A resonance noise reduction device design method for low-frequency booming noise of a vehicle body structure

Abstract

This invention provides a design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures. The method includes: acquiring noise data and vibration data of various body panels during vehicle operation when booming noise occurs; identifying the target frequency and target panel of the resonant noise reduction device; creating a finite element model of the vehicle body and performing modal analysis to extract modal information of the target panel with a main vibration mode close to the target frequency; identifying the installation location and mass of the resonant noise reduction device; acquiring the available space volume of the resonant noise reduction device structure; and creating a simulation model of the resonant noise reduction device based on the target frequency and available space volume. The resonant noise reduction device in this invention, based on the actual booming noise performance in a vehicle, achieves frequency-selective noise reduction through reasonable design of structural stiffness and mass. It is applicable to vibration and noise reduction of all thin-walled panels of automotive bodies, has high versatility, achieves lightweighting, is scientifically effective, unaffected by the environment, and exhibits high performance stability.

Description

Technical Field

[0001] This invention relates to a design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures, and pertains to the field of vehicle manufacturing technology. Background Technology

[0002] In automotive body structures, the thin-walled nature of the wall panels makes them susceptible to external excitations, causing low-frequency vibrations that radiate noise into the vehicle interior, resulting in a booming sound problem. To address this issue, the industry commonly employs three main noise reduction methods: First, using traditional asphalt-based damping or butyl rubber damping devices on the body panels. However, this method is effective at high frequencies but less so at mid- and low frequencies, and its damping performance is significantly affected by ambient temperature. Second, identifying design weaknesses in the early stages of automotive body design and incorporating reinforcing ribs or plates into the thin-walled structure. However, this method only transfers the resonant frequency of the thin-walled panels and cannot completely eliminate the frequency of external excitation sources, potentially leading to new noise problems. Third, using traditional dynamic vibration absorption devices on the body panels. This involves adding a special subsystem to the main vibration system to transfer the vibration energy of the main system to the additional subsystem, thereby reducing the vibration of the main system. However, this method is limited by installation space and requires significant compromises in terms of weight reduction and cost. Summary of the Invention

[0003] To address the aforementioned problems arising from actual noise generation, this invention provides a design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures. The specific technical solution is as follows:

[0004] A design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures includes:

[0005] S100, acquire noise data and vibration data of various body panels when the vehicle roars during operation, and confirm the target main frequency and target panel of the resonant noise reduction device.

[0006] S200, create a finite element model of the vehicle body and perform modal analysis to extract modal information of the target panel with a main vibration mode that is close to the target main frequency, and confirm the installation position and quality of the resonant noise reduction device;

[0007] S300, obtain the available space volume of the resonant noise reduction device structure;

[0008] S400 creates a simulation model of the resonant noise reduction device based on the target frequency of the resonant noise reduction and the available space volume.

[0009] Preferably, in step S100, the noise data during the booming sound and the vibration data of each panel of the vehicle body are obtained based on a vibration and noise testing method:

[0010] By arranging noise sensors inside the vehicle and vibration acceleration sensors on thin-walled panels of the vehicle body that may generate roaring noise, and by reading the vehicle engine speed signal, the vehicle noise time-domain signal and the vibration acceleration time-domain signal of each panel of the vehicle body when the roaring noise occurs are obtained by measuring the noise sensor and vibration acceleration sensor. Then, the vehicle engine speed signal is tracked by performing fast Fourier transform on each time-domain signal and obtaining the signal of the vehicle noise sound pressure and the vibration acceleration of each panel as a function of engine speed when the roaring noise occurs.

[0011] In the noise data, the engine excitation frequency corresponding to the maximum sound pressure level amplitude is the main frequency of the roaring noise. The main frequency of the roaring noise is the target main frequency of the resonant noise reduction device. The target main frequency is used to determine the modal frequency of the resonant noise reduction device.

[0012] When the roaring sound occurs, in the time-domain signal of the vibration acceleration of each panel of the vehicle body, at the target main frequency, the thin-walled plate corresponding to the maximum vibration acceleration amplitude is the target panel of the resonant noise reduction device. The target panel is used to determine the mounting plate of the resonant noise reduction device.

[0013] Preferably, in step S200, the vehicle body finite element model is created in Hypermesh, and then modal analysis is performed on the created vehicle body finite element model:

[0014] Extract the mode shape when the target main frequency is close and the main vibration mode position is consistent with the target panel position. The installation position of the resonant noise reduction device is near the position of the maximum displacement of the mode shape. At the same time, extract the modal mass of the mode shape. 0.1-0.2 times the modal mass is the mass of the resonant noise reduction device.

[0015] Preferably, in the modal analysis, the upper limit of the analysis frequency is 1.5-2 times the dominant frequency of the booming noise.

[0016] Preferably, the finite element model of the vehicle body includes the body-in-white, doors, front and rear windshields, and rearview mirrors, carpets, protective panels, and dashboard mounted on the body-in-white.

[0017] Preferably, the engine excitation frequency is calculated as follows:

[0018] f = n × i / (60 × 2);

[0019] In the formula, n is the engine speed and i is the number of engine cylinders.

[0020] Preferably, the available space volume for obtaining the resonant noise reduction device structure in S300 is:

[0021] The space at the installation location of the resonant noise reduction device is checked, and the distances between the surrounding components and the target panel in each direction are measured. Finally, the length, width, and height dimensions that can be used to arrange the resonant noise reduction device are determined, and the usable space volume is obtained.

[0022] Preferably, S400 includes:

[0023] S401, based on the working principle of dynamic vibration absorption, the simulation model of the resonant noise reduction device is simplified into a single-degree-of-freedom spring-mass system. The elastic stiffness part is simulated by a metal plate or beam structure, and the mass part is simulated by a counterweight structure.

[0024] S402, through design optimization, obtains the design parameters of each component in the simulation model of the resonant noise reduction device;

[0025] S403, after rounding the design parameters and substituting them into the simulation model of the resonant noise reduction device, calculate the first-order mode frequency of the simulation model of the resonant noise reduction device.

[0026] S404, determine whether the difference between the first-order modal frequency and the target main frequency of the resonant noise reduction device simulation model meets the preset conditions. If yes, the resonant noise reduction device simulation model is used as the design model of the resonant noise reduction device; if no, adjust the stiffness of the elastic part in the single-degree-of-freedom spring-mass system and repeat steps S402-S403.

[0027] Preferably, in step S402, the design is optimized as follows:

[0028] The three elements of optimization are defined. Design variables are established for the design parameters of each component in the simulation model of the resonant noise reduction device. The deviation between the modal frequency of the resonant noise reduction device and the main frequency of the roaring noise is used as the design constraint. The minimum quality of the simulation model of the resonant noise reduction device is used as the design objective. Combined with the optimization algorithm, optimization analysis is performed to obtain the design parameters of each component of the resonant noise reduction device.

[0029] Preferably, the design parameters include thickness, shape, and size.

[0030] The beneficial effects of this invention compared to the prior art are as follows:

[0031] The resonant noise reduction device in this invention can be made of thin metal sheets such as aluminum and iron, making it inexpensive. It can also be distributed, requiring minimal space.

[0032] The resonant noise reduction device in this invention achieves frequency-selective noise reduction by rationally designing the structural stiffness and mass based on the actual performance of the roaring sound in a vehicle. It is applicable to vibration reduction and noise reduction of all thin-walled panels of the automobile body and has high versatility.

[0033] The resonant noise reduction device in this invention uses an optimization algorithm to obtain design parameters, so that the structure can achieve lightweighting while ensuring functionality. It is scientific, effective, unaffected by the environment, and has high performance stability. Attached Figure Description

[0034] Figure 1 The process of this invention Figure 1 ;

[0035] Figure 2 The process of this invention Figure 2 ;

[0036] Figure 3 The spectrum of the RMS value of the in-vehicle noise without the resonant noise reduction device as a function of rotational speed according to the present invention. Figure 1 ;

[0037] Figure 4 The spectrum of the RMS value of the in-vehicle noise without the resonant noise reduction device as a function of rotational speed according to the present invention. Figure 2 ;

[0038] Figure 5 The present invention is a mode shape of the target panel with a frequency close to the target main frequency and a main vibration mode that is the target panel.

[0039] Figure 6 This is a schematic diagram of the resonant noise reduction device of the present invention, simplified as a single-degree-of-freedom spring-mass system. Figure 1 ;

[0040] Figure 7 This is a schematic diagram of the resonant noise reduction device of the present invention, simplified as a single-degree-of-freedom spring-mass system. Figure 2 ;

[0041] Figure 8 This is a diagram illustrating the optimization and iteration process of the resonant noise reduction device of the present invention.

[0042] Figure 9 This is a schematic structural diagram of the automobile body of the present invention;

[0043] Figure 10 This is a comparison chart of the simulated noise reduction effects of the present invention;

[0044] Figure 11 This is a comparison chart showing the noise reduction effect of the vehicle tested according to the invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] like Figure 1 As shown, a design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures includes:

[0048] S100, acquire noise data and vibration data of various body panels when the vehicle roars during operation, and confirm the target main frequency and target panel of the resonant noise reduction device.

[0049] S200, create a finite element model of the vehicle body and perform modal analysis to extract modal information of the target panel with a main vibration mode that is close to the target main frequency, and confirm the installation position and quality of the resonant noise reduction device;

[0050] S300, obtain the available space volume of the resonant noise reduction device structure;

[0051] S400 creates a simulation model of the resonant noise reduction device based on the target frequency of the resonant noise reduction and the available space volume.

[0052] In S100, the noise data during the booming sound and the vibration data of each panel of the vehicle body were obtained based on the vibration and noise test method:

[0053] By arranging noise sensors inside the vehicle and vibration acceleration sensors on thin-walled panels of the vehicle body that may generate roaring noise, and by reading the vehicle engine speed signal, the vehicle noise time-domain signal and the vibration acceleration time-domain signal of each panel of the vehicle body when the roaring noise occurs are obtained by measuring the noise sensor and vibration acceleration sensor. Then, the vehicle engine speed signal is tracked by performing fast Fourier transform on each time-domain signal and obtaining the signal of the vehicle noise sound pressure and the vibration acceleration of each panel as a function of engine speed when the roaring noise occurs.

[0054] In the noise data, the engine excitation frequency corresponding to the maximum sound pressure level amplitude is the main frequency of the roaring noise. The main frequency of the roaring noise is the target main frequency of the resonant noise reduction device. The target main frequency is used to determine the modal frequency of the resonant noise reduction device.

[0055] When the roaring sound occurs, in the time-domain signal of the vibration acceleration of each panel of the vehicle body, at the target main frequency, the thin-walled plate corresponding to the maximum vibration acceleration amplitude is the target panel of the resonant noise reduction device. The target panel is used to determine the mounting plate of the resonant noise reduction device.

[0056] In S200, the vehicle body finite element model is created in Hypermesh, and then modal analysis is performed on the created vehicle body finite element model:

[0057] Extract the mode shape when the target main frequency is close and the main vibration mode position is consistent with the target panel position. The installation position of the resonant noise reduction device is near the position of the maximum displacement of the mode shape. At the same time, extract the modal mass of the mode shape. 0.1-0.2 times the modal mass is the mass of the resonant noise reduction device.

[0058] The vehicle body structure is divided into units and each structure is assigned material properties. Sheet metal is simulated using shell elements, castings are simulated using solid elements, weld points and weld seams are simulated using spot and seam elements respectively, and components that do not provide stiffness, such as carpets, are simulated using lumped mass elements.

[0059] In modal analysis, the upper limit of the analysis frequency is 1.5-2 times the dominant frequency of the booming noise.

[0060] The finite element model of the vehicle body includes the body-in-white, doors, front and rear windshields, and rearview mirrors, carpets, protective panels, and dashboard mounted on the body-in-white.

[0061] The engine excitation frequency is calculated as follows:

[0062] f = n × i / (60 × 2);

[0063] In the formula, n is the engine speed and i is the number of engine cylinders.

[0064] The available space volume for obtaining the resonant noise reduction device structure in S300 is:

[0065] The space at the installation location of the resonant noise reduction device is checked, and the distances between the surrounding components and the target panel in each direction are measured. Finally, the length, width, and height dimensions that can be used to arrange the resonant noise reduction device are determined, and the usable space volume is obtained.

[0066] like Figure 2 As shown, S400 includes:

[0067] S401, based on the working principle of dynamic vibration absorption, the simulation model of the resonant noise reduction device is simplified into a single-degree-of-freedom spring-mass system. The elastic stiffness part is simulated by a metal plate or beam structure, and the mass part is simulated by a counterweight structure.

[0068] S402, through design optimization, obtains the design parameters of each component in the simulation model of the resonant noise reduction device;

[0069] S403, after rounding the design parameters and substituting them into the simulation model of the resonant noise reduction device, calculate the first-order mode frequency of the simulation model of the resonant noise reduction device.

[0070] S404, determine whether the difference between the first-order modal frequency and the target main frequency of the resonant noise reduction device simulation model meets the preset conditions. If yes, the resonant noise reduction device simulation model is used as the design model of the resonant noise reduction device; if no, adjust the stiffness of the elastic part in the single-degree-of-freedom spring-mass system and repeat steps S402-S403.

[0071] In S402, the design is optimized as follows:

[0072] The three elements of optimization are defined. Design variables are established for the design parameters of each component in the simulation model of the resonant noise reduction device. The deviation between the modal frequency of the resonant noise reduction device and the main frequency of the roaring noise is used as the design constraint. The minimum quality of the simulation model of the resonant noise reduction device is used as the design objective. Combined with the optimization algorithm, optimization analysis is performed to obtain the design parameters of each component of the resonant noise reduction device.

[0073] Design parameters include thickness, shape, and size.

[0074] Example 2

[0075] like Figure 3 As shown, Figure 3 The spectrum of in-vehicle noise sound pressure level varies with engine speed. The peak noise speed is 1160 rpm. The engine is a 4-cylinder engine, and the corresponding excitation frequency is 38.7 Hz. Therefore, the target main frequency of the resonant noise reduction device is 38.7 Hz.

[0076] like Figure 4 As shown, Figure 4 The image shows the RMS values ​​of the vibration signals located in the middle of the rear enclosure and the middle of the top enclosure as a function of engine speed. At the target main frequency of 38.7Hz, which corresponds to an engine speed of 1160 rpm, both the middle of the rear enclosure and the middle of the top enclosure show peak values ​​at this speed. However, the vibration acceleration value is the largest in the middle of the top enclosure. Therefore, the top enclosure wall panel is the target panel for the installation of the resonant noise reduction device.

[0077] Extract the mode shapes when the target's main frequency is close and the main vibration mode position coincides with the target panel position. The location near the maximum displacement of the mode shape is the installation position of the resonant noise reduction device. Simultaneously, extract the modal mass of this mode shape. 0.1-0.2 times the modal mass is the mass of the resonant noise reduction device. Figure 5 As shown, the frequency of this modal is 37Hz, which is close to the target main frequency of 38.7Hz. Furthermore, the main vibration mode is characterized by the unevenness of the top wall panel, consistent with the target panel. Therefore, the maximum displacement of this modal is the installation location of the resonant noise reduction device. The modal mass of this mode is 2.58Kg, and the total mass of the resonant noise reduction device is 0.258-0.516Kg.

[0078] like Figure 6-7As shown in S401, based on the working principle of dynamic vibration absorption, the simulation model of the resonant noise reduction device is simplified into a single-degree-of-freedom spring-mass system. The elastic stiffness part is simulated by a metal plate or beam structure, and the mass part is simulated by a counterweight structure.

[0079] A simplified single-degree-of-freedom spring-mass system is constructed from a metal base, a cantilever, and a counterweight. The cantilever and base are integrated, with a bend at the connection point to make the cantilever 10mm higher than the base. The cantilever is made of aluminum, and the counterweight is made of iron. The counterweight is attached to the cantilever by bolts or structural adhesive through a surface-to-surface connection. The cantilever simulates the elastic stiffness of the system, and the counterweight simulates the mass of the system.

[0080] like Figure 8 As shown in S402, the design parameters of each component of the simulation model of the resonant noise reduction device are obtained through design optimization.

[0081] Figure 8 To simplify the single-degree-of-freedom system, after 12 iterations, the component design dimensions that meet the design constraints and objectives were finally obtained. The final thickness of the base and cantilever was 1.409 mm, and the thickness of the counterweight was 2.000 mm. At this point, the first-order modal frequency of the system was 38.7 Hz. Meanwhile, the weight of the system was reduced from the initial 0.0948 kg to 0.0814 kg, achieving the goal of lightweighting.

[0082] In S403, the design parameters are rounded off and substituted into the simulation model of the resonant noise reduction device. The first-order modal frequencies of the simulation model of the resonant noise reduction device are then calculated, as shown in Table 1.

[0083]

[0084] Table 1

[0085] In Table 1, the rounded thickness values ​​of the base and counterweight are 1.4 mm and 2 mm, respectively. Using the rounded thickness information, the first-order modal frequency is calculated to be 38.3 Hz through simulation model.

[0086] In step S404, it is determined whether the difference between the first-order modal frequency of the simulation model of the resonant noise reduction device and the target dominant frequency meets the preset conditions. If yes, the simulation model of the resonant noise reduction device is used as the design model of the resonant noise reduction device; otherwise, the stiffness of the elastic part in the single-degree-of-freedom spring-mass system is adjusted, and steps S402-S403 are repeated until the difference between the first-order modal frequency of the simulation model and the target noise reduction frequency meets the preset conditions. As shown in Table 1, in this example, the first-order modal frequency of 38.3Hz of the final resonant noise reduction mechanism simulation model deviates from the target dominant frequency of 38.7Hz by 0.4Hz, which meets the preset conditions and meets the requirements for engineering use. This simulation model can be used as the design model of the resonant noise reduction device structure.

[0087] Example 3

[0088] In some embodiments of the present invention, the target device is a thin-walled panel of an automobile body. In use, the resonant noise reduction device is installed at a predetermined mounting position on the target panel for noise reduction. Specifically, as... Figure 9 As shown, the resonant noise reduction device is installed on the target panel using structural adhesive. Each resonant noise reduction device can serve as a base unit. Based on the aforementioned modal mass and the mass of a single resonant noise reduction device, the number of base units is determined to be four, arranged in a 2x2 array or distributed manner at the installation positions defined on the target panel. The final mass of the resonant noise reduction device used is 0.0814Kg*4=0.33Kg, which is significantly lighter than the 1~2Kg mass of traditional dynamic vibration absorbers.

[0089] In some embodiments of the present invention, such as Figures 10-11 As shown, comparing the noise signals inside the vehicle with and without the resonant noise reduction device, it can be seen that by installing the resonant noise reduction device, the simulation results show that the amplitude is reduced by about 6 dB(A) near the main frequency of the roaring sound, while the actual vehicle noise amplitude is reduced by about 4 dB(A) at the main frequency of the roaring sound.

Claims

1. A design method for a resonant noise reduction device targeting low-frequency booming noise in vehicle body structures, characterized in that, include: S100, acquire noise data and vibration data of various body panels when the vehicle roars during operation, and confirm the target main frequency and target panel of the resonant noise reduction device. S200, create a finite element model of the vehicle body and perform modal analysis to extract modal information of the target panel with a main vibration mode that is close to the target main frequency, and confirm the installation position and quality of the resonant noise reduction device; S300, obtain the available space volume of the resonant noise reduction device structure; S400 creates a simulation model of the resonant noise reduction device based on the target frequency of the resonant noise reduction and the available space volume.

2. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 1, characterized in that, In S100, the noise data during the booming sound and the vibration data of each panel of the vehicle body are obtained based on the vibration and noise test method: By arranging noise sensors inside the vehicle and vibration acceleration sensors on thin-walled panels of the vehicle body that may generate roaring noise, and by reading the vehicle engine speed signal, the vehicle noise time-domain signal and the vibration acceleration time-domain signal of each panel of the vehicle body when the roaring noise occurs are obtained by measuring the noise sensor and vibration acceleration sensor. Then, the vehicle engine speed signal is tracked by performing fast Fourier transform on each time-domain signal and obtaining the signal of the vehicle noise sound pressure and the vibration acceleration of each panel as a function of engine speed when the roaring noise occurs. In the noise data, the engine excitation frequency corresponding to the maximum sound pressure level amplitude is the main frequency of the roaring noise. The main frequency of the roaring noise is the target main frequency of the resonant noise reduction device. The target main frequency is used to determine the modal frequency of the resonant noise reduction device. When the roaring sound occurs, in the time-domain signal of the vibration acceleration of each panel of the vehicle body, at the target main frequency, the thin-walled plate corresponding to the maximum vibration acceleration amplitude is the target panel of the resonant noise reduction device. The target panel is used to determine the mounting plate of the resonant noise reduction device.

3. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 1, characterized in that, In S200, the vehicle body finite element model is created in Hypermesh, and then modal analysis is performed on the created vehicle body finite element model: Extract the mode shape when the target main frequency is close and the main vibration mode position is consistent with the target panel position. The installation position of the resonant noise reduction device is near the position of the maximum displacement of the mode shape. At the same time, extract the modal mass of the mode shape. 0.1-0.2 times the modal mass is the mass of the resonant noise reduction device.

4. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 3, characterized in that, In the modal analysis, the upper limit of the analysis frequency is 1.5-2 times the dominant frequency of the booming noise.

5. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 3, characterized in that, The finite element model of the vehicle body includes the body-in-white, doors, front and rear windshields, and rearview mirrors, carpets, protective panels, and dashboard installed on the body-in-white.

6. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 2, characterized in that, The engine excitation frequency is calculated as follows: f = n × i / (60 × 2); In the formula, n is the engine speed and i is the number of engine cylinders.

7. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 1, characterized in that, The available space volume for obtaining the resonant noise reduction device structure in S300 is: The space at the installation location of the resonant noise reduction device is checked, and the distances between the surrounding components and the target panel in each direction are measured. Finally, the length, width, and height dimensions that can be used to arrange the resonant noise reduction device are determined, and the usable space volume is obtained.

8. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 1, characterized in that, The S400 includes: S401, based on the working principle of dynamic vibration absorption, the simulation model of the resonant noise reduction device is simplified into a single-degree-of-freedom spring-mass system. The elastic stiffness part is simulated by a metal plate or beam structure, and the mass part is simulated by a counterweight structure. S402, through design optimization, obtains the design parameters of each component in the simulation model of the resonant noise reduction device; S403, after rounding the design parameters and substituting them into the simulation model of the resonant noise reduction device, calculate the first-order mode frequency of the simulation model of the resonant noise reduction device. S404, determine whether the difference between the first-order modal frequency and the target main frequency of the resonant noise reduction device simulation model meets the preset conditions. If yes, the resonant noise reduction device simulation model is used as the design model of the resonant noise reduction device; if no, adjust the stiffness of the elastic part in the single-degree-of-freedom spring-mass system and repeat steps S402-S403.

9. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 8, characterized in that, In S402, the design is optimized as follows: The three elements of optimization are defined. Design variables are established for the design parameters of each component in the simulation model of the resonant noise reduction device. The deviation between the modal frequency of the resonant noise reduction device and the main frequency of the roaring noise is used as the design constraint. The minimum quality of the simulation model of the resonant noise reduction device is used as the design objective. Combined with the optimization algorithm, optimization analysis is performed to obtain the design parameters of each component of the resonant noise reduction device.

10. The design method for a resonant noise reduction device for low-frequency booming noise in vehicle body structure according to claim 9, characterized in that, The design parameters include thickness, shape, and size.

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