Vehicle-mounted loudspeaker stress simulation test method and system considering bolt pre-tightening force

Abstract

The invention discloses a vehicle-mounted loudspeaker stress simulation test method and system considering bolt pre-tightening force. The vehicle-mounted loudspeaker stress simulation test method comprises the steps that a geometric figure, a random vibration condition and a bolt pre-tightening force condition of a vehicle-mounted loudspeaker are provided, the random vibration condition is a vibration load applied to the vehicle-mounted loudspeaker by a vehicle, and the bolt pre-tightening force condition is the magnitude of a force applied to the vehicle-mounted loudspeaker by a fastening bolt; establishing a finite element simulation model according to the geometric figure, selecting a solid mechanical physical field, setting a random vibration condition for base excitation, setting a surface, in contact with a vehicle body, of the vehicle-mounted loudspeaker as a fixed constraint boundary, and loading an equivalent boundary load on the fixed constraint boundary according to a bolt pre-tightening force condition; and performing transient solution on the finite element simulation model, and outputting a stress test result. According to the invention, simulation analysis can be carried out on the performance of the vehicle-mounted loudspeaker under the working conditions of loading bolt pretightening force and random vibration, and the installation reliability and the vibration reliability are improved.

Description

Technical Field

[0001] The invention relates to a stress simulation test method and system for a vehicle-mounted loudspeaker considering bolt pre-tightening force. Background Art

[0002] Car speakers are a key component of the vehicle's audio system, and their performance directly impacts the passenger's auditory experience and driving safety. During actual use, these speakers must withstand a variety of complex environmental conditions, including extreme temperature fluctuations and random vibrations caused by road conditions. These environmental factors pose significant challenges to the structural integrity and acoustic performance of these speakers.

[0003] To ensure the performance and reliability of automotive speakers in extreme environments, a series of environmental adaptability tests are typically required, including random vibration testing and high and low temperature environmental testing. However, these physical testing methods have certain limitations, such as high cost, long cycle times, limited repeatability, and may not fully simulate the complex conditions of actual use environments.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] In view of this, the present invention provides an environmental stress simulation test method and system for a vehicle-mounted speaker, which simulates and analyzes the performance of the vehicle-mounted speaker under loading bolt preload and random vibration conditions, thereby improving the installation reliability and vibration reliability of the vehicle-mounted speaker.

[0006] The present invention adopts the following technical solutions:

[0007] A stress simulation test method for a vehicle-mounted speaker comprises the following steps:

[0008] S1. Provide the geometry of the vehicle speaker, random vibration conditions, and bolt preload conditions. The random vibration conditions are the vibration load applied to the vehicle speaker by the vehicle, and the bolt preload conditions are the magnitude of the force applied to the vehicle speaker by the fastening bolts, with the vehicle speaker being secured to the vehicle by the fastening bolts.

[0009] S2. Establishing a finite element simulation model based on the geometric figure, wherein a solid mechanics physical field is selected, the random vibration condition of step S1 is set as a base excitation, the surface of the vehicle speaker in contact with the vehicle body is set as a fixed constraint boundary, and an equivalent boundary load is applied to the fixed constraint boundary according to the bolt preload condition of step S1;

[0010] S3. Perform transient solution on the finite element simulation model and output stress test results.

[0011] In a preferred embodiment, in step S1, the random vibration condition is a time domain signal; in step S3, a transient study is selected, and the stress test results include stress distribution diagrams at multiple moments and / or stress curves varying with time.

[0012] In a more preferred embodiment, the random vibration condition includes an acceleration curve varying with time.

[0013] In a preferred embodiment, in step S1, the geometric model of the vehicle speaker includes geometric models of a box, a bracket, and a magnetic circuit assembly, wherein the box includes a main body for enclosing an internal sound cavity and a bolt column extending outward from the main body, and the vehicle speaker is fixed to the vehicle by the bolt column.

[0014] In a more preferred embodiment, in step S2, the surface of each bolt column in contact with the vehicle body is set as a fixed constraint boundary.

[0015] In a preferred embodiment, in step S2, in COMSOL Multiphysics software, the spatial dimension is selected as 3D, the physical field interface is selected as solid mechanics, and the study type is selected as time domain;

[0016] Importing the geometry into COMSOL Multiphysics software;

[0017] Importing the random vibration condition and the bolt preload;

[0018] Setting a solid mechanics physical field interface includes: (1) inputting a material damping value of the vehicle-mounted speaker; (2) setting the mounting surface of the bolt column as a fixed constraint boundary; (3) adding a boundary load: adding an imported bolt preload on the fixed constraint boundary; (4) adding a base excitation: setting a random vibration load according to the imported random vibration condition;

[0019] Draw the grid.

[0020] In a preferred embodiment, in step S3, a transient study is selected and the output time step is set.

[0021] In a preferred embodiment, it is determined whether the stress test result meets the design requirements. If the result is yes, the simulation test is terminated; if the result is no, the geometric figure or material parameters are modified, and steps S2 and S3 are repeated.

[0022] In a preferred embodiment, the vehicle-mounted speaker includes a vehicle-mounted woofer or a vehicle-mounted subwoofer.

[0023] The present invention also adopts the following technical solutions:

[0024] A vehicle-mounted speaker stress simulation test system comprises a memory and a processor, wherein the memory stores a computer program and the processor implements the vehicle-mounted speaker stress simulation test method when executing the computer program.

[0025] The present invention adopts the above scheme and has the following advantages:

[0026] This invention proposes a stress simulation testing method and system for vehicle-mounted speakers that considers bolt preload. This method simulates and analyzes the performance of vehicle-mounted speakers under conditions of bolt preload and random vibration, improving their installation and vibration reliability. It accurately predicts speaker performance and reliability, guiding product design improvements and enhancing market competitiveness. This method can identify potential issues early in product development, avoiding failures during later physical testing and reducing R&D costs and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 The figure is a flow chart of a stress simulation test method for a vehicle-mounted speaker according to an embodiment of the present invention.

[0029] Figure 2 The figure shows a geometric model of a vehicle-mounted speaker according to an embodiment of the present invention.

[0030] Figure 3 A meshed finite element simulation model of a vehicle-mounted speaker according to an embodiment of the present invention is shown.

[0031] Figure 4 A fixed constraint boundary according to an embodiment of the present invention is shown.

[0032] Figure 5 The equivalent boundary load of the bolt preload in an embodiment of the present invention is shown.

[0033] Figure 6 A random vibration load curve according to an embodiment of the present invention is shown.

[0034] Figure 7 A stress curve diagram according to an embodiment of the present invention is shown.

[0035] Figure 8 FIG. 1 shows a stress distribution diagram of a vehicle-mounted speaker at a certain moment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to help understand the present invention, but does not constitute a limitation of the present invention.

[0037] The examples of this embodiment relate to the field of vehicle-mounted speakers, specifically to a stress simulation test method and system for vehicle-mounted speakers taking into account bolt preload. This stress simulation test method uses COMSOL Multiphysics software to simulate and analyze the performance of vehicle-mounted speakers under random vibration conditions and loading spiral preload conditions, aiming to improve the installation reliability and vibration reliability of vehicle-mounted speakers. Although computer simulation technology has been widely used in recent years, and COMSOL Multiphysics software, as a multi-physics field simulation tool, has demonstrated powerful capabilities in simulating and analyzing physical phenomena such as mechanics, acoustics, and thermals, it often focuses on the simulation of a single environmental factor, and no simulation research under the coupling of random vibration and high and low temperatures has been reported. Existing simulation methods often ignore the effects of bolt preload and vehicle vibration on vehicle-mounted speakers. The actual bolt preload, etc. may have a significant impact on the local and overall dynamic characteristics of the mounting hole.

[0038] Therefore, this implementation proposes a COMSOL simulation method specifically for the random vibration of vehicle speakers under bolt preload conditions. This method can more accurately simulate the random vibration dynamic response of vehicle speakers under different installation conditions, providing a more comprehensive and efficient solution for product design and testing. It can accurately predict the performance and reliability of vehicle speakers, thereby guiding product design improvements and enhancing market competitiveness. This simulation method can identify potential issues in the early stages of product design, optimize product structure, and improve product reliability. It also reduces the need for physical experiments, avoids failures during later physical testing, and reduces R&D costs and time.

[0039] Reference Figure 1 As shown, a stress simulation test method for a vehicle-mounted speaker in an embodiment includes the following steps:

[0040] S1. Provide the geometry of the vehicle speaker, random vibration conditions, and bolt preload conditions. The random vibration conditions are the vibration load applied to the vehicle speaker by the vehicle, and the bolt preload conditions are the magnitude of the force applied to the vehicle speaker by the fastening bolts, with the vehicle speaker being secured to the vehicle by the fastening bolts.

[0041] S2. Establishing a finite element simulation model based on the geometric figure, wherein a solid mechanics physical field is selected, the random vibration condition of step S1 is set as a base excitation, the surface of the vehicle speaker in contact with the vehicle body is set as a fixed constraint boundary, and an equivalent boundary load is applied to the fixed constraint boundary according to the bolt preload condition of step S1;

[0042] S3. Perform transient solution on the finite element simulation model and output stress test results.

[0043] The geometric model of the car speaker includes the geometric models of the box, bracket, and magnetic circuit assembly. The box includes a body for enclosing an internal sound cavity and bolts extending outward from the body. The car speaker is fixed to the vehicle by bolts. In one embodiment, the car speaker is a relatively large car speaker such as a car woofer or a car subwoofer. Figure 2 The configuration shown is for an in-vehicle subwoofer mounted in the trunk of a vehicle.

[0044] In step S1, the random vibration condition is a time-domain signal; specifically, the random vibration condition can be an acceleration curve that varies with time. In step S3, a transient study is selected, and the stress test results include stress distribution diagrams at multiple moments and / or stress curves that vary with time.

[0045] In step S1, the bolt preload condition is determined based on empirical or measured values. It is the force exerted on the interface between the vehicle speaker and the vehicle (specifically, the bolt studs on the enclosure) after the vehicle speaker is bolted to the vehicle. Bolt preload can be applied directly or by applying an equivalent compressive load.

[0046] In step S2, in COMSOL Multiphysics, select 3D as the spatial dimension, solid mechanics as the physics interface, and time domain as the study type.

[0047] Import the geometry into COMSOL Multiphysics software;

[0048] Import random vibration conditions and high and low temperature conditions;

[0049] Set up the solid mechanics physics interface, including: (1) inputting the material damping value of the vehicle speaker; (2) setting the mounting surface of the bolt column as a fixed constraint boundary; (3) adding base excitation: setting the random vibration load based on the imported random vibration condition;

[0050] Set up the solid heat transfer physics interface, including adding a heat flux, selecting convective heat flux as the flux type, setting the heat transfer coefficient and the external temperature, where the external temperature is set based on the imported high and low temperature conditions.

[0051] Setting up multiphysics, including: selecting the thermal expansion option to couple solid mechanics with heat transfer in solids;

[0052] Draw the grid.

[0053] In step S2, the physical field can include "Solid Mechanics" or "Shell" physical fields. If solid-shell coupling is used, the "Shell" physical field and the "Solid-Shell Multi-Physical Field Connection Relationship" must also be added.

[0054] In step S3, the stress test result includes a stress distribution diagram and / or a stress curve diagram varying with time.

[0055] In step S3, a transient study is selected and the output time step is set. For example, the output step can be set to 1 s.

[0056] After step S3, the stress test results are determined to see if they meet the design requirements. If so, the simulation ends. If not, the geometry or material parameters are modified (for example, increasing the thickness in areas with greater stress), and steps S2 and S3 are repeated. In one embodiment, after the calculation is complete, the simulation results are post-processed to determine whether the design requires optimization or improvement. If optimization is required, the above steps are repeated until the simulation results meet expectations.

[0057] A vehicle-mounted speaker environmental stress simulation test system comprises a memory and a processor. The memory stores a computer program. The processor implements an environmental stress simulation test method for the vehicle-mounted speaker when executing the computer program.

[0058] Figure 2 A model diagram for stress simulation testing of a vehicle-mounted speaker is shown, which includes a speaker box 1, a bracket 2, a magnetic circuit component (not shown in the figure), etc.

[0059] The specific process of the environmental stress simulation test of the model is as follows:

[0060] (1) Geometry drawing: Draw the 3D geometry model used for the environmental stress simulation test model, such as Figure 2 shown.

[0061] This 3D geometric model is a simplified model of a car speaker, including a box 1, a bracket 2 and a magnetic circuit assembly. That is, only components with larger volume or heavier weight are considered, while the diaphragm, voice coil, elastic wave and other components are lighter in mass and have less impact on stress, so these lighter components are omitted to reduce the amount of calculation. The material of the box 1 and the bracket 2 is plastic; the magnetic circuit assembly includes a magnetic conductive part (U iron or T iron), a magnet and a front piece. The magnetic circuit assembly is arranged in the bracket 2 and the box 1, so it is not shown in the figure. The box 1 is a slender flat box as a whole. The box 1 includes a main body 10 for enclosing an internal sound cavity and a plurality of bolt columns 11 provided on the box 10, wherein some of the bolt columns 11 can extend outward from the main body 10, or some of the bolt columns 11 are directly opened on the main body 10. In the example shown in the accompanying drawings, the body 10 is provided with three bolt posts 11. Two of these posts extend outward from the outer edge of the body 10, and the third is located between these two posts and is directly embedded in the body 10. Each bolt post 11 is provided with multiple reinforcing ribs to increase its strength. These bolt posts 11 are provided with mounting holes for the bolts to pass through. The surface of the bolt post 11 that contacts the vehicle body is the surface where the bolt preload is applied.

[0062] (2) Establishing COMSOL simulation model:

[0063] 1) Open COMSOL Multiphysics and add a spatial dimension, physics interface, and study type. For this example, the spatial dimension is 3D, the physics interface is Solid Mechanics, and the study type is Time Domain.

[0064] 2) Import the geometric figures in "Geometry" and process the figures in COMSOL if necessary.

[0065] 3) Set material parameters, including those of the box and bracket, such as density, Young's modulus, Poisson's ratio, etc.

[0066] 4) Input random vibration. Random vibration conditions are as follows Figure 6 As shown, data can be imported through "Global Definitions -> Interpolation", paying attention to the corresponding units. Here, the random vibration condition is the acceleration curve that changes with time.

[0067] 5) Set up the "Solid Mechanics" physics interface: ① "Linear Elastic Material -> Damping": Enter the damping values ​​of different materials, including the damping values ​​of the box, bracket, and magnetic circuit components. ② "Fixed Constraint": In this case, the constraint boundary is as follows Figure 4 The blue area in the middle is the contact surface between the bolt column on the car speaker box and the car body. Figure 4 Bolt preload is applied to the blue area (i.e., fixed constraint boundary) in the figure. In this case, the equivalent boundary load of bolt preload is as follows: Figure 5 ④ Add "base excitation" to set random vibration conditions: set random vibration load. The load data has been imported in 4). The load data is set according to the most demanding environment of the target vehicle model (such as bumpy road). In this embodiment, Figure 6 As shown, the load data includes: acceleration from about -7.5 to about 8.5 m / s within a period of 1 s 2 Apply the specified random vibration to the specified fixed constraint boundary to simulate the vibration transmitted to the vehicle speakers during actual operation.

[0068] 6) Draw the grid. In this embodiment, the grid is divided as follows Figure 3 shown.

[0069] 7) Solution and post-processing

[0070] a) Select a transient study and set the output time step in "Study -> Transient". The output time interval should not be too large. In this example, it is set to 1s.

[0071] b) Click Calculate.

[0072] c) After the calculation is completed, the simulation results are post-processed and the stress curve graph changing with time is output ( Figure 7 ) and stress distribution diagram. Figure 7 , corresponding to the change of load and temperature over time, outputs the corresponding stress change over time, where the stress is between 0 and about 33MPa. Figure 8 The stress distribution diagram on the car speaker at a certain moment is shown, and it can be clearly seen that the stress is more concentrated and the structure is relatively weak.

[0073] After the calculation is complete, the simulation results are post-processed to determine whether the design needs to be optimized. If optimization is required, the above steps need to be repeated until the simulation results meet expectations.

[0074] As shown in this specification and claims, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0075] It is further understood that in the present disclosure, "plurality" refers to two or more than two, and other quantifiers are similar.

[0076] It will be further understood that the terms "first," "second," and the like are used to describe various types of information, but such information should not be limited to these terms. These terms are used solely to distinguish information of the same type from one another and do not indicate a particular order or level of importance. In fact, the terms "first," "second," and the like are fully interchangeable. For example, first information could be referred to as second information, and similarly, second information could be referred to as first information without departing from the scope of this disclosure.

[0077] The above embodiment is only for illustrating the technical concept and features of the present invention and is a preferred embodiment. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention.

Claims

1. A stress simulation test method for a vehicle-mounted speaker, characterized in that: The steps include: S1. Provide the geometry of the vehicle speaker, random vibration conditions, and bolt preload conditions. The random vibration conditions are the vibration load applied to the vehicle speaker by the vehicle, and the bolt preload conditions are the magnitude of the force applied to the vehicle speaker by the fastening bolts, with the vehicle speaker being secured to the vehicle by the fastening bolts. S2. Establishing a finite element simulation model based on the geometric figure, wherein a solid mechanics physical field is selected, the random vibration condition of step S1 is set as a base excitation, the surface of the vehicle speaker in contact with the vehicle body is set as a fixed constraint boundary, and an equivalent boundary load is applied to the fixed constraint boundary according to the bolt preload condition of step S1; S3. Perform transient solution on the finite element simulation model and output stress test results.

2. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: In step S1, the random vibration condition is a time domain signal; in step S3, a transient study is selected, and the stress test results include stress distribution diagrams at multiple moments and / or stress curves varying with time.

3. The vehicle-mounted speaker stress simulation test method according to claim 2, characterized in that: The random vibration condition includes an acceleration profile that varies with time.

4. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: In step S1, the geometric model of the vehicle speaker includes the geometric models of the box, the bracket and the magnetic circuit assembly. The box includes a main body for enclosing an internal sound cavity and a bolt column provided on the main body. The vehicle speaker is fixed to the vehicle through the bolt column.

5. The vehicle-mounted speaker stress simulation test method according to claim 4, characterized in that: In step S2, the surface of each bolt column in contact with the vehicle body is set as a fixed constraint boundary.

6. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: In step S2, in COMSOL Multiphysics, select 3D as the spatial dimension, solid mechanics as the physics interface, and time domain as the study type. Importing the geometry into COMSOL Multiphysics software; Importing the random vibration condition and the bolt preload; Setting a solid mechanics physical field interface includes: (1) inputting a material damping value of the vehicle-mounted speaker; (2) setting the mounting surface of the bolt column as a fixed constraint boundary; (3) adding a boundary load: adding an imported bolt preload on the fixed constraint boundary; (4) adding a base excitation: setting a random vibration load according to the imported random vibration condition; Draw the grid.

7. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: In step S3, select transient study and set the output time step.

8. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: Determine whether the stress test result meets the design requirements, and if so, end the simulation test; If the answer is no, the geometric figure is modified or the material parameters are modified, and steps S2 and S3 are repeated.

9. The vehicle-mounted speaker stress simulation test method according to claim 1, characterized in that: The vehicle-mounted speaker includes a vehicle-mounted woofer or a vehicle-mounted subwoofer.

10. A vehicle-mounted speaker stress simulation test system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the vehicle-mounted speaker stress simulation test method according to any one of claims 1 to 9 is implemented.

Images