A method and device for predicting the boundary element calculation of wheel-rail contact

Abstract

The present invention relates to the field of accelerated wheel-rail contact boundary element calculation, and specifically to an estimation method and device for accelerated wheel-rail contact boundary element calculation, which can determine a suitable potential contact area, ensure calculation accuracy, avoid redundant calculation costs, and improve calculation efficiency. The scheme includes: determining the potential contact area, the geometric gap distribution of the wheel-rail contact point, and the creep rate and spin of the wheel-rail contact point; obtaining the corresponding longitudinal distribution of compressive stress according to the geometric gap distribution of the wheel-rail contact point; solving the normal exact solution through the complementary energy expression according to the geometric gap distribution and the longitudinal distribution of compressive stress; obtaining the initial solution of wheel-rail tangential contact through the normal exact solution; and solving the exact solution using the tangential boundary element model through the initial solution. The present invention is suitable for accelerating wheel-rail contact boundary element calculation.

Description

Technical Field

[0001] The invention relates to the field of accelerated wheel-rail contact boundary element calculation, and in particular to an estimation method and device for accelerated wheel-rail contact boundary element calculation. Background Art

[0002] The wheel-rail system is an important component of the operation of railway vehicles. The railway system supports and guides the train through wheel-rail contact. The mechanical behavior of wheel-rail contact directly reflects the quality of wheel-rail contact. Accurate evaluation is very important to ensure safe, stable and economical operation of railways. In view of the fact that current testing technology cannot effectively capture the mechanical behavior within the wheel-rail contact patch, the key to studying wheel-rail contact behavior is to establish an accurate and reliable contact mechanics model using analytical methods or numerical methods. At present, there are three types of methods for solving wheel-rail contact problems: boundary element method, fast algorithm and finite element method.

[0003] The existing technology mainly has the following disadvantages:

[0004] 1. There is no clear method to determine the boundary of the rectangular potential contact area. The determination of the boundary often depends on the experience of the researcher. If the potential contact area is too large, it will increase the redundant calculation cost, and if it is too small, it will not be able to obtain accurate calculation results.

[0005] 2. In the calculation of normal contact, the previous method first assumes that the contact area is the entire potential contact area, and the contact stress is evenly distributed in the contact area, and then iterates the result in the entire rectangular area to meet the boundary conditions. The above initial assumptions lead to a large number of iterations in the previous method.

[0006] 3. In terms of tangential contact calculation, the previous method first assumes that the entire contact area is a sticking area and the tangential stress is 0, and then iterates to obtain the stick-slip area distribution and tangential stress distribution results in the entire contact area to meet the boundary conditions. The above initial assumptions lead to a large number of iterations in the previous method. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an estimation method and device for accelerating wheel-rail contact boundary element calculation, which can determine the appropriate potential contact area, ensure the calculation accuracy, avoid redundant calculation costs, and improve the calculation efficiency.

[0008] The present invention adopts the following technical solutions to achieve the above-mentioned purpose. On the one hand, the present invention provides an estimation method for accelerating wheel-rail contact boundary element calculation, comprising:

[0009] Step 1: determine the potential contact area, the geometric gap distribution of the wheel-rail contact point, and the creep rate and spin of the wheel-rail contact point;

[0010] Step 2: Obtain the corresponding longitudinal distribution of compressive stress according to the geometric gap distribution of the wheel-rail contact point;

[0011] Step 3, according to the geometric gap distribution and the longitudinal distribution of compressive stress, the normal exact solution is solved by the complementary energy expression;

[0012] Step 4: Obtain the initial solution of wheel-rail tangential contact through the normal exact solution;

[0013] Step 5: Obtain the exact solution using the tangential boundary element model through the initial solution.

[0014] Furthermore, step 1 specifically includes:

[0015] Determine potential contact areas through reduction factors;

[0016] The wheel-rail contact point is determined by the trace method, and the contact geometry parameters are determined by discretizing the wheel and rail coordinates. The lateral contact geometry gap is calculated using the following formula: g(y) = z w (y)-z r (y), g(y) represents the lateral contact geometric gap, z w (y) and z r (y) represents the geometric profile of the rail;

[0017] The lateral and longitudinal contact boundaries of the potential area are determined respectively. The lateral contact boundary is determined by the geometric gap and the permeability as follows: f(y) = εδ-g(y)≥0, where δ represents the permeability, ε represents the reduction factor, and f(y) represents the lateral contact boundary. The longitudinal contact boundary is calculated as follows: a(y) represents the longitudinal contact boundary, and A is the curvature at the contact point;

[0018] The three-dimensional contact geometric gap distribution within the set distance from the wheel-rail contact point is calculated through the potential area lateral and longitudinal contact boundaries. The calculation method is as follows: z(x,y)=f(y)+Ax 2 , z(x,y) represents the geometric gap;

[0019] Longitudinal creep rate c x , tangential creep rate c y and spin c φ The calculation method is as follows:

[0020] c y = -sinψcos(φ+δ(y)), Where R1 is the nominal rolling radius, δ(y) is the contact angle, φ is the side rolling angle, ψ is the shaking angle, and R(y) is the contact radius.

[0021] Furthermore, step 2 specifically includes:

[0022] Divide the simplified algorithm calculation grid, and insert the geometric gap, the lateral and longitudinal contact boundaries of the potential area into the calculation grid by interpolation;

[0023] Taking the geometric gap as the input parameter, the initial solution of the wheel-rail contact normal is calculated, and the transverse normal stress distribution is set to be proportional to the longitudinal length of the contact spot. Then: a0 is the longitudinal semi-axis length at y=0, p(y) represents the compressive stress at x=0,

[0024] Where N is the normal force, calculated by the following formula:

[0025]

[0026] Where E ν and μ are the elastic modulus and Poisson's ratio, respectively.

[0027] The longitudinal distribution of the compressive stress in the contact spot follows the following formula: p(x,y) represents the compressive stress distribution along the longitudinal direction.

[0028] Furthermore, step 3 specifically includes:

[0029] Divide the boundary element calculation grid, and insert the geometric gap and the longitudinal distribution of the compressive stress into the current grid as parameter input by interpolation;

[0030] The complementary energy expression of the wheel-rail normal contact problem is established as follows:

[0031] Where p Iz 、p Jz Expressed as the normal stress at element I and J; A IzJz It is defined as the difference in normal elastic displacement of unit I caused by unit J bearing unit load; h I is the normal gap between two contacting bodies when they are in rigid contact.

[0032] The wheel-rail contact patch shape, compressive stress distribution and normal contact force are solved according to the complementary energy expression. The calculation is completed when the iteration meets the following boundary conditions: C represents the contact area, and E represents the non-contact area. I Represents the geometric gap where elastic deformation occurs at the I element.

[0033] Furthermore, step 4 specifically includes:

[0034] The exact solutions of creep rate, spin and normal are used as input quantities;

[0035] The simplified model of Trial and Fastsim is brought in to obtain the initial solution of wheel-rail tangential contact.

[0036] Furthermore, step 5 specifically includes:

[0037] The initial solution is inserted into the boundary element calculation grid divided during the normal contact calculation as an input parameter by interpolation; the complementary energy expression of the wheel-rail rolling tangential contact is established, and the expression is as follows:

[0038] Where w Ii is the amount of rigid sliding experienced at unit I during the period [t', t]; B IiJj It is defined as the difference in tangential elastic displacement of unit I caused by unit J bearing unit load; p Ii and p Jj is the tangential stress distribution at unit I, J, g I is the tangential contact boundary at unit U, and x and y are the two directions of the contact tangent plane coordinate system axis.

[0039] The accurate tangential stress distribution, creep force and creep moment are obtained by ConvexGS algorithm.

[0040] In another aspect, the present invention provides an estimation device for accelerating wheel-rail contact boundary element calculation, the device comprising:

[0041] Parameter acquisition module, used to determine the potential contact area, the geometric gap distribution of the wheel-rail contact point, and the creep rate and spin of the wheel-rail contact point;

[0042] A stress acquisition module is used to obtain the corresponding longitudinal distribution of compressive stress according to the geometric gap distribution of the wheel-rail contact point;

[0043] The complementary energy solution module is used to solve the normal exact solution through the complementary energy expression according to the geometric gap distribution and the longitudinal distribution of compressive stress;

[0044] Initial solution module, used to obtain the initial solution of wheel-rail tangential contact through the normal exact solution;

[0045] The exact solution module is used to obtain the exact solution using the tangent boundary element model through the initial solution.

[0046] Furthermore, the parameter acquisition module is specifically used to determine the potential contact area through the reduction factor;

[0047] The wheel-rail contact point is determined by the trace method, and the contact geometry parameters are determined by discretizing the wheel and rail coordinates. The lateral contact geometry gap is calculated using the following formula: g(y) = z w (y)-z r (y), g(y) represents the lateral contact geometric gap, z w (y) and z r (y) represents the geometric profile of the rail;

[0048] The lateral and longitudinal contact boundaries of the potential area are determined respectively. The lateral contact boundary is determined by the geometric gap and the penetration amount in the following way: f(y) = ε-g(y) ≥ 0, δ represents the penetration amount, ε represents the reduction factor, and f(y) represents the lateral contact boundary; the longitudinal contact boundary is calculated as follows: a(y) represents the longitudinal contact boundary, and A is the curvature at the contact point;

[0049] The three-dimensional contact geometric gap distribution within the set distance from the wheel-rail contact point is calculated through the potential area lateral and longitudinal contact boundaries. The calculation method is as follows: z(x,y)=f(y)+Ax 2 , z(x,y) represents the geometric gap;

[0050] Longitudinal creep rate c x , tangential creep rate c y and spin c φ The calculation method is as follows:

[0051] c y = -sinψcos(φ+δ(y)), Where R1 is the nominal rolling radius, δ(y) is the contact angle, φ is the side rolling angle, ψ is the shaking angle, and R(y) is the contact radius.

[0052] Furthermore, the stress acquisition module is specifically used to divide the simplified algorithm calculation grid, and insert the geometric gap, the lateral and longitudinal contact boundaries of the potential area into the calculation grid by interpolation;

[0053] Taking the geometric gap as the input parameter, the initial solution of the wheel-rail contact normal is calculated, and the transverse normal stress distribution is set to be proportional to the longitudinal length of the contact spot. Then: a0 is the longitudinal semi-axis length at y=0, p(y) represents the compressive stress at x=0,

[0054]

[0055] The longitudinal distribution of the compressive stress in the contact spot follows the following formula: p(x,y) represents the compressive stress distribution along the longitudinal direction.

[0056] Furthermore, the initial solution module is specifically used to use the creep rate calculated by the parameter acquisition module and the normal exact solution calculated in the spin and complementary energy solution module as input quantities; bring them into the Trial and Fastsim simplified models to obtain the initial solution of wheel-rail tangential contact; the exact solution module is specifically used to insert the initial solution into the boundary element calculation grid divided during the normal contact calculation as an input parameter by interpolation;

[0057] The complementary energy expression of wheel-rail rolling tangential contact is established as follows:

[0058] Where w Ii is the amount of rigid sliding experienced at unit I during the period [t', t]; B IiJj It is defined as the difference in tangential elastic displacement of element I caused by unit load on element J. Ii and p Jj is the tangential stress distribution at unit I, J.

[0059] The accurate tangential stress distribution, creep force and creep moment are obtained by ConvexGS algorithm.

[0060] The beneficial effects of the present invention are:

[0061] The present invention determines the potential contact area by reducing the factor, and can determine the appropriate potential contact area;

[0062] The present invention obtains the longitudinal distribution of compressive stress according to the transverse and longitudinal contact boundaries of the potential area and the three-dimensional contact geometric gap distribution; solves the wheel-rail contact spot shape, compressive stress distribution and normal contact force through the complementary energy expression according to the geometric gap distribution and the longitudinal distribution of compressive stress; finally, solves the exact solution through the initial solution using the tangential boundary element model, which not only ensures the calculation accuracy but also avoids redundant calculation costs, provides the initial contact area and compressive stress distribution value in the normal contact, and provides the initial stick-slip distribution and shear stress distribution value in the tangential contact, which can improve the calculation efficiency of the boundary element. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a schematic diagram of meshing of potential contact areas of the boundary element method in the prior art;

[0064] Figure 2 1 is a schematic diagram of comparison results under the condition of -2 mm lateral displacement provided by an embodiment of the present invention, (a) normal iteration number (b) normal calculation time (c) tangential iteration number (d) tangential calculation time;

[0065] Figure 3 Schematic diagram of the iterative process of the calculation results when the lateral displacement is -2 mm provided by an embodiment of the present invention, (a) contact spot shape (b) normal stress distribution (c) stick-slip distribution (d) tangential stress distribution;

[0066] Figure 4 1 is a schematic diagram of comparing the number of iterations under different lateral displacements provided by an embodiment of the present invention, (a) normal iteration number (b) normal calculation time (c) tangential iteration number (d) tangential calculation time;

[0067] Figure 5Schematic diagram of contact solution provided by an embodiment of the present invention, (a) normal stress distribution in the contact spot (b) tangential stress distribution and stick-slip distribution in the contact spot;

[0068] Figure 6 It is a flow chart of an estimation method for accelerating wheel-rail contact boundary element calculation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0069] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0070] Before describing the embodiment of the present invention, the present invention first briefly describes the existing boundary element solution.

[0071] The boundary element method based on Kalker's exact theory (variational method) transforms the basic equation of classical elastic mechanics into the complementary energy expression of rolling contact problem through the variation of displacement, and introduces the infinite half-space hypothesis to simplify it into:

[0072]

[0073] Where h is the normal gap between two contacting bodies when they are in rigid contact; δ p is the penetration amount; u z and u τ (τ=x,y) is the elastic displacement difference of the contact body in the normal z, longitudinal x and transverse y directions; p z and p τ is the contact stress in the corresponding direction; u τ ' represents the tangential elastic displacement difference at the previous moment; g = μp z represents the tangential contact boundary, μ is the constant friction coefficient; W τ is the rigid sliding amount.

[0074] In the formula, the unknown solutions are the elastic displacement difference and the contact stress, and these two physical quantities can be related by the Boussinesq-Cerruti force-displacement equation under the elastic half-space assumption:

[0075]

[0076] In the formula, A IJ is the influence factor, which represents the elastic displacement generated at unit I when unit J is subjected to unit load.

[0077] For wheel-rail rolling contact, since the material properties of wheels and rails are similar, they are considered to be the same material in this paper, so that the normal and tangential problems can be decoupled.

[0078] Since the simplified formula has no analytical expression, the boundary element method is used to discretize it, such as Figure 1 As shown in the figure. The rectangular elements shown in the figure represent potential contact areas, and the determination of their boundaries often depends on the experience of researchers. The solid elements in the figure represent the areas where contact occurs, and their normal and tangential contact solutions can be obtained by NORM and TANG algorithms respectively.

[0079] Compared with the prior art, the present invention provides an initial contact area and a compressive stress distribution value in normal contact, and provides an initial stick-slip distribution and a shear stress distribution value in tangential contact, thereby improving the calculation efficiency of the boundary element method.

[0080] Specifically, the solution adopted by the present invention is as follows Figure 6 As shown, specifically including:

[0081] Step 1: Determine potential contact areas and geometric parameters

[0082] In the specific implementation of the method of the present invention, the penetration amount δ is required as the input amount. If the input amount is the normal contact force, the penetration amount can be calculated by Hertz theory. This patent proposes a reduction factor ε=0.85 to determine the appropriate potential contact area.

[0083] (1) First, the wheel-rail contact point is determined by the trace method, and the contact geometric parameters (contact angle δ(y), roll angle φ, yaw angle ψ, contact radius R(y), etc.) are determined by discretizing the wheel and rail coordinates. The influence of the yaw angle is not considered in the present invention, so the longitudinal contact geometric gap can be simplified to follow the elliptical distribution, and the transverse contact geometric gap g(y) is calculated using the following formula:

[0084] g(y)=z w (y)-z r (y), z w (y) and z r (y) represents the geometric profile of the rail.

[0085] (2) In the wheel-rail contact boundary element calculation, the lateral and longitudinal potential contact boundaries need to be determined separately. In the calculation method proposed in the present invention, the lateral boundary f(y) is determined by the geometric gap and the penetration:

[0086] f(y)=εδ-g(y)≥0, for the longitudinal boundary a(y) of the potential contact area, it is assumed that it follows the Hertz hypothesis along the rolling direction: A is the curvature at the contact point;

[0087] (3) The three-dimensional contact geometric gap distribution near the wheel-rail contact point can be obtained by the boundary of the potential contact area in (2):

[0088] z(x,y)=f(y)+Ax 2, z(x,y) represents the geometric gap.

[0089] (4) After the contact point is determined and the above contact geometric parameters are obtained, the longitudinal creep rate c can be calculated by the following formula x , tangential creep rate c y and spin c φ :

[0090] c y = -sinψcos(φ+δ(y)), Where R1 is the nominal rolling radius.

[0091] Step 2: Establish a normal simplified model to solve the initial shape of the contact patch and the compressive stress distribution

[0092] (1) Divide the simplified algorithm calculation grid (nx, ny), and interpolate the geometric gap z(x, y) and potential contact area calculated in step 1 to the current grid;

[0093] (2) Using the above geometric gap as input parameters, the simplified model proposed by Kik-Piotrowski is used to calculate the initial solution of the wheel-rail contact normal. For the compressive stress p(y) at x = 0, the KP method assumes that the transverse normal stress distribution is proportional to the longitudinal length of the contact spot:

[0094] a0 is the length of the longitudinal semi-axis at y=0. Since the elastic deformation at the contact point is equal to the penetration, the maximum stress p0 in the contact spot can be determined by the following formula:

[0095] N is the normal force, calculated by the following formula:

[0096]

[0097] Where E v and μ are the elastic modulus and Poisson's ratio, respectively.

[0098] Finally, the compressive stress distribution in the contact patch along the longitudinal direction follows the following formula:

[0099] Step 3: Use the normal boundary element model to solve the normal exact solution

[0100] (1) Divide the boundary element calculation grid (mx, my), and interpolate the geometric gap z(x, y) in step 1 and the compressive stress distribution p(x, y) in step 2 to the current grid as parameter input;

[0101] (2) The complementary energy expression of the wheel-rail normal contact problem is established as follows:

[0102] Where p Iz 、p Jz Expressed as the normal stress at element I and J; A IzJz It is defined as the difference in normal elastic displacement of unit I caused by unit J bearing unit load; h I is the normal gap between two contacting bodies when they are in rigid contact.

[0103] (3) The NormCG algorithm proposed by Vollebregt is used to solve the wheel-rail contact patch shape, compressive stress distribution and normal contact force. The calculation is considered complete when the iteration satisfies the following boundary conditions:

[0104] C represents the contact area, E represents the non-contact area, and p Jz represents the normal stress at the J element, e I Indicates the geometric gap at unit I. In the present invention, the permissible error is 1E-3 to control the number of algorithm iterations.

[0105] Step 4: Establish a tangential simplification algorithm to obtain the initial stick-slip distribution and tangential stress distribution in the contact patch

[0106] (1) The creep rate and spin calculated in step 1 and the normal exact solution calculated in step 3 are used as input;

[0107] (2) Substitute the simplified model of Trial+Fastsim into the initial solution of wheel-rail tangential contact.

[0108] Step 5: Obtain the exact tangent solution using the tangent boundary element model

[0109] The initial solution is inserted into the current grid as input parameters by interpolation. In the tangential contact calculation, the boundary element calculation grid divided in the normal contact calculation is used for the convenience of understanding the calculation.

[0110] The complementary energy expression of wheel-rail rolling tangential contact is established as follows:

[0111] Where w Ii is the amount of rigid sliding experienced at unit I during the period [t', t]; B IiJj It is defined as the difference in tangential elastic displacement of unit I caused by unit J bearing unit load; p Ii and p Jj is the tangential stress distribution at unit I, J.

[0112] The ConvexGS algorithm proposed by Vollebregt is used to obtain accurate tangential stress distribution, creep force and creep moment. At the same time, the invention uses an allowable error of 1E-3 to control the number of iterations of the tangential algorithm.

[0113] The method of the present invention is compared with the traditional method in terms of the number of algorithm iterations and calculation time, and the rationality of the allowable error value proposed by the present invention is explained.

[0114] Figure 2 The number of iterations and calculation time of the present invention and the previous method under the typical working condition of -2mm lateral displacement are compared, where the initial estimated grid (nx,ny) is (11,11), the boundary element algorithm iteration grid (mx,my) is (81,81), the allowable error in normal and tangential calculations is 1E-3, and the calculation time results are based on the previous boundary element algorithm as a reference object. The calculation time of the present invention is compared with the calculation time of the previous method to demonstrate the effect of the patented method in reducing the calculation time. Figure 2 (a) and (b) show that, in terms of normal contact, the number of iterations of the previous method is 13 times, while the number of iterations of the method proposed in the present invention is 5 times, which is 8 times less; in terms of calculation time, compared with the previous method, the calculation time of the calculation method of the present invention is reduced by 46%; Figure 2 (c) and (d) show that, in terms of tangential contact, the number of iterations of the previous method is 45, and the number of iterations of the method proposed in the present invention is 31, which is 18 times less, and the calculation efficiency is improved by 31%. In addition, compared with the previous method, the calculation time of the method of the present invention is reduced by 45%. Therefore, from the number of iterations and the calculation time, it can be seen that the method of the present invention has a significant effect.

[0115] Figure 3 The change process of iterative calculation between the previous method and the method of the present invention under the above working conditions is shown. From the results, it can be seen that the previous method starts the iteration from the entire rectangular potential area during the iterative calculation, and assumes that the initial contact spot shape is the entire rectangular potential contact area ( Figure 3 (a)) and the normal stress is 0 ( Figure 3 (b)), the tangential iteration calculation is that the contact patch is entirely an adhesive area ( Figure 3 (c)) and the tangential stress is 0 ( Figure 3 (d)), and the method of the present invention provides a relatively accurate initial prediction value by a simplified algorithm, which makes it easier for the boundary element algorithm to converge during iterative calculation and avoids additional iterative processes. This is the main reason why the method of the present invention can reduce the number of iterations.

[0116] Without loss of generality, Figure 4 The changes in the number of iterations and calculation time of the wheel-rail calculation method of the present invention and the previous boundary element algorithm under different lateral displacement conditions are compared. The horizontal axis in the figure represents the increase of the lateral displacement from -8mm to 8mm, with an increment of 0.1mm, including 161 contact conditions. The vertical axis is the number of iterations, where the allowable error of the control iteration calculation is 1E-3. Figure 4As shown in (a) and (b), in terms of normal contact, the number of iterations of the conventional boundary element algorithm is maintained at 12 to 17 times, while the number of iterations of the method of the present invention can be reduced by 6 to 8 times. Compared with the conventional method, the average calculation time of the method of the present invention is reduced by 55%. Figure 4 (c) and (d) show that the method of this patent has a better effect on tangential contact, which can reduce the number of algorithm iterations by 8 to 12 times and reduce the average calculation time by 33%. From the number of iterations and calculation time, it can be seen that the method proposed by the present invention has a more significant effect under general contact conditions.

[0117] The present invention will be further described below in conjunction with specific data.

[0118] The wheel-rail contact between the S1002CN wheel profile and the CN60 rail profile is taken as an example, where the lateral displacement is 7.78 mm, the input normal contact force N is 83.3 kN, and the penetration δ is solved by Hertz theory.

[0119] Step1: Use the formula g(y)=z w (y)-z r (y) Obtain the lateral contact geometry, using the formula f(y) = εδ-g(y) ≥ 0 and the formula Obtain the boundary of the potential contact area, and then use the formula z(x,y)=f(y)+Ax 2 Obtain the three-dimensional geometric gap distribution.

[0120] Step 2: Divide the initial estimated calculation grid (nx,ny) into (21,21) as described in step 2, and solve the normal initial solution when the lateral displacement is 7.78mm.

[0121] Step 3: Using the method described in step 3, divide the boundary element algorithm iterative grid (mx,my) into (101,101), and use the normal boundary element algorithm NormCG to solve the exact solution. The result is as follows Figure 5 (a) shown.

[0122] Step 4: As described in step 4, the creep rate and spin calculation results and the normal results are used as input, and the tangential fast algorithm is used to solve the tangential initial solution.

[0123] Step 5: Using the tangential boundary element algorithm described in step 5, the tangential exact solution is obtained. The result is as follows: Figure 5 (b) as shown.

[0124] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for estimating the boundary element calculation of wheel-rail contact, characterized in that: The method comprises: Step 1: determine the potential contact area, the geometric gap distribution of the wheel-rail contact point, and the creep rate and spin of the wheel-rail contact point; Step 2: Obtain the corresponding longitudinal distribution of compressive stress according to the geometric gap distribution of the wheel-rail contact point; Step 3, according to the geometric gap distribution and the longitudinal distribution of compressive stress, the normal exact solution is solved by the complementary energy expression; Step 4: Obtain the initial solution of wheel-rail tangential contact through the normal exact solution; The exact solutions of creep rate, spin and normal are used as input quantities; Substitute the Trial and Fastsim simplified models to obtain the initial solution of wheel-rail tangential contact; Step 5, using the tangent boundary element model to solve the exact solution through the initial solution; The initial solution is inserted into the boundary element calculation grid divided during normal contact calculation as input parameters by interpolation; The complementary energy expression of wheel-rail rolling tangential contact is established as follows: Where W Ii is the rigid sliding amount experienced by the unit at the time interval [t′, t]; B IiJj It is defined as the difference in tangential elastic displacement of unit I caused by unit J bearing unit load; p Ii and p Jj is the tangential stress distribution at unit I, J, g I is the tangential contact boundary at element I, x and y are the two directions of the contact tangent plane coordinate system axis; The accurate tangential stress distribution, creep force and creep moment are obtained by ConvexGS algorithm.

2. The estimation method for accelerating wheel-rail contact boundary element calculation according to claim 1, characterized in that: Step 1 specifically includes: Determine potential contact areas through reduction factors; The wheel-rail contact point is determined by the trace method, and the contact geometry parameters are determined by discretizing the wheel and rail coordinates. The lateral contact geometry gap is calculated using the following formula: g(y) = z w (y)-z r (y), g(y) represents the lateral contact geometric gap, z w (y) and z r (y) represents the geometric profile of the rail; The lateral and longitudinal contact boundaries of the potential area are determined respectively. The lateral contact boundary is determined by the geometric gap and the permeability as follows: f(y) = εδ-g(y)≥0, where δ represents the permeability, ε represents the reduction factor, and f(y) represents the lateral contact boundary. The longitudinal contact boundary is calculated as follows: a(y) represents the longitudinal contact boundary, and A is the curvature at the contact point; The three-dimensional contact geometric gap distribution within the set distance from the wheel-rail contact point is calculated through the potential area lateral and longitudinal contact boundaries. The calculation method is as follows: z(x, y) = f(y) + Ax 2 , z(x, y) represents the geometric gap; Longitudinal creep rate c x , tangential creep rate c y and spin c φ The calculation method is as follows: c y = -sinψcoS(φ+δ(y)), Where R1 is the nominal rolling radius, δ(y) is the contact angle, φ is the side rolling angle, ψ is the shaking angle, and R(y) is the contact radius.

3. The estimation method for accelerating wheel-rail contact boundary element calculation according to claim 2, characterized in that: Step 2 specifically includes: Divide the simplified algorithm calculation grid, and insert the geometric gap, the lateral and longitudinal contact boundaries of the potential area into the calculation grid by interpolation; Taking the geometric gap as the input parameter, the initial solution of the wheel-rail contact normal is calculated, and the transverse normal stress distribution is set to be proportional to the longitudinal length of the contact spot. Then: a0 is the longitudinal semi-axis length at y=0, p(y) represents the compressive stress at x=0, N represents the normal force; The longitudinal distribution of the compressive stress in the contact spot follows the following formula: p(x,y) represents the compressive stress distribution along the longitudinal direction.

4. The estimation method for accelerating wheel-rail contact boundary element calculation according to claim 3 is characterized in that: Step 3 specifically includes: Divide the boundary element calculation grid, and insert the geometric gap and the longitudinal distribution of the compressive stress into the current grid as parameter input by interpolation; The complementary energy expression of the wheel-rail normal contact problem is established as follows: Where p Iz 、p Jz Expressed as the normal stress at element I and J; A IzJz It is defined as the difference in normal elastic displacement of unit I caused by unit J bearing unit load; h I is the normal gap between two contacting bodies when they are in rigid contact; The wheel-rail contact patch shape, compressive stress distribution and normal contact force are solved according to the complementary energy expression. The calculation is completed when the iteration meets the following boundary conditions: C represents the contact area, E represents the non-contact area, and p Jz represents the normal stress at the J element, e I Represents the geometric gap at the I unit.

5. An estimation device for accelerating wheel-rail contact boundary element calculation, used to implement the estimation method for accelerating wheel-rail contact boundary element calculation as claimed in any one of claims 1 to 4, characterized in that: The device comprises: Parameter acquisition module, used to determine the potential contact area, the geometric gap distribution of the wheel-rail contact point, and the creep rate and spin of the wheel-rail contact point; A stress acquisition module is used to obtain the corresponding longitudinal distribution of compressive stress according to the geometric gap distribution of the wheel-rail contact point; The complementary energy solution module is used to solve the normal exact solution through the complementary energy expression according to the geometric gap distribution and the longitudinal distribution of compressive stress; The initial solution module is used to obtain the initial solution of wheel-rail tangential contact through the normal exact solution. Specifically, it is used to take the creep rate and spin calculated by the parameter acquisition module and the normal exact solution calculated in the complementary energy solution module as input quantities; bring them into the Trial and Fastsim simplified models to obtain the initial solution of wheel-rail tangential contact; An exact solution module is used to solve an exact solution using a tangent boundary element model through an initial solution, and is specifically used to insert the initial solution into the boundary element calculation grid divided during normal contact calculation as an input parameter by interpolation; The complementary energy expression of wheel-rail rolling tangential contact is established as follows: Where w Ii is the amount of rigid sliding experienced at unit I during the period [t', t]; B IiJj It is defined as the difference in tangential elastic displacement of unit I caused by unit J bearing unit load; p Ii and p Jj is the tangential stress distribution at unit I, J, g I is the tangential contact boundary at element I, x, y are the two directions of the contact tangent plane coordinate system axis; The accurate tangential stress distribution, creep force and creep moment are obtained by ConvexGS algorithm.

6. The estimation device for accelerating wheel-rail contact boundary element calculation according to claim 5, characterized in that: The parameter acquisition module is specifically used to determine the potential contact area through the reduction factor; The wheel-rail contact point is determined by the trace method, and the contact geometry parameters are determined by discretizing the wheel and rail coordinates. The lateral contact geometry gap is calculated using the following formula: g(y) = z w (y)-z r (y), g(y) represents the lateral contact geometric gap, z w (y) and z r (y) represents the geometric profile of the rail; The lateral and longitudinal contact boundaries of the potential area are determined respectively. The lateral contact boundary is determined by the geometric gap and the permeability as follows: f(y) = εδ-g(y)≥0, where δ represents the permeability, ε represents the reduction factor, and f(y) represents the lateral contact boundary. The longitudinal contact boundary is calculated as follows: a(y) represents the longitudinal contact boundary, and A is the curvature at the contact point; The three-dimensional contact geometric gap distribution within the set distance from the wheel-rail contact point is calculated through the potential area lateral and longitudinal contact boundaries. The calculation method is as follows: z(x,y)=f(y)+Ax 2 , z(x,y) represents the geometric gap; Longitudinal creep rate c x , tangential creep rate c y and spin c φ The calculation method is as follows: c y = -sinψcos(φ+δ(y)), Where R1 is the nominal rolling radius, δ(y) is the contact angle, φ is the side rolling angle, ψ is the shaking angle, and R(y) is the contact radius.

7. The estimation device for accelerating wheel-rail contact boundary element calculation according to claim 6, characterized in that: The stress acquisition module is specifically used to divide the simplified algorithm calculation grid, and insert the geometric gap, the lateral and longitudinal contact boundaries of the potential area into the calculation grid by interpolation; Taking the geometric gap as the input parameter, the initial solution of the wheel-rail contact normal is calculated, and the transverse normal stress distribution is set to be proportional to the longitudinal length of the contact spot. Then: a0 is the longitudinal semi-axis length at y=0, p(y) represents the compressive stress at x=0, N represents the normal force; The longitudinal distribution of the compressive stress in the contact spot follows the following formula: p(x,y) represents the compressive stress distribution along the longitudinal direction.

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