Analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function

Abstract

The present invention discloses an analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function, comprising the following steps: establishing a simplified acoustic cavity model proportional to the size of a vehicle body, wherein the simplified acoustic cavity model simulates the instrument panel acoustic cavity with a small acoustic cavity and simulates the cockpit with a large acoustic cavity, and a gap is provided between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system; calculating the acoustic transfer function ATF from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point; simulating and analyzing the effect of the gap width, length, depth, and resonant cavity changes on the ATF. The present invention analyzes and verifies the effect of the gap width, gap depth, gap length, and resonant cavity volume on the acoustic transfer function in the Helmholtz resonance system, and improves the modal frequency accuracy of the system and the accuracy of the noise transfer function during modeling.

Description

Technical Field

[0001] The invention relates to the field of automobile development, and in particular to an analysis and modeling method for reproducing the influence of a sound cavity gap on a sound transfer function. Background Art

[0002] The vehicle body is a response system to all stimuli and a key control link. The vibration and noise performance (NVH) of the vehicle body is mainly evaluated through the noise transfer function index. In the early stage of project development, the noise transfer function (NTF) is currently mainly predicted by simulation analysis. However, since the acoustic-vibration coupling involves the multi-physics coupling of the structure and the flow field, the problem is complex and there are many influencing factors, and the accuracy of the simulation analysis has not been effectively improved. The gap between the sound field formed by the envelope of the interior decoration such as the dashboard and the sheet metal structure and the sound field of the cockpit has a greater impact on NTF. When performing simulation analysis, it is necessary to consider the impact of the connection gap between the sound cavities and the impact of the system they constitute.

[0003] Traditional acoustic cavity modeling methods do not consider connectivity at gaps or only transmit node displacement information through common node connections. Existing patents mainly focus on macroscopic body panel contribution analysis methods to NTF and optimization methods based on contribution analysis, such as first performing contribution analysis through simulation, and then knowing structural optimization through simulation, but they focus on contribution analysis and structural optimization, and do not focus on modeling details; for example, by decomposing the transfer function path, the noise transfer function is decomposed into the vibration transfer function from the attachment point to the panel and the noise transfer function from the panel to the human ear, and the main contribution path is determined according to the peak correspondence to guide the optimization of the actual vehicle, but they focus on contribution analysis, and are actually carried out through experiments, without involving modeling and simulation, and the scheme is complex and the accuracy is not high. Summary of the invention

[0004] The main purpose of the present invention is to provide an analysis and modeling method and system for reproducing the influence of acoustic cavity gap on acoustic transfer function, which has a simple solution and can improve the simulation accuracy of acoustic transfer function.

[0005] The technical solution adopted by the present invention is:

[0006] Provided is an analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function, comprising the following steps:

[0007] A simplified acoustic cavity model proportional to the size of the vehicle body is established. The simplified acoustic cavity model uses a small acoustic cavity to simulate the acoustic cavity of the instrument panel, and a large acoustic cavity to simulate the cockpit. A gap is set between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system.

[0008] Calculate the acoustic transfer function (ATF) from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point;

[0009] Simulate and analyze the impact of changes in gap width, length, and depth on ATF.

[0010] Following the above technical solution, when simulating and analyzing the effect of gap width change on ATF, the effect on ATF under different gap widths is simulated and analyzed with other conditions unchanged; for cockpit front excitation-cabin rear ATF response, as the gap becomes wider, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for instrument panel cabin excitation-cabin rear ATF response, the ATF increases as the gap width increases.

[0011] Following the above technical solution, when simulating and analyzing the effect of the change in gap length on ATF, the effect on ATF under different gap lengths is simulated and analyzed with other conditions unchanged; for the front part of the cockpit excitation-the rear part of the cockpit ATF response, as the gap becomes longer, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for the instrument panel cabin excitation-the rear part of the cockpit ATF response, the ATF increases as the length of the gap increases.

[0012] Following the above technical solution, when simulating and analyzing the effect of the change in gap depth on ATF, the effect on ATF at different gap depths is simulated and analyzed while other conditions remain unchanged; for the cockpit front excitation-cockpit rear ATF response, the change in gap depth has little effect on it; for the instrument panel cabin excitation-cockpit rear ATF response, ATF decreases as the depth of the gap increases.

[0013] Following the above technical solution, when simulating and analyzing the impact of the change in the resonant cavity volume on the ATF, the impact on the ATF under different instrument panel cavity volumes is simulated and analyzed when other conditions remain unchanged; for the front of the cockpit excitation-the rear of the cockpit ATF response, the change in the resonant cavity volume has little effect on it; for the instrument panel cabin excitation-the rear of the cockpit ATF response, the ATF decreases with the increase of the resonant cavity volume.

[0014] Following the above technical solution, the analysis of the simplified acoustic cavity model is applied to the simulation analysis of the noise transfer function of the real vehicle. Specifically, the gaps of the real vehicle are added to the simulation model, and the width, length and depth of different gaps are changed, and the influence on the noise transfer function is simulated and analyzed respectively.

[0015] The present invention also provides an analysis and modeling system for reproducing the effect of acoustic cavity gap on acoustic transfer function, comprising the following steps:

[0016] A simplified acoustic cavity model building module is used to build a simplified acoustic cavity model that is proportional to the size of the vehicle body. The simplified acoustic cavity model uses a small acoustic cavity to simulate the acoustic cavity of the instrument panel, and a large acoustic cavity to simulate the cockpit. A gap is provided between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system.

[0017] Construct an ATF function module to calculate the acoustic transfer function (ATF) from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point;

[0018] The simulation module is used to simulate and analyze the impact of changes in gap width, length, and depth on ATF.

[0019] Following the above technical solution, when the simulation module simulates and analyzes the impact of the change in gap width on ATF, it simulates and analyzes the impact on ATF under different gap widths when other conditions remain unchanged; for the front of the cockpit excitation-the rear of the cockpit ATF response, as the gap becomes wider, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for the instrument panel cabin excitation-the rear of the cockpit ATF response, the ATF increases as the width of the gap increases.

[0020] Following the above technical solution, when the simulation module simulates and analyzes the impact of the change in gap length on ATF, it simulates and analyzes the impact on ATF under different gap lengths when other conditions remain unchanged; for the front of the cockpit excitation-the rear of the cockpit ATF response, as the gap becomes longer, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for the instrument panel cabin excitation-the rear of the cockpit ATF response, the ATF increases as the length of the gap increases.

[0021] Following the above technical solution, when the simulation module simulates and analyzes the impact of changes in gap depth on ATF, the simulation module simulates and analyzes the impact on ATF at different gap depths while keeping other conditions unchanged; for the front cockpit excitation-rear cockpit ATF response, the change in gap depth has little effect on it; for the instrument panel cabin excitation-rear cockpit ATF response, ATF decreases as the depth of the gap increases.

[0022] The present invention also provides a computer storage medium, which stores a computer program that can be executed by a processor, and the computer program executes the analysis and modeling method for reproducing the influence of the acoustic cavity gap on the acoustic transfer function described in the above technical solution.

[0023] The beneficial effects of the present invention are as follows: the present invention establishes a simplified acoustic cavity model of a Helmholtz resonance system close to the volume of an actual vehicle acoustic cavity, analyzes and verifies the influence of the gap width, gap depth, gap length and resonance cavity volume in the Helmholtz resonance system, and clarifies that the key factors of gap modeling are the gap width, gap depth, gap length and resonance cavity volume. The present invention also clarifies the influence mechanism and basic influence rules of the existence of the gap through analysis and simulation, and clarifies the key parameter acquisition method of the acoustic cavity gap in the actual vehicle model, the simulation method, and the connection modeling method between the gap model and the two side cavities.

[0024] Further combined with the actual vehicle status, the influence of the existence of gaps on the acoustic cavity mode and acoustic transfer function, as well as the influence on the noise transfer function NTF are derived. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 It is a simplified illustration of the infinite volume Helmholtz resonance system theory;

[0027] Figure 2 It is a simplified illustration of the theory of a finite volume single degree of freedom Helmholtz resonance system;

[0028] Figure 3 It is a simplified diagram of the theory of a finite volume two-degree-of-freedom Helmholtz resonance system;

[0029] Figure 4 It is a simplified model of the vehicle type and a schematic diagram of the ATF path;

[0030] Figure 5 It is a schematic diagram of the effect of the change of gap width on ATF;

[0031] Figure 6 It is a schematic diagram of the effect of the change of gap length on ATF;

[0032] Figure 7 It is a schematic diagram of the effect of the change of gap depth on ATF;

[0033] Figure 8 It is a schematic diagram of the effect of the change of the resonant cavity volume on the ATF;

[0034] Fig. 9 It is a flow chart of the analysis and modeling method for reproducing the effect of the acoustic cavity gap on the acoustic transfer function according to an embodiment of the present invention;

[0035] Figure 10(a)-Figure 10(d) This is a schematic diagram of the vibration state of the Helmholtz system simulation reproduction model according to the embodiment of the present invention. Figure 1 ;

[0036] Figure 11(a)-Figure 11(d) This is a schematic diagram of the vibration state of the Helmholtz system simulation reproduction model according to the embodiment of the present invention. Figure 2 ;

[0037] Fig.12 It is a schematic diagram of error analysis of a simulation reproduction model of a Helmholtz system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] The present invention analyzes and derives the action mechanism of the gap as follows:

[0040] Taking the Z-direction of the rear mounting point of the front bracket - the main driver's ear point NTF as an example, the transmission path analysis is carried out. After the excitation point is struck, the vibration of the excitation point is transmitted to each panel of the vehicle body. Since the excitation point is located at the front and there are large panels such as the front panel at the front, the energy causes vibration in the panels such as the front panel, thereby compressing the sound cavity and causing the sound pressure of the instrument panel sound cavity to change. The change in sound pressure is transmitted to the cavity inside the car through the gaps and openings on the instrument panel. The gap is an important transmission path for the change in sound pressure, which is characterized by the fact that the sound pressure change encounters a suddenly narrowed gap during the transmission process, and then is transmitted to the larger volume of the cockpit sound field through the gap. This is very similar to the Helmholtz resonance system in a finite volume.

[0041] The role of the gap is equivalent to the head and neck in the Helmholtz resonance system, and the instrument panel sound cavity is equivalent to the resonant cavity. Because the volumes of the two are relatively large, the cockpit is equivalent to a finite volume cavity close to the opening. The model of the Helmholtz resonance system is theoretically derived, and the formula for the typical connection type of the actual vehicle is derived.

[0042] According to the Helmholtz resonance system model, combined with the connection state between the cavities of the actual vehicle, the typical formula of the Helmholtz resonance system is 1: infinite volume single degree of freedom system = classic opening model. Figure 1 As shown, the theoretical formula is derived as follows:

[0043]

[0044] From acoustics we know With correction factor

[0045] and

[0046]

[0047] If V changes very little and S remains unchanged, then dA / dx = 0, dV = -Adx, V = V0

[0048]

[0049] Finite volume single degree of freedom system, such as the attached Figure 2 As shown in the figure, the finite volume single degree of freedom system is the most common connection state between cavities in a real car. Its resonant frequency is derived as follows:

[0050] When V1=V2, the equivalent stiffness Then the resonant frequency f=√2f 自由场 ;

[0051] When V1 and V2 are arbitrary volumes, the equivalent stiffness The resonance frequency f 自由场 ;

[0052] When V2>>V1, the resonance frequency = f 自由场 ;

[0053] In the above formula, CONSTANT is a constant.

[0054] A two-degree-of-freedom system with equal stiffness and mass, as shown in the attached Figure 3 As shown, in a two-degree-of-freedom system with equal stiffness and mass, one of the frequency solutions is equal to the frequency solution of a single degree of freedom of infinite volume, that is,

[0055] f1=f 自由场 , another solution is f2=√3f 自由场 This model helps us verify whether the simulation model complies with the Helmholtz resonance system in the finite element model.

[0056] Secondly, the present invention establishes a simplified model to verify the simulatability of the Helmholtz resonance system in the finite element simulation analysis model, as shown in Appendix 1.

[0057] A finite element model of an acoustic cavity with a volume of 1m*1m*1m is established. Through calculation, it can be obtained that its first-order acoustic cavity mode is 170Hz. According to the theoretical statement of the acoustic cavity mode, f=C / 2L, the simulation is consistent with the theory.

[0058] In the finite element model, the resonance frequency,

[0059] By establishing a two-degree-of-freedom system model of equal volume, the resonant frequency of the single-degree-of-freedom system with the same resonant cavity volume is obtained, and the infinite volume is verified to verify the reproduction of the Helmholtz resonance system in the finite element model.

[0060] When the volume of the acoustic cavity is large enough, its resonant frequency is close to the first-order modal frequency of the two-degree-of-freedom system.

[0061] Appendix 1 Helmholtz system simulation reproduction model and results

[0062]

[0063] Secondly, a simplified acoustic cavity model with the same size as the vehicle body is established, with a small acoustic cavity simulating the instrument panel acoustic cavity and a large acoustic cavity simulating the cockpit. The volume ratio is close to 1:11, which is very close to the actual vehicle. The acoustic transfer function (ATF) from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point is calculated, as shown in the attached figure. Figure 4 shown.

[0064] Based on the above analysis and derivation principles, the embodiment of the present invention provides an analysis and modeling method for reproducing the effect of the acoustic cavity gap on the acoustic transfer function, such as Fig. 9 As shown, it mainly includes the following steps:

[0065] S1. Establish a simplified acoustic cavity model that is proportional to the size of the vehicle body. The simplified acoustic cavity model uses a small acoustic cavity to simulate the acoustic cavity of the instrument panel, and a large acoustic cavity to simulate the cockpit. A gap is set between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system.

[0066] S2, calculate the acoustic transfer function ATF from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point;

[0067] S3. Simulate and analyze the impact of changes in gap width, length, depth, and resonant cavity on ATF.

[0068] When studying the effect of the change in gap width on ATF, a set of gap width variables are designed with other conditions unchanged, and the effect of ATF under different widths is simulated and analyzed.

[0069] As attached Figure 5 As shown in the figure, for the cockpit front excitation - cockpit rear ATF response, as the gap becomes wider, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases with the increase of the gap; it can be obtained that when the gap width is small enough, its resonance frequency is far away from the first-order modal frequency of the cockpit, and the effect on the acoustic transfer function inside the cockpit is very small and can be ignored; while for the acoustic transfer function from the instrument panel to the cockpit, the gap width is very sensitive.

[0070] When studying the effect of gap length, Figure 6As shown in the figure, for the cockpit front excitation-cockpit rear ATF response, as the gap becomes longer, when the resonant frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases with the increase of the gap; for the instrument panel cabin excitation-cockpit rear ATF response, the ATF increases with the increase of the gap length; it can be obtained that when the gap length is small enough, its resonant frequency is far away from the first-order modal frequency of the cockpit, and the effect on the acoustic transfer function inside the cockpit is very small and can be ignored. When the resonant frequency is close to the main cabin mode, the effect is greater; and for the acoustic transfer function from the instrument panel cabin to the cockpit, the gap length is very sensitive.

[0071] When studying the effect of gap depth, Figure 7 As shown in the figure, for the cockpit front excitation-cockpit rear ATF response, the change of gap depth has little effect on it; for the instrument panel cabin excitation-cockpit rear ATF response, the ATF decreases with the increase of gap depth; it can be concluded that the change of gap depth has very little effect on the acoustic transfer function of the cockpit and can be ignored; while for the acoustic transfer function from the instrument panel cabin to the cockpit, the gap length is very sensitive and needs to be considered.

[0072] When studying the influence of the instrument panel cavity, if the Figure 8 As shown. The left side is the ATF response of the cockpit front excitation-cockpit rear, and the right side is the ATF response of the instrument panel cabin excitation-cockpit rear. For the cockpit front excitation-cockpit rear ATF response, the change of the resonant cavity volume has little effect on it; for the instrument panel cabin excitation-cockpit rear ATF response, the ATF decreases with the increase of the resonant cavity volume; it can be obtained that the resonant cavity volume has a very small effect on the acoustic transfer function of the cockpit and can be ignored; and for the acoustic transfer function from the instrument panel cabin to the cockpit, the resonant cavity volume is very sensitive. In the actual vehicle state, there are multiple cavities such as the instrument panel cavity and the auxiliary instrument panel cavity that may be connected to the cockpit through gaps. When modeling, it is necessary to ensure that the volume of these cavities is accurate.

[0073] The in-car acoustic transfer function (ATF) characterizes the transfer characteristics of the in-car sound field, while the noise transfer function (NTF) combines the transfer characteristics of the structural field, the coupling characteristics of the structure and the sound field, and the transfer characteristics of the in-car sound cavity; the change trend of the NTF can be evaluated by the change trend of the ATF of the in-car sound field. Therefore, the research conclusions of the simplified model can also be applied to the simulation analysis of the noise transfer function of the real vehicle. The main parts of the body that have gap connections with the cabin cavity are: the main instrument panel, the auxiliary instrument panel, the ceiling, the door, and the trunk. Each of these cavities is coupled with the structural parts of the body, including interior parts and sheet metal parts. Inevitably, when excitation is generated at the suspension and suspension excitation points, there will always be vibration energy that first responds through these cavities and then is transmitted to the cabin ear point through the cavity. From this perspective, the gap connection between the sound cavities is very important, and a large part of the cabin response and the body structure is indirectly transmitted through other cavities. The modeling method of the gap can be fluid modeling, with the attribute of air, and the connection unit between the gap and the cavity is called MPC. Therefore, in the real car model, there are many types of connection models similar to the simplified Helmholtz system (determined by the location of the gap). For example, the gap between the instrument panel sound cavity and the cockpit mainly exists in the assembly gap between the various components on the instrument panel; the gap between the ceiling sound cavity and the cockpit mainly exists in the assembly gap between the ceiling and the top cover and the assembly gap around the sunroof; the gap between the trunk and the cockpit in a three-box car mainly exists in the trumpet and vent; the gap between the door sound cavity and the cockpit mainly exists in the assembly gap between the various components of the door guard plate and between it and the door inner panel.

[0074] From the principle analysis of the simplified model, it can be seen that the key parameters affecting the transfer function of the Helmholtz resonance system are: gap length L, gap width W, gap depth D and the volume of the resonant cavity V. The accuracy of modeling these key parameters has a great influence on the accuracy of the noise transfer function.

[0075] The following uses the modeling of the instrument panel acoustic cavity and the cockpit acoustic cavity as an example to illustrate the specific implementation of the method of the present invention.

[0076] The analysis and modeling method for reproducing the effect of the acoustic cavity gap on the noise transfer function in the embodiment of the present invention mainly includes the following steps:

[0077] The W, D, L and V data of the gaps on the instrument panel can be obtained through the BOM table and the gap flushness data. Finite element modeling is performed on these gaps, and the unit built is a 3D fluid unit with air attributes.

[0078] Considering the connection between the gap and the acoustic cavities on both sides, generally, the grid size of the acoustic cavity models on both sides is between 30-50mm, while the size of the gap is between 0.5-2mm. The size difference between the two is very large, and they cannot be connected through a common node. An equivalent connection method must be considered. It has been verified that the MPC unit connection and the common node connection have exactly the same effect and can be replaced with each other. Compared with the common node connection, the MPC unit does not require a one-to-one correspondence. It only needs to consider searching for connection within a certain tolerance range, which is more efficient.

[0079] The MPC unit is used to connect the gap unit, the instrument panel acoustic cavity model and the cockpit model to form a Helmholtz resonance system. For the volume V, it is necessary to consider the space occupied by the HAVC (air conditioning system) in the instrument panel acoustic cavity. When modeling, its volume is removed to ensure the accuracy of V.

[0080] Based on the experiment, the traditional common node modeling method and the modeling method considering gaps are compared. Compared with the traditional modeling method, the modeling method considering gaps has higher modal frequency accuracy and noise transfer function (NTF) accuracy.

[0081] The method for reproducing the effect of the acoustic cavity gap on the acoustic transfer function in the embodiment of the present invention is summarized as follows:

[0082] Firstly, according to the transmission path of vibration and sound of the actual vehicle and combined with the Helmholtz resonance system theory, the influence of the gap is simulated and analyzed by the Helmholtz resonance system.

[0083] Secondly, based on the configuration of small sound cavity-gap-large sound cavity of the actual vehicle, a typical simplified theoretical model of Helmholtz resonance system including gap is derived.

[0084] Again, a simplified model is established and it is verified that the finite element model can accurately reproduce the Helmholtz resonance system.

[0085] Next, a simplified model close to the volume ratio of the actual vehicle was established, and the key parameters of gap modeling, including width, length, depth, resonant cavity volume and their influence, were clarified.

[0086] Finally, the above rules are applied to the real vehicle model. Taking the instrument panel acoustic cavity as an example, the gap is simulated by fluid grid, and the MPC unit is used as the connection between the gap and the two side cavities to establish a real vehicle simulation model. The effectiveness of the method is verified through experimental benchmarking and benchmarking with traditional methods.

[0087] In summary, through analysis and modeling methods, the present invention knows that the key factors affecting the acoustic cavity gap on the acoustic cavity mode and the acoustic transfer function are: gap width, gap length, gap depth, and resonant cavity volume; in addition, the existence of the gap adds a first-order mode to the system, and accordingly, changes the distribution of the sound field, thereby causing the acoustic transfer function to change. This change has a great impact on the resonant cavity-main cavity path, and the impact on the internal path of the main cavity depends on the resonant frequency. When the resonant frequency is far away from the mode of the main cavity, the impact is very small, and when the resonant frequency is close to the main cavity mode, there is a certain impact.

[0088] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. An analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function, characterized in that: The following steps are involved: A simplified acoustic cavity model proportional to the size of the vehicle body is established. The simplified acoustic cavity model uses a small acoustic cavity to simulate the acoustic cavity of the instrument panel, and a large acoustic cavity to simulate the cockpit. A gap is set between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system. Calculate the acoustic transfer function (ATF) from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point; The simulation analyzes the impact of changes in gap width, length, depth, and resonant cavity on ATF.

2. The analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 1, characterized in that: When simulating and analyzing the effect of gap width change on ATF, the effect of different gap widths on ATF is simulated and analyzed with other conditions unchanged; for cockpit front excitation-cabin rear ATF response, as the gap becomes wider, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for instrument panel cabin excitation-cabin rear ATF response, the ATF increases as the gap width increases.

3. The analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 1, characterized in that: When simulating and analyzing the effect of gap length change on ATF, the effect on ATF under different gap lengths is simulated and analyzed with other conditions unchanged; for cockpit front excitation-cabin rear ATF response, as the gap becomes longer, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for instrument panel cabin excitation-cabin rear ATF response, the ATF increases as the gap length increases.

4. The analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 1, characterized in that: When simulating and analyzing the effect of the change in gap depth on ATF, the effect on ATF at different gap depths is simulated and analyzed with other conditions unchanged; for the cockpit front excitation-cockpit rear ATF response, the change in gap depth has little effect on it; for the instrument panel cabin excitation-cockpit rear ATF response, ATF decreases as the gap depth increases.

5. The analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 1, characterized in that: When simulating and analyzing the effect of changes in the resonant cavity volume on ATF, the simulation analysis is conducted on the effect on ATF under different instrument panel cavity volumes while other conditions remain unchanged; for cockpit front excitation-cabin rear ATF response, the change in the resonant cavity volume has little effect on it; for instrument panel cabin excitation-cabin rear ATF response, ATF decreases as the resonant cavity volume increases.

6. The analysis and modeling method for reproducing the effect of acoustic cavity gap on acoustic transfer function according to any one of claims 1 to 5, characterized in that: The analysis of the simplified acoustic cavity model is applied to the simulation analysis of the noise transfer function of a real vehicle. Specifically, the gaps of the real vehicle are added to the simulation model, and the width, length and depth of different gaps are changed, and the impact on the noise transfer function is simulated and analyzed respectively.

7. An analysis and modeling system for reproducing the effect of acoustic cavity gap on acoustic transfer function, characterized in that: The following steps are involved: A simplified acoustic cavity model building module is used to build a simplified acoustic cavity model that is proportional to the size of the vehicle body. The simplified acoustic cavity model uses a small acoustic cavity to simulate the acoustic cavity of the instrument panel, and a large acoustic cavity to simulate the cockpit. A gap is provided between the small acoustic cavity and the large acoustic cavity, and the simplified acoustic cavity model is a verified Helmholtz resonance system. Construct an ATF function module to calculate the acoustic transfer function (ATF) from the instrument panel acoustic cavity excitation point and the cockpit front excitation point to the cockpit rear response point; The simulation module is used to simulate and analyze the impact of changes in gap width, length, and depth on ATF.

8. The analysis and modeling system for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 7, characterized in that: When the simulation module simulates and analyzes the impact of gap width changes on ATF, it simulates and analyzes the impact on ATF under different gap widths when other conditions remain unchanged; for the front of the cockpit excitation-the rear of the cockpit ATF response, as the gap becomes wider, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for the instrument panel cabin excitation-the rear of the cockpit ATF response, the ATF increases as the width of the gap increases.

9. The analysis and modeling system for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 7, characterized in that: When the simulation module simulates and analyzes the impact of gap length changes on ATF, it simulates and analyzes the impact on ATF under different gap lengths when other conditions remain unchanged; for the front of the cockpit excitation-the rear of the cockpit ATF response, as the gap becomes longer, when the resonance frequency is close to the first-order modal frequency region of the cockpit, the ATF decreases as the gap increases; for the instrument panel cabin excitation-the rear of the cockpit ATF response, the ATF increases as the length of the gap increases.

10. The analysis and modeling system for reproducing the effect of acoustic cavity gap on acoustic transfer function according to claim 7, characterized in that: When the simulation module simulates and analyzes the impact of changes in gap depth on ATF, the simulation module analyzes the impact on ATF at different gap depths while keeping other conditions unchanged; for the front cockpit excitation-rear cockpit ATF response, the change in gap depth has little effect on it; for the instrument panel cabin excitation-rear cockpit ATF response, ATF decreases as the depth of the gap increases.

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