Simulation of Nonlinear Galloping of Ice-Wind Composite Contact Network, Risk Assessment Method and Medium
By constructing an irregular icing aerodynamic parameter library and introducing aerodynamic hysteresis correction and a time-varying stiffness model, the problem that traditional linear models cannot accurately predict the galloping characteristics of the overhead contact line under combined ice and wind conditions is solved. This enables accurate simulation and risk assessment of the starting wind speed and galloping amplitude, and is applicable to safety assessment of electrified railways and urban rail transit.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA RAILWAY CONSTR ELECTRIFICATION BUREAU GRP CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies, when simulating the nonlinear galloping of overhead contact lines under the combined effects of ice and wind, neglect aerodynamic hysteresis and geometric stiffness nonlinearity. This results in the inability to accurately predict the initiation point and large-amplitude galloping characteristics of self-excited galloping at low wind speeds, posing a safety hazard.
By constructing an irregular icing aerodynamic parameter library, introducing an unsteady load model with aerodynamic hysteresis correction and a time-varying stiffness model with tension coupling, and using CFD fluid simulation and the Newmark-β method for time-domain iterative solution, the aerodynamic load is corrected and the stiffness matrix is updated in real time, and the aerodynamic-structure strongly coupled dynamic equation is constructed.
It enables accurate simulation and risk assessment of nonlinear galloping of overhead contact lines, improves the prediction accuracy of start-up wind speed and galloping amplitude, and is suitable for safety assessment in extreme icy wind environments.
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Figure CN122334085A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of simulation computing technology, and in particular to a simulation method and medium for nonlinear galloping of ice-wind composite contact networks. Background Technology
[0002] The pantograph-catenary system (or pantograph-catenary system for short) is the core of energy transmission for electric traction vehicles such as electrified railways and urban rail transit (metro, tram). It enables a continuous and stable power supply from the ground power grid to the onboard traction system while the train is moving at high speed.
[0003] In areas with severe cold and strong winds, the overhead contact system of high-speed railways often faces the combined effects of icing and strong winds. After icing (especially when irregular cross-sections such as crescent shapes are formed), the aerodynamic shape of the contact wire and catenary changes significantly, making them highly susceptible to large-scale low-frequency galloping under specific wind speeds. Existing technologies for simulating the pantograph-catenary system mostly adopt the "quasi-steady theory," which assumes that the instantaneous aerodynamic force depends only on the instantaneous angle of attack and linearizes the aerodynamic coefficients at the initial position. This traditional method has two major drawbacks: (1) It ignores the aerodynamic hysteresis effect: When the iced conductor undergoes large-scale twisting or rapid movement, there is a time delay in the separation and reattachment of the airflow. The traditional quasi-steady model ignores the high-order nonlinear aerodynamic damping term generated by the rate of change of angle of attack, resulting in the inability to accurately predict the initiation point of self-excited galloping of the contact network under low wind speeds. (2) It ignores the nonlinearity of geometric stiffness caused by large deformation: Traditional methods often assume that the stiffness matrix is constant, but in reality, icing galloping is accompanied by huge tension fluctuations, and the geometric stiffness of the contact network changes drastically with tension. The linear model cannot reflect this change.
[0004] In summary, existing technologies cannot accurately reproduce the limiting cycle oscillation characteristics under combined ice and wind conditions, leading to an overly optimistic assessment of the wind resistance safety of the overhead contact system, which poses potential safety hazards. Summary of the Invention
[0005] This application provides a method and medium for simulating and assessing the nonlinear galloping of ice-wind composite contact networks, which can at least solve the problem that traditional linear models cannot accurately predict large-scale galloping characteristics.
[0006] In a first aspect, this application provides a simulation method for nonlinear galloping of ice-wind composite contact networks, comprising the following steps: Step S100: Construct an irregular icing aerodynamic parameter library, and obtain the static aerodynamic coefficients of the icing contact line and the catenary under different angles of attack. The static aerodynamic coefficients include at least the static lift coefficient C. L,static ; Step S200: Construct an unsteady load model with aerodynamic hysteresis correction. In each time step, calculate the full effective angle of attack α based on the instantaneous vibration velocity of the contact wire nodes. effAnd introduce the factor of angle of attack change rate The formula for calculating unsteady aerodynamic coefficients, correcting for aerodynamic loads under the quasi-steady assumption, where the unsteady lift coefficient C... L (α, The formula for calculating ) is:
[0007] In the formula, C L (α) eff , ) represents the corrected unsteady lift coefficient, k h V is the aerodynamic hysteresis attenuation coefficient, D is the characteristic diameter of the icing conductor, and V is the characteristic diameter of the conductor. rel The instantaneous relative wind speed of the contact wire node with respect to the airflow; Step S300: Construct a time-varying stiffness model with tension coupling. Based on the instantaneous tension changes caused by the combined ice and wind loads, update the geometric stiffness matrix of the contact wire unit in real time, and construct the aerodynamic-structural strongly coupled dynamic equations, where the total stiffness matrix is expressed as:
[0008] In the formula, K total (t) is the instantaneous total stiffness matrix of the contact wire element at time t, used to update the restoring force term in the dynamic equations, K elastic Let K be the linear elastic stiffness matrix of the contact wire element, T(t) be the instantaneous axial tension of the element at time t under the combined load of ice wind and structural vibration, and K be the linear elastic stiffness matrix of the contact wire element. g (T(t)) is the time-varying geometric stiffness matrix, which is a function of the axial tension of the element and is used to characterize the nonlinear contribution of tension to the transverse stiffness of the structure. Step S400: Use the Newmark-β method to perform time-domain iterative solution of the aerodynamic-structural strongly coupled dynamic equations and output the displacement time history of the contact wire nodes.
[0009] Furthermore, in step S100, the irregular icing aerodynamic parameter library is constructed using CFD fluid simulation, specifically including: using a structured mesh, where the height of the first-layer mesh satisfies the wall y... + Value less than 1, use Using a turbulence model, the incompressible Navier-Stokes equations are solved to obtain the static lift coefficient C in the range of -180° to 180°. L Drag coefficient C D and torque coefficient C M The static aerodynamic coefficient function was obtained by fitting Fourier series.
[0010] Furthermore, in step S200, the full effective angle of attack α eff The calculation formula is:
[0011] In the formula, α0 is the initial angle of attack. , V represents the instantaneous vibration velocity of the overhead contact line in the horizontal and vertical directions, respectively. wind For ambient wind speed.
[0012] Furthermore, in step S200, the aerodynamic hysteresis attenuation coefficient k h The method for determining it is: by identifying the static lift coefficient curve C L,static (α) The slope abrupt change characteristics near the stall angle of attack, and the calibration is performed in combination with dynamic CFD simulation or wind tunnel test data.
[0013] Further, in step S200, the instantaneous relative wind speed V rel The calculation formula is:
[0014] In the formula, , These represent the instantaneous vibration velocities of the overhead contact line in the horizontal and vertical directions, respectively.
[0015] Furthermore, in step S200, the formula for calculating the dynamic effective wind attack angle is:
[0016] In the formula, θ twist (t) represents the instantaneous torsion angle of the icy conductor.
[0017] Furthermore, in step S200, the rate of change of angle of attack is introduced. The relevant nonlinear damping terms are used to calculate the aerodynamic hysteresis force.
[0018] By introducing -k h The hysteresis characteristics of aerodynamic forces can be reproduced at the numerical level.
[0019] Further, in step S300, the finite element mass matrix and stiffness matrix of the tension-coupled contact network are constructed. The mass matrix M needs to calculate the eccentric mass and moment of inertia of the crescent-shaped ice structure based on the ice thickness. The geometric stiffness matrix K needs to be reassembled at each time step based on the element axial force T(t) calculated in the previous substep. g (T):
[0020] The overall dynamic equations of the overhead contact system are updated as follows:
[0021] In the formula, M, C, K total (t) represents the mass matrix, damping matrix, and time-varying stiffness matrix of the icing contact wire, respectively. , U and F represent the acceleration, velocity, and displacement vectors of the overhead contact line, respectively. aero For the aerodynamic vector of the icing contact wire, F gravity This represents the load vector of the overhead contact line under the influence of gravity.
[0022] Secondly, this application provides a risk assessment method for ice and wind composite contact networks. Based on the above simulation method, the displacement time history of the contact network nodes is obtained, and the contact network galloping amplitude ratio is calculated. Based on the galloping amplitude ratio, it is determined whether there is a risk to the contact network.
[0023] Thirdly, this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the simulation method for nonlinear galloping of ice-wind composite contact network as described in any one of claims 1 to 8.
[0024] The technical solution adopted in this application can achieve the following beneficial effects: This application successfully constructs an unsteady aerodynamic negative damping mechanism by introducing an unsteady aerodynamic correction term related to the rate of change of angle of attack and a geometric stiffness matrix updated in real time with tension. It can simulate the negative aerodynamic damping effect that traditional linear methods cannot capture, significantly improving the prediction accuracy of the starting wind speed and maximum amplitude of galloping. It solves the technical problem that traditional quasi-steady linear models cannot accurately predict the large-amplitude galloping characteristics of icy contact networks, and realizes accurate simulation and evaluation of starting wind speed, galloping amplitude and risk level. It is suitable for the analysis of the survivability of contact networks under extreme icy wind environments. Attached Figure Description
[0025] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.
[0026] In the attached diagram: Figure 1 This is a flowchart of the simulation method disclosed in the embodiments of this application.
[0027] Figure 2 This is a schematic diagram of the windward section of the overhead contact line disclosed in the embodiments of this application.
[0028] Figure 3 This is a schematic diagram of the hysteresis loop of the unsteady lift coefficient of the icing contact network disclosed in the embodiments of this application.
[0029] Figure 4 This is a graph showing the ice-covered and rising curves of the contact wire at the positioning points in the test case. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0031] In related technologies, the simulation of pantograph-catenary systems generally adopts a quasi-steady aerodynamic model plus a linear structural stiffness model. However, this approach has two drawbacks. First, it neglects the aerodynamic hysteresis effect: the quasi-steady assumption holds that the instantaneous aerodynamic force depends only on the current instantaneous angle of attack α(t), and is independent of the history or rate of change of the angle of attack. However, when the icing conductor twists significantly or moves rapidly, there is a time delay between airflow separation and reattachment. Therefore, the aerodynamic force depends not only on the current angle of attack but also on the rate of change of the angle of attack. ;neglect First, it misses an important nonlinear aerodynamic damping mechanism, leading to an inaccurate prediction of the initiation wind speed during galloping (potentially underestimating or overestimating). Second, it neglects geometric stiffness nonlinearity: traditional methods treat the stiffness matrix as a constant (containing only the material's elastic stiffness); however, during icy galloping, conductor tension fluctuates drastically, and tension significantly contributes to lateral stiffness (e.g., the greater the tension in a string, the greater the lateral stiffness); ignoring tension changes leads to structural stiffness distortion, making it impossible to simulate the geometric nonlinear behavior during large-scale galloping. The combination of these two major flaws results in a significant deviation between traditional simulation results and actual galloping characteristics (such as the amplitude of the limit cycle oscillation and the critical initiation wind speed), leading to an overly optimistic assessment of the overhead contact system's wind resistance safety and posing potential safety hazards.
[0032] To address this, this application provides a method and medium for simulating and assessing the nonlinear galloping of ice-wind composite contact networks. By introducing an unsteady aerodynamic correction factor and a time-varying geometric stiffness matrix, it solves the problem that traditional linear models cannot accurately predict large-scale galloping characteristics, as detailed in the following embodiments.
[0033] Example 1
[0034] This embodiment provides a simulation method for nonlinear galloping of a composite ice-wind contact network, such as... Figure 1 As shown, it includes the following steps: Step S100: Construct a library of aerodynamic parameters for irregular icing, obtain the static aerodynamic coefficients of the icing contact wire and catenary under different angles of attack, and draw a schematic diagram of the stress on the windward section of the contact wire as shown in Figure 100. Figure 2As shown, the static aerodynamic coefficient includes at least the static lift coefficient C. L,static ; Step S200: Construct an unsteady load model with aerodynamic hysteresis correction. In each time step, calculate the full effective angle of attack α based on the instantaneous vibration velocity of the contact wire nodes. eff And introduce the factor of angle of attack change rate The formula for calculating unsteady aerodynamic coefficients, correcting for aerodynamic loads under the quasi-steady assumption, where the unsteady lift coefficient C... L (α, The formula for calculating ) is:
[0035] In the formula, C L (α) eff , ) represents the corrected unsteady lift coefficient, k h V is the aerodynamic hysteresis attenuation coefficient, D is the characteristic diameter of the icing conductor, and V is the characteristic diameter of the conductor. rel The instantaneous relative wind speed of the contact wire node with respect to the airflow; When the wire twists rapidly Larger, -k h The projector dynamically adjusts aerodynamic forces, causing the lift coefficient to exhibit a "hysteresis loop," such as... Figure 3 As shown. This correction term is mathematically equivalent to introducing velocity-dependent nonlinear aerodynamic damping, which can accurately simulate negative aerodynamic damping that traditional methods cannot capture, thereby correctly predicting the initiation conditions and self-excited vibration characteristics of galloping.
[0036] Step S300: Construct a time-varying stiffness model with tension coupling. Based on the instantaneous tension changes caused by the combined ice and wind loads, update the geometric stiffness matrix of the contact wire unit in real time, and construct the aerodynamic-structural strongly coupled dynamic equations, where the total stiffness matrix is expressed as:
[0037] In the formula, K total (t) is the instantaneous total stiffness matrix of the contact wire element at time t, used to update the restoring force term in the dynamic equations, K elastic Let K be the linear elastic stiffness matrix of the contact wire element, T(t) be the instantaneous axial tension of the element at time t under the combined load of ice wind and structural vibration, and K be the linear elastic stiffness matrix of the contact wire element. g (T(t)) is the time-varying geometric stiffness matrix, which is a function of the axial tension of the element and is used to characterize the nonlinear contribution of tension to the transverse stiffness of the structure. During the gyratory motion, the conductor tension T(t) fluctuates in real time with the ice and wind load and structural vibration. Tension changes alter the lateral stiffness: the greater the tension, the greater the conductor's stiffness against lateral bending (geometric stiffness effect). By reassembling the conductor at each time step based on the current tension, the total stiffness matrix is dynamically updated with the motion state, accurately reflecting the geometric nonlinearity under large deformations.
[0038] Step S400: Use the Newmark-β method to perform time-domain iterative solution of the aerodynamic-structural strongly coupled dynamic equations and output the displacement time history of the contact wire nodes.
[0039] Specifically, in step S100, the irregular icing aerodynamic parameter library is constructed using CFD fluid simulation, which specifically includes: using a structured mesh, where the height of the first-layer mesh satisfies the wall y... + Value less than 1, use Using a turbulence model, the incompressible Navier-Stokes equations are solved to obtain the static lift coefficient C in the range of -180° to 180°. L Drag coefficient C D and torque coefficient C M The static aerodynamic coefficient function was obtained by fitting Fourier series.
[0040] Specifically, in step S200, the full effective angle of attack α eff The calculation formula is:
[0041] In the formula, α0 is the initial angle of attack. , V represents the instantaneous vibration velocity of the overhead contact line in the horizontal and vertical directions, respectively. wind For ambient wind speed.
[0042] Specifically, in step S200, the aerodynamic hysteresis attenuation coefficient k h The method for determining it is: by identifying the static lift coefficient curve C L,static (α) The slope abrupt change characteristics near the stall angle of attack, and the calibration is performed in combination with dynamic CFD simulation or wind tunnel test data.
[0043] Specifically, in step S200, the instantaneous relative wind speed V rel The calculation formula is:
[0044] In the formula, , These represent the instantaneous vibration velocities of the overhead contact line in the horizontal and vertical directions, respectively.
[0045] Specifically, in step S200, the formula for calculating the dynamic effective wind attack angle is:
[0046] In the formula, θ twist (t) represents the instantaneous torsion angle of the icy conductor.
[0047] Specifically, in step S200, the rate of change of angle of attack is introduced. The relevant nonlinear damping terms are used to calculate the aerodynamic hysteresis force.
[0048] By introducing -k h The hysteresis characteristics of aerodynamic forces can be reproduced at the numerical level.
[0049] Specifically, in step S300, the finite element mass matrix and stiffness matrix of the tension-coupled contact network are constructed. The mass matrix M needs to calculate the eccentric mass and moment of inertia of the crescent-shaped ice based on the ice thickness. The geometric stiffness matrix K needs to be reassembled at each time step based on the element axial force T(t) calculated in the previous substep. g (T):
[0050] The overall dynamic equations of the overhead contact system are updated as follows:
[0051] In the formula, M, C, K total (t) represents the mass matrix, damping matrix, and time-varying stiffness matrix of the icing contact wire, respectively. , U and F represent the acceleration, velocity, and displacement vectors of the overhead contact line, respectively. aero For the aerodynamic vector of the icing contact wire, F gravity This represents the load vector of the overhead contact line under the influence of gravity.
[0052] Example 2
[0053] This embodiment provides a risk assessment method for ice and wind composite contact networks. Based on the simulation method in Embodiment 1, the displacement time history of the contact network nodes is obtained, and the contact network galloping amplitude ratio is calculated. Based on the galloping amplitude ratio, it is determined whether there is a risk to the contact network.
[0054] Example 3
[0055] This embodiment provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the nonlinear galloping simulation method of the ice-wind composite contact network in Embodiment 1.
[0056] Experimental Example 1 This test example simulates the conditions under which the contact wire and catenary tension combination is 25+20kN, the operating speed is 200km / h, the ambient wind is 10m / s, and the contact wire is 5m long with the catenary covered by 10mm of ice. Other conditions are calculated similarly. The specific steps are as follows: Step S100: Construct a library of aerodynamic parameters for irregular icing and perform CFD simulation on the crescent-shaped icing contact line using FLUENT software. A structured mesh is used, with the first layer mesh height of 0.04 mm to satisfy $y + <1$, simulating the flow field at different angles of attack (-180° to 180°, step size 5°). Using Turbulence model, solving the incompressible Navier-Stokes equations. Extracting the lift coefficient C. L Drag coefficient C D and torque coefficient C M The static aerodynamic coefficient function C was obtained by Fourier series fitting. L,static (α) etc.
[0057] Step S200: Construct an unsteady load model with aerodynamic hysteresis correction. Unlike existing technologies that directly look up tables, this invention introduces unsteady correction when calculating aerodynamic loads. The specific steps are as follows: (1) Calculation of instantaneous relative wind speed:
[0058] In the formula, , These represent the instantaneous vibration velocities of the overhead contact line in the horizontal and vertical directions, respectively.
[0059] (2) Calculation of dynamic effective wind angle of attack:
[0060] In the formula, θ twist (t) represents the instantaneous torsion angle of the icy conductor.
[0061] (3) Introduction of the rate of change of angle of attack The relevant nonlinear damping terms are used to calculate the aerodynamic hysteresis force.
[0062] By introducing -k h The hysteresis characteristics of aerodynamic forces were reproduced at the numerical level.
[0063] Step S300: Construct the finite element mass matrix and stiffness matrix of the tension-coupled contact network. The mass matrix M needs to calculate the eccentric mass and moment of inertia of the crescent-shaped ice structure based on the ice thickness. The geometric stiffness matrix K needs to be reassembled at each time step based on the element axial force T(t) calculated in the previous substep. g (T):
[0064] The overall dynamic equations of the overhead contact system are updated as follows:
[0065] In the formula, M, C, K total (t) represents the mass matrix, damping matrix, and time-varying stiffness matrix of the icing contact wire, respectively. , U and F represent the acceleration, velocity, and displacement vectors of the overhead contact line, respectively. aero For the aerodynamic vector of the icing contact wire, F gravity This represents the load vector of the overhead contact line under the influence of gravity.
[0066] Step S400: Solve the above strongly nonlinear equations using the Newmark-β step-by-step integration method. Since the stiffness matrix K... total and load vector F aero Both are related to the state vector U, The coupling requires Newton-Raphson iterations at each time step until equilibrium is reached. The displacement, velocity, and tension time histories of the contact wire nodes at any given time are calculated, and the displacement z(t) and velocity of the mid-span node are extracted. (t), such as Figure 4 As shown, the amplitude ratio is calculated to determine whether the overhead contact line is in an aerodynamically stable or aerodynamically divergent state, thereby assessing the risk of overhead contact line galloping.
[0067] This experimental example solves the technical problem that traditional quasi-steady linear models cannot accurately predict the large-scale galloping characteristics of icing contact networks by introducing an "unsteady aerodynamic correction term related to the rate of change of angle of attack" and a "geometric stiffness matrix updated in real time with tension," and achieves accurate simulation and evaluation of the start-up wind speed, galloping amplitude, and risk level.
[0068] The above embodiments of this application focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.
[0069] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A simulation method for nonlinear galloping of a composite ice-wind contact network, characterized in that, Includes the following steps: Step S100: Construct an irregular icing aerodynamic parameter library, and obtain the static aerodynamic coefficients of the icing contact line and the catenary under different angles of attack. The static aerodynamic coefficients include at least the static lift coefficient C. L,static ; Step S200: Construct an unsteady load model with aerodynamic hysteresis correction. In each time step, calculate the full effective angle of attack α based on the instantaneous vibration velocity of the contact wire nodes. eff And introduce the factor of angle of attack change rate The formula for calculating unsteady aerodynamic coefficients, correcting for aerodynamic loads under the quasi-steady assumption, where the unsteady lift coefficient C... L (α, The formula for calculating ) is: In the formula, C L (α) eff , ) represents the corrected unsteady lift coefficient, k h V is the aerodynamic hysteresis attenuation coefficient, D is the characteristic diameter of the icing conductor, and V is the characteristic diameter of the conductor. rel The instantaneous relative wind speed of the contact wire node with respect to the airflow; Step S300: Construct a time-varying stiffness model with tension coupling. Based on the instantaneous tension changes caused by the combined ice and wind loads, update the geometric stiffness matrix of the contact wire unit in real time, and construct the aerodynamic-structural strongly coupled dynamic equations, where the total stiffness matrix is expressed as: In the formula, K total (t) is the instantaneous total stiffness matrix of the contact wire element at time t, used to update the restoring force term in the dynamic equations, K elastic Let K be the linear elastic stiffness matrix of the contact wire element, T(t) be the instantaneous axial tension of the element at time t under the combined load of ice wind and structural vibration, and K be the linear elastic stiffness matrix of the contact wire element. g (T(t)) is the time-varying geometric stiffness matrix, which is a function of the axial tension of the element and is used to characterize the nonlinear contribution of tension to the transverse stiffness of the structure. Step S400: Use the Newmark-β method to perform time-domain iterative solution of the aerodynamic-structural strongly coupled dynamic equations and output the displacement time history of the contact wire nodes.
2. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 1, characterized in that, In step S100, the irregular icing aerodynamic parameter library is constructed using CFD fluid simulation, specifically including: using a structured mesh, with the first-layer mesh height satisfying the wall y + Value less than 1, use Using a turbulence model, the incompressible Navier-Stokes equations are solved to obtain the static lift coefficient C in the range of -180° to 180°. L Drag coefficient C D and torque coefficient C M The static aerodynamic coefficient function was obtained by fitting Fourier series.
3. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 1, characterized in that, In step S200, the full effective angle of attack α eff The calculation formula is: In the formula, α0 is the initial angle of attack. , V represents the instantaneous vibration velocity of the overhead contact line in the horizontal and vertical directions, respectively. wind For ambient wind speed.
4. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 3, characterized in that, In step S200, the aerodynamic hysteresis attenuation coefficient k h The method for determining it is: by identifying the static lift coefficient curve C L,static (α) The slope abrupt change characteristics near the stall angle of attack, and the calibration is performed in combination with dynamic CFD simulation or wind tunnel test data.
5. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 3, characterized in that, In step S200, the instantaneous relative wind speed V rel The calculation formula is: In the formula, , These represent the instantaneous vibration velocities of the overhead contact line in the horizontal and vertical directions, respectively.
6. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 5, characterized in that, In step S200, the formula for calculating the dynamic effective wind attack angle is: In the formula, θ twist (t) represents the instantaneous torsion angle of the icy conductor.
7. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 6, characterized in that, In step S200, the rate of change of angle of attack is introduced. The relevant nonlinear damping terms are used to calculate the aerodynamic hysteresis force. By introducing -k h The hysteresis characteristics of aerodynamic forces can be reproduced at the numerical level.
8. The simulation method for nonlinear galloping of a composite ice-wind contact network according to claim 1, characterized in that, In step S300, the finite element mass matrix and stiffness matrix of the tension-coupled contact network are constructed. The mass matrix M requires calculation of the eccentric mass and moment of inertia of the crescent-shaped ice structure based on the ice thickness. The geometric stiffness matrix K is reassembled at each time step based on the element axial force T(t) calculated in the previous substep. g (T): The overall dynamic equations of the overhead contact system are updated as follows: In the formula, M, C, K total (t) represents the mass matrix, damping matrix, and time-varying stiffness matrix of the icing contact wire, respectively. , U and F represent the acceleration, velocity, and displacement vectors of the overhead contact line, respectively. aero For the aerodynamic vector of the icing contact wire, F gravity This represents the load vector of the overhead contact line under the influence of gravity.
9. A risk assessment method for ice and wind composite overhead contact lines, characterized in that, The displacement time history of the contact wire node is obtained based on the simulation method described in any one of claims 1 to 8, and the contact wire galloping amplitude ratio is calculated. Based on the galloping amplitude ratio, it is determined whether there is a risk to the contact wire.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the nonlinear galloping simulation method for ice-wind composite contact networks as described in any one of claims 1 to 8.