cut-off frequency of the impedance tube, obtain the measurement result of the normal incidence acoustic transmission loss of the small-sized sample; and according to the number of configuration layers of the small-sized sample, construct a calculation model for the difference in acoustic transmission loss, and based on the calculation model for the difference in acoustic transmission loss, obtain the difference result of the normal incidence and random incidence acoustic transmission losses;

[0007] S3: Based on the measurement result of the normal incidence acoustic transmission loss and the difference result of the normal incidence and random incidence acoustic transmission losses, obtain an estimated value of the random incidence acoustic transmission loss, and evaluate the sound insulation effect of the small-sized sample according to the estimated value of the random incidence acoustic transmission loss.

[0008] In one embodiment of the present invention, in step S2, the method for obtaining the normal-incidence acoustic transmission loss measurement result of the small-size sample is as follows:

[0009] S21: placing the small-sized sample in an impedance tube, scanning the impedance tube using a plane wave signal, and measuring the sound pressure and particle velocity at the front end and the end of the impedance tube respectively when the end of the impedance tube is open or closed, including:

[0010] When the end of the impedance tube is open, the sound pressure and particle velocity are expressed as:

[0011] ,

[0012] When the end of the impedance tube is closed, the sound pressure and particle velocity are expressed as:

[0013] ,

[0014] in, is the transfer matrix of the small-size sample, Represents the front end of the impedance tube, is the front-end sound pressure measured when the end of the impedance tube is open, is the end sound pressure measured when the end of the impedance tube is open, is the particle velocity at the front end of the impedance tube measured when the end is open, is the particle velocity at the end of the impedance tube measured when the end is open; Indicates the end of the impedance tube, is the front-end sound pressure measured when the end of the impedance tube is closed, is the end sound pressure measured when the end of the impedance tube is closed, is the particle velocity at the front end of the impedance tube measured when the end is closed, is the particle velocity at the end of the impedance tube measured when the end is closed;

[0015] S22: Calculating a transfer matrix of the small-size sample according to the sound pressure and particle velocity at the front end and the end of the impedance tube;

[0016] S23: Based on the transfer matrix, obtain the normal-incident sound transmission loss of the small-sized sample.

[0017] In one embodiment of the present invention, the normal incidence acoustic transmission loss of the small-sized sample is obtained. as follows:

[0018] ,

[0019] in, is the normal incidence transmission coefficient, , For testing the thickness of small-sized samples; 、 、 、 All are elements of the transfer matrix; is the characteristic impedance of air.

[0020] In an embodiment of the present invention, in step S2, the method for obtaining the difference result of the normal incidence and diffuse incidence sound transmission loss is as follows:

[0021] S24: Set a preset threshold, and determine whether the number of configuration layers of the small-sized sample is greater than the preset threshold:

[0022] If the number of configuration layers of the small-sized sample is greater than the preset threshold, in the quality control area, the normal incidence sound wave and the diffuse incidence sound wave are respectively incident on the surface of the small-sized sample to obtain the incident sound power of the normal incidence sound wave and the incident sound power of the diffuse incidence sound wave;

[0023] Based on the incident sound power of the normal incidence sound wave and the incident sound power of the diffuse incidence sound wave, a finite element model of the normal incidence sound transmission loss and a finite element model of the diffuse incidence sound transmission loss in the quality control area are respectively established;

[0024] Since the difference between the normal incidence sound wave and the diffuse incidence sound transmission loss in the stiffness control area is close to 0 dB, based on the finite element model of the normal incidence sound transmission loss and the finite element model of the diffuse incidence sound transmission loss, the sound transmission loss difference calculation model is obtained;

[0025] If the number of configuration layers of the small-sized sample is less than or equal to the preset threshold, in the quality control area, under forced vibration, the diffuse sound wave is incident on the surface of the small-sized sample to calculate the diffuse incidence transmission coefficient of the small-sized sample;

[0026] According to the diffuse incidence transmission coefficient, an expression for the diffuse incidence sound transmission loss is obtained;

[0027] Based on the known mass law expression of the normal incidence sound transmission loss and the expression of the diffuse incidence sound transmission loss, the sound transmission loss difference calculation model is obtained;

[0028] S25: Based on the sound transmission loss difference calculation model, obtain the difference result of the normal incidence and diffuse incidence sound transmission loss.

[0029] In an embodiment of the present invention, if the number of configuration layers of the small-sized sample is greater than the preset threshold, the sound transmission loss difference calculation model is:

[0030] ,

[0031] Among them, is the finite element model of the normal incidence sound transmission loss, is the finite element model of the diffuse incidence sound transmission loss; the and the are both calculated through the following expression of the sound transmission finite element model :

[0032] ,

[0033] Among them, represents the incident sound power, , and are respectively the incident angle and the azimuth angle of the acoustic wave signal, S is the surface area of the structure, is the normal incidence acoustic wave or the diffuse incidence acoustic wave. When θ = 0 , the incident sound power of the normal incidence acoustic wave is obtained; represents the transmitted sound power, , represents the transpose, is the amplitude of the normal vibration velocity of the structure; is the real part of the radiation impedance matrix Z, also known as the radiation resistance matrix.

[0034] In an embodiment of the present invention, when is the normal incidence acoustic wave, the normal incidence acoustic wave is a plane acoustic wave, which is incident on the surface of the small-size sample at an angle θ, and its wave equation is:

[0035] ,

[0036] Among them, is the plane acoustic wave amplitude, 0, , respectively represent the wave vector components of the normal incidence acoustic wave in the x, y, z direction;

[0037] When is the diffuse incidence acoustic wave, the diffuse incidence acoustic wave is the sum of N incoherent plane acoustic waves propagating in random directions, and its wave equation is:

[0038] ,

[0039] Among them, is the plane acoustic wave amplitude, , , respectively represent the diffuse incidence acoustic wave in thex, y, z The wave vector component in the direction.

[0040] In an embodiment of the present invention, if the number of configured layers of the small-sized sample is less than or equal to the preset threshold, the acoustic transmission loss difference calculation model is:

[0041] ,

[0042] Wherein, is the mass law expression of the known normal incidence acoustic transmission loss, is the normal incidence acoustic wave frequency, is the surface density of the plate, is the characteristic impedance of air; , is the random incidence transmission coefficient.

[0043] In an embodiment of the present invention, the calculation method of the random incidence transmission coefficient is as follows:

[0044] ,

[0045] Wherein, A is the surface area of the small-sized sample, is the side length ratio of the small-sized sample, ≤1, , n is the layer number of the small-sized sample; represents the critical frequency of the panel supporting shear stress; is the characteristic impedance of air; c is the propagation speed of the acoustic wave in the medium.

[0046] Based on the same inventive concept, the present invention also provides a device for estimating the random incidence acoustic transmission loss of a small-sized sample, which device includes an impedance tube, a signal generator, a power amplifier, a sound source amplifier, and a digital acquisition and analysis system. The digital acquisition and analysis system is used to implement the steps of the method for estimating the random incidence acoustic transmission loss of the small-sized sample as described above;

[0047] Wherein, the small-sized sample to be measured is installed in the impedance tube, and the signal generator is used to generate the initial acoustic wave signal required during the measurement; the initial acoustic wave signal is amplified by the power amplifier to obtain a first acoustic wave signal; the sound source amplifier processes the first acoustic wave signal to obtain a second acoustic wave signal; the second acoustic wave signal is transmitted into the impedance tube to enable the second acoustic wave signal to interact with the sample to be measured;

[0048] The digital acquisition and analysis system processes and analyzes the collected acoustic wave signals to obtain the normal incidence acoustic transmission loss of the sample to be measured. According to the number of configuration layers of the small-sized sample, the digital acquisition and analysis system respectively constructs a calculation model for the difference in acoustic transmission loss between normal incidence and random incidence based on a finite element numerical analysis model and a theoretical prediction formula, and based on the calculation model for the difference in acoustic transmission loss, obtains the result of the difference in acoustic transmission loss between normal incidence and random incidence. Based on the measured result of the normal incidence acoustic transmission loss and the result of the difference in acoustic transmission loss between normal incidence and random incidence, an estimated value of the random incidence acoustic transmission loss is obtained.

[0049] The present invention also provides a computer storage medium, which stores a computer software product. The computer software product includes several instructions for causing a computer device to execute the steps of the method for estimating the random incidence acoustic transmission loss of the small-sized sample described above.

[0050] The above technical solution of the present invention has the following advantages compared with the prior art:

[0051] By combining the measured result of the normal incidence acoustic transmission loss of the small-sized sample and the constructed calculation model for the difference in acoustic transmission loss, the present invention can more accurately estimate the random incidence acoustic transmission loss of the small-sized sample. This method not only considers the physical characteristics of the sample but also the directionality of the incident acoustic wave, thereby improving the accuracy of the sound insulation effect evaluation. In addition, the present invention is applicable to small-sized samples with various numbers of configuration layers. Whether it is a single-layer or multi-layer structure, it can be adapted by adjusting the calculation model for the difference in acoustic transmission loss. This increases the versatility and practicality of the method. Description of the Drawings

[0052] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the drawings, where

[0053] Figure 1 is a flowchart of the method for estimating the random incidence acoustic transmission loss of the small-sized sample provided in Embodiment 1 of the present invention;

[0054] Figure 2 is a specific flowchart of the method for estimating the random incidence acoustic transmission loss of the small-sized sample provided in Embodiment 1 of the present invention;

[0055] Figure 3 is a comparison diagram of the finite element numerical calculation model of the present invention and the actual measurement result;

[0056] Figure 4 is a diagram of the results of the normal incidence and random incidence acoustic transmission losses obtained by constructing a finite element numerical analysis model of a sandwich panel in the quality control area;

[0057] Figure 5 It is a comparison result diagram of the sound transmission loss difference of a single-layer aluminum plate predicted based on a finite element numerical analysis model and theoretical formulas in the quality control area;

[0058] Figure 6 It is a schematic structural diagram of a small-size sample random incidence sound transmission loss estimation device provided in the second embodiment of the present invention;

[0059] Explanation of the reference numerals in the specification drawings: 10. Impedance tube; 20. Signal generator; 30. Power amplifier; 40. Sound source amplifier; 50. Digital acquisition and analysis system. Detailed implementation manners

[0060] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited are not intended to limit the present invention. Embodiment 1

[0061] Refer to Figure 1 and Figure 2 As shown, the present invention provides a method for estimating the random incidence sound transmission loss of a small-size sample, and the method includes the following steps:

[0062] S1: Obtain a small-size sample with a surface size meeting the measurement conditions. To ensure that the sound wave transmission path is not disturbed, the surface area of the small-size sample matches the inner cross-sectional size of the impedance tube used to place it;

[0063] S2: Within the cut-off frequency of the impedance tube, obtain the normal incidence sound transmission loss measurement result of the small-size sample; and according to the configuration layer number of the small-size sample, construct a sound transmission loss difference calculation model, and based on the sound transmission loss difference calculation model, obtain the normal incidence and random incidence sound transmission loss difference results;

[0064] S3: Based on the normal incidence sound transmission loss measurement result and the normal incidence and random incidence sound transmission loss difference results, obtain the random incidence sound transmission loss estimated value, and according to the random incidence sound transmission loss estimated value, evaluate the sound insulation effect of the small-size sample.

[0065] Further, in step S2, within the cut-off frequency of the impedance tube, the method for obtaining the normal incidence sound transmission loss measurement result of the small-size sample is as follows:

[0066] S21: Place the small-sized sample in an impedance tube for experimental testing of the normal incidence sound transmission loss. Use a plane wave signal to scan the inside of the impedance tube. Within the cut-off frequency of the tube, for small-sized samples with different properties on the front and back sides, generally use the two-measurement method of open and closed ends. When measuring for the second time, the impedance at the end of the tube should be different from that in the first measurement. Specifically:

[0067] Under the conditions of the open or closed end of the impedance tube, measure the sound pressure and particle velocity at the front and end of the impedance tube respectively, including:

[0068] When the end of the impedance tube is open, the sound pressure and particle velocity are expressed as:

[0069] ,

[0070] When the end of the impedance tube is closed, the sound pressure and particle velocity are expressed as:

[0071] ,

[0072] Among them, is the transfer matrix of the small-sized sample, represents the front end of the impedance tube, is the front-end sound pressure measured when the end of the impedance tube is open, is the end sound pressure measured when the end of the impedance tube is open, is the front-end particle velocity measured when the end of the impedance tube is open, is the end particle velocity measured when the end of the impedance tube is open; represents the end of the impedance tube, is the front-end sound pressure measured when the end of the impedance tube is closed, is the end sound pressure measured when the end of the impedance tube is closed, is the front-end particle velocity measured when the end of the impedance tube is closed, is the end particle velocity measured when the end of the impedance tube is closed;

[0073] S22: Calculate the transfer matrix of the small-sized sample according to the sound pressure and particle velocity at the front and end of the impedance tube;

[0074] S23: Based on the transfer matrix, obtain the normal incidence sound transmission loss of the small-sized sample , as follows:

[0075] ,

[0076] Among them, is the normal incidence transmission coefficient, , To test the thickness of small-sized samples; 、 、 、 All are elements of the transfer matrix; is the characteristic impedance of air.

[0077] Furthermore, in step S2, the method for obtaining the difference result of the sound transmission loss between normal incidence and random incidence is as follows:

[0078] S24: Set the preset threshold t = 3, and determine whether the number of configuration layers of the small-sized sample is greater than the preset threshold:

[0079] If the number of configuration layers of the small-sized sample > 3, a finite element numerical analysis model of the sound transmission loss difference is constructed theoretically by the equivalent single-layer method and the hybrid layer-by-layer method, including:

[0080] In the quality control area, a normal incidence sound wave and a random incidence sound wave are respectively incident on the surface of the small-sized sample to obtain the incident sound power of the normal incidence sound wave and the incident sound power of the random incidence sound wave;

[0081] Based on the incident sound power of the normal incidence sound wave and the incident sound power of the random incidence sound wave, a finite element model of the normal incidence sound transmission loss and a finite element model of the random incidence sound transmission loss in the quality control area are respectively established;

[0082] Since the difference between the normal incidence sound wave and the random incidence sound transmission loss in the stiffness control area is close to 0 dB, based on the finite element model of the normal incidence sound transmission loss and the finite element model of the random incidence sound transmission loss, the sound transmission loss difference calculation model is obtained as:

[0083] ,

[0084] where, is the finite element model of the normal incidence sound transmission loss, is the finite element model of the random incidence sound transmission loss; the and the are both calculated through the following expression of the sound transmission finite element model :

[0085] ,

[0086] where, represents the incident sound power, , and are respectively the incident angle and azimuth angle of the sound wave signal, and S is the surface area of the structure. is the normal incident sound wave or the random incident sound wave. When θ = 0 , the incident sound power of the normal incident sound wave is obtained; represents the transmitted sound power, , represents the transpose, is the amplitude of the structural normal vibration velocity; is the real part of the radiation impedance matrix Z, also known as the radiation resistance matrix.

[0087] Furthermore, when is the normal incident sound wave, the normal incident sound wave is a plane wave and is incident on the surface of the small-sized sample at an angle θ . Its wave equation is:

[0088] ,

[0089] wherein, is the plane wave amplitude, 、 、 respectively represent the wave vector components of the normal incident sound wave in the x, y, z direction;

[0090] When is the random incident sound wave, the diffuse sound field formed by the random incident sound wave can be regarded as the sum of N incoherent plane waves propagating in random directions. Its wave equation is:

[0091]

[0092] wherein, is the plane wave amplitude, 、 、 respectively represent the wave vector components of the random incident sound wave in the x, y, z direction.

[0093] If the number of configuration layers of the small-sized sample ≤ 3, a sound transmission loss difference calculation model is obtained by using a theoretical formula, including: in the quality control area, under forced vibration, a random sound wave is incident on the surface of the small-sized sample, and the random incident transmission coefficient of the small-sized sample is calculated;

[0094] According to the random incident transmission coefficient, a random incident sound transmission loss expression is obtained;

[0095] Based on the mass law expression of the known normal incident sound transmission loss and the random incident sound transmission loss expression, the sound transmission loss difference calculation model is:

[0096] ,

[0097] Among them, is the mass law expression of the known normal incidence sound transmission loss, is the normal incidence sound wave frequency, is the surface density of the plate, is the characteristic impedance of air; , is the random incidence transmission coefficient of the plate under forced vibration in the mass control area. Specifically, the random incidence transmission coefficient is calculated as follows:

[0098] ,

[0099] Among them, A is the surface area of the small-sized sample, is the side length ratio of the small-sized sample, ≤1, , n is the layer number of the small-sized sample; represents the critical frequency of the panel supporting shear stress, , B is the bending stiffness of the plate; for a single-layer homogeneous plate, the formula can be further expanded into an expression about the material properties of the plate , ρ is the density, λ is the Poisson's ratio, E is the Young's modulus; is the characteristic impedance of air; c is the propagation speed of sound waves in the medium;

[0100] S25: Based on the sound transmission loss difference calculation model, obtain the results of the difference between the normal incidence and random incidence sound transmission losses.

[0101] In order to verify that the finite element numerical analysis model has good accuracy, the equivalent single-layer method and the hybrid layer-by-layer method theory were used to construct a finite element numerical analysis model of a 2-mm aluminum plate under simply supported boundary conditions, and the finite element simulation results of the normal incidence sound transmission loss were calculated; in the laboratory, the four-microphone method was used for measurement, and two microphones were placed at the front end and the end of the impedance tube where the same aluminum plate was placed to obtain the measurement results of the normal incidence sound transmission loss. After the measurement was completed, the measurement results obtained from the experiment were compared with the finite element simulation results. As Figure 3 shown, the degree of coincidence between the two is relatively high, indicating that the established finite element numerical analysis model has good accuracy.

[0102] Based on the equivalent single-layer method and the hybrid layer-by-layer method theories, finite element models for the normal incidence sound transmission loss and the diffuse incidence sound transmission loss of a sandwich panel with a fixed boundary condition and a surface size of 0.2 m × 0.2 m, with each layer being a configuration of 2 mm gypsum board + 2 mm fiberboard + 2 mm gypsum board in turn, are established in the quality control area. The estimated normal incidence sound transmission loss curve and the diffuse incidence sound transmission loss curve are as Figure 4 shown, where the difference in the stiffness control region is close to 0 dB.

[0103] As Figure 5 shown, based on the finite element numerical analysis model and the theoretical prediction formula constructed above, detailed computational analyses are carried out for two different-sized single-layer aluminum plates (the specifications of test plate 1 are 2 m × 2 m and the thickness is 2 mm; the specifications of test plate 2 are 3 m × 3 m and the thickness is 6 mm) under fixed boundary conditions. The specific computational contents include the normal incidence sound transmission loss curve and the diffuse incidence sound transmission loss curve, and by calculating the difference between these two curves, it serves as a computational example to verify the consistency of the results of the finite element numerical calculation model and the theoretical prediction formula.

[0104] The calculation results show that within the quality control region, for samples with relatively simple structures and small sizes (i.e., test plate 1), the results obtained from the finite element numerical calculation model and the results obtained from the theoretical prediction formula show a high degree of consistency. The trends of the normal incidence sound transmission loss curve and the diffuse incidence sound transmission loss curve obtained by both are in agreement, and the error is within 2 dB.

[0105] This result fully verifies the accuracy and reliability of the finite element numerical calculation model in predicting the sound transmission loss of single-layer aluminum plates, and also shows the applicability of the theoretical prediction formula under specific conditions.

[0106] In step S3, based on the measured results of the normal incidence sound transmission loss and the difference results between the normal incidence and diffuse incidence sound transmission losses , an estimated value of the diffuse incidence sound transmission loss is obtained. The main sources of the diffuse incidence sound transmission loss are the inevitable systematic errors and random errors in the actual measurement of the normal incidence sound transmission loss, as well as the truncation errors in establishing the finite element numerical model and the errors caused by simplification in the derivation of the analytical expression.

[0107] Taking the estimated value of the diffuse incidence sound transmission loss as an index to measure the sound insulation performance of small-sized samples in actual applications, the sound insulation effect of the small-sized samples is evaluated. This evaluation result can provide a strong reference basis for material selection, structural design, and construction quality control in building engineering, so as to ensure that the building engineering meets the expected standards in terms of acoustic performance. Embodiment 2

[0108] Based on the same inventive concept as Embodiment 1, the present invention also provides a device for estimating the random-incidence sound transmission loss of small-sized samples. As Figure 6 shown, the device includes an impedance tube 10, a signal generator 20, a power amplifier 30, a sound source amplifier 40, and a digital acquisition and analysis system 50. The digital acquisition and analysis system 50 is used to implement the steps of the method for estimating the random-incidence sound transmission loss of small-sized samples described in Embodiment 1 above;

[0109] Among them, the impedance tube 10 usually has a specific size and shape to ensure that the propagation of sound waves in the tube conforms to the expected acoustic characteristics, providing a controllable acoustic test environment for the sample to be measured. The small-sized sample to be measured is installed in the impedance tube 10, and the signal generator 20 is used to generate the initial sound wave signal (normal-incidence sound wave or random-incidence sound wave) required during the measurement.

[0110] In order to optimize the sound wave signal transmission in the impedance tube 10, minimize signal attenuation, and the absorption of the sound wave signal by the sample to be measured, the power of the initial sound wave signal is amplified by the power amplifier 30 to obtain the amplified first sound wave signal, so as to form an effective sound wave field in the impedance tube 10; the sound source amplifier 40 further enhances the power and stability of the sound wave signal, that is, performs signal processing operations such as filtering and phase adjustment on the first sound wave signal to obtain a second sound wave signal; the second sound wave signal is transmitted into the impedance tube 10 to cause the second sound wave signal to interact with the sample to be measured.

[0111] The digital acquisition and analysis system 50 integrates multiple sensors, data acquisition devices, and data analysis modules. Two sensors are placed at the front end and the end of the impedance tube 10 respectively, and the sensors are used to collect the sound wave signals after passing through the small-sized sample to be measured; the data acquisition device converts the collected sound wave signals into digital data for storage; the data analysis module processes and analyzes the collected sound wave signals to obtain the normal-incidence sound transmission loss of the sample to be measured.

[0112] Furthermore, according to the number of configuration layers of the small-sized sample, the data analysis module respectively constructs a calculation model for the difference in sound transmission loss between normal incidence and random incidence based on the finite element numerical analysis model and the theoretical prediction formula, and based on the calculation model for the difference in sound transmission loss, obtains the result of the difference in sound transmission loss between normal incidence and random incidence. Based on the measured result of the normal-incidence sound transmission loss and the result of the difference in sound transmission loss between normal incidence and random incidence, an estimated value of the random-incidence sound transmission loss is obtained, and according to the random-incidence sound transmission loss value, the sound insulation effect of the sample to be measured is evaluated. Embodiment 3

[0113] The present invention also provides a computer storage medium, which stores a computer software product. The computer software product includes a number of instructions for causing a computer device to execute the steps of the method for estimating the random-incidence acoustic transmission loss of a small-sized sample described in the first embodiment above.

[0114] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0115] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0116] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0117] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0118] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An estimation method for the random-incidence sound transmission loss of small-sized samples, characterized in that, It includes the following steps: S1: Obtain a small-sized sample with surface dimensions meeting the measurement conditions, where the surface area of the small-sized sample matches the inner cross-sectional dimensions of the impedance tube for placing it; S2: Within the cut-off frequency of the impedance tube, obtain the measurement result of the normal-incidence sound transmission loss of the small-sized sample; and construct a sound transmission loss difference calculation model according to the number of configuration layers of the small-sized sample. Based on the sound transmission loss difference calculation model, obtain the result of the difference between the normal-incidence and diffuse-incidence sound transmission losses; S3: Based on the measurement result of the normal-incidence sound transmission loss and the result of the difference between the normal-incidence and diffuse-incidence sound transmission losses, obtain an estimated value of the diffuse-incidence sound transmission loss. According to the estimated value of the diffuse-incidence sound transmission loss, evaluate the sound insulation effect of the small-sized sample; Among them, in step S2, the method for obtaining the result of the difference between the normal-incidence and diffuse-incidence sound transmission losses is as follows: S24: Set a preset threshold, and judge whether the number of configuration layers of the small-sized sample is greater than the preset threshold: If the number of configuration layers of the small-sized sample is greater than the preset threshold, construct a finite element numerical analysis model of the sound transmission loss difference through the equivalent single-layer method and the hybrid layer-by-layer method theory, including: In the mass control region, respectively use normal-incidence sound waves and diffuse-incidence sound waves to incident on the surface of the small-sized sample to obtain the incident sound power of the normal-incidence sound waves and the incident sound power of the diffuse-incidence sound waves; Based on the incident sound power of the normal-incidence sound waves and the incident sound power of the diffuse-incidence sound waves, respectively establish a finite element model of the normal-incidence sound transmission loss and a finite element model of the diffuse-incidence sound transmission loss in the mass control region; Since the difference between the normal-incidence and diffuse-incidence sound transmission losses in the stiffness control region is close to 0 dB, based on the finite element model of the normal-incidence sound transmission loss and the finite element model of the diffuse-incidence sound transmission loss, the sound transmission loss difference calculation model is obtained as: ΔSTL = STL1 - STL2 Where, STL1 is the finite element model of the normal-incidence sound transmission loss, and STL2 is the finite element model of the diffuse-incidence sound transmission loss; both STL1 and STL2 are calculated through the following expression of the sound transmission finite element model STL: Among them, W i represents the incident acoustic power, θ and are respectively the incident angle and azimuth angle of the acoustic wave signal, S is the surface area of the structure, p i is the normally incident acoustic wave or the randomly incident acoustic wave. When θ = 0, the incident acoustic power of the normally incident acoustic wave is obtained; W r represents the transmitted acoustic power in the semi-infinite fluid domain obtained by the near-field method based on the radiation element, H represents the transpose, v n is the amplitude of the normal vibration velocity of the structure; R is the real part of the radiation impedance matrix Z, also known as the radiation resistance matrix; When p i is an incident sound wave at normal incidence, the incident sound wave at normal incidence is a plane sound wave, which is incident on the surface of the small-sized sample at an angle θ, and its wave equation is: Among them, is the plane acoustic wave amplitude, and k x , k y , k z respectively represent the wave vector components of the normally incident acoustic wave in the x, y, and z directions; When p i is a randomly incident sound wave, the diffuse sound field formed by the randomly incident sound wave can be regarded as the sum of N plane sound waves propagating in N non-coherent random directions, and its wave equation is: wherein, is the plane acoustic wave amplitude, and k xn , k yn , k zn respectively represent the wave vector components of the randomly incident acoustic wave in the x, y, and z directions; If the number of configuration layers of the small-sized sample is less than or equal to the preset threshold, calculate the sound transmission loss difference calculation model using the theoretical formula, including: in the mass control region, under forced vibration, use diffuse sound waves to incident on the surface of the small-sized sample, and calculate the diffuse-incidence transmission coefficient of the small-sized sample; According to the diffuse-incidence transmission coefficient, obtain the expression of the diffuse-incidence sound transmission loss; Based on the known mass law expression of the normal-incidence sound transmission loss and the expression of the diffuse-incidence sound transmission loss, the sound transmission loss difference calculation model is obtained as: ΔSTL = STL1 - STL2 Among them, is the mass law expression of the known normal incidence sound transmission loss, f is the normal incidence sound wave frequency, m is the surface density of the plate, τ nr is the random incidence transmission coefficient of the plate under forced vibration in the mass control area; S25: Based on the sound transmission loss difference calculation model, obtain the result of the difference between the normal-incidence and diffuse-incidence sound transmission losses.

2. The method for estimating the random-incidence sound transmission loss of small-sized samples according to claim 1, characterized in that, In step S2, within the cut-off frequency of the impedance tube, the method for obtaining the measurement result of the normal-incidence sound transmission loss of the small-sized sample is as follows: S21: Place the small-sized sample in an impedance tube, scan the impedance tube using a plane-wave signal, and set the ends of the impedance tube to two states: open and closed. For each state, measure the sound pressure and particle velocity at the front and end of the impedance tube, including: When the end of the impedance tube is open, the sound pressure and particle velocity are expressed as: When the end of the impedance tube is closed, the sound pressure and particle velocity are expressed as: Among them, is the transfer matrix of the small-sized sample. x = 0 represents the front end of the impedance tube. p1 is the front-end sound pressure measured when the end of the impedance tube is open. p1' is the end sound pressure measured when the end of the impedance tube is open. u1 is the particle velocity at the front end measured when the end of the impedance tube is open. u1' is the particle velocity at the end measured when the end of the impedance tube is open. x = d represents the end of the impedance tube. p2 is the front-end sound pressure measured when the end of the impedance tube is closed. p2' is the end sound pressure measured when the end of the impedance tube is closed. u2 is the particle velocity at the front end measured when the end of the impedance tube is closed. u2' is the particle velocity at the end measured when the end of the impedance tube is closed. S22: Calculate the transfer matrix of the small-sized sample based on the sound pressure and particle velocity at the front and end of the impedance tube. S23: Obtain the normal incidence sound transmission loss of the small-sized sample based on the transfer matrix.

3. The method for estimating the random-incidence sound transmission loss of a small-sized sample according to claim 2, characterized in that The normal incidence sound transmission loss STL0 of the small-sized sample is obtained as follows: Among them, τ p is the normal incidence transmission coefficient, d is the thickness of the small-sized sample for testing; T 11 , T 12 , T 21 , T 22 are all elements of the said transfer matrix; ρ0c is the characteristic impedance of air.

4. An apparatus for estimating the random-incidence sound transmission loss of a small-sized sample, characterized in that, It includes an impedance tube, a signal generator, a power amplifier, a sound source amplifier, and a digital acquisition and analysis system. The digital acquisition and analysis system is used to implement the steps of the method for estimating the random incidence sound transmission loss of a small-sized sample according to any one of claims 1 to 3. Among them, the small-sized sample to be measured is installed in the impedance tube, and the signal generator is used to generate the initial acoustic wave signal required during the measurement; the initial acoustic wave signal is amplified by the power amplifier to obtain the first acoustic wave signal; the sound source amplifier processes the first acoustic wave signal to obtain the second acoustic wave signal; the second acoustic wave signal is transmitted into the impedance tube to enable the second acoustic wave signal to interact with the sample to be measured. The digital acquisition and analysis system processes and analyzes the acquired acoustic wave signals to obtain the normal incidence sound transmission loss of the sample to be measured; according to the number of configuration layers of the small-sized sample, the digital acquisition and analysis system respectively constructs a calculation model for the difference in sound transmission loss between normal incidence and random incidence based on a finite element numerical analysis model and a theoretical prediction formula, and based on the calculation model for the difference in sound transmission loss, obtains the result of the difference in sound transmission loss between normal incidence and random incidence. Based on the measurement result of the normal incidence sound transmission loss and the result of the difference in sound transmission loss between normal incidence and random incidence, an estimated value of the random incidence sound transmission loss is obtained.

5. A computer storage medium, characterized in that, The computer storage medium stores a computer software product. The computer software product includes a number of instructions for causing a computer device to execute the steps of the method for estimating the random incidence sound transmission loss of a small-sized sample according to any one of claims 1 to 3.

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