How to predict steel rail light bands

Abstract

To provide a method for predicting the state of a light band formed on a steel rail after a vehicle passes over the steel rail, thereby evaluating the matching state of a wheel-rail based on the predicted light band, which is useful for the maintenance of the steel rail. [Solution] A first amount of material loss of the steel rail from a state where no light band occurs on the surface of the steel rail to the appearance of a light band is determined, a second amount of material loss of each lattice cell of the contact patch formed on the steel rail to be detected after a vehicle has passed over the steel rail to be detected a predetermined number of times, and a target area where the second amount of material loss is equal to or greater than the first amount of material loss is determined to be an area having a light band, and the position and width of the light band formed on the steel rail to be detected are predicted based on information of the contact patch formed after the vehicle has passed over the steel rail to be detected a predicted number of times.

Description

[Technical field]

[0001] The present invention relates to the technical field of track engineering data processing, in particular to predicting steel rail light belts It concerns the method. [Background technology]

[0002] The steel rail light band is the contact area between the wheels and the steel rail after the vehicle has passed over the steel rail several times. The change in the light band reflects whether the wheel-rail relationship is normal. This is an important feature, which can effectively prevent some problems caused by the change in the steel rail light band. It is possible. However, currently there is a lack of technology to predict the light band of steel rails, and railway maintenance work is The work is incomplete. Summary of the Invention

[0003] The present application provides a method for predicting the steel rail light band, and after a vehicle passes over a steel rail, The state of the light band formed on the steel rail is predicted, and the wheel-rail alignment is calculated based on the predicted light band. It can evaluate the matching condition and is useful for the maintenance of steel rails. To achieve this, the present application adopts the following technical solutions: In a first aspect, the present application provides a method for predicting steel rail light bands, the method comprising: The step includes the steps of: The first material loss amount of the steel rail during the process is determined, and the vehicle is located on the steel rail to be detected. After a certain number of passes, the second of each grid cell of the contact patch formed on the steel rail to be detected The amount of material loss is predicted, and a target area where the second amount of material loss is equal to or greater than the first amount of material loss is detected by the optical microscope. The area is determined to have a band, which is formed after the vehicle passes over the steel rail to be detected a predicted number of times. Based on the information of the contact patch, the position and Predict the width of the gap. In a possible implementation, each time a vehicle passes over a steel rail to be detected, An elliptical contact patch is formed on the steel rail, and the target area is the overlap of multiple elliptical contact patches. Based on this, the predicted number of times the vehicle passes over the steel rail to be detected is calculated. Based on the information of the contact patch formed after passing through the steel rail, The step of predicting the position and width of the light band includes: The information of the elliptical contact patch formed each time the ball passes over the ball is acquired, and the elliptical contact patch The information includes the center point and semi-axis length of the elliptical contact patch, where the coordinates of the center point are the wheel center. The origin of the wheelset coordinate system is 0, which is the center of the wheelset. The X-axis of the wheelset coordinate system runs along the longitudinal direction of the steel rail, and the The Z axis of the wheelset coordinate system is vertically downward, and the Y axis of the wheelset coordinate system is the steel rail. The contact pad extends along the transverse direction of the contact hole and forms a right-handed coordinate system with the X and Z axes. The major axis of the contact patch is along the X-axis direction, and the minor axis of the elliptical contact patch is along the Y-axis direction. Based on the center points and semi-axis lengths of the multiple elliptical contact patches that form the region, points within the target region are Determine the two intersection points with the boundary of the target region along the Y axis of the wheelset coordinate system, where , the coordinate of the point in the target area on the X-axis of the wheelset coordinate system, and The coordinates of the two intersections on the Y axis indicate the position of the light band formed on the steel rail to be detected. is used to indicate the distance between the coordinates of these two intersection points on the Y axis of the wheelset coordinate system. The distance is used to indicate the width of the light band. In a possible implementation, the surface of the steel rail goes from no light band to light band. The step of determining a first material loss amount of the steel rail in the process includes: , the first surface fractal dimension of the steel rail with the light band and the first surface fractal dimension of the steel rail without the light band The second surface fractal dimension is obtained, and the surface fractal dimension of the steel rail is The wheel specimen and surface fractal dimension are used to indicate the roughness of the second surface fractal. Wheel-rail friction tests were performed on the steel rail specimens of the three-dimensional of steel rail specimen when the surface fractal dimension of the specimen reaches the first surface fractal dimension The material loss amount is determined as a first material loss amount. In a possible implementation, the first surface fractal dimension is made of a steel rail with a light band. The maximum value of the surface fractal dimension of the multiple steel rail specimens obtained by The surface fractogram of multiple steel rail specimens made of steel rails without light bands was is the average value of the dimension. In a possible implementation, the contacts formed each time the vehicle passes over the steel rail to be detected. When the contact patch is divided into a number of grid cells, the vehicle is placed on a predetermined steel rail to be detected. After passing the number of times, the second material of each grid cell of the contact patch formed on the steel rail to be detected The step of predicting the amount of material loss includes: Each time, the amount of material loss in each grid cell of the contact patch formed on the steel rail to be detected is After the vehicle passes over the steel rail to be detected a predetermined number of times, The amount of material loss in each grid cell of the contact patch formed on the The amount of loss is obtained, and during the process of the vehicle passing over the steel rail to be detected a predetermined number of times, When the wheel passes through the steel rail, the contact point between the wheel and the steel rail to be detected is in one of the multiple lattice cells. Located within the In a possible implementation, each time a vehicle passes over a steel rail to be detected, The steps of predicting the amount of material loss in each grid cell of a contact patch formed on a steel rail are as follows: Each time the vehicle passes a steel rail to be detected, the wheel-rail contact point determine wheel-rail contact information corresponding to the grid cell in which the wheel-rail contact information is located, Wheel-rail contact stress in the grid cell in which the wheel-rail contact point is located, and The wheel-rail contact information includes the relative wheel-rail slippage when the wheel rolls through the cell. The wheel-rail wear model is used to obtain the amount of material loss in the grid cell, and the wheel-rail wear The model was developed to describe the relationship between the wheel-rail contact information and the steel rail material loss. Used. In a possible implementation, the wheel-rail contact points in the lattice cells in which the wheel-rail contact points are located. stress JPEG0007675968000002.jpg79 is JPEG0007675968000003.jpg27119, where x is the coordinate of the wheel-rail contact point on the X axis of the wheelset coordinate system. where y is the coordinate of the wheel-rail contact point on the Y axis of the wheelset coordinate system, and a is the ellipse is the major semi-axis length of the elliptical contact patch, b is the minor semi-axis length of the elliptical contact patch, and N is the vehicle is the wheel-rail contact normal force when passing over the steel rail to be detected. In a possible implementation, the wheel-rail relative slip as the wheel rolls through the grid cell is running distance JPEG0007675968000004.jpg79 is JPEG0007675968000005.jpg2683, where JPEG0007675968000006.jpg77 is the lateral sliding velocity of the wheel within the grid cell, JPEG0007675968000007.jpg87 is the longitudinal sliding speed of the wheel within the grid cell, JPEG0007675968000008.jpg77 is the wheel rolling forward speed, JPEG0007675968000009.jpg710 is the length of a lattice cell, Here, the lateral and longitudinal sliding velocities of the wheel in one grid cell are calculated based on the track rigidity. Based on the flexible coupling dynamics model and the wheel-rail rolling contact model, Required. In a possible implementation, the method for predicting steel rail light bands provided by the present application includes: The method further includes generating a plurality of sets of stochastic dynamics parameters, The dynamic parameters are used to simulate the motion of a vehicle passing over a steel rail. Each set of stochastic dynamics parameters is used: vehicle axle load, vehicle passing speed, wheel-rail Includes coefficient of friction and steel rail unevenness. This application uses a test method to measure the time required for a steel rail to go from no light banding to the time when light banding occurs. The first material loss amount during the process is determined, and the first material loss amount formed after the wheel-rail contact is performed a predetermined number of times is determined. When the material loss of each grid cell of the contact patch reaches the first loss amount, a light band appears on the steel rail. Based on the contact patch information, the light band formed on the steel rail surface was determined to be By predicting the position and width, the state of the light band formed on the steel rail can be predicted and predicted. Based on the measured light band, the wheel-rail matching condition can be evaluated. This is useful for maintaining the system. [Brief description of the drawings]

[0004] [Figure 1] FIG. 2 is a schematic diagram of a wheelset coordinate system provided by an embodiment of the present application. [Diagram 2] FIG. 1 is a schematic diagram of a method for predicting steel rail light bands provided by an embodiment of the present application. [Diagram 3] FIG. 2 is a schematic diagram of a method for predicting steel rail light bands provided by an embodiment of the present application. [Figure 4] FIG. 2 is a schematic dimensional diagram of a wheel specimen and a steel rail specimen provided by an embodiment of the present application. [Diagram 5] FIG. 2 is a schematic diagram illustrating the change in material loss of steel rail during wheel-rail friction process provided by an embodiment of the present application; [Figure 6] FIG. 2 is a schematic diagram showing the change in material loss rate of steel rail during wheel-rail friction process provided by an embodiment of the present application; [Figure 7] FIG. 2 is a schematic diagram illustrating the change of surface fractal dimension of steel rail during wheel-rail friction process provided by an embodiment of the present application; [Figure 8] 3 is a schematic diagram of a method for predicting steel rail light bands provided by an embodiment of the present application; [Figure 9] 4 is a schematic diagram of a method for predicting steel rail light bands provided by an embodiment of the present application. [Figure 10] 1 is a schematic diagram of a steel rail light belt provided by an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] First, some technical terms related to the embodiments of this application will be explained. 1. Steel rail light strip During the repeated contact and friction between the steel rail surface and the wheels, the oxide layer on the steel rail surface The bright marks formed by wear are called photic zones. Observing and analyzing the light bands on steel rails provides important information on steel rail wear, wheel wear, etc. This information reflects the operational status of the railway and allows the railway to be maintained and repaired in a timely manner as necessary. Measures can be taken. The light band is formed by long-term wheel-rail interaction and the light band on the steel rail surface The formation process includes a material rapid wear stage, a light band formation stage and a light band stabilization stage. Here, the rapid material wear stage refers to the stage in which the material loss of the steel rail occurs after wheel-rail friction begins. The amount of ions increases rapidly, but no obvious bright marks have yet formed on the steel rail surface. The light band formation stage refers to the stage where the wheel-rail continues to rub against each other and the material loss of the steel rail increases. The material loss rate continues to increase, but gradually the visible bright markings appear on the steel rail surface. The light band stabilization stage refers to the stage in which the material loss of the steel rail gradually increases and the material The material loss rate continues to decrease, and the light band traces in the wheel-rail contact area gradually become apparent, and the light This refers to a stage in which the area is basically stable. 2. Surface fractal dimension The surface fractal dimension measures the roughness (i.e., the degree of irregularity and unevenness) of an object surface. It is a quantitative indicator to determine the In the embodiments of the present application, the surface roughness of a steel rail refers to the degree of unevenness of the surface of the steel rail. The unevenness of the steel rail surface is caused by the manufacturing process of the steel rail or by over-use. This is due to wear or corrosion during the process. The surface fractal dimension of the steel rail is determined by different methods, and in the examples of this application The box counting method was used to obtain the surface fractal dimension of the steel rail. The test method mainly uses measuring instruments (such as microscopes) to observe the microscopic surface morphology of steel rails and Count the number of boxes required to cover the rail surface and calculate the fractal dimension. Calculate the value of the fractal dimension according to the formula. The formula for calculating the fractal dimension is as follows: can be, JPEG0007675968000010.jpg2582In the above formula, Ds represents the surface fractal dimension of the steel rail, and i represents the surface fractal dimension of the steel rail during the measurement process. represents the smallest measurement scale that is continuously distributed on the lens surface (i.e., the positive scale divided by the projection surface). The length of the sides of a rectangular cell, a unit cube used to measure the third dimension in a three-dimensional rough surface. field), and N(i) is the number of measurement scales, i.e., the number of squares packed into the rough surface. , i.e., the number of boxes required to cover the steel rail surface configuration. Details of determining the surface fractal dimension of steel rails using the box-counting method The details belong to the prior art, and further detailed description is omitted in the embodiments of the present application. will be done. 3. Wheelset coordinate system The wheelset coordinate system is defined based on the running state of the vehicle on steel rails. For example, as shown in FIG. 1, the origin 0 of the wheel set coordinate system is the wheel set on the center line of the wheelset (i.e. the center line of the left and right wheels of the vehicle), and The axis extends along the longitudinal direction of the steel rail (i.e., the direction of vehicle travel or wheel rolling). , the Z axis of the wheelset coordinate system is vertically downward, and the Y axis of the wheelset coordinate system is the Extending along the rail's lateral direction (i.e., horizontally to the right in Figure 1), the X-axis and Z-axis Together they form a right-handed coordinate system. The wheelset coordinate system is used to calculate the position and orientation of the wheelset relative to the track, the wheel and the steel It serves as a reference standard used to describe contact relationships of steel rails, etc. When a vehicle passes over a steel rail, the contact point between the wheel and the steel rail (wheel-rail The wheel-rail contact relationship is described by the Hertzian mechanics theory. Based on this relationship, after the vehicle passes over the steel rail, the wheel-rail contact point is placed on the steel rail. An elliptical contact patch is formed with its center point at the center of the wheel set. The major axis is along the X-axis of the wheelset coordinate system, and the minor axis is along the Y-axis of the wheelset coordinate system. In view of the current lack of a method for predicting the light band of a steel rail, the embodiment of the present application A method for predicting the light band on a steel rail after a vehicle has passed over the steel rail a predetermined number of times is provided. It predicts the condition of the light band formed on the surface in advance, evaluates the matching condition of the wheel and rail, and Useful for rail maintenance. The method provided by the embodiments of the present application is applicable to any scenario where wheel-rail friction exists. Steel rails in the light belt, some switch areas (intersections of multiple tracks) It is used to predict the rail light zone. In the following examples, it is mainly the turn out zone. This paper takes the example of a steel rail light belt prediction process in the turnout zone. As shown in FIG. 2, the method for predicting the steel rail light belt provided by the embodiment of the present application is as follows: Includes S100 to S300. S100, the process from when no light bands are generated on the surface of the steel rail to when light bands are generated Determine the amount of material loss in the steel rail at the The first material loss is the light band that appears on the steel rail during the contact process between the wheel and the steel rail. The first material loss is the limit value. When the material loss of the steel rail reaches the first material loss amount, there will be obvious light bands on the steel rail surface. is known to appear. Optionally, as shown in FIG. 2 and FIG. 3, the above S100 is specifically S101 to S102. This can be achieved by: S101, First surface fractal dimension of steel rail with light band and steel without light band Obtain the second surface fractal dimension of the rail. The surface fractal dimension of the steel rail is used to indicate the roughness of the steel rail surface, The larger the value of the surface fractal dimension of the steel rail, the rougher the steel rail surface is. do. Here, the steel rail having a light band is a steel rail having a visible light band on the surface of the steel rail. rails, for example, the steel rails used are selected as steel rails with light strips, Or other steel rails with light bands may be selected. Steel rails without light bands are steel Steel rails that do not have a light band on the surface of the iron rail. For example, steel rails that do not have a light band are not used. Unused steel rails (steel rails shipped from the factory and not used) may be used. stomach. In the examples of this application, for steel rails with and without light strips The fractal dimension was measured respectively, and the first surface fractal dimension and the second surface fractal dimension were calculated. Get the original. Selectable, the first surface fractal dimension is made of steel rails with light bands is the maximum value of the surface fractal dimension of the multiple steel rail test pieces, and the second surface fractal The dimensions are the surface fractals of multiple steel rail specimens made of steel rails without light bands. is the average value of the dimensions. In one embodiment, the steel rail used is selected as a steel rail having a light band. The unused steel rails were selected as steel rails without light bands and box counted. The surface fractal dimensions of the steel rail with and without the light band were calculated using the The measurement process includes steps 1 to 3: Step 1: Using steel rails with and without light bands, Prepare a test piece. For example, the dimensions of the steel rail specimen are 2*2*1cm, and the number of steel rail specimens is The number is 50. Step 2, determine the surface fractal dimension of each steel rail specimen. The surface morphology of each steel rail test piece is observed using a laser microscope, etc., and the corresponding The number of boxes is counted and the surface fractal dimension is calculated by the above formula (1). Calculate the surface fractal dimension. All steel rails, selectable between steel rails without light strips and steel rails with light strips After obtaining the surface fractal dimension of the specimen, according to the Rajada criterion (i.e., the 3σ criterion), Steel rail test pieces of steel rails with light bands and steel rails of steel rails without light bands The surface fractal dimension of each test piece was subjected to outlier removal processing, and the surface fractal dimension was calculated. The processing principle of the 3σ rule is as follows: (μ-3σ,μ +3σ) surface fractal dimensions within the range are retained, and surface fractal dimensions outside the range are excluded. , where μ is the average value of the surface fractal dimension, and σ is the standard deviation of the surface fractal dimension. be. Step 3: Surface fractal dimension of multiple steel rail specimens of steel rails with light bands The maximum value was taken as the first surface fractal dimension, and multiple steel rail tests were performed on steel rails without light bands. The average value of the surface fractal dimensions of the test pieces is taken as the second surface fractal dimension. For example, a plurality of steel rails having a light band after being processed according to the Rajada criteria. The maximum value of the surface fractal dimension of the test specimen was 2.09 (i.e., the first surface fractal (dimension), multiple steel rails of steel rails without light bands after processing according to the Rajada criteria The average value of the surface fractal dimension of the ball specimen is 2.24 (i.e., the second surface fractal dimension). In the embodiment of the present application, the surface fractal dimension is used to estimate the surface fractal dimension of a steel rail. When judging whether there is a light band, 2.24 is the judgment standard for steel rails without light bands, and 2. .09 is selected as the standard for steel rails with light bands. S102, wheel test piece and steel ray test piece whose surface fractal dimension is the second surface fractal dimension Wheel-rail friction tests were performed on the steel rail specimens, and the surface fractograms of the steel rail specimens were The amount of material loss of the steel rail specimen when the surface fractal dimension reaches the first surface fractal dimension is calculated as the first Determined as the amount of material loss. In the examples of this application, wheel-rail friction tests were performed on wheel specimens and steel rail specimens. A rubbing test was performed to measure the change in the steel rail from the state where no light bands were generated to the state where light bands were generated. Calculate the amount of material loss of the steel rail (i.e., the first material loss amount). Specifically, During the friction process, material wear occurs on the steel rail surface, and the surface fractal dimension of the steel rail increases to When the surface fractal dimension reaches 1, it means that a light band appears on the steel rail. The material loss of the steel rail is the first material loss. The steel rail specimens used for the wheel-rail friction tests have a surface fractal dimension of 2 The steel rail specimens are of non-linear dimensions (i.e., steel rails without light bands) and have a surface flatness of 100 mm. Steel rails with a fractal dimension of the second surface fractal dimension have been shipped and are not in use. After being shipped, the steel rails are subject to various factors and may corrode. In actual sampling, the first steel rail specimens selected were shipped. The selected flat surface is likely to be relatively smooth because it is freshly cut and uncorroded. A smooth steel rail specimen is scaled so that its surface fractal dimension is the second surface fractal dimension. may be subjected to a corrosion treatment prior to use in wheel-rail friction tests. In some examples, steel rail specimens are subjected to accelerated corrosion treatment using a neutral salt spray test. For example, a steel rail specimen may be prepared so that its surface fractal dimension is 2.24. After atomizing it at a concentration of 5%, it is placed in an environment of sodium chloride neutral salt solution. Wheel-rail friction test: Dimensions of wheel test piece, steel rail test piece and vehicle axle load can be calculated according to the Hertz simulation rule (see the prior art for the specific calculation process) (This is not described in detail in this application.) By way of example, referring to FIG. The outer diameter of the piece is 59.4mm, the inner diameter is 29.7mm, and the wheel width is 10mm. The wheel has a 5mm-wide protrusion in the middle, and the test specimen is fixed to the inner annular wall of the wheel test specimen. To accommodate this, there is a 6mm x 3.5mm slot. The outer diameter of the steel rail specimen is 60 mm, the inside diameter is 29.7 mm, and the width of the steel rail is 10 mm. The vehicle's axle load may be 17t (tons). In addition, the parameters of the wheel-rail friction test are load, wheel specimen rotation speed, steel rail The wheel test specimen rotation speed and rotation slip ratio are included. For example, the load is 310N, and the wheel test specimen Rotation speed: 400 r / min, steel rail specimen rotation speed: 398 r / min, rotation slip: The tap rate is set to 0.5%. During the wheel-rail friction process, the test piece is rotated every 100 turns. The surface condition of the steel rail was observed, and the micromorphology of the steel rail surface was recorded until the contact light zone appeared. The surface roughness and diameter are measured. With the above settings, wheel-rail rolling contact fatigue is tested in a friction machine (e.g., GPM rolling contact fatigue test machine). The process of the steel rail light band formation after the friction machine is simulated. The diameter change of the steel rail surface is measured with a micrometer, and the steel rail test piece is examined with a microscope, etc. The surface morphology was observed, its surface fractal dimension was calculated, and the surface fractal dimension of the steel rail specimen was calculated. Obtain the amount of material loss of the steel rail specimen when the surface fractal dimension is above the first surface fractal dimension. do. In the examples of this application, the standard for measuring the amount of material loss of the steel rail is the wear of the steel rail. The wear depth is the radial change of the steel rail (i.e., the above It should be understood that the change in diameter is equal to or greater than the change in diameter of the Based on the data recorded during the friction test, the change in the amount of material loss of the steel rail during the friction process was The change in the material loss rate of steel rails (shown in Figure 5) and the change in the material loss rate of steel rails (shown in Figure 6) The change in the surface fractal dimension of the ball (shown in Figure 7) can be analyzed. 5 to 7, the initial steel rail surface fractal dimension was 2.24. When rotating and rubbing at 100 to 500 turns, the amount of material loss increases rapidly, and the material loss rate The material wear rate is rapidly decreased, and the material wear rate is increased when the test piece is 500 to 1200 turns. As it rotates and rubs, the amount of material loss continues to increase and the rate of material loss decreases, at which point the specimen A visible light-bright mark gradually forms on the surface, this stage belongs to the light-band formation stage, and the test The light band is considered to have formed when the specimen rotates and rubs at 1200 turns. When rotating and rubbing at 200 to 20,000 turns, the amount of material loss gradually increases, and the material loss rate The intensity continues to decrease, the light band traces in the contact area gradually become apparent, and the bright areas are basically stable. If the surface fracturing of steel rails does not increase any more, this stage belongs to the light zone stable stage. When the fractal dimension is 2.09 (first surface fractal dimension), the amount of material loss is 0.09 mm It is. The above S100 and S200 have caused a light band to appear on the steel rail surface instead of a non-existent one. During the process, the amount of material loss of the steel rail is obtained, and the amount of material loss is displayed on the steel rail by light. Used as a criterion for determining whether a band exists and, if so, to predict the location and width of the band do. S200, after the vehicle passes over the steel rail to be detected a predetermined number of times, A second amount of material loss for each grid cell of a contact patch formed on the substrate is predicted. In addition, the light band of the steel rail to be detected (one steel rail) is predicted and the steel rail is detected. Each time a vehicle passes over a steel rail to be detected, a detection An elliptical contact patch is formed on the steel rail to be detected. After several passes over the rail, the steel rail to be detected repeatedly comes into contact with the wheel, resulting in multiple contact points. After the contact patches are formed with different degrees of overlap, the steel rail to be detected A final contact patch is formed on the surface of the light beam (the contact patch is not necessarily a light zone). Each elliptical contact patch is divided into a number of grid cells, and the vehicle is placed on the steel rail to be detected. The final contact patch formed after multiple passes contains a number of lattice cells, The surface area of ​​the steel rail corresponding to each grid cell in each grid cell experiences material loss. The following simulation method is used to simulate the vehicle passing through the steel rail in different postures. The above S200 is specifically designed to predict the amount of material loss in steel rails, as shown in Figures 3 and 8. This includes S201 to S202 described below. S201, every time a vehicle passes over a steel rail to be detected, The amount of material loss in each grid cell of the formed contact patch is predicted. When a vehicle passes over a steel rail, the wheels come into contact with the steel rail at a single point (i.e., the wheels Each time the vehicle passes over the steel rail, the vehicle's shape changes. The contact points between the wheel and the steel rail (hereafter referred to as the wheel-rail contact points) may be different from each other due to the difference in the force. The friction coefficient (called friction coefficient) may vary and the wheel may wear at the wheel-rail contact point after the wheel comes into contact with the steel rail. Wear occurs and bright contact patches form. In one embodiment, the above step S201 is realized by the following steps S2011 to S2012. This can be done. S2011, each time the vehicle passes the steel rail to be detected, the wheel-rail contact point is located The wheel-rail contact information corresponding to the grid cells is then determined. Here, the wheel-rail contact information is the wheel-rail contact point in the lattice cell where the wheel-rail contact point is located. wheel-rail contact stress, and wheel-rail relative slippage when the wheel rolls through a grid cell Includes. Optionally, wheel-rail contact points and shapes should be detected every time the vehicle passes a steel rail. Based on the shape parameters of the contact patch, the lattice cell where the wheel-rail contact point is located is determined. The wheel-rail contact stresses in the wheel can be calculated. In the actual mechanical analysis of wheel-rail contact, the geometry and contact of the wheel and steel rail are considered. Taking into account factors such as contact stress distribution, the elliptical model better represents the shape of the contact patch. Therefore, the shape of the contact patch is considered to be elliptical. Wheel-rail contact stresses in the grid cells in which the wheel-rail contact points are located JPEG0007675968000011.jpg79 satisfies equation (2): JPEG0007675968000012.jpg27119 formula (2) where x is the coordinate of the wheel-rail contact point on the X-axis of the wheelset coordinate system, and y is the is the coordinate of the wheel-rail contact point on the Y axis of the wheelset coordinate system. In equation (2), a and b are the shape parameters of the elliptical contact patch, and a is the represents the length of the major semi-axis of the patch (i.e., the longitudinal semi-axis length of the contact patch), and b is the diameter of the elliptical contact patch. represents the length of the minor semi-axis of the contact patch (lateral semi-axis length of the contact patch), and N is the wheel-rail contact normal force Represents. In one implementation, the coordinates (x,y,z) of the wheel-rail contact point are determined in the wheel-rail space It can be calculated according to the contact geometric relationship (please refer to the prior art for details). For example, the coordinates of the wheel-rail contact points can be solved using the tracing method, specifically, As shown in equation (3): JPEG0007675968000013.jpg57129 formula (3) In the above formula, d w is the wheel tread contact angle, JPEG0007675968000014.jpg1590, l x , l y , l zare the direction cosines in the X, Y, and Z directions of the wheelset coordinate system, respectively. , JPEG0007675968000015.jpg861, JPEG0007675968000016.jpg955, JPEG0007675968000017.jpg834,f,y and y w are the side roll angle, swing head angle and lateral displacement of the wheel set, respectively. is the quantity x o2 , y o2 , z o2 is the center of the wheel rolling circle in the wheelset coordinate system are the coordinates of JPEG0007675968000018.jpg950, JPEG0007675968000019.jpg951, JPEG0007675968000020.jpg949, R r is the radius of the wheel rolling circle, and d w is the wheel tread rolling circle in the wheelset coordinate system is the Y-axis coordinate. In one implementation, the longitudinal semi-axis length a and the lateral semi-axis length b of the elliptical contact patch are Hertzian tangents. It can be calculated according to the haptic mechanics assumptions, specifically shown in the following formula (4): JPEG0007675968000021.jpg5379 formula (4) In the formula, N is the wheel-rail contact normal force, m and n are Hertz contact coefficients, A and B are the relative curvature constants, and k1 and k2 are constants related to the wheel-rail material. When the wheel-rail contact points of the steel rail are different, N, m, n, A and B are different. In some embodiments, the wheel rolling forward speed, the grid cell in which the wheel-rail contact point is located The wheels are lattice-aligned based on the length of the grid cell, the lateral and longitudinal sliding speeds of the wheels within the grid cell. Calculate the wheel-rail relative slippage when rolling through a child cell. Specifically, the wheel-rail relative slippage when the wheel rolls through a grid cell JPEG0007675968000022.jpg79 is calculated using the following formula (5): JPEG0007675968000023.jpg2683 formula (5) In the above formula, JPEG0007675968000024.jpg77 is the lateral sliding velocity of the wheel within the grid cell, JPEG0007675968000025.jpg87 is the longitudinal sliding speed of the wheel within the grid cell, JPEG0007675968000026.jpg77 is the wheel rolling forward speed. In equation (5), the lateral sliding velocity of the wheel within the grid cell ( JPEG0007675968000027.jpg77) and longitudinal glide velocity ( JPEG0007675968000028.jpg87) is a dynamic model of track rigid-flexible coupling and wheel-rail rolling contact The model is based on the rigid-flexible coupling. The lateral displacement, swing head angle and side roll angle of the wheel set are calculated based on the dynamic model. Then, based on the lateral displacement of the wheel set, the swing head angle and the side roll angle, The coordinate system transformation matrix required for the wheel-rail rolling contact model is calculated using the rigid longitudinal The creep rate, rigid lateral creep rate and rigid rotational creep rate are obtained, and finally, Based on the rigid longitudinal creep rate, the rigid lateral creep rate and the rigid rotational creep rate Based on this, the lateral sliding speed of the wheel in the grid cell is JPEG0007675968000029.jpg77 and the longitudinal sliding velocity of the wheel within the grid cell Calculate JPEG0007675968000030.jpg87. In addition, since the vehicle's motion state may be different each time it passes over the steel rail, The wheel-rail contact points of the wheels and steel rails may be different, and the degree of wear of the steel rails may also be different. There are different possibilities. In an embodiment of the present application, a vehicle running on a steel rail is simulated using a plurality of sets of stochastic dynamics parameters. The different motion states of the vehicle are simulated when passing through, and a set of stochastic dynamics parameters is Also called one stochastic dynamics sample, where each set of stochastic dynamics parameters is vehicle axle load, vehicle passing speed, wheel-rail friction coefficient and steel rail irregularity, where: Vehicle axle load, vehicle passing speed and wheel-rail friction coefficient are important influencing factors of wheel wear. Steel rail irregularity (also called stochastic irregularity) refers to the geometrical variation of the track in the turnout zone. It refers to the irregular situation where the geometric shape deviates from the ideal state in spatial position. Different positions (e.g. different entrance and turnout positions) when passing through the gate The irregularities are horizontal irregularities, directional irregularities, height irregularities and gauge irregularities. Includes convex etc. The plurality of sets of stochastic dynamics parameters are stochastically generated and selectively sampled. A total of 100 stochastic dynamics samples were collected using the Latin hypercube stochastic sampling method. The wavelength range of 100 stochastic irregularities is 1-100m. do. Based on the description of the stochastic dynamics parameters, specifically, for the turnout zone, the trajectory The road rigid-flexible coupling dynamics model is given by the following equation (6): Using the out-orbit rigid-flexible coupling dynamics model: JPEG0007675968000031.jpg8147 formula (6) where G is the vehicle axle load, JPEG0007675968000032.jpg811 is the turnout total mass, JPEG0007675968000033.jpg85 is the vehicle turnout system acceleration, K is the total rigid matrix, JPEG0007675968000034.jpg106 C is the vehicle passing speed, JPEG0007675968000035.jpg86 is the wheel-rail friction coefficient, x, y, z are the coordinates of the wheel-rail contact point, {P} C teeth is the total weighting matrix, JPEG0007675968000036.jpg843 is a steel rail bump. In Eq. (6), except for the stochastic dynamics parameters, the other parameters The meter is a constant. In addition, m in the above formula (3) for calculating the wheel-rail contact point 1 is {P} in formula (6). C in Combined with equations (3) and (6), the wheel-rail contact point and the lateral displacement of the wheelset are The amount, swing head angle and side roll angle can be calculated, and further, in conjunction with equation (2), Wheel-rail contact stress You can get JPEG0007675968000037.jpg79. For the i-th lattice cell of the contact patch, its wheel-rail rolling contact model is expressed by the following equation (7 ) becomes: JPEG0007675968000038.jpg5741 formula (7) Where: JPEG0007675968000039.jpg810 is the rigid longitudinal creep rate, JPEG0007675968000040.jpg910 is the rigid lateral creep rate, JPEG0007675968000041.jpg911 is the rigid rotation creep rate, JPEG0007675968000042.jpg915 is the vertical forward speed difference, JPEG0007675968000043.jpg1725 is the lateral forward velocity difference, JPEG0007675968000044.jpg1625 is the relative rotation speed difference, JPEG0007675968000045.jpg812 is the initial speed of the wheel rolling forward, JPEG0007675968000046.jpg1011 is the coordinate system transformation matrix ( JPEG0007675968000047.jpg1011 needs to be calculated). Coordinate system transformation matrix JPEG0007675968000048.jpg1011 is JPEG0007675968000049.jpg1012 and Contains JPEG0007675968000050.jpg1011, whose formula is: In the formula JPEG0007675968000051.jpg46159, JPEG0007675968000052.jpg88 is the left-hand transformation matrix, JPEG0007675968000053.jpg89 is the right-hand transformation matrix, JPEG0007675968000054.jpg88, JPEG0007675968000055.jpg89 is the wheel-rail contact angle on the left and right sides. The above vehicle-turnout track rigid-flexible coupling dynamic model is used to determine the wheel After calculating the lateral displacement, swing head angle and side roll angle of the rule set, the coordinate system transformation line is Substitute into the column formula JPEG0007675968000056.jpg1011 is calculated, and then the coordinate system transformation matrix Substituting JPEG0007675968000057.jpg1011 into equation (7), the rigid longitudinal creep rate is JPEG0007675968000058.jpg88, JPEG0007675968000059.jpg98, You can get JPEG0007675968000060.jpg99, JPEG0007675968000061.jpg88, JPEG0007675968000062.jpg98, JPEG0007675968000063.jpg99 is substituted into the formula below, and the lateral sliding speed of the wheel within the grid cell is calculated. JPEG0007675968000064.jpg77 and the longitudinal sliding velocity of the wheel within the grid cell JPEG0007675968000065.jpg87: JPEG0007675968000066.jpg23101x, y are the coordinates of the wheel-rail contact point, and y w is the lateral displacement of the wheelset. As mentioned above, JPEG0007675968000067.jpg77 and JPEG0007675968000068.jpg87 is substituted into equation (5) to obtain the wheel-rail relative slippage in the wheel-rail contact information. I get JPEG0007675968000069.jpg710. S2012, wheel-rail contact information is input into the wheel-rail wear model to form one lattice cell Obtain the amount of material loss in the loop. The above wheel-rail wear model is a transformation between the wheel-rail contact information and the amount of steel rail material loss. Used to describe relationships. The wheel-rail wear model is shown in equation (8): JPEG0007675968000070.jpg2048 formula (8) In the above formula, JPEG0007675968000071.jpg611 is the amount of material loss in the lattice cell, JPEG0007675968000072.jpg810 is the wear coefficient, JPEG0007675968000073.jpg68 is the wheel-rail contact stress within the grid cell, JPEG0007675968000074.jpg69 is the wheel-rail relative slippage when the wheel rolls through the cell, JPEG0007675968000075.jpg66 is the hardness of a steel rail. In an embodiment of the present application, a vehicle is controlled by a plurality of sets of stochastic dynamics parameters to move along a steel rail. Simulate different vehicle motion states as it passes through, and each set of stochastic dynamics parameters is Since the data corresponds to the wheel-rail contact point, S2011-S2012 ensure that the vehicle The grid cells in which each wheel-rail contact point is located during one pass of the steel rail in motion. Calculate the amount of material loss. S202, after the vehicle passes over the steel rail to be detected a predetermined number of times, The amount of material loss in each lattice cell of the contact patch formed on the second Get the loss amount. Here, during the process in which the vehicle passes over the steel rail to be detected in different postures a predetermined number of times, When the wheel passes through, the contact point between the wheel and the steel rail to be detected is one of the multiple grid cells. Located within. In the embodiment of the present application, a vehicle passes over the steel rail to be detected a predetermined number of times in different postures. During the process, the number of times the wheel-rail contact point falls into each lattice cell is counted, and the material of the lattice cell is The amount of material loss is accumulated, and the amount of material loss in the grid cell is calculated by dividing the amount of material loss by the amount of material loss that occurs each time the vehicle passes through the grid cell. It is the product of the amount of material lost and the number of times S300, a target area in which the second material loss amount is equal to or greater than the first material loss amount is defined as an area having a light band. and determining the contact patch formed after the vehicle passes over the steel rail to be detected a predicted number of times. Based on the information, the position and width of the light band formed on the steel rail to be detected is predicted. After the vehicle has passed over the steel rail to be detected a certain number of times, the second amount of material loss in a grid cell is Above the first material loss amount, a light band will appear in this area on the steel rail to be detected. and a region consisting of lattice cells in which the second material loss amount is equal to or greater than the first material loss amount is a region in which the second material loss amount is equal to or greater than the first material loss amount. area of ​​the band and further predicts the position and width of the light band based on the contact patch information. If the second material loss amount of the grid cell is smaller than the first material loss amount, the It indicates that there is no obvious light band in this area yet, and there is no need to predict the location and width of the light band. stomach. As can be seen from the above embodiment, every time a vehicle passes over a steel rail to be detected, An elliptical contact patch is formed on the steel rail to be detected, and the target area with the light band is multiplied. is the overlapping area of ​​the number of elliptical contact patches. As shown in Figs. 8 and 9, the above S300 can be selectively replaced by S301 to S302. This can be achieved. S301, an elliptical contact patch formed every time a vehicle passes over a steel rail to be detected The information of the elliptical contact patch includes the center point and semi-axis length of the elliptical contact patch. In addition, the function formula for the elliptical contact patch can be obtained from the center point and semi-axis length of the elliptical contact patch. It should be understood that the coordinates of the center point of the ellipse are based on the wheelset coordinate system. The wheel set coordinate system is shown in FIG. 1 and the wheel set coordinate system in the above embodiment. Please refer to the related description of the rule set coordinate system. When a vehicle passes over the steel rail to be detected M times (M is a predetermined number of times), the wheels and the steel There are M wheel-rail contact points between the rails, and each wheelset contact point has an elliptical contact pad. Corresponds to Chi. The center point of the elliptical contact patch is the wheel-rail contact point when the vehicle passes through the steel rail. The calculation method of the wheel-rail contact point coordinates and the semi-major axes (a and b) of the ellipse is See equations (3) and (4) in the examples. S302, based on the center points and semi-axis lengths of a plurality of elliptical contact patches forming a target area, A point in the target area has two intersections with the boundary of the target area along the Y axis of the wheelset coordinate system. and determining the coordinates of a point in the target area on the X-axis of the wheelset coordinate system, and The coordinates of the two intersections on the Y-axis of the coordinate system are the distances of the light bands formed on the steel rail to be detected. Used to indicate the position, between the coordinates of two intersections on the Y axis of the wheelset coordinate system The distance is used to indicate the width of the light band. For example, referring to FIG. 10, the target area (light zone) is the overlap of contact patch 1 and contact patch 2. The boundary of the target area is assumed to be an elliptical contact area (i.e., the shaded area in the figure). It is composed of a part of the boundary of patch 1 and a part of the boundary of elliptical contact patch 2. For example, if we take an arbitrary point (say point C) in the wheelset coordinate system, the coordinates of point C on the X-axis are After being given, the point C is aligned along the Y axis of the wheelset coordinate system to the two intersections with the boundary of the target area. The method for determining the difference points (points A and B in the figure) is as follows: The coordinates of point C on the X-axis are calculated by the elliptical contact By substituting this into the function formula for patch 1, we can calculate the coordinates of point A on the Y axis, and the coordinates of point C on the X axis. By substituting the coordinates into the function formula for elliptical contact patch 2, we can calculate the coordinate of point B on the Y axis. , and further calculate the distance between points A and B, which is the width of the light band at point C. Determining two corresponding intersection points of a plurality of points in the target area on the X-axis by the above method. In this way, the situation of the entire light belt can be known. For example, take a single point C as an example. Then, the coordinate of point C on the X axis is c1, the coordinate of point A on the Y axis is b1, and the coordinate of point B on the Y axis is If it is assumed that the distance between points A and B is b2 and d, the position of the light band is given by c1 and ( b1, b2), and the point with the X-axis coordinate value c1 has a width range (b 1, b2), indicating the presence of a light band of width d. The coordinates representing the position and width of the light bands mentioned above are in the wheelset coordinate system and can be selected In addition, the position and width of the light strip may be expressed using a steel rail coordinate system, and the wheel The coordinates of the set coordinate system can be converted to the steel rail coordinate system by coordinate transformation. The origin of the steel rail coordinate system is located on the center line of the steel rail, and the three axes are defined by the wheel set. This is similar to the definition of the three axes of the coordinate system. The above method allows the vehicle to pass over the steel rail a certain number of times before testing the different cross sections of the steel rail. The width of the light band formed is predicted, and the evaluation index of the wheel-rail matching state is calculated to determine the wheel - The matching status of rails can be evaluated, so that steel rails can be maintained in a timely manner. For example, the evaluation index of the wheel-rail matching condition is The longitudinal rate of change in width (LRW) may be used. The method for calculating the longitudinal rate of change in width of the light band is the same as that of the prior art. For details, please refer to the technical description and they will not be repeated in the examples of this application. Based on the above, the method for predicting the steel rail light belt provided by the embodiment of the present application is The method uses a test method to measure the progress of a steel rail from no light band to the development of light bands. A first amount of material loss is determined for each grid cell of the contact patch after a predetermined number of wheel-rail contacts. When the amount of material loss reaches a first loss amount, it is determined that a light band has formed on the steel rail; Predicting the location and width of light bands formed on steel rail surfaces based on contact patch information This allows us to predict the state of the light band formed on the steel rail, The wheel-rail matching condition can be evaluated based on the predicted light zone, and the steel rail This is useful for maintaining the system. The above is merely a specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. However, all modifications and replacements that a person skilled in the art could easily conceive within the technical scope of the present invention are intended to be included in the present invention. Therefore, the scope of protection of the present invention is as defined in the claims. It shall be in accordance with the scope.

Claims

1. The process of steel rail surface from no light band to the light band appearing on the surface. determining a first amount of material loss in the roll; After the vehicle passes over the steel rail to be detected a predetermined number of times, a shape is formed on the steel rail to be detected. predicting a second amount of material loss for each grid cell of the contact patch formed; determining a target area having a light band where the second amount of material loss is equal to or greater than the first amount of material loss; , a contact patch formed after the vehicle has passed over the steel rail to be detected a predicted number of times. Based on the information, the position and width of the light band formed on the steel rail to be detected are predicted. and 16. A method for predicting steel rail light bands, comprising:

2. Every time the vehicle passes over the steel rail to be detected, and the target area is an overlapping area of ​​the plurality of elliptical contact patches. It is an area, The contact pattern formed after the vehicle passes over the steel rail to be detected a predicted number of times. Based on the information of the switch, the position and width of the light band formed on the steel rail to be detected are determined. The step of predicting includes: An elliptical contact patch formed each time the vehicle passes over the steel rail to be detected The information of the elliptical contact patch includes a center point and a semi-axis length of the elliptical contact patch. Including, The coordinates of the center point are expressed in coordinates based on a wheelset coordinate system, and the wheelset seat The origin 0 of the coordinate system is located on the center line of the wheel set, and the X-axis of the wheel set coordinate system is The Z-axis of the wheelset coordinate system extends along the longitudinal direction of the steel rail and is oriented vertically downward. The Y axis of the wheelset coordinate system extends along the lateral direction of the steel rail, and the X axis and Together with the Z axis, it forms a right-handed coordinate system, the major axis of the elliptical contact patch is along the X axis direction, The minor axis of the elliptical contact patch is along the Y-axis, The target area is determined based on the center points and semi-axis lengths of a plurality of elliptical contact patches that define the target area. A point within the region is determined by two intersections with the boundary of the target region along the Y axis of the wheelset coordinate system. Determine the difference score, where the coordinate of the point in the target area on the X-axis of the wheelset coordinate system, and the The coordinates of the two intersections on the Y-axis of the Eelset coordinate system are the positions on the steel rail to be detected. is used to indicate the position of the light band formed on the Y axis of the wheel set coordinate system. the distance between the coordinates of the two intersections is used to indicate the width of the light band; The method of claim 1 ,

3. The steel rail surface is subjected to a process from when no light band is generated to when a light band is generated. The step of determining a first amount of material loss of the iron rail includes: The first surface fractal dimension of the steel rail with the light band and the second surface fractal dimension of the steel rail without the light band 2. Obtain the surface fractal dimension. The surface fractal dimension of the steel rail is the roughness of the steel rail surface. Used to indicate the size of A wheel specimen and a steel rail specimen having a surface fractal dimension of the second surface fractal dimension. A wheel-rail friction test is carried out on the test piece, and the surface fractogram of the steel rail test piece is obtained. the amount of material loss of the steel rail specimen when the surface fractal dimension reaches the first surface fractal dimension.

2. The method of claim 1, wherein the first amount of material loss is determined as

4. The first surface fractal dimension is a surface fractal dimension of a plurality of steel rails made of the steel rails having the light bands. is the maximum value of the surface fractal dimension of the test piece, The second surface fractal dimension is a surface fractal dimension of a plurality of steel rails made of steel rails having no light zone.

4. The method according to claim 3, characterized in that the surface fractal dimension is an average value of the surface fractal dimension of the ball test piece. Law.

5. Each time the vehicle passes over the steel rail to be detected, a contact patch is formed. It is divided into lattice cells, After the vehicle passes over the steel rail to be detected a predetermined number of times, predicting a second amount of material loss for each lattice cell of the contact patch formed on the Including, Each time a vehicle passes over the steel rail to be detected, a shape is generated on the steel rail to be detected. predict the amount of material loss for each grid cell of the contact patch formed; After the vehicle passes over the steel rail to be detected a predetermined number of times, The material loss of each lattice cell of the contact patch formed in the A loss amount is obtained, and during the process of the vehicle passing over the steel rail to be detected a predetermined number of times, During each pass, the contact point between the wheel and the steel rail to be detected is located in one of the plurality of grid cells.

2. The method of claim 1, wherein the first and second vertices are located within one grid cell.

6. Every time the vehicle passes over the steel rail to be detected, The step of predicting the amount of material loss for each lattice cell of the contact patch formed on the fruit, Each time the vehicle passes over the steel rail to be detected, the wheel-rail contact point is located. determining wheel-rail contact information corresponding to a grid cell, said wheel-rail contact information being Wheel-rail contact stress in the lattice cell in which the wheel-rail contact point is located, and The wheel-rail relative sliding distance when rolling through a child cell is included, The wheel-rail contact information is input into a wheel-rail wear model, and material loss in the grid cells is calculated. The wheel-rail wear model is based on wheel-rail contact information and steel rail material loss.

6. The method of claim 5, wherein the method is used to describe variation relationships between quantities.

7. Wheel-rail contact stress in the grid cell in which the wheel-rail contact point is located teeth, where x is the coordinate of the wheel-rail contact point on the X-axis of the wheelset coordinate system. y is the coordinate of the wheel-rail contact point on the Y axis of the wheelset coordinate system, and a is the is the length of the major semi-axis of the elliptical contact patch, and b is the length of the minor semi-axis of the elliptical contact patch. N is the wheel-rail contact normal force when the vehicle passes through the steel rail to be detected. and The relative wheel-rail slippage when the wheel rolls through the lattice cell teeth, where is the lateral sliding velocity of the wheel in said grid cell, is the longitudinal sliding speed of the wheel in said grid cell, is the wheel rolling forward speed, is the length of the grid cell, The lateral and longitudinal sliding velocities of the wheels in the grid cells are calculated based on the track rigid flex. It is calculated based on the bull coupling dynamics model and the wheel-rail rolling contact model.

7. The method according to claim 6, wherein:

8. The method comprises: generating a plurality of sets of stochastic kinetic parameters; The plurality of sets of stochastic dynamics parameters are used to estimate the motion of the vehicle as it passes through the steel rail. Each set of stochastic dynamic parameters is used to simulate the dynamic state of the vehicle. , vehicle passing speed, wheel-rail friction coefficient and steel rail unevenness. The method of claim 1.

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