Method for establishing interlayer contact in batches based on vehicle-rail-road-ground coupling model

Abstract

The invention belongs to the technical field of railway engineering computer aided design, and particularly relates to a method for establishing interlayer contact in batches based on a vehicle rail road ground coupling model. In order to truly restore the running service environment of the train, UM software is used for establishing a professional train model, ANSYS software is used for establishing a flexible under-rail model, the two pieces of software are combined for simulation to establish a train-rail-road-ground coupling model, the running condition of the train when an under-rail system participates is simulated, and the running service environment of the train is truly restored. The operation performance of under-rail system abnormalities such as fastener fracture failure, track slab cracking, CA mortar layer deterioration failure and excessive foundation bed settlement can be avoided. After modeling is completed, a programmed language is used for building interlayer contact force elements in batches, interlayer constraint capacity of different aging degrees and degradation degrees is simulated by changing rigidity and damping coefficients of the force elements, or constraint is directly removed to simulate abnormal working conditions such as fracture.

Description

Technical Field

[0001] The present invention belongs to the technical field of railway engineering computer-aided design, and in particular relates to a method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model. Background Art

[0002] As train speeds continue to increase and traction weights grow, the impact loads generated during operation, including the impact force between the wheels and rails and the interaction force between the tracks and the roadbed, will also increase accordingly. Therefore, high-speed and heavy-haul railways place high demands on the safety, reliability, and low-maintenance performance of both tracks and roadbeds.

[0003] In a ballastless track system, the vehicle, track, roadbed, and foundation interact with each other. The rolling cyclic load of the vehicle acts directly on the rail portion of the track subsystem. The shape and position constraints and shock absorption of the rail are borne by the fastener system. The lower track plate is a hard concrete structure that does not absorb impact. Therefore, the vibration between the track plate and the base plate can only be absorbed by the CA mortar layer between the two plates. As a result, deterioration of the rails, fastener system, and CA mortar layer frequently occurs, affecting the safety of train operation. The additional dynamic load generated by the train will also be absorbed by the track plate and base plate. In the long run, this will affect the durability of its lower structure and even the safety of the upper train operation.

[0004] Based on this, truly restoring the vehicle's operating and service environment and analyzing the dynamic interaction between the vehicle and the sub-track system have become urgent issues to be solved. Summary of the Invention

[0005] In response to the above problems, the present invention provides a method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model. The vehicle-track-road-ground coupling model (vehicle-track-roadbed-foundation coupling model) proposed in the present invention can more completely present the interaction between the vehicle and the sub-track foundation in actual operation, and can conveniently set the inter-layer connection and the deterioration of different parts through program modeling. The establishment of the vehicle-track-road-ground coupling system model requires combining the structural characteristics of each subsystem in the vehicle-track-road-ground coupling model, using UM software to establish a professional vehicle model and using ANSYS software to establish a flexible sub-track model. The two softwares are jointly simulated to establish a vehicle-track-road-ground coupling model to simulate the operation of the train when the sub-track system is involved, as well as the operation performance when the sub-track system is abnormal, such as fastener breakage failure, track plate cracking, CA mortar layer deterioration failure, excessive subgrade settlement, etc.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model, comprising the following steps:

[0008] Step 1: Based on the structural characteristics of the actual vehicle-track-road-ground coupling model, the vehicle-track-road-ground coupling model is divided into the vehicle subsystem and the sub-track system;

[0009] Step 2: Use ANSYS software and UM software to jointly build a vehicle-track-road-ground coupling model;

[0010] Step 3: After the modeling is completed, use the programming language to batch establish the interlayer contact force elements.

[0011] Furthermore, in step 1, the sub-track system includes a track subsystem, a roadbed subsystem and a foundation subsystem. The track subsystem includes rails, a fastener system, a track plate, a CA mortar layer, a base plate and an asphalt concrete layer. The roadbed subsystem includes a base bed surface layer, a base bed bottom layer and an embankment. The foundation subsystem includes a cushion layer, CFG pile soil and a bearing layer.

[0012] Furthermore, in step 1, the vehicle subsystem is split into three major parts, namely, a vehicle body, a bogie, and a wheelset, according to a dynamic substructure method, and the three parts are interconnected through various levels of suspension.

[0013] Furthermore, in step 2, a vehicle-track-road-ground coupling model is established by using ANSYS software and UM software for joint modeling, specifically:

[0014] The vehicle subsystem is modeled using UM software, and the contact between the vehicle subsystem and the sub-track system is modeled using the flexible track module in UM software;

[0015] The sub-rail system is modeled using ANSYS software, and a parametric modeling language APDL command stream is used in the ANSYS software to establish a multi-layer coupling model of the sub-rail system;

[0016] The multi-layer coupling model of the sub-track system established by ANSYS software is hierarchically imported into the flexible track module in UM software to realize coupling modeling.

[0017] Furthermore, in step 3, after the modeling is completed, the interlayer contact force elements are batch-established using a programming language, specifically:

[0018] After modeling is complete, the vehicle-track-road-ground coupling model file (input.dat) in the UM software pre-processing module is parsed to locate the code representing the interlayer contact force elements. This is then combined with the "Mail" module in Word software using a programmatic language to batch-generate interlayer contact force elements. This approach is easier to implement and more convenient than manually setting force elements in the UM pre-processing module. Once the model is established, the force element properties can be modified as needed to simulate various degradation conditions.

[0019] Furthermore, the method further includes: after modeling is complete, using the UM software post-processing module to apply excitation to calculate the dynamic response of the vehicle-track-rail-ground coupling model, simulating changes in the dynamic performance parameters of the vehicle-track-rail-ground coupling model. Models can be established and simulated for different scenarios, enabling the construction of scenarios for tracks with different geological conditions and different types of degraded coupling, and is applicable to a variety of operating scenarios, including those involving abnormal train dynamics.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The vehicle-track-road-foundation coupling model of the present invention is established based on the joint simulation of UM and ANSYS software. In view of the respective characteristics of the two software, the present invention utilizes UM's expertise in multi-body dynamics to complete the establishment of the vehicle subsystem structure, and utilizes the diversity of flexible body models of ANSYS finite element software to complete the establishment of three subsystems under the track (track subsystem, roadbed subsystem, foundation subsystem), and uses the ANSYS_UM interface module to couple the models to improve control accuracy. The coupling model can reflect the force transfer law and deformation characteristics between the various structural layers of the railway. Compared with applying equivalent simple harmonic loads or random loads during the operation of the train, this method can more realistically reflect the actual operation of the train, and is more suitable for the safety and stability calculation of my country's increasingly developed high-speed and heavy-load railways. The method according to the present invention can give full play to the flexible modeling characteristics of ANSYS's APDL language programming, is easy to expand and redevelop, and has high theoretical value and commercial development prospects.

[0022] 2. The present invention is suitable for batch establishment of interlayer contact force elements for the vehicle-track-road-ground coupling model. That is, when the sub-rail foundation established in ANSYS software is imported into UM software, the imported model is used to programmatically establish interlayer constraint connections in batches. The interlayer contact force elements in UM software are used to simulate interlayer surface-to-surface contact. By changing the stiffness and damping coefficient of the force element, the interlayer constraint capacity of different degrees of aging and degradation can be simulated, or the constraint can be directly removed to simulate abnormal working conditions such as fracture. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Flowchart of the method for establishing interlayer contact in batches based on vehicle-track-road-ground coupling system.

[0024] Figure 2 This is a structural diagram of the sub-track system.

[0025] Figure 3 Schematic diagram of the vehicle subsystem.

[0026] Figure 4 Schematic diagram of the vehicle-track-road-ground coupling model.

[0027] Figure 5Flowchart for batch modeling using procedural language when modeling. DETAILED DESCRIPTION

[0028] In order to further illustrate the technical solution of the present invention, the present invention is further described below through examples.

[0029] like Figure 1 As shown, the method for establishing interlayer contact in batches based on the vehicle-track-road-ground coupling model of this embodiment includes the following steps:

[0030] Step 1: Based on the structural characteristics of the actual vehicle-track-road-ground coupling model, the vehicle-track-road-ground coupling model is divided into the vehicle subsystem and the sub-track system;

[0031] Among them, the sub-orbital system (such as Figure 2 (as shown) includes a track subsystem, a roadbed subsystem and a foundation subsystem, wherein the track subsystem includes rails, a fastener system (spring bars and pads), a track slab, a CA mortar layer, a base plate and a concrete asphalt layer, the roadbed subsystem includes a subgrade surface layer, a subgrade bottom layer and an embankment, and the foundation subsystem includes a cushion layer, CFG pile soil and a bearing layer;

[0032] According to the dynamic substructuring method, the vehicle subsystem (such as Figure 3 As shown in the figure, it is divided into three parts: car body, bogie and wheelset, which are connected to each other through various levels of suspension.

[0033] Step 2: Use ANSYS software and UM software to jointly build a vehicle-track-road-ground coupling model (such as Figure 4 shown);

[0034] The vehicle subsystem is modeled using UM software. Specifically, the wheelset, bogie, and body models of a specific vehicle model are loaded into the UM software's input module. Parameters such as wheelbase, fixed distance, and track width are set based on the connection relationships. Force elements such as the primary and secondary springs and anti-snaking dampers are assigned properties. Once the vehicle subsystem is established, the contact between the vehicle subsystem and the subrail system is modeled using the flexible track module in UM software. Specifically, the rails are modeled using the flexible track module in UM software.

[0035] The sub-track system is modeled using ANSYS software, and the parametric modeling language APDL command stream is used in ANSYS software to establish a multi-layer coupling model of the sub-track system;

[0036] The multi-layer coupling model of the sub-track system established by ANSYS software is hierarchically imported into the flexible track module in UM software to realize coupling modeling.

[0037] Step 3: After the modeling is completed, use the programming language to batch establish the interlayer contact force elements.

[0038] The method of this embodiment further includes: after the modeling is completed, using the UM software post-processing module to apply excitation to perform dynamic response calculation of the vehicle-track-road-ground coupling model to simulate changes in dynamic performance parameters of the vehicle-track-road-ground coupling model.

[0039] As a further explanation, for the sub-track system, it is composed of rails, fastener system (elastic bars and pads), track slabs, CA mortar layer, base plate, concrete asphalt layer, subgrade surface layer, subgrade bottom layer, embankment, mattress, CFG pile soil and bearing layer in order; among them, the track part can be regarded as a stiffness-damping coupling beam according to the load transfer angle, the rails and fastener system can be regarded as a stiffness-damping coupling beam, the track slabs and CA mortar layer can be regarded as a stiffness-damping coupling beam, and the base plate and concrete asphalt layer can be regarded as a stiffness-damping coupling beam; according to the material differences during the construction of the roadbed part, the subgrade surface layer can be regarded as an elastic layer element, the subgrade bottom layer and embankment can be regarded as an elastic layer element, and the bottom mattress layer, CFG piles and bearing layer are subjected to small forces. If they are not affected by large geological changes, they can be regarded as infinite elastic bodies.

[0040] This example uses ANSYS to establish the sub-track system. The ANSYS-UM interface program included in the UM software is used to read the generated standard file and save the data in the data format required by UM. Therefore, to ensure the accuracy of the force element connection in the UM software, the following requirements must be met in advance when establishing the sub-track system in ANSYS software:

[0041] First, hexahedral meshes are used when establishing the sub-track system in layers. Hexahedral meshes are highly accurate and less prone to distortion. They also make it easier to locate the force element interfaces between multiple flexible bodies in the UM software's Input module, preventing the UM software from automatically connecting adjacent nodes, which would generate tilting force components in the initial state and lead to poor accuracy.

[0042] Second, after the sub-track system layers are built, the flexible body model built in ANSYS is imported using the FEM module of the UM software. The default units for modeling in both ANSYS and UM software are the International System of Units, but the default reference coordinate system directions in the two software are different. The horizontal plane of the model should be drawn on the xoy plane in ANSYS software. This setting can keep the longitudinal centerline of the model consistent with the x-axis direction of the UM software coordinate system, making it easier to match the direction when importing into the UM software. Otherwise, the coordinates need to be converted again.

[0043] Third, the flexible track module in the UM software can use the flexible body in ANSYS as a basis to connect with the flexible track. After setting the length of the flexible body in the post-processing module, the system will automatically generate force elements to replace the fastener system. Therefore, the top surface of the track plate needs to be set to the horizontal plane of the global coordinate system, and the interval positions of the fastener system must have corresponding nodes.

[0044] After the sub-track system in ANSYS software is established according to the above modeling points, the model is imported into the flexible track module in UM. The flexible track module is a professional module of UM software suitable for importing flexible sub-track foundations to establish variable track foundations. There are default rails in this module. After importing the ANSYS model, the inter-layer contact force elements will be used to connect the rails at the preset spacing to simulate the fastener system. Therefore, it is sufficient to import the model below the fastener system.

[0045] After the model is established in ANSYS software, the track slab, CA mortar layer, base plate, concrete asphalt layer, subgrade surface layer, subgrade bottom layer, embankment body and foundation structures are imported through the flexible track module in UM.

[0046] In the UM software, applying interlayer contact force elements requires setting their stiffness and damping properties. In this embodiment, the rail and fastener system is established using the flexible track module in post-processing.

[0047] After importing the ANSYS model, set the single-point force element as a master and use the Word "mail" function to batch set subsequent force elements, and set the inter-layer contact force element connection to simulate the surface connection.

[0048] The following is the code for the stress element:

[0049]

[0050] Among them, "with sfrc1" is the default force element number of UM software, "name="guidaoban-dizuoba n-a1"" is the force element number defined by yourself, "type="bushing" is the force element type, "bd1="guidaoban0228.guidaoba";bd2="dizuoban0228.dizuoban";" are the numbers of the two flexible bodies, "ro1x=;ro1y=;ro1z=;ro2x=;ro2y=;ro2z=;" are the parameter properties of the 6 degrees of freedom of the force element, "positio n=1;" is the identifier of the point of action of the force element on flexible body 1, "p1x=0+0*jianju;p1y=-1.2;p1z=0;p2x=;p2y=;p2z=;" are the positions of the point of action of the force element on flexible body 1, and "po "sition=2;" is the identifier of the force element action point on flexible body 1, "p1x=0+0*jianju;p1y=-1.2;p1z=0.3;p2x=;p2y=;p2z=;" is the position of the force element action point on flexible body 2, where the coordinates of the two positions are the local coordinate system coordinates of the flexible body, "bushing_type=linear;" is the interlayer contact force element type, and "parameters=9e8#9e8#9e8#1.0e5#1.0e5#1.0e5#8.3e4#1.0e4#1.0e4#1.0e3#1.0e3#1.0e3############;" are the property parameters of the 6 degrees of freedom of the force element;

[0051] If you set up a second or more force elements in the UM software, it will be a repeated iteration of this code. Therefore, use this code as the master, change the force element sequence number and the coordinates of the force element's position in the code to compile the code, and then add new force elements in the input module of the UM software. Using this method as a standard, you can set up connections and force elements between other layers.

[0052] like Figure 5 As shown, use Word's "Mail" → "Select Recipients" → "Use Existing List" to create an Excel spreadsheet as the "Existing List". One of the two columns contains the numerical sequence of the force element numbers to be replaced, and the other contains the distance or distance multiples set for the force element coordinates. After selecting Excel as the "Existing List", select the bytes to be replaced and click "Insert Merge Field" → "Select Column A / Column B". After adding all, click "Finish and Merge" to replace all numbers with sequential numbers to create 0-100 force elements. After creation, use "Change text to unformatted text", copy it into the code segment, and reopen the UM file to recognize it. The same applies to creating other columns and other inter-layer contact force elements.

[0053] After the above settings are completed, simulation can be performed in the simulation post-processing module of the UM software, and track spectrum excitation inputs of different states can be applied to obtain a series of safety indicators for train operation.

[0054] Example 2

[0055] This embodiment further describes the method of the present invention in detail in conjunction with the local degradation operation condition of the vehicle-track-road-ground coupling model.

[0056] The vehicle subsystem model is established by taking the French TGV train as an example. The data of each part of the TGV vehicle are shown in Table 1.

[0057] Table 1 Vehicle model data

[0058]

[0059] The subrail system was established in ANSYS finite element software, based on national standards and referenced in relevant literature. The subrail system model length was designed to ensure that the vehicle can travel a certain distance on the track without being affected by boundary effects. The subrail foundation length was also set at 60 meters, and the boundary locations were fixed using zero-degree-of-freedom interlayer contact force elements. The geometric and physical parameters of the subrail system are shown in Table 2.

[0060] Table 2 Under-track system parameters

[0061]

[0062] The excitation applied during this dynamic simulation was the UIC-bad-1000m track spectrum, and the additional abnormal excitation was the degradation characteristic of the track. The model was loaded with a loading step of 0.001s. The simulation was divided into five speed gradients: 160km / h, 200km / h, 250km / h, 300km / h, and 350km / h. The reliability of the coupled model was verified by comparing the maximum and mean values of the dynamic response of the Wuhan-Guangzhou ballastless test section in previous ballastless track joint commissioning and comprehensive track dynamics testing tests with the maximum and mean values of the measured data. The comparison results are shown in Table 3.

[0063] Table 3 Model reliability verification

[0064]

[0065] The maximum values of each item in the model simulation results of this embodiment differ from the measured results by less than 20%. Although the maximum mean values differ by a large multiple, the differences are all within the same order of magnitude. Therefore, it can be considered that the model has a certain degree of reliability.

[0066] The foregoing shows and describes the principal features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0067] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model, characterized in that: The following steps are involved: Step 1: Based on the structural characteristics of the actual vehicle-track-road-ground coupling model, the vehicle-track-road-ground coupling model is divided into the vehicle subsystem and the sub-track system; Step 2: Use ANSYS software and UM software to jointly build a vehicle-track-road-ground coupling model; Step 3: After the modeling is completed, use the programming language to batch establish the interlayer contact force elements.

2. The method for establishing interlayer contact in batches based on the vehicle-track-road-ground coupling model according to claim 1, characterized in that: In step 1, the sub-track system includes a track subsystem, a roadbed subsystem and a foundation subsystem. The track subsystem includes rails, a fastener system, a track slab, a CA mortar layer, a base plate and a concrete asphalt layer. The roadbed subsystem includes a subgrade surface layer, a subgrade bottom layer and an embankment. The foundation subsystem includes a cushion layer, CFG pile soil and a bearing layer.

3. The method for establishing interlayer contact in batches based on the vehicle-track-road-ground coupling model according to claim 2, characterized in that: In step 1, the vehicle subsystem is split into three parts: a vehicle body, a bogie, and a wheelset according to a dynamic substructure method, and the three parts are interconnected through various levels of suspension.

4. The method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model according to claim 2, characterized in that: In step 2, a vehicle-track-road-ground coupling model is established by using ANSYS software and UM software for joint modeling, specifically: The vehicle subsystem is modeled using UM software, and the contact between the vehicle subsystem and the sub-track system is modeled using the flexible track module in UM software; The sub-rail system is modeled using ANSYS software, and a parametric modeling language APDL command stream is used in the ANSYS software to establish a multi-layer coupling model of the sub-rail system; The multi-layer coupling model of the sub-track system established by ANSYS software is hierarchically imported into the flexible track module in UM software to realize coupling modeling.

5. The method for establishing interlayer contact in batches based on the vehicle-track-road-ground coupling model according to claim 1, characterized in that: In step 3, after the modeling is completed, the interlayer contact force elements are batch-established using a programming language, specifically: After the modeling is completed, the vehicle-track-road-ground coupling model file input.dat in the UM software pre-processing module is parsed to locate the code position representing the inter-layer contact force element. Combined with the "Mail" module in the Word software, a programming language is used to batch establish the inter-layer contact force elements.

6. The method for establishing interlayer contact in batches based on a vehicle-track-road-ground coupling model according to claim 1, characterized in that: The method further includes: after the modeling is completed, using the UM software post-processing module to apply excitation to perform dynamic response calculation of the vehicle-track-road-ground coupling model, and simulating changes in dynamic performance parameters of the vehicle-track-road-ground coupling model.

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