Method for improving the ability of catenary additional conductor to resist wind-induced vibration caused by train

Abstract

The present invention proposes a method for improving the ability of additional conductors of a contact network to resist wind-induced vibration caused by trains. By generating an installation curve for the additional conductors and adjusting the tension setting of the additional conductors, it is ensured that the safety factor with respect to the maximum breaking force within the service temperature range meets the standard; the train wind spectrum is applied to a simulation model of the additional conductors taking into account the tension setting and the clamp setting; the tension of the additional conductors is adjusted with the goal of reducing the maximum stress during the wind-induced vibration of the additional conductors; then the type of the clamps of the additional conductors is optimized; and optimization results of the tension and the clamp type are obtained. The present invention can enhance the ability of the additional conductors to resist wind-induced vibration caused by trains, thereby reducing the risk of fatigue accidents of the additional conductors and their components of the high-speed contact network, and improving the safety and reliability of high-speed rail operation.

Description

Technical Field

[0001] The invention relates to the technical field of improving the anti-vibration capability of an additional conductor of a contact network, in particular to a method for improving the anti-train wind-induced vibration capability of an additional conductor of a contact network. Background Art

[0002] As a crucial component of the unused overhead catenary system, the supplementary conductors, primarily consisting of the positive feeder and protective conductors, are subject to significant vibrations from the wind generated by trains. This vibration can cause fatigue damage to the supplementary conductors and their components, leading to serious faults such as wire breakage and component failure. These factors pose a significant threat to the safe and efficient operation of electrified railways. Therefore, there is an urgent need to improve the supplementary conductors' ability to withstand wind-induced vibrations.

[0003] At present, there are few studies on the vibration of additional conductor systems caused by train wind. Although many scholars have conducted relevant research on the phenomenon of environmental wind-induced buffeting or galloping of the contact network suspension system and put forward various suggestions, such as increasing the tension of the suspension system, shortening the contact network span, and setting up windbreaks, the above studies were all carried out under constant temperature conditions. With the change of service temperature, the tension and other system parameters of the uncompensated additional conductor will change significantly, which will cause a significant change in wind resistance. Therefore, there is an urgent need for a method to improve the resistance of additional conductors to train winds that takes into account the service temperature, so as to achieve a comprehensive improvement in the reliability of additional conductors during service, thereby reducing the risk of fatigue accidents of high-speed contact network additional conductors and their components, and improving the safety and reliability of high-speed rail operation and the efficiency of operation and maintenance. Summary of the Invention

[0004] Aiming at the problem that the wind resistance of the additional conductors of the high-speed railway contact network system needs to be improved in complex service environments, the present invention proposes a method for improving the resistance of the additional conductors to train-induced wind vibration. The method uses the minimum tension of the additional conductors and the type of wire clamp as optimization parameters, and coordinates the two optimization goals of maximum breaking force safety factor and maximum stress to improve the resistance of the additional conductors to train-induced wind vibration.

[0005] The present invention proposes a method for improving the ability of an additional conductor of a contact network to resist wind-induced vibration caused by a train, the method comprising the following steps:

[0006] S1. Determine the installation curve of the additional conductor of the contact network, and obtain the maximum tension of the additional conductor within the service temperature range according to the installation curve. T max and minimum tension T min ;

[0007] S2. Determine the maximum breaking force of the additional wire F breakIs the safety factor greater than 2.5? If not, reduce the minimum tension of the additional wire at the highest temperature, return to step S1, and redetermine the installation curve of the additional wire with the reduced minimum tension; if so, in [ T min , T max ] uniformly select the tension value calculation points within the range of ], and establish the additional wire simulation model within the full service temperature range;

[0008] S3. Obtain the train wind spectrum, substitute the train wind spectrum into the additional conductor simulation model, reproduce the train wind-induced vibration process of the additional conductor, and extract the maximum stress ε of the additional conductor during this process. max ;

[0009] S4. Determine ε max Does it exceed the tensile strength ε of each strand of the additional conductor? break If not, proceed to step S5; if so, determine whether there is further adjustment margin for the minimum tension, and if so, further adjust the minimum tension, return to step S1, and redetermine the installation curve of the additional wire with the adjusted minimum tension; if there is no further adjustment margin for the minimum tension, proceed to step S5;

[0010] S5. Replace the clamp of the additional wire and find the max Smallest clamp type.

[0011] Furthermore, the method for determining the installation curve of the additional overhead wire is:

[0012] ;

[0013] Where, T is the installation curve for additional wires, θ is the temperature, θ 0 is the given temperature, T 0 is the given additional wire tension corresponding to a given temperature, is the linear expansion coefficient of the additional wire; E is the final elastic constant of the additional wire; S is the calculated cross-sectional area of the additional conductor; g is the deadweight load of the attached conductor; L D is the equivalent span of the additional conductor.

[0014] Furthermore, the additional conductor simulation model is established using the finite element method, the additional conductor is simulated using the Timoshenko beam unit, and the wire clamp type setting is simulated by the end constraint method of the additional conductor simulation model to obtain the dynamic characteristics of the additional conductor under its own gravity and train wind.

[0015] Furthermore, the method for obtaining the train wind spectrum is:

[0016] Get the train length L tr , the train nose and train tail when passing the additional wire installation location of the train wind speed extreme value V pn and V pt , forming the train wind speed spectrum;

[0017] Get the train speed v , air density ρ and additional conductor resistance coefficient C D , combined with the train wind speed spectrum, the train wind force spectrum of the additional conductor is formed.

[0018] Furthermore, the train wind speed spectrum It is given by:

[0019] ;

[0020] Where, x' It is the position coordinate with the nose of the train as the origin and the forward direction of the nose as the positive direction.

[0021] Furthermore, the train wind spectrum D ( x ) is given by:

[0022] ;

[0023] Where, t is the time, and the end of the additional wire closer to the nose of the train at the initial moment is the proximal end of the additional wire. L 0 is the initial distance between the nose of the train and the near end of the additional wire at the initial moment, x is the position coordinate with the near end of the additional wire as the origin and the train travel direction as the positive direction, A is the frontal area of the additional conductor, Represents the distance from the nose of the train during the train's journey Wind speed spectrum of the train wind at .

[0024] Furthermore, when the installation curve of the additional conductor of the contact network is initially determined in step S1, the given temperature θ 0 is the typical service temperature or the minimum service temperature, and the corresponding additional wire tension is given T 0 are the tension at typical service temperature and the maximum tension corresponding to the lowest service temperature.

[0025] Furthermore, the method for determining whether there is further adjustment margin for the minimum tension is:

[0026] Adjust the minimum tension and determine the maximum breaking force of the additional wire within the service temperature range. F break The safety factor is greater than 2.5, and ε max Less than ε break Are both true at the same time? If so, it means that there is room for further adjustment of the minimum tension.

[0027] Furthermore, the additional wire has a maximum breaking force F break The safety factor is the maximum breaking force of the additional wire of this model F break and its maximum tension within the service temperature range T max ratio.

[0028] The advantages and positive effects of the present invention are:

[0029] The method for improving the ability of the additional conductors of the contact network to resist wind-induced vibration caused by trains, provided by the present invention, coordinates the two optimization goals of the maximum breaking force safety factor and the maximum stress of the additional conductors during wind-induced vibration caused by trains. By adjusting the minimum tension of the additional conductors at the highest service temperature and the wire clamp type of the additional conductors, it is ensured that the ability of the additional conductors to resist wind-induced vibration caused by trains is improved within the entire service temperature range, thereby achieving improved safety and reliability of the contact network system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, these drawings are intended only to conceptually illustrate the structures described herein and are not necessarily drawn to scale.

[0031] Figure 1 A flow chart of a method for improving the ability of additional overhead wires to resist wind-induced vibrations caused by trains, provided in an embodiment of the present invention;

[0032] Figure 2 Additional wire installation curve provided by an embodiment of the present invention;

[0033] Figure 3 A schematic diagram comparing the parametric train wind speed spectrum model and CFD calculation results provided by an embodiment of the present invention;

[0034] Figure 4 A schematic diagram of a simulation of the wind-induced vibration process of a train with additional conductors provided in an embodiment of the present invention;

[0035] Figure 5A schematic diagram of the safety factor and maximum stress of the maximum breaking force using only tension optimization provided in an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of the optimization effect of a comparative example provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0039] This embodiment provides a method for improving the ability of additional conductors of a contact network to resist wind-induced vibration caused by trains, the method comprising the following steps:

[0040] S1. Determine the installation curve of the additional conductor of the contact network, and obtain the maximum tension of the additional conductor within the service temperature range according to the installation curve. T max and minimum tension T min ;

[0041] S2. Determine the maximum breaking force of the additional wire F break Is the safety factor greater than 2.5? If not, reduce the minimum tension of the additional wire at the highest temperature. T min , return to step S1 and redetermine the installation curve of the additional wire with the reduced minimum tension; if so, then in [ T min , T max ] uniformly select the tension value calculation points within the range of ], and establish the additional wire simulation model within the full service temperature range;

[0042] It should be noted that the maximum breaking force of the additional wire F break The safety factor is the maximum breaking force of the additional wire of this model F breakand its maximum tension within the service temperature range T max The additional conductor simulation model is established using the finite element method, the additional conductor is simulated using the Timoshenko beam unit, and the wire clamp type setting is simulated by the end constraint method of the additional conductor simulation model, thereby obtaining the dynamic characteristics of the additional conductor under its own gravity and the train wind;

[0043] S3. Obtain the train wind spectrum and substitute it into the simulation model of the additional conductor within the full service temperature range to reproduce the train wind-induced vibration process of the additional conductor and extract the maximum stress ε in the additional conductor during this process. max ;

[0044] S4. Determine ε max Does it exceed the tensile strength ε of each strand of the additional conductor? break If not, proceed to step S5; if so, determine whether there is further adjustment margin for the minimum tension, if so, further adjust the minimum tension, return to step S1, and redetermine the installation curve of the additional wire with the adjusted minimum tension; if not, proceed to step S5;

[0045] It should be noted that the method for determining whether there is further adjustment margin for the minimum tension is to adjust the minimum tension and determine the maximum breaking force of the additional wire within the service temperature range. F break The safety factor is greater than 2.5, and ε max Less than ε break Are both true at the same time? If so, it means that there is room for further adjustment of the minimum tension.

[0046] S5. Replace the clamp of the additional wire and find the max Smallest clamp type for optimal results.

[0047] Specifically, the method for determining the installation curve of the additional overhead contact wire in step S1 is:

[0048] ;

[0049] Where, T is the installation curve for additional wires, θ 0 is the given temperature, T 0 is the given additional wire tension corresponding to a given temperature, θ is the temperature, is the linear expansion coefficient of the additional wire; E is the final elastic constant of the additional wire; S is the calculated cross-sectional area of the additional conductor; g is the deadweight load of the attached conductor; L Dis the equivalent span of the additional conductor; it should be noted that when the installation curve of the additional conductor of the contact network is determined for the first time, the given temperature θ 0 is the typical service temperature or the minimum service temperature, and the corresponding additional wire tension is given T 0 are the tension at the typical service temperature and the maximum tension corresponding to the lowest service temperature, respectively. These two sets of data are the inherent parameters of the additional conductor of the overhead contact network;

[0050] The method for obtaining the train wind spectrum described in step S3 is:

[0051] Get the train length L tr , the train nose and train tail when passing the additional wire installation location of the train wind speed extreme value V pn and V pt , forming the train wind speed spectrum;

[0052] Get the train speed v , air density ρ and additional conductor resistance coefficient C D , combining the train wind speed spectrum to form the train wind force spectrum of the additional conductor;

[0053] Among them, the train wind speed spectrum It is given by:

[0054] ;

[0055] Where, x' The position coordinates are based on the nose of the train as the origin and the forward direction of the nose as the positive direction;

[0056] It can be considered that the train nose and train tail pass the additional wire installation location of the train wind speed extreme value V pn and V pt There are three ways to obtain the information: Method 1 is to extract the information at the installation location of the additional wire based on the CFD simulation results. V pn and V pt Method 2 is to give the wind speed according to the on-site measurement results of the train at the location where the additional wire is installed. V pn and V pt Method 3 is to infer the displacement amplitude and other measured results of the additional conductor train during wind-induced vibration. V pn and V pt The specific process is: continuous adjustmentV pn and V pt , carried out finite element simulation of the additional conductor vibration caused by the train, and finally calibrated the displacement amplitude to make the simulation results and the measured results more consistent. V pn and V pt Of course, in order to consider the extreme cases, V pn and V pt Multiply the original value by a certain coefficient;

[0057] The train wind spectrum D ( x ) is given by:

[0058] ;

[0059] Where, t is the time, starting from the initial moment ( t = 0 s), the end of the additional wire closer to the nose of the train is the proximal end of the additional wire. L 0 is the initial distance between the nose of the train and the near end of the additional wire at the initial moment, x is the position coordinate with the near end of the additional wire as the origin and the train travel direction as the positive direction, A is the frontal area of the additional conductor, Represents the distance from the nose of the train during the train's journey In this embodiment, the frontal area of the additional conductor is the product of the cross-sectional diameter of the additional conductor and the length of the beam unit of the finite element model;

[0060] For example, in this embodiment, when the installation curve of the additional wire is initially determined, Figure 2 As shown, given θ 0=20℃, T 0=4kN corresponding installation curve; when adding wires to the maximum breaking force F break When the safety factor is not greater than 2.5, it is necessary to reduce the minimum tension of the additional wire at the highest temperature T min , about the additional wire corresponding to the highest temperature T min The adjustment strategy can be T max =0.4 F break Substituting into the obtained installation curve of the additional conductor, we can calculate Tmin The upper limit of the value of T min and redetermine the installation curve of the additional wire with the reduced minimum tension; when establishing the simulation model of the additional wire within the full service temperature range, this embodiment [ T min , T max ] were evenly selected within the range of , and the finite element method was used to establish an additional conductor simulation model for each tension value calculation point. In the additional conductor simulation model, the additional conductor was simulated by the Timoshenko beam unit. The various parameters of the beam unit were determined by the calculated cross-sectional area, cross-sectional diameter, wire mass, final elastic modulus and other parameters of the additional conductor. The wire clamp of the additional conductor was equivalent to a constraint on both ends of the additional conductor. This example refers to the traditional ship-shaped wire clamp and imposes full constraints on both ends of the additional conductor. When obtaining the train wind force spectrum, the construction of the train wind speed spectrum is based on the analysis and feature extraction of the numerical calculation results of the train wind speed CFD simulation. The numerical calculation results of the train wind speed CFD show that there are significant wind speed peaks in the nose and tail areas, while the wind speed in the middle area of the train is very small. The peak wind speed at the nose is extracted. V pn and peak wind speed at rear V pt Two key characteristic parameters are used to construct a parameterized train wind speed spectrum The comparison between the CFD calculation results of the wind speed spectrum of the train wind and the parameterized model is as follows: Figure 3 As shown in the figure, when reproducing the wind-induced vibration process of the train with additional conductors, the time term t By substituting the coordinate values of each node in the additional conductor simulation model and the average length of the two units connecting the nodes into the train wind spectrum, the train wind load time history curve of each node can be obtained. Based on dynamic integration methods such as NEWMARK-β, the vibration process of additional conductors with different tensions under train wind load can be reproduced. Figure 4 The vibration process diagram of the finite element model of the additional conductor at a certain tension value point. It should be noted that the maximum stress ε of the additional conductor during the train wind-induced vibration process is max The location where the problem occurs is mostly on the outer grid point of the beam unit section near the clamp. In this example, the initial clamp type is the ship-shaped clamp, which is equivalent to the full constraint condition. The preferred clamps include a pre-hinged armored clamp with a certain torsional stiffness and a pre-hinged rotatable anti-fatigue support clamp with full rotational freedom release. The optimization parameters are the additional wire T min and clamp type, the optimization goal is to reduce ε max and guarantee about the maximum breaking force F breakThe safety factor is greater than 2.5. According to the method of this embodiment, as shown in Table 1, the safety factors of three typical models of additional wires are given. T min and the results of the optimal selection of the clamp type;

[0061] Table 1

[0062]

[0063] In the optimization process described in the present invention, the optimal tension setting of the additional conductor is first determined, and then the optimal clamp type of the additional conductor is determined. Figure 5 The maximum stress of the additional conductor and the safety factor of the maximum breaking force after only using the tension optimization result are given. The three typical models of additional conductors still meet the requirements. ε max < ε break and the maximum breaking strength F break The safety factor is greater than 2.5, which means that the wind resistance of the additional conductor can be improved by optimizing the tension alone; Figure 6 The maximum stress time-history curves of the original design and the preferred design were compared, which proved that the method of this embodiment can significantly reduce the maximum stress of the additional conductor during the wind-induced vibration of the train, and significantly improve the wind resistance of the additional conductor.

[0064] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that modifications may be made to the technical solutions described in the above embodiments, or that some of the technical features may be replaced with equivalents; such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for improving the ability of catenary additional conductors to resist wind-induced vibration caused by trains, characterized in that: The method comprises the following steps: S1. Determine the installation curve of the additional conductor of the contact network, and obtain the maximum tension of the additional conductor within the service temperature range according to the installation curve. T max and minimum tension T min ; S2. Determine the maximum breaking force of the additional wire F break Is the safety factor greater than 2.5? If not, reduce the minimum tension of the additional wire at the highest temperature, return to step S1, and redetermine the installation curve of the additional wire with the reduced minimum tension; if so, in [ T min , T max ] uniformly select the tension value calculation points within the range of ], and establish the additional wire simulation model within the full service temperature range; S3. Obtain the train wind spectrum, substitute the train wind spectrum into the additional conductor simulation model, reproduce the train wind-induced vibration process of the additional conductor, and extract the maximum stress ε of the additional conductor during this process. max ; S4. Determine ε max Does it exceed the tensile strength ε of each strand of the additional conductor? break If not, proceed to step S5; if so, determine whether there is further adjustment margin for the minimum tension, and if so, further adjust the minimum tension, return to step S1, and redetermine the installation curve of the additional wire with the adjusted minimum tension; if there is no further adjustment margin for the minimum tension, proceed to step S5; S5. Replace the clamp of the additional wire and find the max Smallest clamp type.

2. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 1, characterized in that: The method for determining the installation curve of the additional conductor of the contact network is as follows: ； Where, T is the installation curve for additional wires, θ is the temperature, θ 0 is the given temperature, T 0 is the given additional wire tension corresponding to a given temperature, is the linear expansion coefficient of the additional wire; E is the final elastic constant of the additional wire; S is the calculated cross-sectional area of the additional conductor; g is the deadweight load of the attached conductor; L D is the equivalent span of the additional conductor.

3. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 1, characterized in that: The additional conductor simulation model is established using the finite element method, the additional conductor is simulated using the Timoshenko beam unit, and the wire clamp type setting is simulated by the end constraint method of the additional conductor simulation model to obtain the dynamic characteristics of the additional conductor under its own gravity and the action of train wind.

4. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 1, characterized in that: The method for obtaining the train wind spectrum is: Get the train length L tr , the train nose and train tail when passing the additional wire installation location of the train wind speed extreme value V pn and V pt , forming the train wind speed spectrum; Get the train speed v , air density ρ and additional conductor resistance coefficient C D , combined with the train wind speed spectrum, the train wind force spectrum of the additional conductor is formed.

5. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 4, characterized in that: The train wind speed spectrum It is given by: ； Where, x' It is the position coordinate with the nose of the train as the origin and the forward direction of the nose as the positive direction.

6. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 5, characterized in that: The train wind spectrum D ( x ) is given by: ； Where, t is the time, and the end of the additional wire closer to the nose of the train at the initial moment is the proximal end of the additional wire. L 0 is the initial distance between the nose of the train and the near end of the additional wire at the initial moment, x is the position coordinate with the near end of the additional wire as the origin and the train travel direction as the positive direction, A is the frontal area of the additional conductor, Represents the distance from the nose of the train during the train's journey Wind speed spectrum of the train wind at .

7. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 2, characterized in that: When the installation curve of the additional conductor of the contact network is determined for the first time in step S1, the given temperature θ 0 is the typical service temperature or the minimum service temperature, and the corresponding additional wire tension is given T 0 are the tension at typical service temperature and the maximum tension corresponding to the lowest service temperature.

8. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 1, characterized in that: The method to determine whether there is further adjustment margin for the minimum tension is: Adjust the minimum tension and determine the maximum breaking force of the additional wire within the service temperature range. F break The safety factor is greater than 2.5, and ε max Less than ε break Are both true at the same time? If so, it means that there is room for further adjustment of the minimum tension.

9. The method for improving the ability of the additional conductor of the overhead contact network to resist wind-induced vibration caused by trains according to claim 1, characterized in that: Additional conductors with respect to maximum breaking force F break The safety factor is the maximum breaking force of the additional wire F break and the maximum tension of the additional wire within the service temperature range T max ratio.

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