A design method for the vertical stiffness of the track in the transition section of the track curve section
By simplifying the track stress model and calculating the rail stiffness parameters of the transition section, the difficulty of setting the rail transition section stiffness in the curved section is solved, and the parameters of the vertical stiffness of the rail in the transition section are calculated are realized, and the mechanical properties of the track and the smooth operation of the train are optimized.
Patent Information
- Application Number
- CN202411291722.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2044-09-14
AI Technical Summary
There are difficulties in setting up the stiffness of the track transition section in the curved area. It is impossible to effectively design the stiffness of the track transition section in the curved area, which affects the smooth operation of the train.
By simplifying the rail force into an elastic foundation beam model, the stiffness setting parameters of the transition section track are calculated, and combined with the train operating conditions, the vertical stiffness design parameters of the transition section track of the curved section are determined.
The vertical stiffness of the rail in the transition section of the curved section is calculated to ensure that the track can better withstand the train load and various forces, optimize the mechanical properties of the track, and improve the stability of the train when passing through the curve section.
Smart Images
Figure CN119272368B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of rail transit, and more specifically, particularly relates to a design method for the vertical stiffness of the track in the transition section of the track curve section. Background Art
[0002] Between different railway track structures, due to differences in parameters such as stiffness, it is necessary to set up a transition section for transition to meet the smoothness of train operation passing through; currently, in the design of the track transition section, mainly the vertical stiffness of one end of the track is gradually transitioned to the vertical stiffness of the other end in the transition section, so that when the train passes through the transition section, it gradually accepts the smooth change and transition of the track stiffness and meets the smoothness of operation. However, in the curve section, when the train runs on the track, its vertical force and lateral force will both change to a certain extent, and the forces on the left and right rails are also different; therefore, currently, the setting of the track transition section is limited to the straight section. With the development of rail transit in recent years, the proportion of the curve section in the track line is increasing, especially the proportion of small-radius curves is more prominent, which brings more and more difficulties to the setting of the track transition section. Therefore, it is very necessary to propose to set up a transition section for the track line in the curve section.
[0003] In the straight track line, the two rails are at the same horizontal plane. When the train runs on the line, the elasticity and load forces borne by the left and right wheels are the same. When the train passes through the track line transition section, the vertical stiffness of the left and right tracks of the track line changes uniformly, which can ensure the relatively smooth operation of the train; however, when the train runs through the curve track, the train will generate a certain centrifugal force. To reduce the adverse effects brought by the centrifugal force to the train, usually a superelevation needs to be set on the track in the curve section, and the component force of the superelevation offsets the influence of the centrifugal force. At the same time, when the train runs in the curve section, due to the centrifugal force, a lateral force will also be generated on the track, resulting in the complexity of the wheel-rail interaction in the curve section being much higher than that in the straight section. Therefore, setting up a transition section in the curve section will have different impacts on the left and right rails, and thus the requirements are also different. Moreover, due to the influence of the superelevation and centrifugal force, it will also have an impact on the change of the lateral stiffness of the track. Therefore, the factors to be considered are much more complex than those of the straight section track.
[0004] The present invention proposes a calculation method for the dynamic change characteristics and influencing factors of the train running on the curve track. Through this calculation method, combined with the track line and train operation conditions, the parameter setting of the track in the transition section of the curve section can be carried out to solve the stiffness method for setting up the track transition section in the curve section. Summary of the Invention
[0005] To solve the above technical problems, the present invention provides a design method for the vertical stiffness of the transition section track in the track curve section, so as to solve the technical problems in the prior art that it is difficult to set the transition section track in the traditional curve section and it is impossible to design the stiffness of the track transition section in the curve section.
[0006] The purpose and effect of a design method for the vertical stiffness of the transition section track in the track curve section of the present invention are achieved by the following specific technical means:
[0007] A design method for the vertical stiffness of the transition section track in the track curve section includes the following steps:
[0008] Step 1: Simplify the force on the rail under the load of the track into an elastic foundation beam model, and determine the force on the rail under the load.
[0009] Step 2: Calculate the stiffness setting parameters of the transition section track.
[0010] Step 3: Calculate the lateral force generated when the train passes through the curve.
[0011] Determine the lateral centrifugal force generated when the train passes through the curve, and reduce the generation of the lateral centrifugal force by the force opposite to the lateral centrifugal force generated by setting the superelevation, and calculate the lateral force generated when the train runs through the track curve line after setting the superelevation.
[0012] Step 4: Calculate the influence of the lateral force on the additional vertical forces on the left and right rails.
[0013] When the train runs on the curve, different additional vertical forces will be generated on the left and right rails by the generated lateral force.
[0014] Step 5: Obtain the calculation formula for the vertical stiffness design parameters of the inner and outer rail transition section tracks.
[0015] In a preferred embodiment, in Step 2, the calculation formula for the stiffness setting parameters of the transition section track is:
[0016]
[0017] Among them, k(x) is the stiffness parameter at point x of the transition section, k 1 is the vertical stiffness of the track at the front end of the transition section, k 2 is the vertical stiffness of the track at the end of the transition section, L is the length of the transition section, and x is the mileage coordinate along the line direction.
[0018] In a preferred embodiment, the calculation formula for the lateral force generated when the train runs through is:
[0019] F zh = F h - f h
[0020] Among them, F zh is the lateral force generated when the train runs through after setting superelevation for the track curve line, F h is the lateral force generated when the train passes through the curve, and f h is the reverse force generated after setting superelevation for the line.
[0021] In a preferred embodiment, in step four, the calculation formula for the additional vertical force of the lateral force on the left and right rails is:
[0022]
[0023] Among them, F s is the additional vertical force, H is the height of the vehicle's center of gravity, and S is the gauge of the track line.
[0024] In a preferred embodiment, the vertical force on the inner rail of the curve is: P n = P - F s ;
[0025] The vertical force on the outer rail of the curve is: P w = P + F s , where P is the train load.
[0026] In a preferred embodiment, in step five, the calculation formula for the vertical stiffness is:
[0027]
[0028] Among them, k w is the design parameter of the vertical stiffness of the outer rail of the curve, and k n is the design parameter of the vertical stiffness of the inner rail of the curve.
[0029] Compared with the prior art, the present invention has the following beneficial effects:
[0030] 1. By simplifying the track force into an elastic foundation beam model, this method establishes the calculation formula for the force of the rail under the action of the load. On this basis, it derives the calculation formula for the stiffness setting parameters of the transition section track, and can determine the vertical stiffness parameters at different positions along the transition section; it provides a basis for solving the problem of reasonably designing the stiffness of the track transition section in the curve section and realizing the parameter calculation of the vertical stiffness of the transition section track in the curve section, which helps to ensure that when the train passes through the transition section of the curve section, the track can better withstand the load and various forces of the train, thereby optimizing the mechanical properties of the track and improving the smoothness when the train passes.
[0031] 2. In calculating the lateral force generated when a train passes through a curve, the calculation formula for the additional vertical force exerted by the lateral force on the left and right tracks after the superelevation is set is derived; based on the above calculations, the specific calculation formula for the vertical stiffness design of the transition section between the inner and outer tracks of the curve is given. Based on the force characteristics of the track under the load in the curve section, it is beneficial to reasonably set the stiffness parameters of the transition section between the inner and outer tracks, reduce the adverse effects of the lateral force and vertical force generated when the train travels in the curve section on the track, and thus ensure the smoothness of the track in the curve section. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 is a flowchart of the steps of a method for designing the vertical stiffness of the transition section of the track in the curve section of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0033] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with the drawings and embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.
[0034] Embodiment:
[0035] Please refer to as Figure 1 shown, the present invention provides a method for designing the vertical stiffness of the transition section of the track in the curve section of the track, including the following steps:
[0036] Step 1: Simplify and model the stress state of the rail when the track is subjected to the train load. Specifically, the rail is regarded as a beam system supported on an elastic foundation. This elastic foundation beam model can better simulate the actual stress situation of the track and provide a theoretical basis for subsequent calculations; based on this model, the calculation formula describing the stress of the rail under the load is derived, providing a basis for accurately evaluating the stress of the straight track section;
[0037] Step 2: Based on the calculation formula of the rail stress, the stress characteristics of the rail in the transition section can be analyzed; due to the curvature change in the transition section, its stress situation is different from that of the straight track section. Therefore, on the basis of the original model, it is necessary to further refine the analysis of the mechanical properties of the transition section and determine the stiffness setting parameters of the transition section of the track accordingly;
[0038] Step 3: Calculate the lateral force generated when the train passes through the curve;
[0039] When a train passes through a curved track, a certain lateral force will be generated due to the action of centrifugal force. This lateral force will have a correlative impact on the displacement deformation and stiffness of the track, and may also affect the smooth operation of the train. Therefore, it is necessary to calculate the lateral centrifugal force generated when the train passes through the curve and take corresponding measures to compensate for it. Specifically, it is to estimate the influence of the centripetal force generated by the superelevation set on the outer side of the track on the gravity force, so as to provide a basis for the design calculation and correction of the track stiffness in the transition section.
[0040] Step Four: After determining the lateral forces generated when the train passes through the curve, it is also necessary to pay attention to the vertical forces imposed on the left and right rails by these lateral forces. When the train is running on a curved track, due to the action of centrifugal force and superelevation, different degrees of vertical additional forces will be generated on the left and right rails. The magnitude and distribution of this vertical force will have a certain impact on the stress state of the rail itself and the overall stability of the track. Therefore, based on the calculated lateral forces of the curve mentioned above, it is necessary to further calculate the additional vertical forces borne by the left and right rails and evaluate their influence on the rail itself and the support structure.
[0041] Step Five: After clarifying the lateral forces generated when the train passes through the curve and the vertical forces imposed on the left and right rails by these lateral forces, the next step is to calculate the design parameters of the vertical stiffness of the track in the transition section between the inner and outer rails. This is very important for ensuring the stability of the track under complex mechanical actions. According to the results of the above calculation and analysis, a formula for the design parameters of the vertical stiffness applicable to the transition section between the inner and outer rails is formulated.
[0042] In Step One, the force calculation formula of the rail under the action of the load is:
[0043]
[0044] Among them, Q is the shear force exerted by the train on the rail, x is the mileage coordinate along the line direction, and y is the vertical displacement of the track. The vertical load P generated by the train on the straight track will directly act on the rail and become the main vertical force borne by the rail, so as to calculate the stress level of the rail when bearing the train load and provide a necessary basis for subsequent structural settings.
[0045] In Step Two, the calculation formula for the stiffness setting parameters of the transition section track is:
[0046]
[0047] Among them, k(x) is the stiffness parameter at point x in the transition section, k 1 is the vertical stiffness of the track at the front end of the transition section, k 2$K$ is the vertical stiffness of the track at the end of the transition section, $L$ is the length of the transition section, $x$ is the mileage coordinate along the line direction, and $y$ is the vertical displacement of the track. It can be obtained from the formula that in the straight section, the stiffness parameters of the left and right tracks are the same. By adjusting the stiffness of the transition section, the smooth transition of the rail under the train load can be achieved, avoiding problems such as local stress concentration or excessive deformation.
[0048] In step three, when the train passes through the curved track, due to the action of the train's motion inertia, a certain centrifugal force will be generated on the horizontal plane of the track. This lateral centrifugal force will apply vertical forces of different degrees to the left and right rails. The calculation formula for the lateral centrifugal force generated when the train passes through the curve is:
[0049]
[0050] In the formula, $F$ h is the lateral force generated when the train passes through the curve, $v$ is the running speed of the train, $R$ is the radius of the curve of the track line, $m$ is the mass of the train, $G$ is the weight of the train, and $g$ is the acceleration due to gravity. By substituting these key parameters into the formula for calculation, the magnitude of the lateral force generated when the train passes through the curve can be predicted, providing an important basis for the track structure setting.
[0051] In order to offset the lateral centrifugal force generated when the train passes through the curve, the measure of setting superelevation is usually taken in the curve section. The so-called superelevation means that the rail surface is raised on the outside of the curved track, thus generating a reverse force opposite to the centrifugal force. By calculating the magnitude of this reverse force, it can be ensured that when the train passes through the curve, the resultant force of these two forces can reach equilibrium, thereby minimizing the unbalanced vertical load borne on both sides of the track to the greatest extent. The calculation formula for the reverse force opposite to the lateral centrifugal force generated after setting superelevation is:
[0052]
[0053] Among them, $f$ h is the reverse force generated after setting superelevation on the line, and $S$ is the gauge of the track line. The superelevation height can be reasonably adjusted according to different line conditions to make the reverse force and the centrifugal force reach equilibrium.
[0054] During the process of the train passing through the curved track, in addition to the above-mentioned lateral centrifugal force, the setting of track superelevation will also cause the generation of another lateral force. Specifically, when the train runs on the curved track with superelevation, due to the action of gravity, the train itself will have a tendency to tilt, thus forming a lateral force on the horizontal plane. The calculation formula for the lateral force generated when the train runs through is:
[0055] $F$ zh $=$ $F$ h $- f$h
[0056] Among them, F zh is the lateral force generated when the train runs through after setting superelevation for the track curve line; by substituting these parameters into the formula for calculation, the magnitude of this lateral force generated due to the train's own inclination can be predicted.
[0057] In Step 4, when analyzing various mechanical effects generated during the train passing through the curved track, the additional vertical forces exerted by the lateral force on the left and right rails also need to be considered. Among them, the calculation formula for the additional vertical forces of the lateral force on the left and right rails is:
[0058]
[0059] Among them, F s is the additional vertical force, H is the height of the vehicle's center of gravity, and S is the gauge of the track line; specifically, when the train is running on the curved track, due to the action of the generated lateral force, an uneven vertical load distribution will be generated on the left and right rails. This unbalanced vertical force will cause the inner rail to bear a greater pressure, while the pressure on the outer rail is relatively small; by substituting these parameters into the corresponding calculation formula, the magnitude of this additional vertical force can be predicted, so as to ensure the balance of the bearing capacity of the left and right rails during track design and avoid potential safety hazards caused by local overloading.
[0060] When the train runs on the curved track, the vertical forces generated on the inner and outer rails are usually different. For the inner and outer rails, the stiffness parameter settings of the transition section must also be corresponding according to their different forces;
[0061] The vertical force on the inner rail of the curve is: P n = P - F s ;
[0062] The vertical force on the outer rail of the curve is: P w = P + F s ;
[0063] The vertical force borne by the track on the outside of the curve section is higher than that on the inside. This is caused by the action of the lateral force. Specifically, the design parameter of the vertical stiffness of the outer rail should be greater than that of the inner rail, so as to ensure that the track bears balanced vertical pressure and avoid uneven settlement or deformation.
[0064] In Step 5, the calculation formula for the vertical stiffness is:
[0065]
[0066] Among them, k w is the design parameter of the vertical stiffness of the outer rail of the curve, k nIt is the design parameter of the vertical stiffness of the inner track of the curve; the specific numerical values of the vertical stiffness required for the inner track and the outer track are obtained, so as to ensure that the entire curve track can provide sufficient bearing capacity and stability in the vertical direction, which is beneficial to ensuring the smoothness of train operation; the problem that the stiffness of the track transition section cannot be reasonably designed in the curve section is solved, and the parameter calculation of the vertical stiffness of the transition section track in the curve section is realized, which helps to ensure that when the train passes through the transition section of the curve section, the track can better bear the load and various forces of the train, thereby optimizing the mechanical properties of the track.
[0067] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.
Claims
1. A design method for the vertical stiffness of a track in a transition section of a track curve section, characterized by: The following steps are included: Step 1: Simplify the force of the rail under the load into an elastic foundation beam model, and determine the force of the rail under the load; Step 2: Calculate the stiffness setting parameters of the transition section track; Step 3: Calculate the lateral force generated when the train passes through the curve; Determine the lateral centrifugal force generated when the train passes through the curve, and reduce the lateral centrifugal force by setting the superelevation to generate the opposite force to the lateral centrifugal force. Calculate the lateral force generated by the train running through the track curve after setting the superelevation; Step 4: Calculate the effect of the lateral force on the additional vertical force on the left and right rails; When a train runs on a curve, the lateral force generated will produce different additional vertical forces on the left and right rails; Step 5: Obtain the calculation formula for the vertical stiffness design parameters of the transition section between the inner and outer rails; In step 2, the calculation formula for the stiffness setting parameters of the transition section track is: Wherein, k(x) is the stiffness parameter at a certain point of the transition section, k1 is the vertical stiffness of the track at the front end of the transition section, k2 is the vertical stiffness of the track at the end of the transition section, L is the length of the transition section, and x is the mileage coordinate along the line direction; In step 5, the vertical stiffness is calculated as: Among them, k w (x) is the design parameter of the vertical stiffness of the outer rail of the curve, k n (x) is the design parameter of the vertical stiffness of the inner rail of the curve, P is the train load, F s is the additional vertical force.
2. The design method of the vertical stiffness of a track in a transition section of a track curve section according to claim 1 is characterized by: The calculation formula of the lateral force generated by the train running is: F zh =F h -f h Among them, F zh After setting superelevation for the track curve line, the lateral force generated by the train running through it, F h is the lateral force generated when the train passes through the curve, f h The reverse force generated after superelevation is set for the line.
3. A design method for the vertical stiffness of a track in a transition section of a track curve section according to claim 2, characterized in that: In step 4, the calculation formula for the additional vertical force on the left and right rails caused by the lateral force is: Among them, F s is the additional vertical force, H is the height of the vehicle's center of gravity, and S is the track gauge.
4. The method for designing the vertical stiffness of a track in a transition section of a track curve section according to claim 3 is characterized by: The vertical force on the inner rail of the curve is: P n =PF s ; The vertical force on the outer rail of the curve is: P w =P+F s ; Where P is the train load.