A method for reproducing the vibration environment of a bogie in service

Abstract

The invention discloses a method for reproducing the service vibration environment of a bogie, comprising the following steps: establishing a multi-rigid-body vehicle dynamics model based on mass parameters, suspension parameters and positioning parameters of various vehicle components, connecting the axle box of the multi-rigid-body vehicle dynamics model with a vibration table, and completing the construction of a rigid-flexible coupling vehicle system dynamics model; inputting the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, driving the initial force related to the input acceleration of the vibration table, and obtaining the acceleration of the vibration table; according to the difference between the obtained acceleration of the vibration table and the measured axle box acceleration, adjusting the driving force of the vibration table by taking the difference as negative feedback, obtaining a stress distribution cloud map of the bogie flexible body changing with time by using a modal stress recovery method, identifying the weak position of the structure through the stress distribution cloud map and the stress response; performing fatigue life verification on the weak position of the structure, and performing structural optimization.

Description

Technical Field

[0001] The invention relates to the field of rail vehicles, and in particular to a method for reproducing a bogie service vibration environment. Background Art

[0002] The existing railway vehicle bogie structure design method mainly checks the static strength and fatigue strength of the structure according to the loads specified in standards such as EN13749\IEC61373, and then optimizes the design of the structure according to the strength calculation results. For example, the bogie frame usually adopts standards such as EN13749 to combine the loads at each interface of the frame for static strength and fatigue strength analysis; while the auxiliary structures of the bogie, such as the antenna beam at the end of the frame and the sand spreading device on the axle box, generally use the vibration load spectrum specified in IEC61373 for random vibration fatigue strength verification.

[0003] However, the quasi-static fatigue strength load specified in EN13749 does not take into account the impact of load frequency on the structure, while the vibration spectrum specified in IEC61373 is quite different from the vibration in the actual service environment of the bogie and cannot accurately reflect the high-frequency vibration load. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for reproducing the service vibration environment of a bogie, comprising the following steps:

[0005] Step 1: Based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, a multi-rigid body vehicle dynamics model is established. Based on the finite element model, modal analysis and substructure reduction methods are used to establish a deformable flexible body of the bogie component; an excitation table is established, and the axle box of the multi-rigid body vehicle dynamics model is connected to the excitation table to complete the construction of the rigid-flexible coupling vehicle system dynamics model;

[0006] Step 2: Input the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, drive the initial force related to the vibration table input and input acceleration, and obtain the acceleration of the vibration table;

[0007] Step 3: According to the difference between the acceleration of the vibration table and the measured acceleration of the axle box, the difference is used as negative feedback to adjust the driving force of the vibration table until the acceleration of the vibration table is consistent with the measured acceleration of the axle box, and then proceed to step 4;

[0008] Step 4: Using the modal stress recovery method, the stress time history at any node on the flexible body is output to obtain the stress response of the bogie structure, and the stress distribution cloud map of the bogie flexible body changing with time is obtained. Through the stress distribution cloud map and stress response, the position where the structural stress is greater than the material yield strength or the stress amplitude is greater than the material fatigue limit is identified, and this position is the structural weak position;

[0009] Step five: For the weak locations of the structure, fatigue life verification is performed based on the time domain method or frequency domain method of structural fatigue, and structural optimization is performed for the locations that do not meet the fatigue life requirements.

[0010] Furthermore, the multi-rigid body vehicle dynamics model is established based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, including:

[0011] The mass parameters are the mass, center of mass position, and moment of inertia of each component of the vehicle structure; the suspension parameters are the stiffness and damping of the steel springs and shock absorbers in the vehicle suspension system; the positioning parameters are the relative positional relationship of each component in the vehicle system. According to the mass parameters, suspension parameters, and positioning parameters, the bodies of each component of the vehicle are established and the corresponding parameters are assigned; according to the connection relationship between each component, an articulated relationship representing the relative degrees of freedom between each component is established; according to the suspension element parameters, a force element is established to simulate the stiffness and damping of the suspension element to complete the construction of the vehicle system model.

[0012] Furthermore, the finite element model is established based on the bogie structure, and the deformable flexible body of the bogie component is established by using modal analysis and substructure reduction methods, including obtaining the modal frequency and modal vibration shape of the bogie component by modal analysis, and then obtaining a substructure file after the model has reduced degrees of freedom according to the substructure reduction method, and establishing the deformable flexible body of the bogie component with the substructure file.

[0013] Furthermore, the measured three-dimensional acceleration of the axle box is input into the rigid-flexible coupling vehicle system dynamics model, the initial force related to the vibration table input and the input acceleration is driven to obtain the acceleration of the vibration table, including the following process: input the measured acceleration a, take the amplification factor m, obtain the initial driving force F=ma, apply the force F to the vibration table, and obtain the acceleration of the vibration table.

[0014] Furthermore, the fatigue life of the weak structural position is verified according to the time domain method or frequency domain method of structural fatigue, and the position that does not meet the fatigue life is structurally optimized, including calculating the power spectrum density of the stress response signal of the weak structural position by the Welch method according to the stress response of the weak structural position, and then calculating the spectral moment of the weak structural position according to the power spectrum density, calculating the bandwidth factor according to the Dirlik method combined with the spectral moment, calculating the damage at the weak structural position in combination with the SN curve of the weak structural position, judging whether the structural life meets the requirements according to the size of the damage value, and realizing fatigue life verification of the weak structural position.

[0015] The beneficial effect of the present invention is that: through the technical solution provided by the present invention, the line excitation that the railway vehicle will be in service can be used as input in the design stage to perform strength verification on the bogie structure, thereby finding the weak points of the structure in the design stage and performing structural optimization, reducing fatigue failure of the bogie in the actual service environment, reducing the number of structural strength tests, and reducing design costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a method for reproducing the service vibration environment of a bogie;

[0017] Figure 2 This is a schematic diagram of the principle of a method for reproducing the service vibration environment of a bogie. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail 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, that is, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention. It should be noted that relational terms such as the terms "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0021] Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a list of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of more restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0022] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0023] like Figure 1 As shown, a method for reproducing the service vibration environment of a bogie comprises the following steps:

[0024] Step 1: Based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, a multi-rigid body vehicle dynamics model is established. Based on the finite element model, modal analysis and substructure reduction methods are used to establish a deformable flexible body of the bogie component; an excitation table is established, and the axle box of the multi-rigid body vehicle dynamics model is connected to the excitation table to complete the construction of the rigid-flexible coupling vehicle system dynamics model;

[0025] Step 2: Input the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, drive the initial force related to the vibration table input and input acceleration, and obtain the acceleration of the vibration table;

[0026] Step 3: According to the difference between the acceleration of the vibration table and the measured acceleration of the axle box, the difference is used as negative feedback to adjust the driving force of the vibration table until the acceleration of the vibration table is consistent with the measured acceleration of the axle box, and then proceed to step 4;

[0027] Step 4: Using the modal stress recovery method, the stress time history at any node on the flexible body is output to obtain the stress response of the bogie structure, and the stress distribution cloud map of the bogie flexible body changing with time is obtained. Through the stress distribution cloud map and stress response, the position where the structural stress is greater than the material yield strength or the stress amplitude is greater than the material fatigue limit is identified, and this position is the structural weak position;

[0028] Step five: For the weak locations of the structure, fatigue life verification is performed based on the time domain method or frequency domain method of structural fatigue, and structural optimization is performed for the locations that do not meet the fatigue life requirements.

[0029] The multi-rigid body vehicle dynamics model is established based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, including:

[0030] The mass parameters are the mass, center of mass position, and moment of inertia of each component of the vehicle structure; the suspension parameters are the stiffness and damping of the steel springs and shock absorbers in the vehicle suspension system; the positioning parameters are the relative positional relationship of each component in the vehicle system. According to the mass parameters, suspension parameters, and positioning parameters, the bodies of each component of the vehicle are established and the corresponding parameters are assigned; according to the connection relationship between each component, an articulated relationship representing the relative degrees of freedom between each component is established; according to the suspension element parameters, a force element is established to simulate the stiffness and damping of the suspension element to complete the construction of the vehicle system model.

[0031] The method of establishing a finite element model based on the bogie structure and using modal analysis and substructure reduction methods to establish a deformable flexible body of the bogie component includes obtaining the modal frequency and modal vibration shape of the bogie component by modal analysis, and then obtaining a substructure file after the model has reduced degrees of freedom according to the substructure reduction method, and establishing the deformable flexible body of the bogie component with the substructure file.

[0032] The method of inputting the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, driving the initial force related to the input acceleration of the vibration table, and obtaining the acceleration of the vibration table includes the following process: inputting the measured acceleration a, taking the amplification factor m, obtaining the initial driving force F=ma, and applying the force F to the vibration table to obtain the acceleration of the vibration table.

[0033] The method of checking the fatigue life of the weak structural position according to the time domain method or frequency domain method of structural fatigue, and optimizing the position that does not meet the fatigue life includes calculating the power spectrum density of the stress response signal by the Welch method according to the stress response of the weak structural position, calculating the spectral moment of the weak structural position according to the power spectrum density, calculating the bandwidth factor according to the Dirlik method combined with the spectral moment, calculating the damage at the weak structural position in combination with the SN curve of the weak structural position, judging whether the structural life meets the requirements according to the size of the damage value, and realizing the fatigue life check of the weak structural position.

[0034] Specifically, based on the simpack software platform, a vehicle system dynamics model excluding the wheel-rail relationship is established.

[0035] In the modeling process, firstly, based on the mass, moment of inertia and structural parameters of each key component of the vehicle itself, the nonlinear characteristics of the dynamic parameters of the suspension components are considered to establish a multi-rigid body vehicle dynamics model. On this basis, a finite element model of the bogie structure is established, and the modal analysis and substructure reduction technology are used to import the simpack software to establish a deformable flexible body of the bogie components. At the same time, a large-mass platform is established at the bottom of the vehicle as an excitation platform, and the axle box of the vehicle system dynamics model is connected to the large-mass platform to complete the construction of the dynamics model and prepare for input excitation.

[0036] The measured axle box acceleration is input into the above-mentioned rigid-flexible coupling vehicle system dynamics model, and an initial force related to the input acceleration is input to the vibration table to drive it. For example, if the input acceleration is a, then an amplification factor m is taken to obtain the initial driving force F=ma. The force F is applied to the vibration table, and the acceleration of the vibration table is obtained as feedback, which is compared with the input acceleration. The difference is used as negative feedback to adjust the driving force of the vibration table, thereby realizing vibration control of the vibration table. This process is carried out using classic PID control.

[0037] After the vibration table reproduces the input acceleration, the modal stress recovery method can be used to output the stress time history at any node on the flexible body to obtain the stress response of the bogie structure, and the stress distribution cloud map of the bogie flexible body can be obtained over time. Through the stress cloud map and stress response, the location with large structural stress, that is, the weak structural location, can be identified; then, according to the time domain method or frequency domain method of structural fatigue, the fatigue life of the weak structural location can be checked, and the location that does not meet the fatigue life can be optimized.

[0038] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for reproducing the vibration environment of a bogie in service, characterized in that: The steps include: Step 1: Based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, a multi-rigid body vehicle dynamics model is established, a finite element model is established based on the bogie structure, and a deformable flexible body of the bogie component is established using modal analysis and substructure reduction methods; an excitation table is established, and the axle box of the multi-rigid body vehicle dynamics model is connected to the excitation table to complete the construction of the rigid-flexible coupling vehicle system dynamics model; Step 2: Input the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, drive the initial force related to the vibration table input and input acceleration, and obtain the acceleration of the vibration table; Step 3: According to the difference between the acceleration of the vibration table and the measured acceleration of the axle box, the difference is used as negative feedback to adjust the driving force of the vibration table until the acceleration of the vibration table is consistent with the measured acceleration of the axle box, and then proceed to step 4; Step 4: Using the modal stress recovery method, the stress time history at any node on the flexible body is output to obtain the stress response of the bogie structure, and the stress distribution cloud map of the bogie flexible body changing with time is obtained. Through the stress distribution cloud map and stress response, the position where the structural stress is greater than the material yield strength or the stress amplitude is greater than the material fatigue limit is identified, and this position is the structural weak position; Step five: For the weak locations of the structure, fatigue life verification is performed based on the time domain method or frequency domain method of structural fatigue, and structural optimization is performed for the locations that do not meet the fatigue life requirements.

2. A method for reproducing the service vibration environment of a bogie according to claim 1, characterized in that: The multi-rigid body vehicle dynamics model is established based on the mass parameters, suspension parameters and positioning parameters of each vehicle component, including: The mass parameters are the mass, center of mass position, and moment of inertia of each component of the vehicle structure; the suspension parameters are the stiffness and damping of the steel springs and shock absorbers in the vehicle suspension system; the positioning parameters are the relative positional relationship of each component in the vehicle system. According to the mass parameters, suspension parameters, and positioning parameters, the bodies of each component of the vehicle are established and the corresponding parameters are assigned; according to the connection relationship between each component, an articulated relationship representing the relative degrees of freedom between each component is established; according to the suspension element parameters, a force element is established to simulate the stiffness and damping of the suspension element to complete the construction of the vehicle system model.

3. A method for reproducing the service vibration environment of a bogie according to claim 2, characterized in that: The method of establishing a finite element model based on the bogie structure and using modal analysis and substructure reduction methods to establish a deformable flexible body of the bogie component includes obtaining the modal frequency and modal vibration shape of the bogie component by modal analysis, and then obtaining a substructure file after the model has reduced degrees of freedom according to the substructure reduction method, and establishing the deformable flexible body of the bogie component with the substructure file.

4. A method for reproducing the service vibration environment of a bogie according to claim 1, characterized in that: The method of inputting the measured three-dimensional acceleration of the axle box into the rigid-flexible coupling vehicle system dynamics model, driving the initial force related to the input acceleration of the vibration table, and obtaining the acceleration of the vibration table includes the following process: inputting the measured acceleration a, taking the amplification factor m, obtaining the initial driving force F=ma, and applying the force F to the vibration table to obtain the acceleration of the vibration table.

5. The method for reproducing the service vibration environment of a bogie according to claim 1, characterized in that: The weak locations of the structure are checked for fatigue life according to the time domain method or frequency domain method of structural fatigue, and the locations that do not meet the fatigue life requirements are optimized. It includes calculating the power spectral density of the stress response signal using the Welch method based on the stress response of the weak position of the structure, calculating the spectral moment of the weak position of the structure based on the power spectral density, calculating the bandwidth factor based on the Dirlik method combined with the spectral moment, calculating the damage at the weak position based on the SN curve of the weak position of the structure, judging whether the structural life meets the requirements based on the size of the damage value, and realizing fatigue life verification of the weak position of the structure.

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