Method for analyzing vibration noise characteristics of single-seam bridge expansion joint under vehicle excitation

Abstract

The invention provides a method for analyzing vibration noise characteristics of a single-seam bridge expansion joint under vehicle excitation. The method comprises the following steps: S1, constructing a vehicle-seam-bridge coupling structure finite element model; s2, calculating vibration response of the bridge expansion joint under vehicle excitation; s3, an acoustic boundary element model and a sound field point are established, vibration noise generated when a vehicle passes through the bridge expansion joint is analyzed and calculated based on sound-vibration coupling, and an expansion joint vibration noise model is obtained; and S4, respectively analyzing the sound contributions of the three sound sources of the finite length main beam, the bridge expansion joint and the vehicle tire finite element model. According to the method, nonlinearity when the vehicle tire is in contact with the expansion joint is considered during vibration analysis; the acoustic contribution of the vehicle tire and the main beam is considered during acoustic analysis, more accurate sound source contribution can be obtained, a foundation is laid for vibration and noise reduction design of the bridge expansion joint, and compared with the prior art, the analysis precision of the vibration noise characteristics of the vehicle passing through the bridge expansion joint is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of traffic technology, and more specifically to a method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation. Background Art

[0002] Bridge expansion joints are key components to ensure vehicle safety and comfort. They are used to adapt to the expansion and contraction of bridges caused by daily temperature differences, seasonal temperature changes, bridge movement caused by vehicle travel, earthquakes, and other factors. In order to adapt to the above deformations, expansion joints are usually set at the ends of beams to block the gaps between two adjacent spans of bridges. However, the discontinuity caused by these expansion joints often causes huge impact forces on passing vehicles, resulting in excessive noise radiation. With the rapid development of transportation systems, residents have increasingly complained about the vibration and noise generated when vehicles pass through bridge expansion joints. At the same time, the noise generated when vehicles pass through expansion joints has become one of the main sources of noise on highway bridges and needs to be solved urgently. Therefore, the vibration characteristics and noise radiation mechanism of expansion joints should be studied, and potential control measures for the former should be sought.

[0003] In the current research on the vibration and noise of bridge expansion joints caused by vehicles, only the bridge expansion joints are modeled, and the vehicle loads are also simplified. Based on the above assumptions, these numerical models are difficult to capture the highly nonlinear contact interaction between the vehicle tires and the expansion joints, which in turn leads to the inability to consider the acoustic contribution of the vehicle tires and the main beam in the acoustic analysis. At the same time, a large number of studies have shown that tire noise is dominant when the vehicle is driving at high speed. Therefore, in order to comprehensively evaluate the vibration and noise characteristics of vehicles passing through bridge expansion joints, and then optimize the vibration and noise reduction design of bridge expansion joints, it is necessary to propose a method for analyzing the vibration and noise characteristics of single-slot bridge expansion joints under vehicle excitation. Summary of the invention

[0004] The purpose of the present invention is to disclose a method for analyzing the vibration and noise characteristics of a single-slit bridge expansion joint under vehicle excitation, so as to solve the problems in the prior art of low accuracy in vibration and noise analysis of bridge expansion joints, insufficient consideration of sound sources, and difficulty in accurately analyzing the vibration and noise characteristics of vehicles passing through bridge expansion joints.

[0005] To achieve the above object, the present invention provides a method for analyzing the vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation, comprising the following steps:

[0006] S1. Establish a vehicle-joint-bridge coupling structure finite element model according to the longitudinal section structure of the bridge expansion joint, including finite element models of a finite-length main beam, a bridge expansion joint and a vehicle tire, and mesh the vehicle-joint-bridge coupling structure finite element model;

[0007] S2, calculating the vibration response of the bridge expansion joint under vehicle excitation, specifically including the following sub-steps:

[0008] S21, performing steady-state analysis, inflating the inner tube of the vehicle tire finite element model until deformation stops and a stable state is reached;

[0009] S22, performing steady-state-transient analysis, applying gravity effect to the vehicle tire finite element model to simulate the actual gravity condition of the vehicle, so that the outer tread layer of the vehicle tire finite element model is in full contact with the finite length main beam, and under the combined action of gravity and contact force, the vehicle tire finite element model reaches a mechanical equilibrium state;

[0010] S23, performing transient analysis, applying translational and rotational speeds to the vehicle tire finite element model, simulating the actual situation of a vehicle passing through a bridge expansion joint, obtaining the vibration response of each node of the vehicle-joint-bridge coupling structure model, and performing a comparison and verification in the time domain and frequency domain with the acceleration data collected by the measured vibration acceleration sensor arranged on the bridge expansion joint;

[0011] S3, extracting the surface mesh of the finite element model of the vehicle-joint-bridge coupling structure in step S1, establishing an acoustic boundary element model and acoustic field points, setting the parameters of the acoustic boundary element model, importing the analysis results of the vibration response in step S2 as boundary conditions of the acoustic boundary element model, and calculating the vibration noise when the vehicle passes through the expansion joint of the bridge based on the acoustic-vibration coupling analysis to obtain the expansion joint vibration noise model;

[0012] S4. According to the expansion joint vibration noise model obtained in step S3, the field point sound pressure calculated by the acoustic boundary element model is derived, the 1 / 3 octave band sound pressure level is calculated, the sound pressure spatial distribution cloud map is drawn and the noise law is analyzed, and the sound contribution of the three sound sources of the finite length main beam, bridge expansion joint and vehicle tire finite element model are analyzed respectively.

[0013] Preferably, in S1, the bridge expansion joint and the finite length main beam are connected by a common node, the vehicle tire finite element model is in surface contact with the finite length main beam and the bridge expansion joint, wherein the outer tread layer of the vehicle tire finite element model is set as a slave surface.

[0014] Preferably, in S1, the process of meshing the finite element model of the vehicle-seam-bridge coupling structure is as follows:

[0015] S11, determining the mesh size of the bridge expansion joint and adding meshes thereto, and the mesh size of the bridge expansion joint meets the requirement that the minimum wavelength contains at least six units;

[0016] S12, determining the grid size of the vehicle tire finite element model and adding a grid thereto, and the grid size of the vehicle tire finite element model is ≤ the grid size of the bridge expansion joint;

[0017] S13. Determine the grid size of the finite length main beam and add grids to it, and the grid size of the finite length main beam is consistent with the grid size of the bridge expansion joint.

[0018] Preferably, in S21, an independent node is created at the center of the vehicle tire finite element model to represent the center of mass, and is rigidly connected to the rim layer on the inner side of the vehicle tire finite element model, and constraints are applied to the vehicle tire finite element model during the inflation stage to constrain all degrees of freedom of the center of mass so that it does not move under the action of the inflation load.

[0019] Preferably, in S22, before applying gravity to the vehicle tire finite element model, the vertical degree of freedom constraint at its center of mass is released so that it can move in the vertical direction;

[0020] The state switching process of steady-state-transient analysis is as follows:

[0021] S221. Through steady-state analysis, the tire model is made close to a mechanical equilibrium state under the action of gravity;

[0022] S221, turn to transient analysis, add 10Ns / m mass damping to the model, control it to quickly balance within 0.5s, and perform transient analysis calculation at this stage;

[0023] S223. Before the transient analysis calculation is completed, the mass damping is set to zero.

[0024] Preferably, the number of acceleration sensors on the bridge expansion joint is set to multiple, all of which are high-frequency acceleration sensors. The multiple acceleration sensors are evenly arranged at different positions of the measured area of ​​the structure field test, and the multiple acceleration sensors are installed in different vertical and longitudinal directions.

[0025] Preferably, in S23, when performing transient analysis, the output time interval Δt of the simulation calculation is determined according to the maximum frequency actually measured for the structure, and the calculation formula is:

[0026] Δt=12f max

[0027] Among them, f max is the maximum frequency of the measured results;

[0028] The simulated vibration calculation results can correspond to the measured frequency; the measured time domain response is converted to the frequency domain through fast Fourier transform, and verified with the numerical simulation results, and then the finite element model of the vehicle-seam-bridge coupling structure is further adjusted.

[0029] Preferably, the simulated vibration calculation results are compared and verified with the measured results, and the following conditions are met:

[0030] a) If the simulated vibration calculation results are highly consistent with the measured results near the peak frequency, the acceleration level change trend in the entire analysis frequency band is generally consistent, and the acceleration level error at the peak frequency is less than 10%, it means that the vehicle-joint-bridge coupling structure finite element model can accurately simulate the vibration of the vehicle passing through the expansion joint, and subsequent noise analysis can be carried out;

[0031] b) If at least one of the following conditions exists: the simulated vibration calculation results are not consistent with the measured results near the peak frequency, the acceleration level change trends in the entire analysis frequency band are greatly different, and the acceleration level error at the peak frequency is ≥10%, it means that the test result error is large. At this time, it is necessary to re-examine the validity of the finite element model of the vehicle-seam-bridge coupling structure.

[0032] Preferably, in S3, the surface mesh of the finite element model of the vehicle-seam-bridge coupling structure is extracted as a rectangular mesh, and then the rectangular mesh is re-divided into a triangular mesh, while retaining the rectangular mesh, wherein the rectangular mesh is used as a plane sound field point, and the triangular mesh is used as an acoustic boundary element model;

[0033] A closed acoustic mesh is added to the outer rim layer of a vehicle tire finite element model.

[0034] Preferably, in S4, when analyzing the acoustic contribution of each sound source, based on the original vehicle-seam-bridge coupled acoustic boundary element model, only the acoustic meshes of the finite length main beam, the bridge expansion joint and the vehicle tire finite element model are retained to respectively establish acoustic models containing only these three sound sources;

[0035] The acoustic contribution evaluation method used is as follows:

[0036] S41. Obtain the 1 / 3 octave sound pressure level of the acoustic model of three sound sources, namely, the finite length main beam, the bridge expansion joint and the vehicle tire finite element model, at the sound field point by fast Fourier transform;

[0037] S42, determining the dominant frequency range of each sound source according to the 1 / 3 octave sound pressure level of the acoustic models corresponding to the three sound sources at the sound field point;

[0038] S43. Compare the dominant frequency range of each sound source with the 1 / 3 octave band sound pressure level calculated at the sound field point by the corresponding vehicle-seam-bridge coupled acoustic boundary element model to determine the acoustic contribution of the three sound sources.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. Construct a vehicle-expansion joint-bridge coupling system model and establish a refined vehicle tire finite element model. Consider the nonlinearity of the vehicle tire in contact with the expansion joint during vibration analysis. Consider the acoustic contribution of the vehicle tire and the main beam at the same time during acoustic analysis, so as to obtain more accurate sound source contribution and lay the foundation for the vibration reduction and noise reduction design of the bridge expansion joint. Compared with the existing technology, the analysis accuracy of the vibration and noise characteristics of vehicles passing through the bridge expansion joint is significantly improved.

[0041] 2. In vibration analysis, the real-time process of vehicles passing through the expansion joints of bridges is dynamically simulated through steady-state-transient analysis, and the coupling model is adjusted based on the structural vibration response of field tests, thereby improving the accuracy and credibility of the numerical simulation model;

[0042] 3. In the acoustic analysis, an acoustic boundary element model is established based on the vehicle-joint-bridge coupled finite element model to simulate the noise characteristics of vehicle tires passing through the expansion joints of bridges, and the acoustic contributions of three sound sources, namely vehicle tires, main beams and bridge expansion joints, are considered to make the noise calculation results more consistent with the measured data. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of a flow chart of a noise characteristic analysis method provided by the present invention;

[0044] Figure 2 A finite element model diagram of the noise characteristic analysis method provided by the present invention;

[0045] Figure 3 A schematic diagram of the measured-simulated acceleration level spectrum in the noise characteristic analysis method provided by the present invention;

[0046] Figure 4 The acoustic boundary element model and the schematic diagram of the plane sound field point in the noise characteristic analysis method provided by the present invention;

[0047] Figure 5 A schematic diagram of a measured-simulated sound pressure level spectrum in the noise characteristic analysis method provided by the present invention;

[0048] Figure 6 This is a schematic diagram of the contribution of sound sources in the noise characteristics analysis method provided by the present invention.

[0049] In the figure:

[0050] Limited length main beam-1; Bridge expansion joint-2; Vehicle tire finite element model-3; External support surface-4;

[0051] Tread layer-31; belt layer-32; carcass layer-33; sidewall layer-34; rim layer-35;

[0052] Center of mass - o. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and equivalent changes or substitutions in functions, methods or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0054] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0055] Ginseng Figure 1 As shown, the present invention discloses a method for analyzing the vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation, comprising the following steps:

[0056] S1. A vehicle-joint-bridge coupling structure finite element model is established according to the longitudinal section structure of the bridge expansion joint structure, including a finite length main beam 1, a bridge expansion joint 2 and a vehicle tire finite element model 3, wherein the bridge expansion joint 2 and the finite length main beam 1 are connected by a common node, the vehicle tire finite element model 3 is in surface contact with the finite length main beam 1 and the bridge expansion joint 2, wherein the outer tread layer 31 of the vehicle tire finite element model 3 is set as a slave surface;

[0057] The number of acceleration sensors on the bridge expansion joint 2 is set to be multiple, all of which are high-frequency acceleration sensors. The multiple acceleration sensors are evenly arranged at different positions of the actual measurement area of ​​the structure field test, and the multiple acceleration sensors are installed in different vertical and longitudinal directions;

[0058] In the contact analysis between the vehicle tire finite element model 3 and the bridge expansion joint 2, a mesh convergence analysis must be performed to ensure the accuracy of the analysis. The vehicle-joint-bridge coupling structure finite element model is meshed. The process is as follows:

[0059] S11, determining the mesh size of the bridge expansion joint 2 and adding a mesh thereto, and the mesh size of the bridge expansion joint 2 meets the requirement that the minimum wavelength contains at least six units, so as to avoid truncation frequency error in subsequent noise analysis;

[0060] S12, determining the grid size of the vehicle tire finite element model 3 and adding grids thereto, and the grid size of the vehicle tire finite element model 3 is ≤ the grid size of the bridge expansion joint 2, so that the vibration response error of the bridge expansion joint 2 is controlled within 5%, so it is necessary to first determine the grid size of the bridge expansion joint 2, and then further determine the final grid size of the vehicle tire finite element model 3 according to the grid size of the bridge expansion joint 2;

[0061] S13, determining the grid size of the finite length main beam 1 and adding a grid thereto, and the grid size of the finite length main beam 1 is consistent with the grid size of the bridge expansion joint 2;

[0062] S2, calculating the vibration response of the bridge expansion joint 2 under vehicle excitation, specifically including the following sub-steps:

[0063] S21, performing steady-state analysis, creating an independent node at the center of the vehicle tire finite element model 3 to represent the center of mass o, and rigidly connecting it to the rim layer 35 inside the vehicle tire finite element model 3, applying constraints to the vehicle tire finite element model 3 during the inflation stage, constraining all degrees of freedom of the center of mass o so that it does not move under the inflation load;

[0064] Inflate the inner tube of the vehicle tire finite element model 3 until it stops deforming and reaches a stable state; when applying inflation pressure to the inner tube of the vehicle tire finite element model 3 according to different vehicle types and different load states of the vehicle, if the main body of the vehicle tire finite element model 3 is a passenger car, the tire pressure range is controlled within 0.2-0.25Mpa; if the main body of the vehicle tire finite element model 3 is a truck, the tire pressure range is controlled within 0.92-1.0Mpa;

[0065] S22, performing steady-state-transient analysis, before applying gravity to the vehicle tire finite element model 3, releasing the vertical degree of freedom constraint at its center of mass o, so that it can move in the vertical direction;

[0066] Gravity is applied to the top of the vehicle tire finite element model 3 to simulate the actual gravity condition of the vehicle, so that the outer tread layer 31 of the vehicle tire finite element model 3 is in full contact with the finite length main beam 1. Under the combined action of gravity and contact force, the vehicle tire finite element model 3 reaches a mechanical equilibrium state, in which the displacement response of the vehicle tire finite element model 3 tends to be stable;

[0067] The state switching process of steady-state-transient analysis is as follows:

[0068] S221. Through steady-state analysis, the tire model is made close to a mechanical equilibrium state under the action of gravity;

[0069] S221, turn to transient analysis, add 10Ns / m mass damping to the model, control it to quickly balance within 0.5s, and perform transient analysis calculations at this stage to reduce calculation time;

[0070] S223. Before the transient analysis calculation is completed, the mass damping is set to zero to avoid affecting the subsequent calculations;

[0071] S23, performing transient analysis, applying translation and rotation speeds to the vehicle tire finite element model 3, simulating the actual situation of the vehicle passing through the bridge expansion joint 2, obtaining the vibration response of each node of the vehicle-joint-bridge coupling structure model, and analyzing and obtaining the structural acceleration level spectrum results on this basis, and performing a comparison and verification in the time domain and frequency domain with the acceleration data collected by the measured vibration acceleration sensor arranged on the bridge expansion joint 2, wherein the acceleration data collected by the measured vibration acceleration sensor is processed into the measured acceleration level spectrum results;

[0072] When performing transient analysis, the output time interval Δt of the simulation calculation is determined according to the maximum frequency of the structure measured. The calculation formula is:

[0073] Δt=12f max

[0074] Among them, f max is the maximum frequency of the measured results;

[0075] Make the simulation vibration calculation results correspond to the measured frequency; convert the measured time domain response to the frequency domain through fast Fourier transform, and verify it with the numerical simulation results. The simulation vibration calculation results are compared with the measured results, and the following are true:

[0076] a) If the simulated vibration calculation results are highly consistent with the measured results near the peak frequency, the acceleration level change trend in the entire analysis frequency band is generally consistent, and the acceleration level error at the peak frequency is less than 10%, it means that the vehicle-joint-bridge coupling structure finite element model can accurately simulate the vibration of the vehicle passing through the expansion joint, and subsequent noise analysis can be carried out;

[0077] b) If at least one of the following conditions exists: the simulated vibration calculation results and the measured results have a low degree of agreement near the peak frequency, the acceleration level change trend in the entire analysis frequency band is greatly different, and the acceleration level error at the peak frequency is ≥10%, it means that the test result error is large. At this time, it is necessary to re-examine the validity of the vehicle-seam-bridge coupling structure finite element model; and then further adjust the vehicle-seam-bridge coupling structure finite element model;

[0078] S3, extracting the surface mesh of the finite element model of the vehicle-slot-bridge coupling structure in step S1, establishing an acoustic boundary element model and an acoustic field point, extracting the surface mesh of the finite element model of the vehicle-slot-bridge coupling structure as a rectangular mesh, and then re-dividing the rectangular mesh into a triangular mesh, while retaining the rectangular mesh, wherein the rectangular mesh is used as a plane acoustic field point, and the triangular mesh is used as an acoustic boundary element model;

[0079] The closure of the acoustic mesh is the key to ensuring the accuracy of the acoustic model. A closed acoustic mesh can prevent the unlimited diffusion of sound waves at the model boundary, which is particularly important for simulating the propagation of sound waves in a limited space. Adding a closed acoustic mesh to the outer rim layer 35 of the vehicle tire finite element model 3 and assigning an acoustic impedance value of 416.5 kg / (m2·s) can accurately simulate the propagation and reflection of sound waves inside the model, while avoiding non-physical leakage of sound waves at the model boundary, ensuring the accuracy and integrity of the acoustic model.

[0080] The acoustic boundary element model parameters are set, the analysis results of the vibration response in step S2 are imported as the boundary conditions of the acoustic boundary element model, and the vibration noise when the vehicle passes through the bridge expansion joint 2 is calculated based on the acoustic-vibration coupling analysis to obtain the expansion joint vibration noise model;

[0081] S4, according to the expansion joint vibration noise model obtained in step S3, the field point sound pressure calculated by the acoustic boundary element model is derived, the 1 / 3 octave sound pressure level is calculated, the sound pressure spatial distribution cloud map is drawn and the noise law is analyzed, and the acoustic contribution of the three sound sources of the finite length main beam 1, the bridge expansion joint 2 and the vehicle tire finite element model 3 is analyzed respectively;

[0082] On the basis of the original vehicle-joint-bridge coupled acoustic boundary element model, only the acoustic meshes of the finite length main beam 1, the bridge expansion joint 2 and the vehicle tire finite element model 3 are retained to establish acoustic models containing only these three sound sources;

[0083] The acoustic contribution evaluation method used is as follows:

[0084] S41, obtaining the 1 / 3 octave sound pressure level of the acoustic models of the three sound sources of the finite length main beam 1, the bridge expansion joint 2 and the vehicle tire finite element model 3 at the sound field point by fast Fourier transform;

[0085] S42, determining the dominant frequency range of each sound source according to the 1 / 3 octave sound pressure level of the acoustic models corresponding to the three sound sources at the sound field point;

[0086] S43. Compare the dominant frequency range of each sound source with the 1 / 3 octave band sound pressure level calculated at the sound field point by the corresponding vehicle-seam-bridge coupled acoustic boundary element model to determine the acoustic contribution of the three sound sources.

[0087] The method of the present invention can be used to analyze the vibration and noise characteristics of a vehicle passing through the expansion joint structure of a bridge, obtain the noise impact of the vehicle on the expansion joint structure of the bridge, and provide a theoretical basis for reducing the vibration and noise when the vehicle passes through the expansion joint structure of the bridge.

[0088] Taking the expansion joint structure of a bridge on a highway as an example, the method of the present invention is given to analyze the vibration and noise characteristics of the expansion joint of the bridge under vehicle excitation:

[0089] 1) Construct a finite element model of the vehicle-seam-bridge coupling structure

[0090] Reference Figure 2 As shown, a refined vehicle-joint-bridge coupling model is established based on the actual design drawings. First, geometric models corresponding to the finite-length main beam 1, the bridge expansion joint 2 and the vehicle tire finite element model 3 are established. The vehicle tire finite element model 3 includes a tread layer 31, a belt layer 32, a carcass layer 33, a sidewall layer 34 and a rim layer 35; the finite-length main beam 1 includes a box beam structure located on both sides of the bridge expansion joint 2; the bridge expansion joint 2 includes anchorage area concrete and expansion joint side beams; in addition, external support surfaces 4 are added at the left and right ends of the vehicle-joint-bridge coupling model;

[0091] Except for the rim layer 35 which uses the shell element Shell163, the rest of the structure uses the solid element Solid164. After the geometric model is established, the unit division is performed;

[0092] The vehicle axle weight is simulated by the added mass method. The mass is directly applied to the node, and the node is connected to the tire mass center o through a spring damping unit. The spring stiffness is set to k = 20N / mm, and the damping coefficient is set to c = 3N s / mm. At the same time, the tire mass center o is rigidly connected to the rim layer 35;

[0093] In terms of meshing, the unit size needs to meet the requirement of 6 units within the minimum wavelength. At the same time, the unit size is gradually relaxed at a position far away from the bridge expansion joint 2 to reduce the calculation time and improve efficiency while ensuring accuracy. The maximum mesh size of the bridge expansion joint 2 is set to 20mm, the maximum frequency of noise analysis is 2800Hz, the maximum mesh size of the finite length main beam 1 is set to 80mm, and the maximum mesh size of the vehicle tire finite element model 3 is determined to be 10mm through mesh convergence analysis.

[0094] 2) Calculate the vibration response of the bridge expansion joint under vehicle excitation

[0095] It is divided into 3 stages:

[0096] 2.1) Phase 1 (time 0-1s), using steady-state analysis, fixing the center of mass o of the vehicle tire finite element model 3, and applying inflation pressure to the inner surface of the vehicle tire finite element model 3. Within 0-0.5s, the air pressure increases from 0 to 220kPa, and then remains constant within 0.5-1s;

[0097] 2.2) Phase 2 (time is 1-3s), using steady-state-transient analysis, steady-state analysis is performed within 1-2s, and transient analysis is performed within 2-3s. During the analysis, the vertical degree of freedom at the center of mass o of the vehicle tire finite element model 3 is released so that it can move freely vertically. At the same time, the surface contact between the vehicle tire finite element model 3 and the finite length main beam 1 is set, the contact algorithm is set to a penalty function, and the dynamic and static friction coefficients are set to 0.2 and 0.3 respectively;

[0098] The finite element model of the vehicle tire 3 is under the action of its own gravity (within 1-1.5s, the gravity increases from 0 to 9.8m / s 2 , and then keep constant), further fully contact with the limited length main beam 1, and make the vehicle tire finite element model 3 obtain initial deformation;

[0099] Then, the transient analysis is started within 2-3 s, and a mass damping of 10 N s / mm is added to the vehicle tire finite element model 3 within 2-2.6 s, so that the displacement response of the vehicle tire finite element model 3 tends to be stable and reaches a mechanical equilibrium state.

[0100] 2.3) In stage 3 (time is 3-3.3s), transient analysis is used to release the rotational and translational degrees of freedom at the center of mass o of the vehicle tire finite element model 3, so that it can move longitudinally along the finite length main beam 1 and rotate around the central axis. At the same time, the corresponding translational speed and rotational angular velocity of the vehicle tire are given, and within 3-3.1s, the translational speed and rotational speed are increased from 0 to the target speed and then remain unchanged. The vibration response of the measuring point when passing through the bridge expansion joint 2 is recorded, and the analysis results of the coupling model are saved.

[0101] A vertical acceleration sensor is set on the bridge expansion joint 2 structure, and the measured time domain response is converted to the frequency domain through fast Fourier transform, and compared with the numerical simulation results at each frequency point. Figure 3 The simulation-measured acceleration spectrum is shown in Figure 1. If the degree of agreement with the measured results near the peak frequency is high and generally consistent, it means that the frequency domain coupling model accurately simulates the vibration of the train during running; if the degree of agreement is poor, the validity of the finite element model needs to be re-examined.

[0102] 3) Establishing acoustic boundary element model

[0103] The surface meshes of the vehicle tire finite element model 3, the finite length main beam 1 and the bridge expansion joint 2 are extracted as acoustic boundary element meshes. The vibration displacement of each node in the obtained vehicle-joint-bridge coupling model is used as a boundary condition and input into the acoustic boundary element model to calculate the vibration noise of the vehicle tire finite element model 3 when passing through the bridge expansion joint 2. And according to the coordinates of the actual measuring points, the field points are set along the external normal direction. The field point plane is 12m×12m, the spacing between each field point is 1.5m, and the center of the field point plane is located in the middle of the expansion joint; refer to Figure 4 The acoustic boundary element model and the schematic diagram of the plane acoustic field points are shown.

[0104] 4) Calculation of expansion joint vibration noise and analysis of sound source contribution

[0105] According to the expansion joint vibration noise model obtained in step S3, the field point sound pressure calculated by the acoustic boundary element model is derived, the 1 / 3 octave sound pressure level is calculated, one octave is divided into three adjacent 1 / 3 octaves, the sound range is divided into 30 1 / 3 octaves, and the sound pressure level spectrum of the measuring point and the plane field point is plotted. Figure 5 If the comparison of the simulated and measured sound pressure level spectra is highly consistent with the measured results near the peak frequency and is generally consistent, it means that the acoustic boundary element model can accurately simulate the vibration and noise when the vehicle passes through the bridge expansion joint 2. Figure 6 The sound pressure spectra of each field point of the three sound sources shown are used to evaluate the acoustic contributions of the three sound sources by drawing the sound pressure spatial distribution cloud diagram and analyzing the noise propagation law.

[0106] According to the calculation results, the 1 / 3 octave sound pressure level of each sound source at each sound field point is obtained, and the near field point and the remote point are selected for sound source comparison analysis. Taking the near field point as an example, within 200Hz, the acoustic contribution of the main beam vibration noise is equivalent to the tire noise; while in the full frequency band (0-1000Hz), the acoustic contribution of the expansion joint vibration noise is much smaller than the tire noise and the main beam vibration noise, indicating that for the bridge expansion joint 2, the acoustic contribution of its structural vibration noise can be ignored.

[0107] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for analyzing the vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation, characterized in that: The following steps are involved: S1, establishing a vehicle-joint-bridge coupling structure finite element model according to the longitudinal section structure of the bridge expansion joint (2), including a finite length main beam (1), a bridge expansion joint (2) and a vehicle tire finite element model (3), and meshing the vehicle-joint-bridge coupling structure finite element model; S2, calculating the vibration response of the bridge expansion joint (2) under vehicle excitation, specifically comprising the following sub-steps: S21, performing steady-state analysis, inflating the inner tube of the vehicle tire finite element model (3) until the inner tube stops deforming and reaches a stable state; S22, performing steady-state-transient analysis, applying a gravity effect to the vehicle tire finite element model (3) to simulate the actual gravity condition of the vehicle, so that the outer tread layer (31) of the vehicle tire finite element model (3) is in full contact with the finite length main beam (1), and under the combined action of gravity and contact force, the vehicle tire finite element model (3) reaches a mechanical equilibrium state; S23, performing transient analysis, applying translational and rotational speeds to the vehicle tire finite element model (3), simulating the actual situation of a vehicle passing through the bridge expansion joint (2), obtaining the vibration response of each node of the vehicle-joint-bridge coupling structure model, and performing a comparison and verification in the time domain and frequency domain with the acceleration data collected by the actual vibration acceleration sensor arranged on the bridge expansion joint (2); S3, extracting the surface mesh of the finite element model of the vehicle-joint-bridge coupling structure in step S1, establishing an acoustic boundary element model and acoustic field points, setting parameters of the acoustic boundary element model, importing the analysis results of the vibration response in step S2 as boundary conditions of the acoustic boundary element model, and calculating the vibration noise when the vehicle passes through the bridge expansion joint (2) based on the acoustic-vibration coupling analysis, to obtain an expansion joint vibration noise model; S4. According to the expansion joint vibration noise model obtained in step S3, the field point sound pressure calculated by the acoustic boundary element model is derived, the 1 / 3 octave band sound pressure level is calculated, a sound pressure spatial distribution cloud diagram is drawn and the noise law is analyzed, and the acoustic contribution of the three sound sources of the finite length main beam (1), the bridge expansion joint (2) and the vehicle tire finite element model (3) are analyzed respectively.

2. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized in that: In S1, the bridge expansion joint (2) is connected to the finite length main beam (1) by a common node, and the vehicle tire finite element model (3) is in surface-to-surface contact with the finite length main beam (1) and the bridge expansion joint (2), wherein the outer tread layer (31) of the vehicle tire finite element model (3) is set as a slave surface.

3. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized in that: In S1, the meshing process of the finite element model of the vehicle-seam-bridge coupling structure is as follows: S11, determining the mesh size of the bridge expansion joint (2) and adding a mesh thereto, and the mesh size of the bridge expansion joint (2) meets the requirement that the minimum wavelength contains at least six units; S12, determining the grid size of the vehicle tire finite element model (3) and adding a grid thereto, and the grid size of the vehicle tire finite element model (3) is ≤ the grid size of the bridge expansion joint (2); S13, determining the grid size of the finite length main beam (1) and adding grids thereto, and the grid size of the finite length main beam (1) is consistent with the grid size of the bridge expansion joint (2).

4. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized in that: In S21, an independent node is created at the center of the vehicle tire finite element model (3) to represent the center of mass (o), and is rigidly connected to the rim layer (35) on the inner side of the vehicle tire finite element model (3). During the inflation stage, constraints are applied to the vehicle tire finite element model (3) to constrain all degrees of freedom of the center of mass (o) so that it does not move under the action of the inflation load.

5. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized in that: In S22, before applying gravity to the vehicle tire finite element model (3), the vertical degree of freedom constraint at its center of mass (o) is released so that it can move in the vertical direction; The state switching process of steady-state-transient analysis is as follows: S221. Through steady-state analysis, the tire model is made close to a mechanical equilibrium state under the action of gravity; S221, turn to transient analysis, add 10Ns / m mass damping to the model, control it to quickly balance within 0.5s, and perform transient analysis calculation at this stage; S223. Before the transient analysis calculation is completed, the mass damping is set to zero.

6. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized by: The number of acceleration sensors on the bridge expansion joint (2) is set to be multiple, all of which are high-frequency acceleration sensors. The multiple acceleration sensors are evenly arranged at different positions in the actual measurement area of ​​the structure field test, and the multiple acceleration sensors are installed in different vertical and longitudinal directions.

7. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 6 is characterized by: In S23, when performing transient analysis, the output time interval Δt of the simulation calculation is determined according to the maximum frequency actually measured for the structure, and the calculation formula is: Δt=12f max Among them, f max is the maximum frequency of the measured results; The simulated vibration calculation results can correspond to the measured frequency; the measured time domain response is converted to the frequency domain through fast Fourier transform, and verified with the numerical simulation results, and then the finite element model of the vehicle-seam-bridge coupling structure is further adjusted.

8. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 7 is characterized by: The simulation vibration calculation results are compared with the measured results, and the following are verified: a) If the simulated vibration calculation results are highly consistent with the measured results near the peak frequency, the acceleration level change trend in the entire analysis frequency band is generally consistent, and the acceleration level error at the peak frequency is less than 10%, it means that the vehicle-joint-bridge coupling structure finite element model can accurately simulate the vibration of the vehicle passing through the expansion joint, and subsequent noise analysis can be carried out; b) If at least one of the following conditions exists: the simulated vibration calculation results are not consistent with the measured results near the peak frequency, the acceleration level change trends in the entire analysis frequency band are greatly different, and the acceleration level error at the peak frequency is ≥10%, it means that the test result error is large. At this time, it is necessary to re-examine the validity of the finite element model of the vehicle-seam-bridge coupling structure.

9. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1 is characterized by: In S3, the surface mesh of the finite element model of the vehicle-seam-bridge coupling structure is extracted as a rectangular mesh, and then the rectangular mesh is re-divided into a triangular mesh, while the rectangular mesh is retained, where the rectangular mesh is used as a plane acoustic field point and the triangular mesh is used as an acoustic boundary element model; A closed acoustic mesh is added to the outer rim layer (35) of the vehicle tire finite element model (3).

10. The method for analyzing vibration and noise characteristics of a single-slot bridge expansion joint under vehicle excitation according to claim 1, characterized in that: In S4, when analyzing the acoustic contribution of each sound source, based on the original vehicle-joint-bridge coupled acoustic boundary element model, only the acoustic meshes of the finite length main beam (1), the bridge expansion joint (2) and the vehicle tire finite element model (3) are retained to establish acoustic models containing only these three sound sources; The acoustic contribution evaluation method used is as follows: S41, obtaining the 1 / 3 octave sound pressure level of the acoustic models of three sound sources, namely, the finite length main beam (1), the bridge expansion joint (2) and the vehicle tire finite element model (3), at the sound field point by fast Fourier transform; S42, determining the dominant frequency range of each sound source according to the 1 / 3 octave sound pressure level of the acoustic models corresponding to the three sound sources at the sound field point; S43. Compare the dominant frequency range of each sound source with the 1 / 3 octave band sound pressure level calculated at the sound field point by the corresponding vehicle-seam-bridge coupled acoustic boundary element model to determine the acoustic contribution of the three sound sources.

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