Wheel-rail contact geometrical relationship evaluation method based on improved wheel abrasion index

Abstract

The invention relates to the field of mechanical engineering, and discloses a wheel-rail contact geometrical relationship evaluation method based on an improved wheel abrasion index, which comprises the following steps: S1, acquiring profile data, S2, performing interpolation processing on coordinate points, S3, calculating tread abrasion loss, S4, calculating an abrasion index wmad, and S5, performing correlation analysis on the abrasion index wmad and wheel-rail contact parameters. And S6, the abrasion index wmad is optimized. The wheel abrasion index constructed by the method has good correlation with the wheel-rail matching equivalent taper, the wheel-rail contact geometric state is intuitively reflected, the index also has strong correlation with the vehicle hunting stability, the pre-evaluation of the vehicle hunting stability is realized through the evaluation of the abrasion index, and the pre-evaluation of the vehicle hunting stability is realized. And then fault tracing of snaking instability is supported, the problem solving efficiency is improved, and the vehicle operation and maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of mechanical engineering, and in particular to the construction of wheel wear indicators of railway vehicles and the evaluation of wheel-rail contact geometric relationship, and is oriented to railway vehicles, including: EMUs, locomotives, urban rail vehicles and other wheel-rail transportation. Background Art

[0002] In the railway system, the wheel and rail profiles are the basis of wheel-rail contact geometry, and they have a decisive influence on the dynamic behavior of the vehicle system. When the vehicle is newly put into use, the contact relationship between the wheel and the rail is good, but as the wear and tear accumulate during use, this contact relationship will change, which will affect the dynamic performance of the vehicle. Studies have shown that wheel-rail wear will lead to abnormal wheel-rail matching equivalent taper, which will affect the running stability of the vehicle and cause problems such as bogie snaking and body snaking. When the vehicle is unstable, it is necessary to track the root cause of the phenomenon, which usually includes obtaining the actual wheel-rail profile and analyzing its contact relationship. However, due to the long running route and high speed, it is difficult to determine the specific track location where the instability occurs. Even if the wheel-rail profile and equivalent taper are obtained, it is difficult to identify the real factors that lead to abnormal contact relationship. This situation easily leads to disputes between the vehicle operation department and the track maintenance department, and there are problems such as buck-passing, inefficiency and high maintenance costs. Therefore, it is necessary to find a new indicator other than the equivalent conicity of wheel-rail contact, which only relies on the single test data of the wheel profile and can effectively reflect the wheel-rail contact geometry and the running stability of the related vehicle, so as to decouple the fault factors of hunting instability and provide support for solving the hunting instability problem.

[0003] The existing wheel-rail contact geometry assessment methods have the following shortcomings:

[0004] 1) The above parameters need to be obtained to calculate the wheel-rail contact geometry parameters, which requires coordination among multiple departments and it is often difficult to locate the accurate rail profile;

[0005] 2) The calculation of the above parameters requires a theoretical method based on the trace method. The calculation process is complicated, and the calculation results are very sensitive to the test data, which is prone to abnormal results;

[0006] 3) The wheel-rail matching equivalent taper is a comprehensive parameter of the wheel-rail contact system, which reflects the matching performance of the wheel and rail. When there is an abnormality in the wheel-rail matching equivalent taper, it is difficult to determine whether it is caused by abnormal wheel wear or abnormal rail wear, which makes it difficult to solve the problem. Summary of the invention

[0007] The present invention is based on the shortcomings and deficiencies of existing wheel wear indicators and wheel-rail contact geometry evaluation methods. The purpose of the present invention is to find a new indicator other than the wheel-rail contact equivalent taper. The evaluation of this indicator only relies on a single test data of the wheel profile, and can effectively reflect the wheel-rail contact state and the related vehicle operation stability, so as to decouple the fault factors of operational instability and provide support for tracking the fault factors of snaking instability. In this way, the present invention aims to more comprehensively evaluate the impact of wheel tread wear on vehicle snaking stability, provide more accurate maintenance and optimization guidance, and thus improve the operational safety and efficiency of railway vehicles.

[0008] To achieve the above object, the present invention provides the following technical solution: a wheel-rail contact geometric relationship evaluation method based on improved wheel wear index, the method comprising the following steps:

[0009] S1. Acquisition of surface data

[0010] First, it is necessary to test and obtain the wheel profile data after wear and the standard profile data of the profile before wear, and convert the coordinate point data into a unified coordinate system;

[0011] S2. Coordinate point interpolation processing

[0012] The wheel tread consists of a series of discrete plane coordinate points (x i ,y i ), due to the influence of tread wear, test conditions and test personnel, its lateral coordinates are usually different. In order to calculate the wheel wear, the coordinate points of the standard wheel profile data and the wheel profile data after measured wear are interpolated by cubic spline to obtain smooth cubic spline functions S1(x) and S2(x);

[0013] S3. Calculation of tread wear

[0014] Using the spline function, the wear value at the specified horizontal coordinate is calculated, so the horizontal coordinate is set to 0, and the tread wear amount w0 at the nominal rolling circle can be obtained as S1(0)-S2(0);

[0015] S4, wear index w mad Calculation

[0016] The interpolation curve S2(x) of the worn profile is translated vertically upward until its nominal rolling circle coordinates coincide with the standard profile. Then, the translated profile S2(x)+w0 is integrated with the standard profile curve S1(x) in the tread wear area [X3, X4], and then the difference in moving wear area w is obtained by subtracting them. mad ;

[0017] S5, wear index w madCorrelation analysis with wheel-rail contact parameters

[0018] Based on the above calculation method, a large amount of measured wheel profile data is used to calculate the wheel wear index w one by one. mad ; Based on the standard rail profile data, the equivalent taper of different measured wheel profiles matching the standard rail profile is calculated; through cross-correlation analysis, the wheel wear index w is obtained mad The mutual correlation coefficient with the equivalent taper is used to evaluate the degree of correlation between the two;

[0019] S6, wear index w mad Optimization

[0020] Perform variable parameter analysis on the tread wear area [X3, X4] to analyze the wheel wear index w in different wear areas mad The mutual correlation coefficient between the equivalent taper and the wear interval value with the highest correlation coefficient is extracted and used as the wear index w mad The final calculation interval is used to optimize the wear index.

[0021] On the basis of the establishment of new wear indicators, the wheel-rail contact geometry relationship is further evaluated. The specific implementation process is as follows:

[0022] 1. Calculation of new wear index and equivalent taper

[0023] New wheel wear index w based on optimization mad , calculate the wear index under the measured wheel profile, and calculate the equivalent taper of wheel-rail matching under different wheel set lateral displacements in combination with the standard rail profile;

[0024] 2. Calculation of equivalent taper change

[0025] The standard wheel profile and standard rail profile are used to calculate the nominal equivalent taper of the wheel-rail matching at a wheelset lateral displacement of 3 mm, and the nominal equivalent taper under the measured worn wheel is subtracted from the nominal equivalent taper under the standard wheel to obtain the nominal equivalent taper change;

[0026] 3. Regression analysis between indicators

[0027] Based on the wheel wear index and the corresponding nominal equivalent taper change, the wear index w mad As the independent variable, the nominal equivalent taper was used as the dependent variable to carry out a univariate regression analysis. By comparing the R 2 Values, compare the goodness of fit of different regression models, and select the regression model with the best fitting effect;

[0028] 4. Prediction of nominal equivalent taper based on wheel wear index

[0029] Using the regression model established above, the wear index w of the new test worn wheel is calculated. mad , the predicted value of the nominal equivalent taper change can be obtained, combined with the nominal equivalent taper value of the profile in the new wheel state, and finally the predicted value of the nominal equivalent taper matching the worn wheel with the standard rail profile can be obtained;

[0030] 5. Wheel-rail contact geometry evaluation

[0031] Based on the existing EMU wheel-rail matching equivalent taper application limit management specifications, combined with the calculated nominal equivalent taper prediction value, the wheel wear state and wheel-rail matching geometric relationship are evaluated to provide guidance for wheel turning and maintenance.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The wheel wear index constructed by the present invention has a good correlation with the equivalent taper of wheel-rail matching, which intuitively reflects the geometric state of wheel-rail contact;

[0034] 2. There is also a strong correlation between this indicator and the vehicle's snaking stability. The evaluation of this wear indicator can be used to pre-evaluate the vehicle's snaking stability, and then support the fault tracing of snaking instability, improve the efficiency of problem solving, and reduce vehicle operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the tread wear amount of the present invention;

[0036] Figure 2 It is a schematic diagram of the tread depression amount of the present invention;

[0037] Figure 3 It is a schematic diagram of the tread wear area of ​​the present invention;

[0038] Figure 4 A schematic diagram of the wear index of a new wheel of the present invention;

[0039] Figure 5 The wheel wear index construction and wheel-rail contact geometric relationship evaluation flow chart of the present invention;

[0040] Figure 6 This is a diagram showing the evolution of the measured wheel surface wear distribution along with the vehicle running mileage according to the present invention;

[0041] Figure 7 is the measured wheel surface wear index w of the present invention mad Evolution diagram with running mileage;

[0042] Figure 8 The equivalent taper variation Δλ3 and the wheel wear index w of the present invention are madThe mapping relationship diagram between them;

[0043] Fig. 9 is the wheel wear index w of the present invention mad Fitting analysis diagram of equivalent taper variation Δλ3 for wheel-rail matching;

[0044] Fig.10 is the wheel wear index w of the present invention mad and vehicle snaking stability index graph. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In view of the problems of existing wheel wear indicators, the present invention proposes a new wheel wear indicator, which aims to more comprehensively evaluate the impact of wheel tread wear on wheel-rail contact geometry and vehicle snaking stability. The key factor affecting wheel-rail contact geometry is the tread shape rather than the wear depth or wear area. Therefore, in order to characterize the difference between the tread shape after wear and the standard tread shape, the present invention proposes a new wheel tread wear indicator wmad, such as Figure 4 As shown, a wheel-rail contact geometric relationship evaluation method based on improved wheel wear index comprises the following steps:

[0047] S1. Acquisition of surface data

[0048] First, it is necessary to test and obtain the wheel profile data after wear and the standard profile data of the profile before wear, and convert the coordinate point data into a unified coordinate system;

[0049] S2. Coordinate point interpolation processing

[0050] The wheel tread consists of a series of discrete plane coordinate points (x i ,y i ), due to the influence of tread wear, test conditions and test personnel, its lateral coordinates are usually different. In order to calculate the wheel wear, the coordinate points of the standard wheel profile data and the wheel profile data after measured wear are interpolated by cubic spline to obtain smooth cubic spline functions S1(x) and S2(x);

[0051] S3. Calculation of tread wear

[0052] Using the spline function, the wear value at the specified horizontal coordinate is calculated, so the horizontal coordinate is set to 0, and the tread wear amount w0 at the nominal rolling circle is S1(0)-S2(0);

[0053] S4, wear index w mad Calculation

[0054] The interpolation curve S2(x) of the worn profile is translated vertically upward until its nominal rolling circle coordinates coincide with the standard profile. Then, the translated profile S2(x)+w0 is integrated with the standard profile curve S1(x) in the tread wear area [X3, X4], and then the difference in moving wear area w is obtained by subtracting them. mad ;

[0055] S5, wear index w mad Correlation analysis with wheel-rail contact parameters

[0056] Based on the above calculation method, a large amount of measured wheel profile data is used to calculate the wheel wear index w one by one. mad ; Based on the standard rail profile data, the equivalent taper of different measured wheel profiles matching the standard rail profile is calculated; through cross-correlation analysis, the wheel wear index w is obtained mad The mutual correlation coefficient with the equivalent taper is used to evaluate the degree of correlation between the two;

[0057] S6, wear index w mad Optimization

[0058] Perform variable parameter analysis on the tread wear area [X3, X4] to analyze the wheel wear index w in different wear areas mad The mutual correlation coefficient between the equivalent taper and the wear interval value with the highest correlation coefficient is extracted and used as the wear index w mad The final calculation interval is used to optimize the wear index.

[0059] On the basis of the establishment of new wear indicators, the wheel-rail contact geometry relationship is further evaluated. The specific implementation process is as follows:

[0060] 1. Calculation of new wear index and equivalent taper

[0061] New wheel wear index w based on optimization mad , calculate the wear index under the measured wheel profile, and calculate the equivalent taper of wheel-rail matching under different wheel set lateral displacements in combination with the standard rail profile;

[0062] 2. Calculation of equivalent taper change

[0063] The standard wheel profile and standard rail profile are used to calculate the nominal equivalent taper of the wheel-rail matching at a wheelset lateral displacement of 3 mm, and the nominal equivalent taper under the measured worn wheel is subtracted from the nominal equivalent taper under the standard wheel to obtain the nominal equivalent taper change;

[0064] 3. Regression analysis between indicators

[0065] Based on the wheel wear index and the corresponding nominal equivalent taper change, the wear index w mad As the independent variable, the nominal equivalent taper was used as the dependent variable to carry out a univariate regression analysis. By comparing the R 2 Values, compare the goodness of fit of different regression models, and select the regression model with the best fitting effect;

[0066] 4. Prediction of nominal equivalent taper based on wheel wear index

[0067] Using the regression model established above, the wear index w of the new test worn wheel is calculated. mad , obtain the predicted value of the nominal equivalent taper change, and combine it with the nominal equivalent taper value of the profile in the new wheel state, and finally obtain the predicted value of the nominal equivalent taper matching the worn wheel with the standard rail profile;

[0068] 5. Wheel-rail contact geometry evaluation

[0069] Based on the existing EMU wheel-rail matching equivalent taper application limit management specifications, combined with the calculated nominal equivalent taper prediction value, the wheel wear state and wheel-rail matching geometric relationship are evaluated to provide guidance for wheel turning and maintenance.

[0070] Wheel wear indicators

[0071] At present, the industry has established some wear indicators based on wheel wear data to evaluate the wheel tread wear status, including: wheel tread wear amount, tread depression amount and tread wear area. The definitions of these wear indicators are as follows:

[0072] Tread wear w0: height difference between standard profile and measured profile at nominal rolling circle, see Figure 1 .

[0073] Tread depression w h : The difference between the raised part and the sunken part within the wheel tread, see Figure 2 .

[0074] Tread wear area w ad : In the tread wear area, the measured data before and after wear are integrated at discrete points, and then the difference is made to obtain the wear area, see Figure 3 .

[0075] The overall process framework of the above implementation plan is as follows Figure 5 shown.

[0076] Next, based on the different types of wheel profile data obtained from previous tests and according to the implementation process of the above invention, an example analysis is carried out. Taking into account the differences in wheel wear, wheel profile tracking test data with two different wear forms are selected to carry out wear and wheel-rail contact geometry analysis.

[0077] Firstly, based on the measured discrete data points of wheel tread profile, the evolution law of the average value of wheel tread wear of the whole train with the running mileage of the EMU is obtained through statistical analysis. The results are as follows: Figure 6 shown.

[0078] Then, the wear amount of the above wheel profile at the nominal rolling circle is calculated by cubic spline interpolation, and the results are summarized as follows: Figure 7 shown.

[0079] Then, based on the rolling circle wear of each wheel, the new wheel wear index constructed by the present invention is used to calculate the w of each wheel profile. mad , the results are as follows Figure 7 shown.

[0080] Next, based on the measured wheel profile data and the standard CHN60 rail profile, the equivalent conicity of the wheel-rail matching is calculated, and the equivalent conicity reference value under the matching of the standard wheel profile and the standard rail profile is subtracted to obtain the equivalent conicity change Δλ3 of different wheels, which is related to the wheel wear index w mad The mapping relationship between Figure 8 shown.

[0081] The wheel wear index w mad As the independent variable, the equivalent taper change Δλ3 is taken as the dependent variable, and polynomial fitting is carried out to obtain the fitting curve, as shown in Fig. 9 As shown, the R of the polynomial fit is 2 The value is 0.93, indicating that the goodness of fit is very good. The fitting formula is as follows:

[0082] Δλ3=0.02268+0.00835w mad +0.000135w mad 2

[0083] Table 1 below gives the application standards of key influencing factors of EMU wheel turning and repair, focusing on the control of the equivalent taper of wheel-rail matching, and gives the application limit. Based on the above fitting formula, the wear index w of the measured wheel profile is calculated madWe can quickly predict the equivalent taper change Δλ3 when the wheel profile matches the standard 60 rail profile, and combine the wheel-rail matching benchmark value of the wheel profile in the new wheel state to obtain the nominal equivalent taper prediction value when the worn wheel matches the standard 60 rail profile. Compare the predicted value with the application standard in Table 1 to evaluate the wheel wear state and guide the wheel turning and maintenance.

[0084] Table 1: Application standards for key factors affecting wheel turning and repair

[0085]

[0086] In addition, based on the vehicle vibration data obtained from the previous tracking test, Fig.10 The wheel wear index w is given mad The mapping relationship between the wheel wear index and the vehicle snaking stability index (including the bogie snaking stability index and the body snaking stability index, the larger the index value, the worse the stability). It can be seen that the wheel wear index has a significant impact on the snaking stability index, which is manifested as follows: when w mad When it is less than 0, as the wheel wear index w mad The decrease of w will slightly reduce the frame snaking stability and significantly reduce the body snaking stability. mad When it is greater than 0, as the wheel wear index w mad The increase of the wheel wear index w mad The test and calculation can indirectly evaluate the vehicle's snaking stability. Therefore, when the vehicle is snaking instability, the wear test and wear index w based on the wheel profile are used to mad The calculation can assess whether the hunting instability is caused by abnormal wheel wear, thereby tracing the instability factors and carrying out targeted wheel grinding to solve the hunting instability problem.

[0087] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0088] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wheel-rail contact geometric relationship evaluation method based on improved wheel wear index, characterized by: The method comprises the following steps: S1. Acquisition of surface data First, it is necessary to test and obtain the wheel profile data after wear and the standard profile data of the profile before wear, and convert the coordinate point data into a unified coordinate system; S2. Coordinate point interpolation processing The wheel tread consists of a series of discrete plane coordinate points (x i ,y i ), due to the influence of tread wear, test conditions and test personnel, its lateral coordinates are usually different. In order to calculate the wheel wear, the coordinate points of the standard wheel profile data and the wheel profile data after measured wear are interpolated by cubic spline to obtain smooth cubic spline functions S1(x) and S2(x); S3. Calculation of tread wear Using the spline function, the wear value at the specified horizontal coordinate is calculated, so the horizontal coordinate is set to 0, and the tread wear amount w0 at the nominal rolling circle can be obtained as S1(0)-S2(0); S4, wear index w mad Calculation The interpolation curve S2(x) of the worn profile is translated vertically upward until its nominal rolling circle coordinates coincide with the standard profile. Then, the translated profile S2(x)+w0 is integrated with the standard profile curve S1(x) in the tread wear area [X3, X4], and then the difference in moving wear area w is obtained by subtracting them. mad ; S5, wear index w mad Correlation analysis with wheel-rail contact parameters Based on the above calculation method, a large amount of measured wheel profile data is used to calculate the wheel wear index w one by one. mad ; Based on the standard rail profile data, the equivalent taper of different measured wheel profiles matching the standard rail profile is calculated; through cross-correlation analysis, the wheel wear index w is obtained mad The mutual correlation coefficient with the equivalent taper is used to evaluate the degree of correlation between the two; S6, wear index w mad Optimization Perform variable parameter analysis on the tread wear area [X3, X4] to analyze the wheel wear index w in different wear areas mad The mutual correlation coefficient between the equivalent taper and the wear interval value with the highest correlation coefficient is extracted and used as the wear index w mad The final calculation interval is used to optimize the wear index. On the basis of the establishment of new wear indicators, the wheel-rail contact geometry relationship is further evaluated. The specific implementation process is as follows:

1. Calculation of new wear index and equivalent taper New wheel wear index w based on optimization mad , calculate the wear index under the measured wheel profile, and calculate the equivalent taper of wheel-rail matching under different wheel set lateral displacements in combination with the standard rail profile; 2. Calculation of equivalent taper change The standard wheel profile and standard rail profile are used to calculate the nominal equivalent taper of the wheel-rail matching at a wheelset lateral displacement of 3 mm, and the nominal equivalent taper under the measured worn wheel is subtracted from the nominal equivalent taper under the standard wheel to obtain the nominal equivalent taper change; 3. Regression analysis between indicators Based on the wheel wear index and the corresponding nominal equivalent taper change, the wear index w mad As the independent variable, the nominal equivalent taper was used as the dependent variable to carry out a univariate regression analysis. By comparing the R 2 Values, compare the goodness of fit of different regression models, and select the regression model with the best fitting effect; 4. Prediction of nominal equivalent taper based on wheel wear index Using the regression model established above, the wear index w of the new test worn wheel is calculated. mad , the predicted value of the nominal equivalent taper change can be obtained, combined with the nominal equivalent taper value of the profile in the new wheel state, and finally the predicted value of the nominal equivalent taper matching the worn wheel with the standard rail profile can be obtained; 5. Wheel-rail contact geometry evaluation Based on the existing EMU wheel-rail matching equivalent taper application limit management specifications, combined with the calculated nominal equivalent taper prediction value, the wheel wear state and wheel-rail matching geometric relationship are evaluated to provide guidance for wheel turning and maintenance.

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