An analysis method for separating vehicle structure vibration based on the acceleration transmission path

Abstract

The present invention discloses an analysis method for separating vehicle structure vibration based on an acceleration transfer path, which method includes: establishing a transfer path analysis model of the vehicle; conducting tests and deriving and calculating a transfer function between the acceleration on the body side of the mount bushing and the acceleration of the body response point; under the vehicle operating conditions, obtaining the acceleration spectra of each mount bushing on the body side and calculating the acceleration transmitted by each transfer path; synthesizing the acceleration of the body response point under the vehicle operating conditions and the contribution amounts of the vibration transmitted by each path. By experimentally deriving the acceleration-acceleration transfer function of each path from the body side of the mount bushing to the body response point, and then combining with the vibration acceleration data of the body side of the mount bushing under any vehicle operating conditions, transfer path analysis can be carried out, which has technical advantages such as high efficiency and low cost. At the same time, it is proposed to use the acceleration-acceleration transfer function from the excitation point to the response point for TPA analysis, enriching the TPA technology.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle vibration transfer path analysis, and particularly relates to an analysis method for separating vehicle structure vibration based on acceleration transfer path. Background Art

[0002] During the operation of a vehicle, engine excitation and road surface excitation are transmitted to the vehicle body structure through paths such as mounts - suspensions, causing the vehicle body structure (steering wheel, seat, floor, etc.) to be forced to vibrate. This is a typical multi - excitation - multi - path vibration coupling transmission process. If the vibration transmission design or matching of the path is unreasonable, the vehicle vibration will be perceived by the driver, seriously affecting the vehicle quality.

[0003] Transfer Path Analysis (TPA for short), for example: classical TPA. This technology can study the magnitude of vibration transmitted by each path and its contribution to the total vibration, and has the technical advantages of locating and identifying key paths from complex vibration coupling transmissions, guiding the provision of targeted improvement directions, etc., and is widely used in the field of vehicle vibration and noise. However, the classical TPA technology is time - consuming and resource - demanding in use. (1) It is necessary to arrange a large number of vibration sensors, conduct a large number of vibration transfer function tests, and obtain the dynamic stiffness parameters of the bushings at key positions (mounts, suspensions). It takes about three weeks from the planning to the completion of a single TPA test. If it is an NVH problem analysis and troubleshooting test, it takes even longer. The classical TPA technology does not adapt to the development cycle of modern vehicles; (2) In addition to the commonly used NVH test equipment, the dynamic stiffness parameters of the bushings are also required to calculate the equivalent force of the excitation source at the mounts. The dynamic stiffness parameters of the bushings are related to the excitation frequency, excitation amplitude, and pre - load magnitude, and corresponding test methods need to be formulated according to the force characteristics of the bushings under the vehicle operating conditions. The acquisition of the dynamic stiffness parameters of the bushings is laborious, inconvenient, and costly. The foreign supplier's quotation for a two - way pre - load dynamic stiffness device with a test frequency within 200 Hz is as high as more than 4 million, and many vehicle manufacturers do not have the equipment to test the dynamic stiffness of bushings. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an analysis method for separating vehicle structure vibration based on acceleration transfer path, with a fast, efficient, and novel analysis process.

[0005] To solve the above - mentioned technical problem, the present invention provides an analysis method for separating vehicle structure vibration based on acceleration transfer path, including the following steps:

[0006] Step 1: Taking the vehicle engine as the vibration source, the engine mount bushing as the transfer path, and the vehicle body as the receiver, establish the transfer path analysis model of the vehicle;

[0007] Step 2: Conduct tests and derive and calculate the acceleration \(a\) of the body side of the mounting bushing i \(a(\omega)\) of the body response point 12_i The acceleration-acceleration transfer function \(ATF(\omega)\) between i \(a(\omega)\), where \(i\) is the path number and \(\omega\) is the angular frequency;

[0008] Step 3: Under the vehicle operating conditions, obtain the acceleration \(a(\omega)\) of the body side of each of the mounting bushings, and calculate the acceleration \(a(\omega)\) transmitted by each of the transfer paths according to the acceleration-acceleration transfer function \(ATF(\omega)\) and the acceleration \(a(\omega)\) of the body side of the mounting bushing; b_i \(a(\omega)\), and according to the acceleration-acceleration transfer function \(ATF(\omega)\) and the acceleration \(a(\omega)\) of the body side of the mounting bushing i \(a(\omega)\) and calculate the acceleration \(a(\omega)\) transmitted by each of the transfer paths b_i \(a(\omega)\); p_i (\omega);

[0009] Step 4: According to the acceleration \(a(\omega)\) transmitted by each of the transfer paths, calculate the acceleration \(a(\omega)\) of the body response point and the contribution \(a(\omega)\) of each of the transfer paths under the vehicle operating conditions. p_i \(a(\omega)\), calculate the acceleration \(a(\omega)\) of the body response point and the contribution \(a(\omega)\) of each of the transfer paths c \(a(\omega)\) under the vehicle operating conditions con_i (\omega).

[0010] In the above analysis method for separating vehicle structure vibration based on the acceleration transfer path, the acceleration-acceleration transfer function on each path from the body side (i.e., the hammering point) of the mounting bushing to the body response point is derived through tests, and then combined with the vibration acceleration data of the body side of the mounting bushing under any vehicle operating conditions, the transfer path analysis can be carried out. There is no need to use the dynamic stiffness parameter of the engine mounting bushing to obtain the equivalent force at the mounting bushing, saving the complex calculation process, and having technical advantages such as high efficiency and low cost. At the same time, the acceleration-acceleration transfer function from the excitation point to the response point is proposed for TPA analysis and the theoretical derivation is given, enriching the TPA technology.

[0011] The tests are carried out by using the exciter method or the force hammer method, which is simple and easy to implement.

[0012] As an improvement to the analysis method for separating vehicle structure vibration based on the acceleration transfer path of the present invention, in Step 1, the engine mounting bushings include the left mount, the right mount, and the lower link mount. The vibration of each mounting bushing has components in the \(x\), \(y\), and \(z\) directions, with a total of nine transfer paths. Among them, the transfer path numbers \(i\) in the \(x\), \(y\), and \(z\) directions of the left mount correspond to 1, 2, and 3 respectively; the transfer path numbers \(i\) in the \(x\), \(y\), and \(z\) directions of the right mount correspond to 4, 5, and 6 respectively; the transfer path numbers \(i\) in the \(x\), \(y\), and \(z\) directions of the rear mount bushing correspond to 7, 8, and 9 respectively.

[0013] Preferably, in the second step, during the test: take the position at 12 o'clock of the steering wheel as the vehicle body response point, and take the direction perpendicular to the plane where the steering wheel is located as the target vibration direction.

[0014] Assume that the vehicle is subjected to m excitation forces, and each excitation force has three direction components of x, y, and z. Each excitation force component corresponds to n specific transfer paths. Then, this excitation force component and a certain corresponding transfer path generate a system response component. The x, y, and z directions of the vehicle refer to the vehicle length, vehicle width, and vehicle height directions respectively.

[0015] According to the TPA theory, take the vibrations of the vehicle's three engine mounts in the x, y, and z directions as the input ends of the corresponding transfer paths, and take the vibration in the direction perpendicular to the plane where the steering wheel is located at 12 o'clock of the steering wheel as the target point. There are 9 transfer paths from the engine mount bushing to the target point. Therefore, a 9×1 transfer path analysis model can be proposed.

[0016] As another improvement of the analysis method for separating vehicle structure vibrations based on acceleration transfer paths in the present invention, the second step includes:

[0017] Step A1: Conduct a test on the i-th transfer path to obtain the acceleration a 12_i (ω) of the vehicle body response point and the acceleration-force transfer function VTF i (ω) between the input force F i (ω) on the vehicle body side of the mount bushing of this i-th transfer path,

[0018]

[0019] where ω is the angular frequency, i = 1, 2, 3...n, i is the path number, and n is the number of transfer paths.

[0020] Furthermore,

[0021]

[0022] where M 12_i , B 12_i , K 12_i are respectively the mass matrix, damping matrix, and stiffness matrix corresponding to the structure system from the vehicle body side of the mount bushing of the i-th transfer path to 12 o'clock of the steering wheel.

[0023] Step A2: During the test on the i-th transfer path, obtain the acceleration-force transfer function IPI i (ω) between the acceleration a i (ω) of the vehicle body side of the mount bushing and the input force F i (ω) of the vehicle body side of the mount bushing of this i-th transfer path,

[0024]

[0025] Furthermore,

[0026]

[0027] wherein, M i , B i , K i are respectively the mass matrix, damping matrix, and stiffness matrix of the local hammering point of the i-th path.

[0028] Step A3: According to the acceleration-force transfer function VTF i (ω) and the acceleration-force transfer function IPI i (ω), derive and calculate the acceleration a i (ω) of the body side of the suspension bushing of the i-th transfer path and the acceleration a 12_i (ω) of the body response point, and the acceleration-acceleration transfer function ATF i (ω) therebetween.

[0029] Preferably,

[0030]

[0031] Furthermore,

[0032]

[0033] In the above steps A1 - A3, the acceleration-force transfer functions VTF i (ω) and IPI i (ω) are directly obtained through experiments, and then the acceleration-acceleration transfer function VTF i (ω) is ingeniously obtained through derivation and calculation of the quotient of the transfer functions.

[0034] As another improvement of the analysis method for separating vehicle structure vibration based on the acceleration transfer path of the present invention, in the third step, according to the acceleration-acceleration transfer function ATF i (ω) and the acceleration a b_i (ω) of the body side of the suspension bushing, calculating the acceleration a p_i (ω) transmitted by each transfer path includes:

[0035] Multiplying the acceleration a b_i (ω) of the body side of the suspension bushing by the acceleration-acceleration transfer function ATF i (ω) to obtain the acceleration a p_i (ω) transmitted by each transfer path.

[0036] Calculation formula:

[0037] a p_i (ω) = ATF i (ω) * a b_i (ω)....(4)

[0038] In addition, in Step 3, the acceleration a of the vehicle body side of each of the suspension bushings is obtained b_i When (ω), the Z - direction vibration acceleration signal of the vehicle body side of the right suspension bushing is used as the reference point for the phase of each acceleration signal, and at the same time, the acceleration a0(ω) of the vehicle body response point is obtained for verifying the acceleration a c (ω) of the vehicle body response point calculated in Step 4

[0039] As another improvement of the analysis method for separating vehicle structure vibration based on the acceleration transfer path of the present invention, in Step 4, calculating the acceleration a c (ω) of the vehicle body response point under the vehicle operating conditions includes:

[0040] Superposing and synthesizing the accelerations a p_i (ω) transmitted by each of the transfer paths in the frequency domain to calculate the acceleration a c (ω) of the vehicle body response point

[0041] Calculation formula:

[0042]

[0043] Further, in Step 4, calculating the contribution a con_i (ω) of each of the transfer paths under the vehicle operating conditions includes:

[0044] Step B1: Calculating the amplitude |a c (ω)| and phase φ of the acceleration a c (ω) of the vehicle body response point

[0045] Suppose

[0046]

[0047]

[0048] Then:

[0049]

[0050] It should be noted that the above accelerations a 12_i (ω), a i (ω), ab_i (ω) and a p_i (ω), and F i (ω) are all complex numbers, including amplitude and phase information, and their calculations are all carried out according to the operation rules of complex numbers.

[0051] Step B2: According to the acceleration a transmitted by each of the transmission paths p_i (ω) and the acceleration a of the vehicle body response point c (ω), calculate the contribution amount a of each of the transmission paths con_i (ω),

[0052] Calculation formula:

[0053]

[0054] where γ is the angle between a p_i (ω) and a c (ω).

[0055] In summary, by adopting the above analysis method for separating vehicle structure vibration based on acceleration transmission paths, the vibration transmission and path identification of each path in a complex vibration system can be conveniently and quantitatively studied, enriching the TPA theory and testing technology. It can be applied not only in the field of vehicle vibration, but also extended to other fields. This technical method has high efficiency, low cost, and strong application and reference value.

[0056] In terms of high efficiency: By adopting this acceleration TPA method, relatively few sensor points are required during the experiment, the dynamic stiffness parameters of the bushings are not needed, and it takes about three days from the planning to the completion of a single test; while the classical TPA test takes about three weeks from the planning to the completion.

[0057] In terms of low cost: By adopting this acceleration TPA method, common NVH test equipment can complete the work according to the technical steps and calculation procedures in the present invention, without the need to purchase additional equipment and testing and analysis software; while the classical TPA method requires the purchase of expensive dynamic stiffness equipment to obtain the dynamic stiffness parameters of the bushings, and the purchase of commercial TPA software modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In the drawings:

[0059] Figure 1 is the flow chart of the method of the present invention.

[0060] Figure 2 is the schematic diagram of the position of the engine mount bushings of the present invention.

[0061] Figure 3 is the acceleration - force transfer function VTF from the body side of the right mount bushing to the 12 o'clock target direction of the steering wheel obtained by the test of the present inventioni Spectral signal diagram of (ω).

[0062] Figure 4 The acceleration - force transfer function IPI on the body side of the right mount bushing obtained from the tests of the present invention i Spectral signal diagram of (ω).

[0063] Figure 5 The acceleration - acceleration transfer function ATF from the body side of the right mount bushing to the 12 - o'clock target direction of the steering wheel obtained by calculation of the present invention i Spectral signal diagram of (ω).

[0064] Figure 6 The vibration acceleration a on the body side of the right mount bushing under the vehicle operating conditions of the present invention b_i Spectral signal diagram of (ω).

[0065] Figure 7 The acceleration a in the 12 - o'clock target direction of the steering wheel calculated under the vehicle operating conditions of the present invention c Comparison spectral signal diagram of (ω) and the measured acceleration a0(ω) of the body response point

[0066] Figure 8 The vibration acceleration a transmitted to the 12 - o'clock position of the steering wheel by each transmission path under the vehicle operating conditions of the present invention p_i (ω).

[0067] Figure 9 The contribution schematic diagram of the vibration transmitted by each path to a c (ω) at a frequency of 32 Hz under the vehicle operating conditions of the present invention Detailed implementation manners

[0068] The following further describes the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be noted here that the description of these implementation manners is for helping to understand the present invention, but does not constitute a limitation to the present invention.

[0069] Example 1

[0070] Definition of key terms:

[0071] Acceleration TPA: In the present invention, it mainly refers to a method for analyzing the transmission path of vehicle structure vibration by taking the acceleration at key points as an intermediate parameter, deriving the acceleration - acceleration transfer function from the hammering point to the path from the acceleration - force transfer function of the path and the acceleration - force transfer function of the hammering point, and combining the acceleration data at key points under vehicle operating conditions.

[0072] Vehicle structure vibration: During vehicle operation, the dynamic load of the excitation source (power train, road surface, etc.) transfers vibration energy to the vehicle structure through the transmission path, causing the vehicle structure to generate forced vibration.

[0073] Vibration synthesis and decomposition: Using the acceleration TPA method in the present invention, the vibration of the response point is calculated by using the acceleration-acceleration transfer function and the acceleration data at key points under the vehicle operating conditions, and the vibration of the response point is decomposed onto each transfer path.

[0074] Path contribution: The vibration of the response point is decomposed onto each transfer path to study the contribution relationship of the vibration transmitted by the path to the vibration of the response point.

[0075] Figure 1 An analysis method for separating vehicle structure vibration based on acceleration transfer path according to the present invention is shown. As Figure 1 shown, the analysis method for separating vehicle structure vibration based on acceleration transfer path includes the following steps:

[0076] Step 1: Taking the vehicle engine as the vibration source, the engine mount bushing as the transfer path, and the vehicle body as the receiver, a transfer path analysis model of the vehicle is established.

[0077] Step 2: Conduct tests and obtain the transfer function ATF i (ω) between the acceleration a 12_i (ω) on the body side of the mount bushing and the acceleration a i (ω) of the body response point, where ω is the angular frequency, i is the path number, i = 1, 2, 3... n, and n is the number of transfer paths.

[0078] During the test, acceleration sensors are arranged on the body side of the engine mount bushing and at the 12 o'clock position of the steering wheel, and a force sensor is arranged on the impact hammer. As Figure 2 shown, the engine is connected to the vehicle body through a total of three mount bushings, namely the left mount bushing, the right mount bushing, and the rear tie rod mount bushing. Each mount bushing has vibration components in the x, y, and z directions, for a total of nine transfer paths. Among them, the x, y, and z direction path numbers of the left mount are i = 1, 2, 3; the x, y, and z direction path numbers of the right mount are i = 4, 5, 6; the x, y, and z direction path numbers of the rear mount bushing are i = 7, 8, 9. Taking the 12 o'clock position of the steering wheel of the vehicle body as the response point and taking the direction perpendicular to the plane of the steering wheel as the target vibration direction, the excitation shaker or the hammering method is used for the test, and the transfer function of each transfer path can be directly measured.

[0079] Description of the test process using the hammering method:

[0080] Step A1: Conduct a test on the i-th transfer path to obtain the transfer function VTF 12_i (ω) between the acceleration a i (ω) of the body response point and the input force F i(ω).

[0081] Hammer the engine mount bushing body side in the x, y, and z directions in sequence with a force hammer. The hammering points should be as close as possible to the elastic center of the mount bushing. In the corresponding 9 transfer path tests, obtain the acceleration a of the steering wheel 12 o'clock in the direction perpendicular to the steering wheel plane (denote this direction as the target direction of the steering wheel 12 o'clock). 12_i (ω) and the input force F on the bushing body side of the mount corresponding to this transfer path i (ω) between the acceleration-force transfer function VTF i (ω):

[0082]

[0083] where ω is the angular frequency, i is the path number, i = 1, 2, 3…n, and n is the number of transfer paths.

[0084] Furthermore,

[0085]

[0086] where M 12_i , B 12_i , K 12_i are respectively the mass matrix, damping matrix, and stiffness matrix corresponding to the structure system from the bushing body side of the i-th transfer path to the steering wheel 12 o'clock.

[0087] As Figure 3 shown, it is the spectral signal of the acceleration-force transfer function VTF i (ω) from the right bushing body side to the target direction of the steering wheel 12 o'clock, including the amplitude spectrum and phase spectrum. The three lines respectively refer to the acceleration-force transfer function curves of the corresponding transfer paths when hammering in the x, y, and z directions.

[0088] Step A2: In the test of the i-th transfer path, obtain the acceleration a of the bushing body side i (ω) and the input force F on the bushing body side of this i-th transfer path i (ω) between the transfer function IPI i (ω).

[0089] While conducting the above test, obtain the acceleration data around the hammering point (the distance between the acceleration sensor and the hammering point is less than 3 cm), and obtain the acceleration-force transfer function IPI i (ω) of the acceleration response and excitation in the same direction at the hammering point:

[0090]

[0091] Furthermore,

[0092]

[0093] Among them, M i , B i , K i are respectively the mass matrix, damping matrix, and stiffness matrix of the local hammering point of the i-th path.

[0094] As Figure 4 shown, it is the spectral signal of the acceleration-force transfer function IPI i (ω) on the body side of the right mount bushing (i.e., at the hammering point), where the three lines refer to the acceleration-force transfer function curves of the corresponding transfer paths when hammering in the x, y, and z directions respectively.

[0095] Step A3: According to the transfer function VTF i (ω) and the transfer function IPI i (ω), calculate the transfer function ATF i (ω) between the acceleration a 12_i (ω) on the body side of the mount bushing and the acceleration a i (ω) of the body response point for the i-th transfer path:

[0096]

[0097] Furthermore,

[0098]

[0099] As Figure 5 shown, it is the spectral signal of the acceleration-acceleration transfer function ATF i (ω) from the body side of the right mount bushing to the 12 o'clock target direction of the steering wheel, where the three lines refer to the acceleration-acceleration transfer function curves of the corresponding transfer paths when hammering in the x, y, and z directions respectively.

[0100] Acceleration dB:

[0101]

[0102] Step three: Under the vehicle operating conditions, obtain the acceleration a b_i (ω) of each mount bushing on the body side, and calculate the acceleration a i (ω) transmitted by each transfer path according to the transfer function ATF b_i (ω) and the acceleration a p_i (ω) of the mount bushing on the body side:

[0103] Multiply the acceleration a b_i (ω) of the mount bushing on the body side by the transfer function ATF i (ω) to obtain the acceleration a transmitted by each transfer pathp_i (ω),

[0104] a p_i (ω) = ATF i (ω) * a b_i (ω)....(4)

[0105] It is possible to measure data under any working conditions. For example, when the transmission is in the second gear, the engine speed is stable at about 1000 rpm, and the vehicle is traveling at a constant speed on a good asphalt road surface (the vibration transmission of the suspension path is reduced by reducing the road surface load input), the Z-direction vibration acceleration signal on the vehicle body side of the right mount bushing is used as the reference point for the phase of each acceleration signal. According to the steps in Step 2, the vibration acceleration a of each mount bushing on the vehicle body side is obtained b_i (ω) spectral signals, including amplitude spectrum and phase spectrum.

[0106] Then, according to the above formula (4), calculate the acceleration a transmitted by each transmission path p_i (ω). This vehicle has a total of three mount bushings, and each mount bushing has three translational directions, for a total of 9 vibration transmission paths. When the transmission is in the second gear and the engine speed is stable at about 1000 rpm, the final calculation results are as Figure 8 shown. Among them, the paths with significant vibration transmission at 32 Hz are 3, 6, and 7, which are the vibration transmission paths corresponding to the Z-direction of the left mount, the Z-direction of the right mount, and the X-direction of the lower tie rod bushing

[0107] As Figure 6 shown, it is the spectrum of the vibration acceleration a of the vehicle body side of the right mount bushing b_i (ω), where the three lines respectively refer to the acceleration-acceleration transfer function curves of the corresponding transmission paths when hammering in the x, y, and z directions

[0108] In addition, simultaneously obtain the acceleration a0(ω) of the vehicle body response point, which is used to verify the acceleration a c (ω) of the vehicle body response point calculated in Step 4. That is, obtain the spectral signal of the acceleration a0(ω) in the target direction of 12 o'clock of the steering wheel when traveling at a constant speed of 1000 rpm, as Figure 7 shown

[0109] Step 4: According to the acceleration a transmitted by each transmission path p_i (ω), calculate the acceleration a of the vehicle body response point and the contribution a of each transmission path c (ω) under the vehicle working conditions con_i (ω). Path contribution: Decompose the vibration of the response point into each transmission path, and study the contribution relationship of the vibration transmitted by the path to the vibration of the response point

[0110] The acceleration a transmitted by each transmission path p_i(ω) is accumulated to obtain the acceleration a of the body response point c (ω),

[0111] Calculation formula:

[0112]

[0113] Using the acceleration-acceleration transfer function ATF(ω) from the body side of the mounting bushing to the 12 o'clock target direction of the steering wheel in Step 2 and the acceleration a b_i (ω) on the body side of the mounting bushing during constant speed driving at 1000 rpm in Step 3, calculate the acceleration a c (ω) spectral signal in the 12 o'clock target direction of the steering wheel according to the above formula (5), as Figure 7 shown. At 1000 rpm, the second-order excitation of the four-cylinder engine is around 33 Hz. It can be seen from Figure 7 that the direct measurement of the vibration at 12 o'clock of the steering wheel is 4.8 dB (33 Hz), and the calculation result of the acceleration TPA is 0.79 dB (32 Hz). The calculation result of the acceleration TPA is basically consistent with the direct measurement result in terms of frequency, with a small amplitude error and a relatively close overall vehicle trend of the curve, indicating the effectiveness of the acceleration TPA method in this invention for complex engineering problems.

[0114] Furthermore, in Step 4, calculate the contribution a con_i (ω) of each transfer path under the vehicle operating conditions, including:

[0115] Step B1: Calculate the amplitude and phase of the acceleration a c (ω) of the body response point. Let

[0116]

[0117]

[0118] Then:

[0119]

[0120] Among them, it should be noted that the above accelerations a 12_i (ω), a i (ω), a b_i (ω) and a p_i (ω), as well as F i (ω) are all complex numbers, containing amplitude and phase information, and their calculations are all carried out according to the operation rules of complex numbers.

[0121] Step B2: According to the acceleration a p_i (ω) transmitted by each transfer path and the acceleration a c(ω) and the acceleration a of the vehicle body response point c The amplitude of (ω), calculate the contribution of each transfer path a con_i (ω),

[0122] Calculation formula:

[0123]

[0124] Among them, γ is a p_i (ω) and a c The included angle between (ω).

[0125] Calculate the contribution of the vibration transmitted by each path to a(ω) according to the acceleration TPA method in the invention. The results are as c shown. When the transmission is in the second gear and the engine speed is stable at about 1000 rpm, the acceleration amplitudes transmitted by paths 3, 6, and 7 at 32 Hz are 0.56 m / s2, 0.3 m / s2, and 1.09 m / s2 respectively. Their vibration contributions to a(ω) are the projections of their respective acceleration amplitudes in the direction of a(ω). Figure 9 shown. When the transmission is in the second gear and the engine speed is stable at about 1000 rpm, the acceleration amplitudes transmitted by paths 3, 6, and 7 at 32 Hz are 0.56 m / s2, 0.3 m / s2, and 1.09 m / s2 respectively. Their vibration contributions to a(ω) are the projections of their respective acceleration amplitudes in the direction of a(ω). c (ω) are the projections of their respective acceleration amplitudes in the direction of a(ω). c (ω).

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent replacements to the specific implementation manners of the invention, but these changes, modifications or equivalent replacements are all within the scope of the protection of the pending claims of the invention.

Claims

1. An analysis method for separating vehicle structure vibration based on the acceleration transmission path, characterized in that It includes the following steps: Step 1: Establish a transfer path analysis model of the vehicle with the vehicle's engine as the vibration source, the engine's mounting bush as the transfer path, and the vehicle body as the receiver. Step 2: Conduct tests and derive and calculate the acceleration \(a\) of the body side of the suspension bushing i (ω) and the acceleration \(a\) of the body response point 12_i (ω) the acceleration-acceleration transfer function \(ATF\) between i (ω), where ω is the angular frequency, \(i\) is the path number, \(i = 1, 2, 3…n\), and \(n\) is the number of transfer paths; Step 3: Under the vehicle operating conditions, obtain the acceleration a of the body side of each of the mounting bushings b_i (ω), and according to the acceleration-acceleration transfer function ATF i (ω) and the acceleration a of the body side of the mounting bushing b_i (ω), calculate the acceleration a transmitted by each of the transfer paths p_i (ω); Step 4: Calculate the acceleration a p_i (ω) of the body response point and the contribution a c (ω) of each of the transfer paths under the vehicle operating conditions according to the acceleration a con_i (ω) transmitted by each of the transfer paths; In the fourth step, calculate the acceleration a of the body response point under the vehicle operating conditions c (ω) includes: The acceleration a transmitted through each of the transmission paths p_i (ω) is superimposed and synthetically calculated in the frequency domain to obtain the acceleration a c (ω) of the vehicle body response point; Calculation formula: In the fourth step, calculate the contribution amount a of each of the transfer paths under the vehicle operating conditions con_i (ω) includes: The acceleration a transmitted according to the transmission path p_i (ω) and the acceleration a of the vehicle body response point c (ω), calculate the contribution amount a of each transmission path con_i (ω); specifically including: Step B1: Calculate the acceleration a of the vehicle body response point c (ω) amplitude |a c (ω)| and phase φ Let Then: The above acceleration a 12_i (ω), a i (ω), a b_i (ω) and a p_i (ω), and F i (ω) are all complex numbers, containing amplitude and phase information, and their calculations are all carried out according to the operation rules of complex numbers; Step B2: According to the acceleration a p_i (ω) transmitted through each of the transmission paths and the acceleration a c (ω) of the vehicle body response point, calculate the contribution amount a con_i (ω) of each of the transmission paths. Calculation formula: where γ is the angle between a p_i (ω) and a c (ω).

2. According to the analysis method for separating vehicle structure vibration based on acceleration transfer path described in claim 1, in step 1, the engine's mounting bush includes a left mount, a right mount, and a lower link mount. The vibration of each mounting bush has components in the x, y, and z directions, with a total of nine transfer paths. Among them, the transfer path numbers i in the x, y, and z directions of the left mount correspond to 1, 2, and 3 respectively; the transfer path numbers i in the x, y, and z directions of the right mount correspond to 4, 5, and 6 respectively; the transfer path numbers i in the x, y, and z directions of the rear mount bush correspond to 7, 8, and 9 respectively.

3. A method for analyzing vehicle structure vibration based on separating the acceleration transmission path according to claim 1 or 2, characterized in that In step 2, during the test: Take the position at 12 o'clock on the steering wheel as the vehicle body response point, and take the direction perpendicular to the plane where the steering wheel is located as the target vibration direction.

4. According to the analysis method for separating vehicle structure vibration based on acceleration transfer path described in claim 1, step 2 includes: Step A1: Conduct a test on the i-th transfer path to obtain the acceleration a of the vehicle body response point 12_i (ω) and the input force F i on the vehicle body side of the mounting bushing of the i-th transfer path, and the acceleration-force transfer function VTF i (ω). The calculation formula is as follows: Step A2: During the test on the i-th transfer path, obtain the acceleration a of the body side of the mounting bushing i (ω) and the input force F i (ω) of the body side of the mounting bushing for the i-th transfer path, and the acceleration-force transfer function IPI i (ω). The calculation formula is as follows: Step A3: According to the acceleration-force transfer function VTF i (ω) and the acceleration-force transfer function IPI i (ω), derive and calculate the acceleration a i (ω) of the body side of the suspension bushing of the i-th transfer path and the acceleration a 12_i (ω) of the body response point, and the acceleration-acceleration transfer function ATF i (ω) therebetween, and the calculation formula is: Where ω is the angular frequency, i is the path number, i = 1, 2, 3…n, and n is the number of transfer paths.

5. The analysis method for separating vehicle structure vibration based on the acceleration transmission path according to claim 1, characterized in that In the third step, according to the acceleration-acceleration transfer function ATF i (ω) and the acceleration a b_i (ω) of the body side of the suspension bushing, calculate the acceleration a p_i (ω) transmitted by each of the transfer paths, including: Multiply the acceleration a on the vehicle body side of the suspension bushing b_i (ω) by the acceleration-acceleration transfer function ATF i (ω) to obtain the acceleration a transmitted by each of the transmission paths p_i (ω); Calculation formula: a p_i ψ(ω)=ATF i ψ(ω)*a b_i ψ(ω)。 6. The analysis method for separating vehicle structure vibration based on the acceleration transmission path according to claim 1, wherein In step 2, the exciter method or the force hammer method is used for the test.

7. The analysis method for separating vehicle structure vibration based on the acceleration transmission path according to claim 1, wherein In the third step, it further includes: under the vehicle operating conditions, obtaining the acceleration a0(ω) of the vehicle body response point, which is used to verify the acceleration a c (ω) of the vehicle body response point calculated in the fourth step.

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