Rail vehicle frame and design method and device thereof

Abstract

The present invention provides a rail vehicle frame and a design method and device thereof. The rail vehicle frame design method comprises the following steps: (A) taking the structural design parameters of the rail vehicle and the structural design parameters of the track as input, establishing a dynamic model of the rail vehicle and the track in a simulation space; (B) applying an excitation signal of frame vibration to a corresponding position of the dynamic model, and applying a track unevenness excitation signal to the dynamic model, to obtain a stress curve of each analyzed part in the frame; (C) calculating the expected life L of each analyzed part; (D) comparing the expected life of each analyzed part calculated in step (C) with the life design value of the frame respectively, if the calculated expected life of each analyzed part is not less than the life design value of the frame, and the difference between the calculated expected life of each analyzed part and the life design value of the frame is not less than the corresponding safety margin, then the structural design parameters of the frame meet the requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of rail vehicles, and relates to a frame design method and device in a rail vehicle bogie, and a rail vehicle frame. Background Art

[0002] The bogie is one of the main components of rail vehicles. Its main functions are to bear the load of the vehicle body and equipment, generate traction and braking force, alleviate the impact of the track on the vehicle, and guide the vehicle to run safely. During operation, the bogie has to withstand the unevenness of the track, which will cause vibration. As the vehicle speed increases, the frame vibration becomes more severe, which may eventually lead to fatigue failure. Therefore, fatigue life design of the bogie frame is required during the design stage.

[0003] At present, the high-cycle fatigue design theories and methods used in the rail vehicle structure design process all start from the SN curve of the material, consider the influence of various coefficients, derive the fatigue design curve, and then perform fatigue resistance verification and design based on the curve.

[0004] like Figure 1 The figure shows the SN curve of a typical material, where Sf is the fatigue limit. A load (stress) lower than the fatigue limit Sf will not cause any damage to the material, which means that the material has an infinite life.

[0005] In the existing rail vehicle design, the maximum fatigue cycle load that the structure can withstand is ensured to be within the fatigue limit of the material during design, that is, the stress on various parts of the rail vehicle (such as vulnerable locations) is less than the fatigue limit Sf, so that the rail vehicle has an infinite fatigue life. However, the rail vehicle bogie designed in this way is heavy and costly, and it is not easy to achieve lightweight rail vehicles. Summary of the invention

[0006] The problem to be solved by the present invention is that the frame designed by the infinite life design method in the existing rail vehicle bogie frame design is heavy, costly and difficult to achieve lightweight rail vehicles. A method and device for designing a rail vehicle frame at key parts of the frame are provided.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a rail vehicle frame design method, comprising the following steps:

[0008] Step (A): using structural design parameters of the rail vehicle and the rail as input, establishing a dynamic model of the rail vehicle and the rail in a simulation space, wherein the structural design parameters of the rail vehicle include structural design parameters of the frame;

[0009] Step (B): applying an excitation signal of frame vibration to a corresponding position of the dynamic model, and applying a track irregularity excitation signal to the dynamic model to obtain a stress curve of each analyzed position in the frame;

[0010] The horizontal axis of the stress curve is the running time or running distance of the rail vehicle in the simulation space, and the vertical axis is the stress on the analyzed part;

[0011] The track irregularity excitation signal is a track irregularity signal collected by a detection vehicle traveling on the track in an actual test;

[0012] The excitation signal of the frame vibration is a vibration signal of a first component measured in an actual test, wherein the first component is defined as: when the rail vehicle is running, the vibration of the frame is at least caused by the vibration of the first component;

[0013] Step (C): Calculate the expected life span L of each analyzed part using the following formula:

[0014] L = 1 / D;

[0015] The total damage value D of each analyzed part is calculated using the following formula:

[0016] D=(n1 / N1)+(n2 / N2)+……+(n K / N K );

[0017] Wherein, K is the number of stress levels in the stress curve of the analyzed part in step (B); n i is the number of cycles in the stress curve of the analyzed part in step (B) for the stress value of the i-th level, N i is the number of stress cycles required for the frame material to reach failure under the stress value of the i-th level, i = 1, 2, ..., K;

[0018] Step (D): Compare the expected life of each analyzed part calculated in step (C) with the life design value of the frame. If the expected life of each analyzed part calculated is not less than the life design value of the frame, the structural design parameters of the frame meet the requirements.

[0019] In the present invention, when analyzing the frame, the vibration signal of the first component that affects the frame vibration is added (the horizontal axis is the time or distance of the rail vehicle running, and the vertical axis is the vibration value of the first component) and the track unevenness signal measured by the detection vehicle (the horizontal axis is the time or distance of the rail vehicle running, and the vertical axis is the track unevenness amplitude), that is, a more comprehensive factor affecting the frame vibration is considered, so a more accurate stress curve of each analyzed part can be obtained. The method of the present application is to design a rail vehicle, so it has not yet formed a product and cannot run on an actual track. By using a detection vehicle, the real track unevenness signal can also be collected. Compared with the method of using a simulated track unevenness signal that has not been measured as an excitation, the method of the present application can better reflect the actual running conditions of the rail vehicle, so that the calculation is more in line with the actual situation. According to the stress curve, the expected life of the analyzed part can be calculated. By comparing the expected life of each analyzed part with the life design value of the frame, it can be determined whether the expected life obtained by simulation meets the requirements. If the expected life obtained by simulation meets the requirements, it means that the structural design parameters of the frame meet the requirements, that is, the frame design is completed. In the present invention, since the life design value of the frame is not obtained according to the infinite life design principle of the SN curve in the prior art, the stress that each position of the frame can withstand is significantly higher than the stress value that the frame can withstand obtained by the infinite life design principle of the prior art, so the frame design can be more lightweight and save material costs. Moreover, since the expected life of each analyzed part (i.e., the key part of the frame) is calculated in the simulation of the present method, although the key part of the frame structure has to withstand a stress greater than the fatigue limit in the SN curve, the expected life of the analyzed part can still meet the requirements (i.e., greater than the life design value of the frame, and the difference with the life design value of the frame is not less than the safety margin), so that while making the frame lightweight, the safety of the designed frame can still be ensured.

[0020] In the above technical solution, in the step (C), if the total damage value D of the analyzed part is ≥ 1, it is determined that the analyzed part is damaged under the conditions of the structural design parameters of the frame.

[0021] Through the above judgment, it can be determined whether the analyzed part is damaged, that is, whether the structural design parameters of the frame are available.

[0022] In the above technical solution, in step (D), if the calculated expected life of each analyzed part is not less than the life design value of the frame, and the difference between the calculated expected life of each analyzed part and the life design value of the frame is not less than the corresponding safety margin, then the structural design parameters of the frame meet the requirements; otherwise, adjust the structural design parameters of the frame related to the analyzed part and return to step (A).

[0023] Through the above arrangement, some analyzed parts of the frame not only have an expected life span greater than the design life span value of the frame, but also have a certain safety margin, further ensuring operational safety.

[0024] In the above technical solution, in step (D), if the calculated expected life of the analyzed part is less than the design life value of the frame, the structural design parameters of the frame related to the analyzed part are adjusted and the process returns to step (A).

[0025] In the present invention, by judging whether the expected life of the analyzed part meets the requirements, it can be judged whether the structural design parameters of the frame related to the part meet the requirements, so that corresponding adjustments can be made quickly in the design to improve the design efficiency.

[0026] In the above technical solution, the vibration signal of the first component is a vibration signal of the first component measured by running the first component when the mounting carrier of the first component is stationary.

[0027] In the present invention, since the positions of the first component and the frame can be determined when the simulated rail vehicle is running, the mounting carrier of the first component can be kept stationary while the first component is running in actual measurement, so that the vibration signal of the first component can be conveniently measured with fewer other interference factors.

[0028] In a preferred solution, the mounting carrier of the first component is a mounting base arranged on the ground or a detection vehicle located on a track.

[0029] In a preferred solution, the vibration signal of the first component is an acceleration signal of the rail vehicle in the lateral and vertical directions.

[0030] In the above technical solution, the first component includes a traction motor and a gear box.

[0031] In the above technical solution, the track irregularity signal includes an irregularity signal collected by the detection vehicle under various operating line conditions.

[0032] Various operating line conditions are various operating line conditions of the designed rail vehicle (various line conditions to be operated). Through the above settings, the track irregularity signal collected by the detection vehicle in the actual test can reflect the actual operating line conditions of the designed rail vehicle, so that the simulation is more in line with the actual situation.

[0033] Preferably, the track irregularity signal is an irregularity amplitude signal.

[0034] In the above technical solution, the analyzed parts include the connection positions between the frame and other components of the rail vehicle, and the analyzed parts also include weld positions on the frame whose spacing from each connection position is not greater than a first preset distance.

[0035] Preferably, the analyzed parts include the connection position between the frame and the primary suspension device, the connection position between the frame and the secondary suspension device, and the connection position between the frame and the gear box.

[0036] More preferably, the analyzed site includes a first connection position, a second connection position, a third connection position, a fourth connection position, a fifth connection position, and a sixth connection position;

[0037] The analyzed part also includes a weld position on the frame that is not more than the first preset distance from the first connection position, a weld position that is not more than the first preset distance from the second connection position, a weld position that is not more than the first preset distance from the third connection position, a weld position that is not more than the first preset distance from the fourth connection position, a weld position that is not more than the first preset distance from the fifth connection position, and a weld position that is not more than the first preset distance from the sixth connection position;

[0038] The first connection position is the connection position between the frame and the primary spring;

[0039] The second connection position is the connection position between the frame and a series of vertical shock absorbers;

[0040] The third connection position is the connection position between the frame and the secondary spring;

[0041] The fourth connection position is the connection position between the frame and the secondary vertical shock absorber;

[0042] The fifth connection position is the connection position between the frame and the secondary lateral shock absorber;

[0043] The sixth connection position is the connection position between the frame and the gear box.

[0044] During the research, the applicant found that the positions where the frame is connected to other structures of the bogie, and the positions of the welds near the connection positions are key positions of the frame (i.e. positions that are more prone to damage), so these positions are analyzed as analyzed parts. If the expected life of these positions meets the requirements, then other positions of the frame are more likely to meet the requirements.

[0045] In the above technical solution, the dynamic model is a rigid-flexible coupling dynamic model.

[0046] The present invention also provides a rail vehicle frame design device, characterized in that it includes a computer device;

[0047] The computer device is configured or programmed to execute the steps of any one of the above methods.

[0048] The present invention also provides a rail vehicle frame, wherein the structural design parameters of the rail vehicle frame are obtained according to any of the methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0050] Figure 1 It is a schematic diagram of the SN curve of typical materials.

[0051] Figure 2 It is a schematic flow chart of the method of the present invention.

[0052] Figure 3 It is a schematic diagram of the stress curve.

[0053] Figure 4 It is a schematic diagram of the number of stress cycles required for the structural material to reach failure under the stress value determined in the SN curve. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] refer to Figure 2 The present invention provides a rail vehicle frame design method, which is characterized by comprising the following steps:

[0056] Step (A): taking the structural design parameters of the rail vehicle and the structural design parameters of the track as input, and establishing a dynamic model of the rail vehicle and the track in a simulation space, wherein the structural design parameters of the rail vehicle include the structural design parameters of the frame;

[0057] Step (B): applying an excitation signal of frame vibration to a corresponding position of the dynamic model, and applying a track irregularity excitation signal to the dynamic model to obtain a stress curve of each analyzed position in the frame;

[0058] The horizontal axis of the stress curve is the running time or running distance of the rail vehicle in the simulation space, and the vertical axis is the stress on the analyzed part;

[0059] The track irregularity excitation signal is a track irregularity signal collected by a detection vehicle traveling on the track in an actual test;

[0060] The excitation signal of the frame vibration is a vibration signal of a first component measured in an actual test, wherein the first component is defined as: when the rail vehicle is running, the vibration of the frame is at least caused by the vibration of the first component;

[0061] Step (C): Calculate the expected life span L of each analyzed part using the following formula:

[0062] L = 1 / D;

[0063] The total damage value D of each analyzed part is calculated using the following formula:

[0064] D=(n1 / N1)+(n2 / N2)+……+(n K / N K );

[0065] Wherein, K is the number of stress levels in the stress curve of the analyzed part in step (B); n i is the number of cycles in the stress curve of the analyzed part in step (B) for the stress value of the i-th level, N i is the number of stress cycles required for the frame material to reach failure under the stress value of the i-th level (which can be obtained based on the SN curve of the frame material), i = 1, 2, ..., K;

[0066] Step (D): Compare the expected life of each analyzed part calculated in step (C) with the life design value of the frame. If the calculated expected life of each analyzed part is not less than the life design value of the frame, the structural design parameters of the frame meet the requirements; otherwise, adjust the structural design parameters of the frame related to the analyzed part and return to step (A).

[0067] The expected life of the analyzed part can be considered as the time from the time the rail vehicle is put into use until the analyzed part is damaged or broken.

[0068] In the present application, the corresponding position of the dynamic model refers to the position where the excitation signal of the frame vibration should be applied. For example, when the first component is a traction motor, the corresponding excitation signal of the frame vibration is the vibration signal of the traction motor, and the excitation signal is applied at the position of the traction motor in the dynamic model.

[0069] If the stress curve obtained in step (B) is Figure 4, that is, K = 2, there are two levels of stress in the stress curve. Figure 3 The stress values ​​of the first and second levels are determined to be S1 and S2 respectively, and the number of cycles n1 and n2 of the stress values ​​of the first and second levels in the stress curve can be determined to be 2. The SN curve of the structural material can also be referred to Figure 4 By querying Figure 4 , that is, the number of stress cycles N1 and N2 required for the frame material to reach failure under the first and second level stress values ​​can be obtained. Figure 4 The process of how to obtain the N1 value from S1 is shown in FIG.

[0070] When the obtained stress curve is more complex, the random vibration load spectrum can be counted according to the rainflow cycle counting method.

[0071] Table 1 shows an example of obtaining the full-cycle load spectrum of the key parts of the frame based on the stress curve in the simulation.

[0072] Table 1 Load spectrum of all working conditions of key parts of the frame obtained by simulation

[0073]

[0074] Dynamic amplitude refers to the stress at each level. For example, the first level of stress is 5Mpa, corresponding to n1=500000, and the second level of stress is 20Mpa, corresponding to n2=40145. Frequency is n in the formula. i .

[0075] According to the SN curve of the material of the key parts of the frame, taking into account factors such as the size, shape, surface processing method and stress concentration factor of the structure, the life of the key parts of the frame is calculated according to Miner's linear cumulative damage theory.

[0076] The specific calculation method of the total damage value D is as follows:

[0077] Step (C1): Calculate the damage amount under a certain fixed load based on the SN curve of the material. You can use the formula d i =n i / N i .

[0078] Where, d i Represents the amount of damage under a certain fixed load. N i Represents the fatigue life (number of load cycles) of the material under this fixed load. N i Represents the number of cycles that this fixed load is subjected to in the full working condition of the structure.

[0079] Step (C2): Based on all the fixed loads and corresponding number of cycles borne by the key parts of the frame under all working conditions, calculate the total damage of the key parts of the frame under the action of all the fixed loads.

[0080] Step (C3): Life span determination: When the total damage D≥1, it is determined to be material failure.

[0081] Step (C4): Considering a certain safety margin, compare the life calculation result with the design result. If the calculation result is greater than the design result, the design meets the requirements; otherwise, redesign.

[0082] Compared with the existing rail vehicle bogie frame design, the bogie frame key part life design method provided by the present invention has the following characteristics:

[0083] 1) Track excitation takes into account the actual track irregularity excitation spectrum during vehicle operation;

[0084] 2) Considering the frame to be flexible, a vehicle-track rigid-flexible coupling system dynamics model based on the frame flexibility was established, and the full-condition load characteristics of the frame were obtained based on the real track excitation, bogie excitation and operating conditions;

[0085] 3) Combined with the SN curve of the key parts material, Miner linear cumulative damage theory is used to calculate the life of the key parts of the structure. When the calculated life is greater than the design life, the design meets the requirements; otherwise, it is redesigned.

[0086] In the step (D), the following judgment may also be made: if the calculated expected life of each analyzed part is not less than the life design value of the frame, and the difference between the calculated expected life of each analyzed part and the life design value of the frame is not less than the corresponding safety margin, then the structural design parameters of the frame meet the requirements; otherwise, adjust the structural design parameters of the frame related to the analyzed part and return to step (A).

[0087] In the step (C), if the total damage value D of the analyzed part is ≥ 1, it is determined that the analyzed part is damaged under the conditions of the structural design parameters of the frame.

[0088] In the present invention, the structural design parameters of the track can reflect the direction of the actual track, or the actual track direction can be ignored, and only a straight track can be established, and only the structural parameters of the track and the relative position of the track vehicle can be considered. After the track irregularity excitation is added to the model, even if the track established in the model is straight, rather than the extension direction of the actual track when the actual detection vehicle measures the track irregularity excitation, it does not actually affect the determination of the stress curve of the analyzed part on the frame.

[0089] The structural design parameters of the track include the structural design parameters of the main track structure. The main track structure includes rails, fasteners, track plates (sleepers) and roadbeds. According to the actual track structural design parameter values, the finite element method is used to establish the elastic model of the main structure of each track, which is imported into the dynamic model. In the dynamic software, the dynamic model of the rigid-flexible coupling system of the track vehicle and the track is established together with the model of the track vehicle (including the frame, car body, and the primary and secondary suspension devices of the vehicle).

[0090] The life design value of the frame can be obtained according to the requirements of the owner, according to the design needs or through engineering experience. When determining the structural design parameters of the rail vehicle frame, the life design value of the frame is also a consideration. The structural parameter values ​​of the frame can be designed according to the life design value of the frame, for example, according to the design parameters of existing projects, experience, etc. However, the structural parameter values ​​of the designed frame need to be verified by this method later. The running distance of the rail vehicle can be obtained by multiplying the running time and the speed of the rail vehicle, or by integrating the speed of the rail vehicle over the running time.

[0091] The vibration signal of the first component is a vibration signal of the first component measured by operating the first component when the mounting carrier of the first component is stationary;

[0092] Preferably, the mounting carrier of the first component is a mounting base arranged on the ground or a detection vehicle located on a track;

[0093] Preferably, the vibration signal of the first component is an acceleration signal of the rail vehicle in the lateral and vertical directions.

[0094] The components that affect the vibration of the frame, i.e., the first components, are mainly other components in the bogie that vibrate during operation, and components that are directly connected to the bogie and vibrate during operation. In this embodiment, the first components include a traction motor and a gear box.

[0095] In actual tests, the operating route of the test vehicle includes various operating route conditions of the designed rail vehicle.

[0096] The track irregularity signal includes an irregularity signal collected by a detection vehicle under various operating line conditions of the designed rail vehicle.

[0097] The operating line conditions of rail vehicles may include turning, straight lines, climbing slopes, driving in tunnels, etc., which are determined based on the actual line conditions on which the designed rail vehicle will operate.

[0098] The track irregularity signal is an irregularity amplitude signal.

[0099] The analyzed parts include connection positions between the frame and other components of the rail vehicle, and the analyzed parts also include weld positions on the frame with a spacing between each connection position not greater than a first preset distance.

[0100] Preferably, the analyzed parts include the connection position between the frame and the primary suspension device, the connection position between the frame and the secondary suspension device, and the connection position between the frame and the gear box.

[0101] More preferably, the analyzed site includes a first connection position, a second connection position, a third connection position, a fourth connection position, a fifth connection position, and a sixth connection position;

[0102] The analyzed part also includes a weld position on the frame that is not more than the first preset distance from the first connection position, a weld position that is not more than the first preset distance from the second connection position, a weld position that is not more than the first preset distance from the third connection position, a weld position that is not more than the first preset distance from the fourth connection position, a weld position that is not more than the first preset distance from the fifth connection position, and a weld position that is not more than the first preset distance from the sixth connection position;

[0103] The first connection position is the connection position between the frame and the primary spring;

[0104] The second connection position is the connection position between the frame and a series of vertical shock absorbers;

[0105] The third connection position is the connection position between the frame and the secondary spring;

[0106] The fourth connection position is the connection position between the frame and the secondary vertical shock absorber;

[0107] The fifth connection position is the connection position between the frame and the secondary lateral shock absorber;

[0108] The sixth connection position is the position where the frame is connected to the gear box.

[0109] The position where the frame is connected to the primary spring and the position where the frame is connected to the primary vertical shock absorber are located at the end of the frame. The position where the frame is connected to the secondary spring and the position where the frame is connected to the secondary vertical shock absorber are located in the middle of the frame. The position where the frame is connected to the gear box is located in the middle of the frame. The first preset distance can be 400 mm.

[0110] The dynamic model is a rigid-flexible coupling dynamic model.

[0111] The present invention also provides a rail vehicle frame design device, including a computer device;

[0112] The computer device is configured or programmed to perform the steps of the method.

[0113] The present invention also provides a rail vehicle frame, wherein the structural design parameters of the rail vehicle frame are obtained according to any of the methods described above.

[0114] At present, the structural design of rail vehicles adopts infinite fatigue life design, that is, the maximum stress at the dangerous point of the structure is controlled not to exceed the fatigue limit. Practice has proved that when the maximum stress at the dangerous point of the rail vehicle structure exceeds the fatigue limit, the entire structure does not suffer fatigue damage. The infinite fatigue life design uses the right branch of the SN curve - the horizontal part of the curve, while the limited fatigue life design uses the left branch of the SN curve - the oblique part of the curve. The method of using the left branch of the SN curve - the oblique part of the curve is to adopt life design, and the ordinate of the oblique line of the curve is the designed life. The present invention provides a life design method for key parts of the bogie frame, which obtains the full-condition load characteristics of the key parts of the frame, and then uses the fatigue damage accumulation method to calculate the frame life. It can not only ensure the safe use of the frame within a certain period of time, but also make the frame more lightweight and save design costs.

[0115] Existing designs often adopt infinite fatigue design ideas for the sake of conservatism, while finite fatigue life design can actually meet design needs under certain conditions. For example, by strictly adopting the method proposed in this patent, it is completely possible to achieve life design of key parts of the structure.

[0116] The number of cycles when fatigue failure occurs at a certain stress amplitude on the SN curve.

[0117] The present invention provides a framework design method, which mainly includes obtaining the full-operation load characteristics of key parts of the framework; on this basis, calculating the life of the key parts of the framework.

[0118] Obtaining full-condition load characteristics of key parts of the structure includes:

[0119] Step (A): Based on the structural design parameters of the vehicle and track system and the multi-body dynamics theory, a vehicle-track rigid-flexible coupling system dynamics model taking into account the flexibility of the structure is established using finite element technology, and the model is verified.

[0120] The vehicle-track rigid-flexible coupling system dynamics model is mainly established using dynamics software (such as UM) and finite element software (such as HyperMesh). The steps of building the dynamics model of the rail vehicle include:

[0121] A1. Establish a three-dimensional finite element model of the structure.

[0122] According to the three-dimensional solid model of the frame, the finite element software Hypermesh or Ansys is used to establish the three-dimensional solid finite element model of the frame, and modal calculation is performed, requiring the calculated modal frequency to be greater than 100Hz. The modal calculation results of the frame are compared with the test results. According to the experience of engineering simulation, the error between the calculated modal and the test modal is required to be controlled within 5%, otherwise, the finite element model of the frame is re-optimized.

[0123] A2. Convert the three-dimensional finite element model of the framework into an elastic body model.

[0124] After the finite element model of the frame is established, the finite element model of the frame is converted into an elastic body model that can be imported into the dynamics software through the finite element software and multi-body dynamics software interface program.

[0125] A3. In the dynamics software, based on the structural parameters of the vehicle suspension system, the vehicle rigid body dynamics model is established using the dynamics software.

[0126] Establish rigid body models such as wheelset, axle box, and vehicle body, establish damping models such as primary vertical shock absorber, secondary vertical shock absorber, and secondary lateral shock absorber, and establish stiffness models such as primary spring and secondary spring;

[0127] A4. Based on the imported frame elastic body model, a rigid-flexible coupling system dynamics model considering the frame elasticity (flexibility) is established, which is mainly established using dynamics software such as UM and Simpack. Its expression is: Where: M represents the vehicle system mass matrix, C represents the vehicle system damping matrix, K represents the vehicle system stiffness matrix, and F(x) represents the vehicle system force matrix.

[0128] The finite element technology is generally used for modeling the frame flexibility. The modeling method is to perform entity modeling and assign material parameters in finite element software such as Hypermesh or Ansys based on the actual model of the frame structure. The method for building the dynamic model of rail vehicles is detailed in the reference "Study on the Curved Passing Performance of High-Speed ​​Vehicles Considering Frame Flexibility".

[0129] After the vehicle-track rigid-flexible coupling system dynamics model is established, its accuracy needs to be verified. Using this model, the running speed of the vehicle is defined as zero, that is, the vehicle is in a stationary state. The suspension frequency and vibration mode of the vehicle system are solved by linear analysis, and compared with the test results to ensure that the vehicle-track rigid-flexible coupling system dynamics model is established accurately.

[0130] Step (B) is based on the actual track irregularity excitation spectrum and bogie excitation, and taking into account the actual vehicle operating conditions, the above dynamic model is used to calculate the full-condition loads of the key parts of the frame.

[0131] In the dynamics software, based on the established dynamics model, the full-condition loads of key parts can be solved by simulation means by considering the actual track irregularity excitation spectrum, bogie excitation and actual vehicle operating conditions.

[0132] The bogie excitation includes but is not limited to the power vehicle bogie traction motor excitation and gearbox excitation. The excitation generated by the motor and gearbox is an important factor affecting the vibration of the bogie frame. The real motor and gearbox excitation is generally obtained by experimental methods. When the vehicle is stationary, the motor or gearbox is operated alone, and then the vibration characteristics of the motor or gearbox (usually expressed as acceleration a) are tested through vibration and noise test software, thereby obtaining the acceleration vibration signal a(t) of the motor or gearbox that changes with time.

[0133] When there are multiple excitation sources of frame vibration, the calculation methods are definitely different. For example, when there is a traction motor on the bogie, the excitation is related to the motor speed, while the excitation of the gearbox is related to the structure of the box. When there are multiple different excitation sources of frame vibration, the excitation signals of various frame vibrations are added to the dynamic model in the simulation space for analysis. The excitation signal of the frame vibration is determined according to the actual situation.

[0134] The flexible modeling of the frame includes but is not limited to establishing a detailed model of the frame weld, which is generally modeled using solid elements.

[0135] The track irregularity is generally tested by a comprehensive inspection train or a track inspection vehicle on the actual train operation line to obtain the track irregularity spectrum value. The track irregularity signal mainly includes track height, track direction, level, and track gauge irregularity signals, which can be expressed by the formula y=f(x), where x represents the operating mileage or operating time, and y represents the height, track direction, level, and track gauge irregularity amplitude.

[0136] The actual track irregularity measured data needs to eliminate outliers to obtain the track irregularity excitation signal, otherwise large errors will occur.

[0137] The full-operating load characteristics of the key parts are usually obtained in the dynamics software. Based on the rigid-flexible coupling system dynamics model established above, the traction motor excitation, gearbox excitation a(t) and measured track unevenness spectrum excitation f(x) are imported through the data import interface in the dynamics software. Then, according to the design interface, the key parts of the structure are determined, and the load characteristics of the key parts of the full-operating conditions are calculated through simulation using the rigid-flexible coupling system dynamics model.

[0138] The present invention can accurately obtain the full-operating load characteristics of the frame during the frame design stage; and can perform life design on the frame during the frame design stage.

[0139] This embodiment is described by taking a key part of a railway vehicle structure as an example. Figure 2 As shown, the specific steps are as follows:

[0140] 1) Based on the three-dimensional solid model of the initial design of the frame, a finite element model considering the flexibility of the frame is established using finite element theory;

[0141] 2) Based on the theory of multi-body system dynamics and combined with the structural parameters of the vehicle and track systems, a dynamic model of the vehicle-track rigid-flexible coupling system considering the flexibility of the structure is established;

[0142] 3) Based on the real track irregularity excitation spectrum, bogie excitation and vehicle operating conditions, the full-condition load characteristics of key parts of the frame are obtained through simulation calculation of the vehicle-track rigid-flexible coupling system dynamics model;

[0143] 4) Count the rain flow cycles of the loads at key locations, combine the SN curves of key structural materials, and use Miner’s fatigue cumulative damage theory to calculate the fatigue life of the frame;

[0144] 5) Considering a certain safety margin, compare the fatigue life calculation result with the design life. If the calculation result is greater than the design result, the life design is completed. Otherwise, the frame is redesigned until the calculation result of the frame fatigue life is greater than the design life.

[0145] Any method used to obtain the full-operating load characteristics of the key parts of the frame falls within the protection scope of the present invention; any method used to calculate the life of the frame based on the full-operating load characteristics of the key parts of the frame falls within the protection scope of the present invention.

[0146] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0147] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent. After reading the present invention, modifications of various equivalent forms of the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

Claims

1. A rail vehicle frame design method, characterized in that: The steps include: Step (A): taking the structural design parameters of the rail vehicle and the structural design parameters of the track as input, and establishing a dynamic model of the rail vehicle and the track in a simulation space, wherein the structural design parameters of the rail vehicle include the structural design parameters of the frame; Step (B): applying an excitation signal of frame vibration to a corresponding position of the dynamic model, and applying a track irregularity excitation signal to the dynamic model to obtain a stress curve of each analyzed position in the frame; The horizontal axis of the stress curve is the running time or running distance of the rail vehicle in the simulation space, and the vertical axis is the stress on the analyzed part; The track irregularity excitation signal is a track irregularity signal collected by a detection vehicle traveling on the track in an actual test; The excitation signal of the frame vibration is a vibration signal of a first component measured in an actual test, wherein the first component is defined as: when the rail vehicle is running, the vibration of the frame is at least caused by the vibration of the first component; Step (C): Calculate the expected life span L of each analyzed part using the following formula: L = 1 / D; The total damage value D of each analyzed part is calculated using the following formula: D=(n1 / N1)+(n2 / N2)+……+(n K / N K ); Wherein, K is the number of stress levels in the stress curve of the analyzed part in step (B); n i is the number of cycles in the stress curve of the analyzed part in step (B) for the stress value of the i-th level, N i is the number of stress cycles required for the structural material to reach failure under the stress value of the i-th level, i=1,2,…,K; Step (D): Compare the expected life of each analyzed part calculated in step (C) with the life design value of the frame. If the expected life of each analyzed part calculated is not less than the life design value of the frame, the structural design parameters of the frame meet the requirements.

2. The rail vehicle frame design method according to claim 1, characterized in that: In the step (D), if the calculated expected life of each analyzed part is not less than the life design value of the frame, and the difference between the calculated expected life of each analyzed part and the life design value of the frame is not less than the corresponding safety margin, then the structural design parameters of the frame meet the requirements; otherwise, adjust the structural design parameters of the frame related to the analyzed part and return to step (A).

3. The rail vehicle frame design method according to claim 1, characterized in that: In the step (D), if the calculated expected life of the analyzed part is less than the design life value of the frame, the structural design parameters of the frame related to the analyzed part are adjusted and the process returns to step (A).

4. The rail vehicle frame design method according to claim 1, characterized in that: The vibration signal of the first component is a vibration signal of the first component measured by running the first component when a mounting carrier of the first component is stationary.

5. The rail vehicle frame design method according to claim 4, characterized in that: The mounting carrier of the first component is a mounting seat arranged on the ground or a detection vehicle located on a track.

6. The rail vehicle frame design method according to claim 4, characterized in that: The vibration signal of the first component is an acceleration signal of the rail vehicle in the lateral direction and the vertical direction.

7. The rail vehicle frame design method according to any one of claims 1, 4-6, characterized in that: The first component includes a traction motor and a gear box.

8. The rail vehicle frame design method according to claim 1, characterized in that: The track irregularity signal includes an irregularity signal collected by a detection vehicle under various operating line conditions.

9. The rail vehicle frame design method according to claim 8, characterized in that: The track irregularity signal is an irregularity amplitude signal.

10. The rail vehicle frame design method according to claim 1, characterized in that: The analyzed parts include connection positions between the frame and other components of the rail vehicle, and the analyzed parts also include weld positions on the frame with a spacing between each connection position not greater than a first preset distance.

11. The rail vehicle frame design method according to claim 10, characterized in that: The analyzed parts include the connection position between the frame and the primary suspension device, the connection position between the frame and the secondary suspension device, and the connection position between the frame and the gear box.

12. The rail vehicle frame design method according to claim 1, characterized in that: The dynamic model is a rigid-flexible coupling dynamic model.

13. A rail vehicle frame design device, characterized in that: This includes computer equipment; The computer device is configured or programmed to perform the steps of the method according to any one of claims 1-12.

14. A rail vehicle frame, characterized in that: The structural design parameters of the rail vehicle frame are obtained according to the method described in any one of claims 1-12.

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