Random vibration simulation method and device of vehicle-mounted loudspeaker and storage medium

Abstract

The invention discloses a random vibration simulation method and device of a vehicle-mounted loudspeaker and a storage medium. The invention discloses a random vibration simulation method for a vehicle-mounted loudspeaker. The method comprises the following steps: establishing a finite element simulation model according to a geometric model of the vehicle-mounted loudspeaker and solving the finite element simulation model; when the finite element simulation model is established, acquiring a frequency domain power spectral density curve of the vehicle-mounted loudspeaker and converting the frequency domain power spectral density curve into a time domain curve; the surface, connected with a vehicle body, of the vehicle-mounted loudspeaker is set as a fixed constraint boundary, and basic excitation is applied to the fixed constraint boundary according to the time domain curve; and selecting transient and mode order reduction solution during solution, and outputting a stress simulation result. According to the method, the simulation efficiency is improved on the premise of ensuring the simulation accuracy, the calculation cost is reduced, the performance of the vehicle-mounted loudspeaker under the random vibration working condition is subjected to simulation analysis, and the installation reliability and the vibration reliability of the vehicle-mounted loudspeaker are improved.

Description

TECHNICAL FIELD

[0001] The application relates to a random vibration simulation method and device of a vehicle-mounted loudspeaker and a storage medium. BACKGROUND

[0002] The vehicle-mounted loudspeaker is a key component of an automobile audio system, and its performance directly affects the auditory experience of passengers and driving safety. In the actual use of an automobile, the vehicle-mounted loudspeaker needs to withstand random vibration caused by road conditions. Such random vibration has a great influence on the structure of the vehicle-mounted loudspeaker. In order to ensure the performance and reliability of the vehicle-mounted loudspeaker, a series of random vibration tests and high-low temperature environment tests are usually required. However, this physical test method has certain limitations, such as high cost, long cycle, limited repeatability, and may not be able to completely simulate the complex conditions in the actual use environment.

[0003] The simulation method can solve the above problems. Among them, the random vibration is mainly reflected in the uneven road, and the load received by the automobile is random. In the driving process of the automobile, the load received by the automobile loudspeaker is mainly random vibration. The existing random vibration simulation methods can be summarized into two categories: modal superposition method in frequency domain and direct transient (time domain) solution.

[0004] Modal superposition method in frequency domain: this method has the characteristics of fast calculation and good convergence, but this method is only based on statistical method for description, and the stress results at each position are statistical results, which represent the maximum value of random vibration under a certain standard deviation. Therefore, the simulation result of the modal superposition method in frequency domain can only represent ; since the result is under a certain standard deviation or a certain probability, the result will not exceed the current calculation result, and the exact value cannot be obtained as in the transient solution.

[0005] Direct transient (time domain) simulation method: the transient solution can better consider the law of change of the actual object with time, and can obtain a simulation result that conforms to the actual working condition. However, this transient simulation method takes a long time, and is often not widely used due to low simulation efficiency.

[0006] The above information disclosed in the background section is only used to strengthen the understanding of the background of the present application, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0007] Therefore, the application provides a random vibration simulation method and device of a vehicle-mounted loudspeaker and a storage medium, which improves the simulation efficiency and reduces the calculation cost under the premise of ensuring the simulation accuracy, simulates and analyzes the performance of the vehicle-mounted loudspeaker under the random vibration working condition, and improves the installation reliability and vibration reliability of the vehicle-mounted loudspeaker.

[0008] The first aspect of the present application provides a random vibration simulation method of a vehicle-mounted speaker, comprising: establishing a finite element simulation model according to a geometric model of the vehicle-mounted speaker and solving;

[0009] In the establishment of the finite element simulation model, the frequency domain power spectral density curve of the vehicle-mounted speaker is converted into a time domain curve; the surface connecting the vehicle-mounted speaker and the vehicle body is set as a fixed constraint boundary, and a basic excitation is applied to the fixed constraint boundary according to the time domain curve;

[0010] In the solving, a transient and mode reduction solving is selected, and a stress simulation result is output.

[0011] In a preferred embodiment, the frequency domain power spectral density curve is a curve of power spectral density varying with frequency, and the time domain curve is a curve of acceleration varying with time.

[0012] In a more preferred embodiment, the basic excitation is a load calculated according to the acceleration.

[0013] In a preferred embodiment, the basic excitation is applied along the normal direction of the surface connecting the vehicle-mounted speaker and the vehicle body.

[0014] In a more preferred embodiment, the vehicle-mounted speaker has multiple surfaces in contact with the vehicle body, and the multiple surfaces are parallel or not parallel, and the basic excitation is respectively applied to the corresponding surfaces along the normal direction of each surface.

[0015] In a preferred embodiment, the finite element simulation model is established and solved by COMSOL Multiphysics software, in the solving, the research type is selected as a transient and mode reduction model, the characteristic frequency analysis is performed first, then the model reduction analysis is performed, and finally the transient analysis is performed, in which the characteristic frequency analysis results of each mode in the mode reduction model are called.

[0016] In a preferred embodiment, the stress simulation result includes one or more of the following: a stress structure diagram at a certain time, a stress maximum value, and a displacement of a stress maximum point.

[0017] In a preferred embodiment, the vehicle-mounted speaker includes a vehicle-mounted subwoofer, the vehicle-mounted subwoofer includes multiple surfaces configured to be fixed on the vehicle body, and several of the multiple surfaces are not parallel, and the basic excitation is respectively applied to the corresponding surfaces along the normal direction of each surface, the basic excitation is an acceleration load calculated according to the time domain curve.

[0018] In a preferred embodiment, the geometric model of the vehicle-mounted speaker comprises geometric models of a cabinet, a support and a magnetic circuit assembly, the cabinet comprises a body for enclosing an internal acoustic cavity and a mounting column extending outward from the body, the vehicle-mounted speaker is fixed to the vehicle through the mounting column, and a surface in contact with the vehicle body is set as a fixed constraint boundary.

[0019] A second aspect of the present application provides a random vibration simulation device for a vehicle-mounted speaker, comprising a memory and a processor, the memory stores a computer program, and the processor implements the random vibration simulation method for the vehicle-mounted speaker when executing the computer program.

[0020] A third aspect of the present application provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the program is executed by a processor to implement the random vibration simulation method for the vehicle-mounted speaker.

[0021] The present application has the following advantages by adopting the above scheme:

[0022] The present application provides a random vibration simulation method for a vehicle-mounted speaker, which simulates and analyzes the performance of the vehicle-mounted speaker under a loaded random vibration condition, can accurately predict the performance and reliability of the speaker, improves the vibration reliability of the vehicle-mounted speaker, thereby guiding the design improvement of the product and improving the market competitiveness of the product. The simulation method improves the simulation efficiency, shortens the simulation time and reduces the calculation cost under the premise of ensuring the simulation accuracy, and solves the problem of long simulation time and low efficiency in time-domain random vibration simulation. Through this method, potential problems can be identified in the early stage of product development, failures in later physical tests can be avoided, and research and development costs and time can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 A flowchart of a random vibration simulation method for a vehicle-mounted speaker according to an embodiment of the present application is shown.

[0025] Figure 2 A geometric model of a vehicle-mounted speaker according to an embodiment of the present application is shown.

[0026] Figure 3 A finite element simulation model of a vehicle-mounted speaker after meshing according to an embodiment of the present application is shown.

[0027] Figure 4 The frequency domain power spectrum density curve and the converted time domain curve in the embodiment of the application are shown.

[0028] Figure 5 The fixed constraint boundary in the embodiment of the application is shown.

[0029] Figure 6 The stress distribution diagram at a certain moment output by the method in the embodiment of the application is shown.

[0030] Figure 7 The simulation result comparison diagram of the embodiment and the comparative example is shown. DETAILED DESCRIPTION

[0031] The preferred embodiments of the application are described in detail below with reference to the accompanying drawings, so that the advantages and features of the application can be more easily understood by those skilled in the art. It should be noted that the description of the embodiments is used to help understand the application, but does not constitute a limitation on the application.

[0032] The embodiment of the present embodiment relates to random vibration simulation of a vehicle-mounted loudspeaker, and aims to solve the problems of long simulation time and low efficiency of the existing time domain random vibration simulation, and proposes a new random vibration simulation method of a vehicle-mounted loudspeaker. Referring to Figure 1 As shown in the figure, the random vibration simulation method of the vehicle-mounted loudspeaker comprises the following steps:

[0033] The geometry structure is preprocessed by using 3D software to simplify the model, wherein mainly some small features are simplified to prepare for the next step of drawing a grid;

[0034] The spatial dimension 3D, solid mechanics interface and selection of transient, model order reduction model interface are added;

[0035] The bass frequency domain power spectrum density curve data is converted into time domain curve data by using Comsol software;

[0036] The material parameters of each component are defined, including Young's modulus, Poisson's ratio and density;

[0037] The boundary conditions are set, the mounting angle of the bass is fixed, and the basic excitation in a certain direction such as the X direction (and the other directions Y, Z are similarly applied) is applied;

[0038] The grid is divided: for small components and components of interest, the grid needs to be refined to better obtain accurate stress;

[0039] The final research type is selected as transient, and the mode order reduction model is selected.

[0040] In summary, the random vibration simulation method uses Comsol software to convert the frequency domain power spectrum density curve data of the vehicle-mounted speaker into time domain curve data; then the time domain signal is applied to the object to be solved; then the transient model reduction option is added in the solver; the existing transient (time domain) random vibration is compared, the efficiency is improved by 22 times, the accuracy difference is 0.2%, and the simulation efficiency is greatly improved. Under the premise of ensuring the accuracy of simulation, the calculation cost is greatly reduced.

[0041] The specific principle of model reduction transient simulation is described as follows:

[0042] Without considering the damping effect, the control equation of the dynamic analysis of the complex structure can be expressed as:

[0043]

[0044] In the formula: M and K are n×n matrices, which are the mass matrix and stiffness matrix of the structure respectively;

[0045] U and U .. are n-dimensional column vectors, which are the displacement and acceleration response vectors of the structure respectively;

[0046] F is an n-dimensional column vector, which is the load acting on the structure;

[0047] n represents the number of degrees of freedom of the original complex structure model.

[0048] Model reduction needs to introduce displacement conversion equation U=TQ, and substitute the displacement conversion equation into the above control equation, and simultaneously left multiply T^T on both sides of the equation, to obtain the following reduced dynamic equation:

[0049] M_RQ .. +K_RQ=F_R

[0050] In the formula: T is an n×m (m<<n) reduced basis matrix composed of m reduced basis vectors;

[0051] Q is an m-dimensional column vector, and m represents the number of degrees of freedom of the reduced model.

[0052] M_R=T^TMT, K_R=T^TKT are the mass and stiffness matrices of the reduced model respectively;

[0053] F_R=T^TF is the load vector of the reduced model.

[0054] In this way, the dynamic equation after reduction has m degrees of freedom, while the original control equation has n degrees of freedom (m<<n).

[0055] For different physical model reduction methods, the main difference is the construction of their reduced basis T. Different reduced basis will cause different computational accuracy and efficiency, efficiency and accuracy are generally contradictory, need to make a choice between accuracy, efficiency according to different problems. The random vibration model reduction method in COMSOL software is based on modal.

[0056] The reduced basis in the modal-based reduced model is determined by the modal, the generalized eigenvalue equation of structural dynamics:

[0057] (K-λM)φ=0

[0058] First, it needs to be decomposed, and a plurality of modes are obtained by characteristic frequency analysis.

[0059] Then these modes are respectively superimposed together in different proportions, as shown in the following formula:

[0060]

[0061] Where z is the sum of the superposition of different modes; λ k is the eigenvalue, the imaginary part represents the modal frequency, and the real part represents the growth rate of the mode (the sign determines the positive or negative contribution of the mode to the overall contribution); is the eigenvector, which represents the mode.

[0062] The random vibration simulation method of the vehicle-mounted loudspeaker of the embodiment comprises: establishing a finite element simulation model according to the geometric model of the vehicle-mounted loudspeaker and solving. When establishing the finite element simulation model, the frequency domain power spectral density curve of the vehicle-mounted loudspeaker is converted into a time domain curve; the surface connecting the vehicle-mounted loudspeaker and the vehicle body is set as a fixed constraint boundary, and the basic excitation is applied to the fixed constraint boundary according to the time domain curve. When solving, the transient and mode reduction solving is selected, and the stress simulation result is output.

[0063] The vehicle-mounted loudspeaker is a sound producing device installed on a vehicle. In the following embodiments, a vehicle-mounted subwoofer installed in the trunk of a vehicle is taken as the simulation analysis object; in other embodiments, the vehicle-mounted loudspeaker can be a loudspeaker installed on the headrest, door panel, etc. of a vehicle. For example, Figure 2As shown, the subwoofer includes a cabinet 1, a bracket 2 and a magnetic circuit assembly. In the following embodiments, only the components with large volume or weight are considered, while the diaphragm, voice coil, damper and other components with light weight and small stress impact are omitted to reduce the amount of calculation. The cabinet 1 and the bracket 2 are made of plastic; the magnetic circuit assembly includes a magnetic conducting piece (U-shaped iron or T-shaped iron), a magnetic steel and a front plate. The magnetic circuit assembly is arranged in the bracket 2 and the cabinet 1, and thus is not shown in the figure. The cabinet 1 includes a body for enclosing an internal sound cavity and a plurality of mounting columns provided on the body and extending outward from the body. The mounting columns are provided with mounting holes for bolts to pass through, and have surfaces 11 in contact with the vehicle body, which are the surfaces subjected to the basic excitation.

[0064] The frequency domain power spectral density curve is a curve of power spectral density (PSD) varying with frequency, and the time domain curve is a curve of acceleration varying with time. The basic excitation is a load calculated according to the acceleration. The basic excitation is applied along the normal direction of the surface 11 connecting the vehicle-mounted loudspeaker and the vehicle body. As shown in the figure, the vehicle-mounted loudspeaker has a plurality of surfaces 11 in contact with the vehicle body, and the plurality of surfaces 11 are parallel or not parallel to each other, and the basic excitation is respectively applied to the corresponding surfaces 11 along the normal direction of each surface 11. Figure 2

[0065] The finite element simulation model is established and solved by COMSOL Multiphysics software. When solving, the research type is selected as transient and mode reduction model. First, characteristic frequency analysis is performed, then model reduction analysis is performed, and finally transient analysis is performed, in which the characteristic frequency analysis results of each mode in the mode reduction model are called.

[0066] The embodiment also relates to a random vibration simulation device of a vehicle-mounted loudspeaker, which includes a memory and a processor. The memory stores a computer program, and the processor implements the random vibration simulation method of the vehicle-mounted loudspeaker when executing the computer program. The random vibration simulation device is one of the components of the vehicle-mounted audio system and can be integrated in the vehicle machine system.

[0067] The embodiment also relates to a computer readable storage medium, which stores a computer program. The program is executed by a processor to implement the random vibration simulation method of the vehicle-mounted loudspeaker.

[0068] Embodiment

[0069] The embodiment provides a random vibration simulation method of a vehicle-mounted subwoofer, which includes the following steps:

[0070] ​(1) 3D model simplification: bass speaker simulation needs to be simplified according to the computing power and computing model. Specifically, some small features that affect mesh generation are deleted, and components such as the paper cone, folded ring, and dust cap of the speaker that do not affect structural calculation are deleted. The simplified geometry model is shown in FIG. 3. Figure 2

[0071] (2) COMSOL simulation model (as shown in FIG. 4) is established: Figure 3

[0072] 1) First, add the spatial dimension 3D, structural mechanics physical field interface in COMSOL Multiphysics software;

[0073] 2) Import the simplified 3D model in "Geometry" to form a union;

[0074] 3) As shown in FIG. 5, use Comsol software to convert the bass speaker frequency domain power spectrum density curve data (upper image in FIG. 5) into time domain curve data (lower curve in FIG. 5); the time domain curve data can be imported by "Global Definition -> Interpolation" to input random vibration into the model; Figure 4 Figure 4 Figure 4

[0075] 4) Set the material parameters of each component (box, support, and magnetic circuit), including Young's modulus, Poisson's ratio, and density;

[0076] 5) Set the boundary conditions, fix the mounting columns of the bass speaker, and set the multiple surfaces on the mounting columns as fixed constraint conditions (shown in blue in FIG. 6), apply the base excitation to the surface of the mounting column in the normal direction such as the X direction (and similarly for other directions Y, Z), which is set according to the acceleration curve at the bottom; Figure 5 Figure 4

[0077] 6) Mesh division: for small components and components of interest, the grid should be refined to better obtain accurate stress, as shown in FIG. 7; Figure 3

[0078] 7) Finally, select the transient type and mode reduction model;

[0079] 8) Submit the calculation, first perform the characteristic frequency analysis (modal), then perform the model reduction analysis, and finally perform the transient analysis. In this step, the "transient" study does not need to recalculate the "solid mechanics" physical field interface, but can directly call the modal results in the reduced model.​​​​​​​​

[0080] (3)Solving and post-processing

[0081] (1) In the results, click on the "3D plot group", right-click to add the body (select the body to be studied), and select solid.misesGp in the expression. The stress structure at each time can be displayed, such as Figure 6 which shows the stress distribution at one time;

[0082] (2) Generate the maximum stress of the body. In the derived values in the results, select the maximum value of the body and select solid.misesGp. Find the point of maximum stress, such as the part of the maximum stress value 4.04817 shown in the left part;

[0083] (3) Generate the displacement of the maximum stress point. In the derived values in the results, select the maximum value of the body and select solid.disp. Obtain the displacement time response at the maximum stress point, such as Figure 7 The blue curve in the middle represents the reduced-order solution.

[0084] After the calculation is completed, the simulation results are post-processed, and it is determined whether the design needs to be optimized and improved. If optimization is needed, the above steps need to be repeated until the simulation results meet the expectations.

[0085] Comparative example

[0086] The comparative example uses a direct transient method, and the only difference from the example is that the final research type is directly selected as "transient", and there is no model reduction.

[0087] Figure 7 The displacement time response curve at the maximum stress point of the example and the comparative example is shown. Referring to Figure 7 , the simulation results of the two methods are similar. Based on the same calculation server, the calculation time of the direct transient method (comparative example) is about 2640 seconds, and the calculation time of the model reduction transient method (example) is about 383 seconds, which is about 15% of the calculation time of the comparative example method.

[0088] The example compares the transient (time domain) random vibration, the efficiency is improved by 22 times, the accuracy difference is 0.2%, and the simulation efficiency is greatly improved and the calculation cost is reduced.

[0089] As shown in the specification and claims, the term "comprises" and "includes" only indicates the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0090] It can be further understood that "multiple" in the disclosure means two or more, and other quantifiers are similar.

[0091] It is further to be understood that the terms "first", "second", etc. are used to describe various information, but the information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other, and do not indicate a particular order or importance. In fact, the expressions "first", "second", etc. can be used interchangeably. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present disclosure.

[0092] The above embodiments are only to illustrate the technical concept and characteristics of the present application, and are a preferred embodiment, the purpose of which is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application.

Claims

1. A method of random vibration simulation of a vehicle-mounted loudspeaker, comprising: A finite element simulation model is established according to the geometric model of the vehicle-mounted speaker and is solved; It is characterized in that: In the establishment of the finite element simulation model, the frequency domain power spectral density curve of the vehicle-mounted speaker is converted into a time domain curve; the surface connecting the vehicle-mounted speaker and the vehicle body is set as a fixed constraint boundary, and a basic excitation is applied to the fixed constraint boundary according to the time domain curve; In the solving, a transient and mode reduction solving is selected, and a stress simulation result is output.

2. The random vibration simulation method of claim 1, wherein The frequency domain power spectral density curve is a curve of power spectral density varying with frequency, and the time domain curve is a curve of acceleration varying with time.

3. The random vibration simulation method of claim 2, wherein, The basic excitation is a load calculated according to the acceleration.

4. The random vibration simulation method of claim 1, wherein The basic excitation is applied along the normal direction of the surface connecting the vehicle-mounted speaker and the vehicle body.

5. The random vibration simulation method of claim 4, wherein, The vehicle-mounted speaker has multiple surfaces in contact with the vehicle body, and the multiple surfaces are parallel or not parallel, and the basic excitation is respectively applied to the corresponding surface along the normal direction of each surface.

6. The random vibration simulation method of claim 1, wherein The finite element simulation model is established by COMSOL Multiphysics software and is solved, in the solving, the research type is selected as a transient and mode reduction model, the characteristic frequency analysis is performed first, then the model reduction analysis is performed, and finally the transient analysis is performed, in which the characteristic frequency analysis result of each mode in the mode reduction model is called.

7. The random vibration simulation method of claim 1, wherein The stress simulation result includes one or more of the following: a stress structure diagram at a certain time, a stress maximum value, and a displacement of a stress maximum point.

8. The random vibration simulation method of claim 1, wherein The vehicle-mounted speaker includes a vehicle-mounted subwoofer, the vehicle-mounted subwoofer includes multiple surfaces configured to be fixed on the vehicle body, and several of the multiple surfaces are not parallel, and the basic excitation is respectively applied to the corresponding surface along the normal direction of each surface, and the basic excitation is an acceleration load calculated according to the time domain curve.

9. A random vibration simulation device of a vehicle-mounted speaker, comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor executes the computer program to implement the random vibration simulation method of the vehicle-mounted speaker according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the program is executed by the processor to implement the random vibration simulation method of the vehicle-mounted speaker according to any one of claims 1 to 8.

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