Fatigue life assessment method and system for rubber outer windshield of rail vehicles

Abstract

The present invention discloses a fatigue life assessment method and system for a rubber outer windshield of a rail vehicle, including: obtaining the material density and stress-strain curve of the rubber outer windshield of the rail vehicle; calculating the coordinate value of the center of the bogie when the rail vehicle passes through curves of different radii as the displacement load of the outer windshield; based on the above data, obtaining the maximum strain value generated by the outer windshield under different curve conditions through finite element simulation analysis; according to the maximum strain value generated under the different curve conditions, and the strain-life relationship of the rubber material of the outer windshield obtained by fitting, the corresponding life value under different curve conditions is obtained. The present invention simulates the working condition of the rail vehicle's curve operation through finite element simulation, and obtains the maximum strain value of the outer windshield under the working condition, and obtains the fatigue life value of the outer windshield based on the strain-life relationship obtained by fitting, thereby realizing the fatigue life assessment of the rubber outer windshield of the vehicle.

Description

Technical Field

[0001] The invention relates to the technical field of fatigue life assessment of rubber outer windshields, and in particular to a method and system for assessing fatigue life of rubber outer windshields of rail vehicles. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As an important component of rail vehicles, the outer windshield is installed at the connection between the two car ends, which can achieve smooth connection between the car ends and improve the vehicle's drag and noise reduction performance. Figure 1 and Figure 2 The outer windshield is mainly composed of a U-shaped capsule and an aluminum frame. The capsule can be EPDM rubber. The outer windshield is a split structure, which is fixed on the two adjacent ends of the EMU. The capsules are in contact but not connected. It has good flexible deformation ability. After the rail vehicle is marshaled, the outer windshields of the adjacent ends are compressed. When the rail vehicle is in a curved running condition, the outer windshields of the two vehicles will be squeezed against each other, and the displacement between the two carriages is provided by squeezing deformation.

[0004] During high-speed operation of rail vehicles, the rubber outer windshield structure will produce lateral deformation under the action of aerodynamic loads. The deformation vibration of the outer windshield will affect the movement of the flow field around the vehicle end, thereby changing the distribution and size of the aerodynamic load, resulting in uneven distribution of aerodynamic force at the end connection of the carriage, seriously affecting driving stability; at the same time, it will also have a great impact on the fatigue life of the outer windshield. Therefore, accurate evaluation of the fatigue life of the outer windshield can timely understand the working status of the outer windshield and ensure stable operation of the vehicle.

[0005] In the existing technology, only the aerodynamic load characteristics of the outer windshield are often studied, and the evaluation of the fatigue life of the outer windshield is rare. At present, the evaluation of the fatigue life of the outer windshield is mostly carried out only through curve fatigue tests, simulating the mechanical fatigue of the outer windshield when the vehicle passes through the curve. This method can only be used for physical verification after the production is completed, and it is impossible to provide technical guidance for the early design. It is also costly and time-consuming. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a method and system for evaluating the fatigue life of a rubber outer windshield of a rail vehicle. The working condition of a rail vehicle running in curve is simulated by finite element simulation, and the maximum strain value of the outer windshield under the working condition is obtained. Based on the strain-life relationship obtained by fitting, the fatigue life value of the outer windshield is obtained, thereby realizing the fatigue life evaluation of the vehicle rubber outer windshield.

[0007] According to a first aspect of an embodiment of the present invention, a method for evaluating fatigue life of a rubber outer windshield of a railway vehicle is provided, comprising:

[0008] Obtain the material density and stress-strain curve of the rubber outer windshield of the rail vehicle;

[0009] According to the radius and number of curve paths on the rail vehicle running line, the bogie center coordinate value when the rail vehicle passes through curves with different radii is calculated as the displacement load of the outer windshield;

[0010] Based on the material density, stress-strain curve and displacement load data of the outer windshield, the maximum strain value of the outer windshield under different curve conditions is obtained through finite element simulation analysis;

[0011] According to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting, the corresponding life values ​​under the different curve working conditions are obtained.

[0012] After obtaining the corresponding life values ​​under different curve conditions, it also includes:

[0013] According to the number of curves on the rail vehicle running line and the corresponding life values ​​under the different curve working conditions, the fatigue factor generated by the curve running of the inner and outer windshields in the line running in unit time is calculated.

[0014] And, based on the fatigue factor and the service life of the outer windshield, a fatigue factor of the outer windshield caused by curved operation in line operation during the entire service life is determined.

[0015] According to a second aspect of an embodiment of the present invention, a rail vehicle rubber outer windshield fatigue life assessment system is provided, comprising:

[0016] An outer windshield parameter acquisition module is used to obtain the material density and stress-strain curve of the rail vehicle rubber outer windshield;

[0017] The displacement load calculation module is used to calculate the bogie center coordinate value when the rail vehicle passes through curves of different radii according to the curve path radius and the number of curve paths on the rail vehicle running line, as the displacement load of the outer windshield;

[0018] A maximum strain value acquisition module is used to obtain the maximum strain value of the outer windshield under different curve conditions through finite element simulation analysis based on the material density, stress-strain curve and displacement load data of the outer windshield;

[0019] The life value calculation module is used to obtain the corresponding life values ​​under different curve working conditions according to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting.

[0020] According to a third aspect of an embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, the processor being used to implement various instructions; the memory being used to store multiple instructions, the instructions being suitable for being loaded by the processor and executing the above-mentioned method for evaluating fatigue life of a rubber outer windshield of a rail vehicle.

[0021] According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, in which a plurality of instructions are stored, wherein the instructions are suitable for being loaded by a processor of a terminal device and executing the above-mentioned method for assessing fatigue life of a rubber outer windshield of a rail vehicle.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention simulates the working conditions of a train running on a curve through finite element simulation, extracts the maximum strain value of the rubber outer windshield, and estimates the fatigue life value of the rubber outer windshield based on the strain-life relationship. The safety margin is large and the conclusion is highly reliable, which can provide a reliable basis for the structural design and life estimation of the outer windshield.

[0024] (2) The present invention uses the center of the train bogie as the control point, calculates the positions of the two control points when the train runs on a curve, and uses them as the displacement load of the outer windshield in the finite element simulation; extracts the maximum strain value of the rubber outer windshield when the train runs on a curve through the finite element simulation; simplifies the three-dimensional model according to the actual dynamics of the train passing through the curve, and makes the simulation process more accurate and simple.

[0025] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic cross-sectional view of a rubber outer windshield in an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the outer windshield connection state in an embodiment of the present invention;

[0028] Figure 3 This is a flow chart of a method for evaluating fatigue life of a rubber outer windshield of a rail vehicle in an embodiment of the present invention;

[0029] Figure 4 is a stress-strain curve diagram of the rubber outer windshield material in an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of displacement load of the rubber outer windshield in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0034] Embodiment 1

[0035] In one or more embodiments, a method for evaluating fatigue life of a rubber outer windshield of a rail vehicle is disclosed, referring to Figure 3 , specifically including the following steps:

[0036] Step (1): obtaining the material density and stress-strain curve of the rubber outer windshield of a rail vehicle;

[0037] Specifically, a rail vehicle rubber windshield sample was selected and its stress S-strain ε variation law was measured through standard tests. Figure 4 The stress S-strain ε relationship curve shown;

[0038] The density and stress-strain curve of the rubber material are imported into the ABAQUS finite element software, and the best matching material parameters (including elastic modulus, Poisson's ratio, etc.) are obtained through fitting the rubber constitutive model provided by the software. Among them, the density of the rubber material is a known property, usually provided by the manufacturer, and can also be determined experimentally.

[0039] Step (2): according to the radius of the curve path and the number of curve paths on the running line of the rail vehicle, the center coordinate value of the bogie when the rail vehicle passes through curves of different radii is calculated as the displacement load of the outer windshield;

[0040] Specifically, according to the operation route, frequency and other information of the rail vehicle, the radius R of the curved path on the line and the number M' of the curved paths on the entire line are counted. Table 1 gives an example of the corresponding radius of the curved path of the rail vehicle and the number of curved paths passed each year.

[0041] Table 1 Number of curves on which trains run

[0042]

[0043]

[0044] Combination Figure 5 , taking the bogie centers (A1, B1) on both sides of the outer windshield as control points, calculate the position coordinates of the two control points when the rail vehicle passes through curves of different radii as the displacement load of the outer windshield; the coordinates include the translation values ​​of the two control points along the X and Y axes and the rotation values ​​along the Z axis. Among them, the position coordinates of the two control points are determined by drawing according to the vehicle parameters (length, fixed distance, coupler rotation center distance, coupler telescopic and stretching amount, etc.) and the curve radius; or determined by software calculation.

[0045] Step (3): Based on the material density, stress-strain curve and displacement load data of the outer windshield, the maximum strain value generated by the outer windshield under different curve conditions is obtained through finite element simulation analysis;

[0046] Specifically, the material, relative position relationship, contact relationship, displacement load and other parameters of the outer windshield capsule are defined in the finite element analysis software, and then simulation calculations are performed to extract the maximum strain value ε generated by the mutual squeezing of the rubber of the outer windshield under different curved path conditions.

[0047] In this embodiment, a tensile test is performed on the selected rubber outer windshield sample in accordance with GB / T 528-2009 to measure the tensile breaking strength of the sample.

[0048] Then, 6 to 8 stress levels were selected, and axial tensile fatigue tests were performed with a stress ratio of 0 (sine wave loading method) and a frequency of 3 to 5 Hz. The fatigue life test data under different strains ε were recorded, as shown in Table 2.

[0049] Table 2 External windshield capsule fatigue life test data

[0050] Strain ε <![CDATA[ε1]]> <![CDATA[ε2]]> … <![CDATA[ε n ]]> Number of cycles N (times) N1 N2 … N

[0051] Step (4): According to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting, the corresponding life values ​​under different curve working conditions are obtained.

[0052] Wherein, ε is the strain of the rubber material in the fatigue test, that is, ε=(Δl+l) / l; l is the test length of the rubber material, and Δl is the length change of the rubber material after the test.

[0053] The strain-life relationship of the outer windshield rubber is obtained by data fitting:

[0054] ε=a×(lgN) 2 +b×(lgN)+c (1)

[0055] a, b, c are the parameters in the fitting equation, and the parameters are different for rubber materials with different formulations.

[0056] Substitute the maximum strain value ε under different curve conditions into formula (1) to calculate the life value N corresponding to each maximum strain value.

[0057] According to the number of curves on the train running line in Table 1, the fatigue factor f generated by the outer windshield running in the curve during line operation can be calculated each year:

[0058] f=M / N (2)

[0059] Assuming that the rated service life of the outer windshield is P years, the fatigue factor F generated by the curve operation of the outer windshield during the entire service life is:

[0060] F=∑f×P=(f1+f2+…+fn)×P (3)

[0061] If F>1, the external windshield can meet the line operation requirements; if F<1, the external windshield cannot meet the line operation requirements.

[0062] Embodiment 2

[0063] In one or more embodiments, a rail vehicle rubber outer windshield fatigue life assessment system is disclosed, comprising:

[0064] An outer windshield parameter acquisition module is used to obtain the material density and stress-strain curve of the rail vehicle rubber outer windshield;

[0065] The displacement load calculation module is used to calculate the bogie center coordinate value when the rail vehicle passes through curves of different radii according to the curve path radius and the number of curve paths on the rail vehicle running line, as the displacement load of the outer windshield;

[0066] A maximum strain value acquisition module is used to obtain the maximum strain value of the outer windshield under different curve conditions through finite element simulation analysis based on the material density, stress-strain curve and displacement load data of the outer windshield;

[0067] The life value calculation module is used to obtain the corresponding life values ​​under different curve working conditions according to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting.

[0068] In some implementations, in order to evaluate whether the outer windshield can meet the line operation requirements, the method further includes:

[0069] The fatigue factor calculation module is used to calculate the fatigue factor generated by the curve operation of the inner and outer windshields in the line operation per unit time according to the number of curves on the rail vehicle operation line and the corresponding life values ​​under different curve working conditions.

[0070] Further, based on the fatigue factor and the rated service life of the outer windshield, a fatigue factor of the outer windshield generated by curved operation in line operation during the entire service life is determined.

[0071] It should be noted that the specific implementation process of the above modules has been described in detail in Example 1 and will not be described in detail here.

[0072] Embodiment 3

[0073] In one or more embodiments, a terminal device is disclosed, including a server, the server including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the method for evaluating fatigue life of a rubber outer windshield of a rail vehicle in Embodiment 1 when executing the program. For the sake of brevity, it will not be described in detail here.

[0074] It should be understood that in this embodiment, the processor may be a central processing unit CPU, and the processor may also be other general-purpose processors, digital signal processors DSP, application-specific integrated circuits ASIC, off-the-shelf programmable gate arrays FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0075] The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0076] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software.

[0077] In other embodiments, a computer-readable storage medium is disclosed, in which a plurality of instructions are stored, wherein the instructions are suitable for being loaded by a processor of a terminal device and executing the method for evaluating fatigue life of a rubber outer windshield of a rail vehicle described in Example 1.

[0078] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0079] The present application is described by flowcharts and / or block diagrams of the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0082] 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 it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating fatigue life of a rubber outer windshield of a rail vehicle, characterized in that: include: Obtain the material density and stress-strain curve of the rubber outer windshield of the rail vehicle; According to the radius and number of curve paths on the rail vehicle running line, the bogie center coordinate value when the rail vehicle passes through curves with different radii is calculated as the displacement load of the outer windshield; Based on the material density, stress-strain curve and displacement load data of the outer windshield, the maximum strain value of the outer windshield under different curve conditions is obtained through finite element simulation analysis; According to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting, the corresponding life values ​​under the different curve working conditions are obtained.

2. A method for evaluating fatigue life of a rail vehicle rubber outer windshield as claimed in claim 1, characterized in that: After obtaining the corresponding life values ​​under different curve conditions, it also includes: According to the number of curves on the rail vehicle running line and the corresponding life values ​​under the different curve working conditions, the fatigue factor generated by the curve running of the inner and outer windshields in the line running in unit time is calculated.

3. A method for evaluating fatigue life of a rail vehicle rubber outer windshield as claimed in claim 2, characterized in that: Based on the fatigue factor and the rated service life of the outer windshield, a fatigue factor of the outer windshield caused by curved operation in line operation during the entire service life is determined.

4. A method for evaluating fatigue life of a rubber outer windshield of a rail vehicle as claimed in claim 3, characterized in that: Based on the fatigue factor generated by the curve operation of the outer windshield during the entire service life of the line, it is determined whether the current outer windshield can meet the line operation requirements.

5. A method for evaluating fatigue life of a rubber outer windshield of a rail vehicle according to any one of claims 1 to 4, characterized in that: Calculate the bogie center coordinates when the rail vehicle passes through curves of different radii, including: The bogie centers (A1, B1) on both sides of the outer windshield are used as control points to calculate the bogie center coordinate values ​​when the rail vehicle passes through curves with different radii; the coordinate values ​​include the translation values ​​of the two control points along the X-axis and the Y-axis and the rotation value along the Z-axis.

6. A method for evaluating fatigue life of a rubber outer windshield of a rail vehicle according to any one of claims 1 to 4, characterized in that: The strain-life relationship of the outer windshield rubber material is obtained by fitting, including: The tensile fracture strength of the outer windshield sample was measured, and axial tensile fatigue tests were carried out on the outer windshield samples at different set stress levels. The strains of the outer windshield samples corresponding to different stress levels and the fatigue life test data corresponding to different strains were recorded. Curve fitting was performed based on the obtained data to obtain the strain-life relationship of the outer windshield rubber material.

7. A rail vehicle rubber outer windshield fatigue life assessment system, characterized in that: include: An outer windshield parameter acquisition module is used to obtain the material density and stress-strain curve of the rail vehicle rubber outer windshield; The displacement load calculation module is used to calculate the bogie center coordinate value when the rail vehicle passes through curves of different radii according to the curve path radius and the number of curve paths on the rail vehicle running line, as the displacement load of the outer windshield; A maximum strain value acquisition module is used to obtain the maximum strain value of the outer windshield under different curve conditions through finite element simulation analysis based on the material density, stress-strain curve and displacement load data of the outer windshield; The life value calculation module is used to obtain the corresponding life values ​​under different curve working conditions according to the maximum strain value generated under the different curve working conditions and the strain-life relationship of the outer windshield rubber material obtained by fitting.

8. A rail vehicle rubber outer windshield fatigue life assessment system as claimed in claim 7, characterized in that: Also includes: The fatigue life assessment module is used to calculate the fatigue factor generated by the curve operation of the inner and outer windshields in the line operation per unit time according to the number of curves on the rail vehicle operation line and the corresponding life values ​​under different curve working conditions; Based on the fatigue factor and the rated service life of the outer windshield, a fatigue factor of the outer windshield caused by curved operation in line operation during the entire service life is determined.

9. A terminal device, comprising a processor and a memory, wherein the processor is used to implement each instruction; and the memory is used to store multiple instructions, characterized in that: The instructions are suitable for being loaded by a processor and executing the method for evaluating fatigue life of a rubber outer windshield of a rail vehicle according to any one of claims 1 to 6.

10. A computer-readable storage medium storing a plurality of instructions, characterized in that: The instruction is suitable for being loaded by a processor of a terminal device and executing the method for evaluating fatigue life of a rubber outer windshield of a rail vehicle according to any one of claims 1 to 6.

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