An equivalent modeling method of acoustic baffle

Abstract

The present application relates to a kind of equivalent modeling method of acoustic baffle, comprising the following steps, step 1, the finite element model of baffle comprising several periodic units is constructed, according to the conventional simulation process of baffle sound performance, the frequency response table of sound absorption coefficient, reflection coefficient, transmission coefficient is obtained by solving model;Step 2, the finite element model of homogeneous material of same size with the above-mentioned baffle finite element model is constructed, and three parameters a, b, c are set as the Young's modulus, Poisson's ratio and density of homogeneous material.The present application reduces the structural complexity of baffle model, the resources and time required for calculation, is conducive to the rapid iterative design of relevant acoustic structure.

Description

Technical field:

[0001] The present invention belongs to the field of acoustic technology, and in particular relates to an equivalent modeling method for an acoustic baffle. Background technology:

[0002] Some baffles contain periodic structures within them. When exposed to an acoustic field, the vibrations of these periodic structures couple with the vibrations of the baffle caused by the sound waves, preventing the sound waves from propagating further, thereby absorbing the sound. Baffle performance can be studied using a periodic model consisting of several elements. However, for large-scale acoustic structures based on baffles, it is not feasible to fully model all the structures within the baffle.

[0003] The current solution is to treat large-area baffles as equivalent to multiple layers of homogeneous material, and simulate the sound absorption performance of the baffle by adjusting the impedance of each layer of material. The problem with this method is that it requires building a multi-layer material model and regulating the performance of each layer of material, making the implementation process complicated. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide an equivalent modeling method for an acoustic baffle, which only requires constructing a local model of a periodic structural baffle for the material parameter fitting and acquisition process. The subsequent baffle modeling only requires constructing a homogeneous plate, which reduces the structural complexity of the baffle model, the resources and time required for calculation, and is conducive to the rapid iterative design of related acoustic structures.

[0005] The technical solution of the present invention is to provide an equivalent modeling method for an acoustic baffle, comprising the following steps:

[0006] Step 1: Construct a finite element model of the baffle containing several periodic units, solve the model according to the conventional simulation process of the baffle acoustic performance, and obtain the frequency response table of the sound absorption coefficient, reflection coefficient, and transmission coefficient;

[0007] Step 2: construct a homogeneous material finite element model of the same size as the baffle finite element model, and set three parameters a, b, and c as the Young's modulus, Poisson's ratio, and density of the homogeneous material;

[0008] Step 3, set a variable whose value is the reflection coefficient of the homogeneous material;

[0009] Step 4: Add a parameter estimation analysis step before the frequency domain analysis step, use the variable set in step 3 as the objective function, and set the optimization method to the least squares method;

[0010] Step 5: Take a frequency value and a reflection coefficient value from the frequency response table of the baffle model sound absorption coefficient calculated in step 1 as the frequency value and fitting target to be solved in the frequency domain analysis step of the homogeneous material model;

[0011] Step 6: Calculate the Young's modulus and Poisson's ratio corresponding to the reflection coefficient at a certain frequency point of the homogeneous material model and the periodic unit baffle model, and output the frequency and the values ​​of the three parameters a, b, and c;

[0012] Step 7, repeating steps 5 and 6 until the reflection coefficient values ​​at each frequency point in the reflection coefficient frequency response table of the periodic unit baffle model are fitted, and the corresponding values ​​of the three parameters a, b, and c of the homogeneous material at different frequencies are obtained;

[0013] In step 8, the corresponding values ​​of the three parameters a, b, and c obtained in step 7 at different frequencies are used as the difference function of the material parameters of the homogeneous material with frequency as the independent variable, and the frequency domain analysis is performed on the homogeneous material to obtain the reflection coefficient of the homogeneous material at this time, and compared with the reflection coefficient of the periodic unit baffle model. The two are basically consistent.

[0014] By setting frequency-dependent material properties, the present invention enables a homogeneous material to be used to model the periodic unit baffle equivalently. Furthermore, by fitting the parameters of the periodic unit baffle model with the homogeneous material model of the baffle at each frequency point, the frequency-dependent material property parameters used for equivalent modeling are obtained.

[0015] Preferably, in step 2, there is no periodic unit in the finite element model of the homogeneous material.

[0016] Preferably, in step 3, the values ​​of the variables set can be replaced by the sound absorption coefficient and transmission coefficient of the homogeneous material. In other words, the sound absorption coefficient and transmission coefficient can also be used to fit the material parameters.

[0017] Preferably, in step 8, the material performance difference function is fitted into a function curve, which is then used in the equivalent modeling of the acoustic baffle. The material performance parameters that vary with frequency are obtained, and parameter estimation can be performed.

[0018] Preferably, when fitting the material parameters corresponding to each frequency point by the reflection coefficient, the variable set in step 3 can be set to the variance of the reflection coefficient of the homogeneous material model and the periodic structure model, and in step 4, an optimization analysis step can be added before the frequency domain analysis step, with the variance as the objective function and the optimization method as minimization to optimize the values ​​of the three parameters a, b, and c.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The present invention uses a homogeneous material whose material parameters change with frequency to construct an equivalent model of a periodic structural baffle. It is only necessary to construct a local model of the periodic structural baffle for the material parameter fitting and acquisition process. The subsequent baffle modeling only requires the construction of a homogeneous plate, which reduces the structural complexity of the baffle model, the resources and time required for calculation, and is conducive to the rapid iterative design of related acoustic structures. Description of the drawings:

[0021] Figure 1 This is an equivalent modeling flow chart of the present invention.

[0022] Figure 2 These are the reflection coefficient results obtained by simulating two different models in the embodiments of the present invention. Specific implementation method:

[0023] The present invention will be further described below with reference to the accompanying drawings:

[0024] like Figure 1 As shown, an equivalent modeling method for an acoustic baffle includes the following steps:

[0025] Step 1: Construct a finite element model of the baffle containing several periodic units, solve the model according to the conventional simulation process of the baffle acoustic performance, and obtain the frequency response table of the sound absorption coefficient, reflection coefficient, and transmission coefficient;

[0026] Step 2: construct a homogeneous material finite element model of the same size as the baffle finite element model, and set three parameters a, b, and c as the Young's modulus, Poisson's ratio, and density of the homogeneous material;

[0027] Step 3, set a variable whose value is the reflection coefficient of the homogeneous material;

[0028] Step 4: Add a parameter estimation analysis step before the frequency domain analysis step, use the variable set in step 3 as the objective function, and set the optimization method to the least squares method;

[0029] Step 5: Take a frequency value and a reflection coefficient value from the frequency response table of the baffle model sound absorption coefficient calculated in step 1 as the frequency value and fitting target to be solved in the frequency domain analysis step of the homogeneous material model;

[0030] Step 6: Calculate the Young's modulus and Poisson's ratio corresponding to the reflection coefficient at a certain frequency point of the homogeneous material model and the periodic unit baffle model, and output the frequency and the values ​​of the three parameters a, b, and c;

[0031] Step 7, repeating steps 5 and 6 until the reflection coefficient values ​​at each frequency point in the reflection coefficient frequency response table of the periodic unit baffle model are fitted, and the corresponding values ​​of the three parameters a, b, and c of the homogeneous material at different frequencies are obtained;

[0032] In step 8, the values ​​of the three parameters a, b, and c obtained in step 7 at different frequencies are used as the difference function of the homogeneous material parameters with frequency as the independent variable, and the frequency domain analysis is performed on the homogeneous material to obtain the reflection coefficient of the homogeneous material at this time.

[0033] In this embodiment, the reflection coefficient results obtained by simulating two different models can be found in Figure 2 It can be seen that compared with the reflection coefficient of the model containing periodic unit baffles, the two are basically consistent.

[0034] The present invention sets frequency-varying material properties so that homogeneous materials can be used to perform equivalent modeling on a periodic unit baffle. By using the homogeneous material model of the baffle to perform frequency-point parameter fitting on the periodic unit baffle model, frequency-varying material performance parameters for equivalent modeling are obtained.

[0035] As a preferred approach, the material parameters used for fitting in step 3 may also be the sound absorption coefficient and the transmission coefficient.

[0036] As a preferred method, in step 8, the material property difference function is fitted into a function curve, which is then used in the equivalent modeling of the acoustic baffle. The material property parameters that vary with frequency are obtained, and parameter estimation can be performed.

[0037] As a preferred method, when fitting the material parameters corresponding to each frequency point by the reflection coefficient, the variable set in step 3 can be set to the variance of the reflection coefficient of the homogeneous material model and the periodic structure model, and in step 4, an optimization analysis step is added before the frequency domain analysis step, with the variance as the objective function and the optimization method as minimization to optimize the values ​​of the three parameters a, b, and c.

[0038] The above description is only for the preferred embodiment of the present invention, which should not be understood as limiting the claims. Any equivalent process changes made using the present invention description are included in the patent protection scope of the present invention.

Claims

1. An equivalent modeling method for an acoustic baffle, characterized by: The following steps are included: Step 1: Construct a finite element model of the baffle containing several periodic units, solve the model according to the conventional simulation process of the baffle acoustic performance, and obtain the frequency response table of the sound absorption coefficient, reflection coefficient, and transmission coefficient; Step 2: construct a homogeneous material finite element model of the same size as the baffle finite element model, and set three parameters a, b, and c as the Young's modulus, Poisson's ratio, and density of the homogeneous material; Step 3, set a variable whose value is the reflection coefficient of the homogeneous material; Step 4: Perform parameter estimation analysis, use the variables set in step 3 as the objective function, and set the optimization method to the least squares method; Step 5: Take a frequency value and a reflection coefficient value from the frequency response table of the baffle model sound absorption coefficient calculated in step 1 as the frequency value and fitting target to be solved in the frequency domain analysis step of the homogeneous material model; Step 6: Calculate the Young's modulus and Poisson's ratio corresponding to the reflection coefficient at a certain frequency point of the homogeneous material model and the periodic unit baffle model, and output the frequency and the values ​​of the three parameters a, b, and c; Step 7, repeating steps 5 and 6 until the reflection coefficient values ​​at each frequency point in the reflection coefficient frequency response table of the periodic unit baffle model are fitted, and the corresponding values ​​of the three parameters a, b, and c of the homogeneous material at different frequencies are obtained; In step 8, the values ​​of the three parameters a, b, and c obtained in step 7 at different frequencies are used as the difference function of the homogeneous material parameters with frequency as the independent variable, and the frequency domain analysis is performed on the homogeneous material to obtain the reflection coefficient of the homogeneous material at this time.

2. The equivalent modeling method of an acoustic baffle according to claim 1, characterized in that: In step 2, there are no periodic elements in the finite element model of the homogeneous material.

3. The equivalent modeling method of an acoustic baffle according to claim 1, characterized in that: In step 3, the values ​​of the variables set can be replaced by the sound absorption coefficient and transmission coefficient of the homogeneous material.

4. The equivalent modeling method of an acoustic baffle according to claim 1, wherein: In step 8, the material performance difference function is fitted into a function curve, which is then used in the equivalent modeling of the acoustic baffle.

5. The equivalent modeling method of an acoustic baffle according to claim 1, wherein: When fitting the material parameters corresponding to each frequency point by the reflection coefficient, the variable set in step 3 can be set as the variance of the reflection coefficient of the homogeneous material model and the periodic structure model, and in step 4, the variance is used as the objective function and the optimization method is minimization to optimize the values ​​of the three parameters a, b, and c.

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