A comprehensive evaluation method and system for tire friction performance based on multi-factor coupling

Abstract

This invention proposes a multi-factor coupled comprehensive evaluation method and system for tire friction performance, comprising: S1, conducting a multi-stage progressive load test on the tire and collecting longitudinal force versus longitudinal displacement relationship curve data at each stage; S2, calculating a multi-stage dynamic weighted friction coefficient based on the longitudinal force data at each stage using progressively weighted coefficients; S3, considering the characteristics of the contact surface material, surface roughness, and contaminant coverage; S4, considering the test environment temperature and relative humidity; S5, determining the dynamic stiffness coupling coefficient of the tire-contact surface system based on the slope of the initial linear segment of the longitudinal force versus longitudinal displacement relationship curve; S6, calculating a comprehensive friction performance index based on the multi-stage dynamic weighted friction coefficient and the dynamic stiffness coupling coefficient; S7, calculating a friction performance stability index through repeated loading tests; and S8, comprehensively evaluating the tire friction performance level based on the comprehensive friction performance index and the friction performance stability index.

Description

Technical Field

[0001] This invention relates to the field of tire performance analysis, and in particular to a comprehensive evaluation method and system for tire friction performance that involves multiple coupled factors. Background Technology

[0002] Tire friction performance is one of the core indicators for evaluating vehicle safety and handling. In existing technologies, the tire friction coefficient is typically determined by the ratio of the peak longitudinal force to the radial load under a single load condition, i.e., using the formula... The calculation yielded the results. However, this traditional evaluation method has the following technical drawbacks:

[0003] First, existing methods only consider the first peak value of the longitudinal force-displacement curve during a single loading process, failing to fully utilize the rich mechanical information contained in the multi-stage loading process. Under actual braking conditions, the friction process between the tire and the road surface is a complex dynamic evolution process, and a single peak value measurement is insufficient to comprehensively reflect the tire's overall friction characteristics.

[0004] Second, existing technologies do not fully consider the coupled influence of contact surface type and condition on the coefficient of friction. Different contact surface materials (such as cement surface, mirror steel plate, asphalt board) and different contact surface conditions (dry, water accumulation, sand and gravel coverage) will significantly change the friction mechanism between the tire and the contact surface. Simple single coefficient correction cannot accurately describe this complex coupling relationship.

[0005] Third, environmental conditions (temperature and humidity) have a significant impact on tire friction performance, but existing technologies lack a systematic correction mechanism for environmental factors, resulting in poor repeatability and comparability of test results.

[0006] Fourth, existing methods do not consider the intrinsic relationship between the dynamic stiffness characteristics and friction performance of the tire-contact system. The stiffness response of a tire during loading is closely related to its friction characteristics; ignoring this coupling relationship will lead to biased evaluation results.

[0007] To address the aforementioned technical problems, this invention proposes a comprehensive evaluation method for tire friction performance based on multi-factor coupling. By introducing multi-stage dynamic weighting coefficients, contact surface state coupling coefficients, environmental correction factors, and tire-contact surface system dynamic stiffness coupling coefficients, a comprehensive and accurate evaluation of tire friction performance is achieved. Summary of the Invention

[0008] This invention aims to at least solve the technical problems existing in the prior art, and in particular, it innovatively proposes a comprehensive evaluation method for tire friction performance based on multi-factor coupling.

[0009] To achieve the above-mentioned objectives of this invention, this invention provides a comprehensive evaluation method for tire friction performance based on multiple coupled factors, comprising the following steps:

[0010] S1, conduct a multi-stage progressive load test on the tire and collect data on the relationship between longitudinal force and longitudinal displacement at each stage;

[0011] S2, Based on the longitudinal force data of each stage, the multi-stage dynamic weighted friction coefficient is calculated using an increasing weighting coefficient;

[0012] S3, determine the contact surface state coupling coefficient based on the material properties, surface roughness and contaminant coverage of the contact surface;

[0013] S4, calculate the environmental condition correction factor based on the ambient temperature and relative humidity of the test environment;

[0014] S5. Determine the dynamic stiffness coupling coefficient of the tire-contact surface system based on the slope of the initial linear segment of the longitudinal force-longitudinal displacement relationship curve.

[0015] S6. Calculate the comprehensive friction performance index based on the multi-stage dynamic weighted friction coefficient, contact surface state coupling coefficient, environmental condition correction factor, and dynamic stiffness coupling coefficient.

[0016] S7, the friction performance stability index is calculated through repeated loading tests;

[0017] S8. Based on the comprehensive friction performance index and friction performance stability index, the tire friction performance is comprehensively rated.

[0018] In a preferred embodiment of the above technical solution, S1 includes: setting a four-stage incremental loading sequence based on a standard radial load, and recording the peak longitudinal force at each stage, wherein the loading sequence dynamically adjusts the stage load difference and termination displacement according to the tire specifications and test load.

[0019] In a preferred embodiment of the above technical solution, S2 includes: setting a weighted coefficient sequence that increases with the number of loading cycles, and performing a weighted average of the peak longitudinal force at each stage to reflect the characteristics of the tire tending to a stable friction state after break-in.

[0020] In the preferred embodiment of the above technical solution, S3 includes: determining a basic correction value based on the material type of the contact surface, performing roughness correction based on the deviation between the surface roughness and the reference roughness, and performing pollutant attenuation correction in combination with the thickness of the water film and sand cover, and obtaining the contact surface state coupling coefficient through multi-level multiplication.

[0021] In a preferred embodiment of the above technical solution, step S4 includes: calculating a temperature correction factor based on the deviation between the test temperature and the reference temperature, calculating a humidity correction factor based on the deviation between the test humidity and the reference humidity, and obtaining an environmental condition correction factor by multiplying the two.

[0022] In a preferred embodiment of the above technical solution, step S5 includes: calculating the average value of the dynamic stiffness during the multi-stage loading process, and obtaining the dynamic stiffness coupling coefficient by power function mapping based on the ratio of the average value to the reference dynamic stiffness.

[0023] In a preferred embodiment of the above technical solution, step S6 includes: multiplying and coupling the multi-stage dynamic weighted friction coefficient, the contact surface state coupling coefficient, the environmental condition correction factor, and the dynamic stiffness coupling coefficient to obtain a comprehensive friction performance index that considers multiple factors such as time sequence characteristics, contact surface state, environmental conditions, and structural stiffness.

[0024] In the preferred embodiment of the above technical solution, S7 includes: performing multiple repeated loadings after the multi-stage loading is completed, calculating the stage friction coefficient based on the peak longitudinal force of each repeated loading, and calculating the friction performance stability index by statistical dispersion.

[0025] This invention discloses a computer system, comprising:

[0026] processor;

[0027] Memory used to store processor-executable instructions;

[0028] The processor is configured to implement the comprehensive evaluation method for tire friction performance applied to multi-factor coupling when executing the executable instructions.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] First, by employing a multi-stage dynamic weighted friction coefficient calculation method, the rich mechanical information contained in multiple loading processes is fully utilized. Compared to existing technologies that only use single peak measurements, the method of this invention can more comprehensively reflect the evolution of tire friction characteristics during actual use, resulting in more reliable evaluation results.

[0031] Second, by establishing a mathematical model of the coupling coefficient of the contact surface state, the influence of contact surface material, surface roughness, and contaminant coverage on tribological performance was systematically quantified. This model considers the interaction of multiple factors and, compared to a simple single-coefficient correction method, can more accurately describe the differences in friction mechanisms under different contact surface conditions.

[0032] Third, the environmental condition correction factor enables a systematic correction of the effects of temperature and humidity, making test results obtained under different environmental conditions comparable.

[0033] Fourth, a quantitative relationship between tire structural characteristics and friction performance was established using the dynamic stiffness coupling coefficient of the tire-contact surface system. This innovation fills a gap in existing technologies for evaluating tire stiffness-friction coupling and provides a new evaluation dimension for tire design optimization.

[0034] Fifth, by introducing a friction performance stability index, a quantitative assessment of the consistency of tire friction performance is achieved. This index can identify problems such as uneven tire structure or fluctuations in material properties, providing an effective technical means for quality control.

[0035] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0037] Figure 1 This is a flowchart of the workflow of the present invention;

[0038] Figure 2 This is a schematic diagram of the composite plate frame of the present invention;

[0039] Figure 3 This is the initial longitudinal force-displacement curve collected in this invention. Schematic diagram;

[0040] Figure 4 This is the initial longitudinal force-displacement curve collected in this invention. Schematic diagram;

[0041] Figure 5 This is a diagram illustrating the collection of invalid data. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0043] like Figure 1 As shown, this invention discloses a comprehensive evaluation method for tire friction performance based on multi-factor coupling, comprising the following steps:

[0044] S1, Multi-stage loading test and dynamic data acquisition: Select the required test contact surface, install it on the integrated testing machine, and fix it with screws. Figure 2 As shown, if a composite board is used, first place the composite board frame on the integrated testing machine, then select the required composite board and install it into the central hollow frame of the composite board frame. Next, fix the composite frame plate to the table of the integrated testing machine with screws. Install the required test tire onto the connecting plate of the integrated testing machine with screws, and add water or sand to the test contact surface according to the test requirements.

[0045] The test pressure is the pressure marked on the tire sidewall (the pressure corresponding to the single tire load). When a specified pressure is specified, use that pressure. After inflating the tire, leave it at room temperature (20~30)℃ for more than 24 hours. If the pressure drops, refill it to the specified pressure and leave it for 15 minutes before testing.

[0046] Multi-stage loading parameters are set according to the standard test load, which is based on the standard radial load. This indicates that the unit is N, when When the load is ≤3000×9.8N, the longitudinal displacement at the end is set to 80mm, and the initial load is... -1000×9.8N, the second loading load is -500×9.8N, the third loading load is The fourth load was +500×9.8N. When When the load is >3000×9.8N, the longitudinal displacement at the end is set to 120mm, and the initial load is... -2000×9.8N, the second loading load is -1000×9.8N, the third loading load is The fourth load was +1000×9.8N.

[0047] The tire was loaded to the target load at a radial loading speed of (50±2.5) mm / min, and the pressure was held for 5s after each loading stage. The test bench was moved along the X-axis at a speed of 50 mm / min. The relative displacement was used as the abscissa and the longitudinal force acting on the tire was used as the ordinate to plot the longitudinal force and longitudinal displacement curves at each stage.

[0048] Figure 3 and 4 Initial data acquisition for longitudinal force-displacement curve Data process;

[0049] S2 performs multi-stage dynamic weighted friction coefficient calculation. For each loading stage, the peak longitudinal force on the longitudinal force-displacement curve is extracted. Let the peak longitudinal force corresponding to the i-th loading stage be... Where i = 1, 2, 3, 4; set the weight coefficients for the loading phase. This coefficient reflects the degree of contribution of different loading stages to the evaluation of tire friction performance;

[0050] Multi-stage dynamic weighted friction coefficient The calculation formula is:

[0051] ;

[0052] in, The multi-stage dynamic weighted friction coefficient is dimensionless; N is the total number of loading stages, N=4; Let be the weight coefficient for the i-th loading stage, dimensionless, and satisfying... That is, as the number of loading times increases, the weighting coefficient gradually increases to reflect the characteristic that the tire tends to a stable friction state after multiple loadings; The peak longitudinal force on the longitudinal force-displacement curve during the i-th loading stage is expressed in N. The standard radial load set for the test is in N; This represents the cumulative sum of the weight coefficients for each stage, calculated using the following formula: .

[0053] Loading phase weight coefficient The determination of the setting follows these principles: Considering the contact surface break-in effect of the tire during the initial loading, as the number of loading cycles increases, the contact state between the tire and the contact surface gradually stabilizes, and the friction characteristics tend to be consistent; therefore, the setting is increased sequentially. =0.8, =0.9, =1.0, =1.1, at this time =3.8, to reflect the greater contribution of data from the later loading stage to the evaluation results. This weighting configuration reflects the engineering experience that there is a break-in period during the initial loading and that the data becomes more stable in the later stages, which is different from simple arithmetic average or single measurement methods.

[0054] S3, Establish the process for determining the coupling coefficient of the contact surface state. Based on the contact surface type and contact surface state used in the experiment, determine the contact surface state coupling coefficient β. This coefficient comprehensively considers the influence of contact surface material properties, surface roughness, and covering state on friction performance.

[0055] The formula for calculating the coupling coefficient β of the contact surface state is:

[0056] ;

[0057] Where β is the contact surface state coupling coefficient, which is dimensionless; This is a dimensionless correction factor for the contact surface material, reflecting the fundamental influence of different contact surface materials, namely cement, mirror steel, smooth cement, and asphalt, on friction performance. , is a dimensionless surface roughness correction coefficient, characterizing the modulating effect of the microstructure of the contact surface on the friction mechanism; The dimensionless correction factor for pollutant coverage describes the attenuation effect of surface coverings such as water films and sand / gravel layers on the coefficient of friction.

[0058] Contact surface material correction factor The value ranges from 0.6 to 1.2, where the composite cement surface corresponds to =1.0, corresponding to composite 8K mirror steel plate =0.7, corresponding to composite smooth cement board =0.85, corresponding to composite asphalt board =1.15. Cement surfaces provide a moderate level of friction as a benchmark; mirror-finish steel plates have a smooth surface and a low coefficient of friction; smooth cement slabs have a dense surface and a slightly lower coefficient of friction than ordinary cement surfaces; asphalt slabs have a suitable roughness and viscoelasticity, resulting in the highest coefficient of friction.

[0059] Surface roughness correction factor The calculation formula is:

[0060] ;

[0061] Wherein, k is the roughness sensitivity coefficient, which is dimensionless and ranges from 0.05 to 0.15, reflecting the response sensitivity of tire rubber to surfaces with different roughness. This represents the arithmetic mean roughness of the contact surface, in μm. The baseline roughness is set at 100 μm, corresponding to the roughness level of a standard cement surface.

[0062] Pollutant Coverage Correction Factor The calculation formula is:

[0063] ;

[0064] in, This is the influence coefficient on water film thickness, in units of... The value ranges from 0.15 to 0.25, representing the ability of a water film of unit thickness to reduce the coefficient of friction. The thickness of the water film on the contact surface is in mm, under dry conditions. =0; The influence coefficient of sand and gravel cover is expressed in units of 1000 ppm. The value ranges from 0.08 to 0.12, representing the ability of a unit thickness of sand and gravel layer to reduce the friction coefficient; This refers to the thickness of the sand and gravel cover layer, in mm. (When there is no sand or gravel cover...) =0.

[0065] S4. Calculate the environmental condition correction factor. Based on the ambient temperature and humidity during the test, calculate the environmental condition correction factor γ to eliminate the influence of environmental factors on the friction coefficient measurement results.

[0066] The formula for calculating the environmental condition correction factor γ is:

[0067] ;

[0068] Wherein, γ is the environmental condition correction factor, which is dimensionless; This is a temperature correction factor, dimensionless. Humidity correction factor, dimensionless; temperature correction factor. The calculation formula is:

[0069] ;

[0070] Where λ is the temperature sensitivity coefficient, with units of 1000 kJ / m². The value ranges from -0.008 to -0.005, reflecting the physical law that increased temperature leads to softening of rubber and a decrease in the coefficient of friction; T is the ambient temperature of the test, in °C. The reference temperature is 23℃, which corresponds to the standard test temperature.

[0071] Humidity correction factor The calculation formula is:

[0072] ;

[0073] Where η is the humidity influence coefficient, dimensionless, ranging from 0.05 to 0.10, characterizing the comprehensive impact of high humidity environment on the contact surface condition and rubber surface properties; RH is the ambient relative humidity, in %%. The baseline humidity is set at 40%, corresponding to the standard test humidity conditions. Convert the percentage of humidity difference to decimal form;

[0074] S5, execute the process of determining the dynamic stiffness coupling coefficient of the tire-contact surface system. During each loading process, record the slope of the initial linear segment of the longitudinal force-displacement curve. This slope reflects the dynamic stiffness characteristics of the tire-contact surface system. Let the dynamic stiffness corresponding to the i-th loading stage be... .

[0075] The formula for calculating the dynamic stiffness coupling coefficient δ of the tire-contact surface system is as follows:

[0076] ;

[0077] Where δ is the dynamic stiffness coupling coefficient of the tire-contact surface system, which is dimensionless; This represents the average dynamic stiffness during multi-stage loading, expressed in N / mm, and is calculated using the following formula: ,Right now ; The reference dynamic stiffness, expressed in N / mm, is the calibrated value of the dynamic stiffness of a standard tire of the same specification measured under dry composite cement board conditions, at an ambient temperature of 23℃ and an ambient humidity of 40%. If this calibration value is unavailable, use [the value]. =400N / mm is used as the default reference value. K0 represents the typical calibration value for a 12R22.5 radial truck tire under standard conditions. For other tire sizes, the K0 value should be determined based on actual calibration results. ξ is the stiffness coupling index, dimensionless, calibrated experimentally based on tire structure type and rubber material properties. The baseline dynamic stiffness is obtained by testing with a standard tire of the same specification. and reference friction coefficient Tire samples with different stiffness designs were selected, and their dynamic stiffness was tested respectively. and coefficient of friction Fitting by power function The value of ξ is determined; for conventional heavy-duty radial tires, ξ is typically in the range of 0.2 to 0.6. This mechanism reveals the nonlinear modulation law of tire structural stiffness characteristics on friction performance, breaking through the limitations of traditional testing methods that separate stiffness and friction analysis.

[0078] Dynamic stiffness The calculation formula is:

[0079] ;

[0080] in, The longitudinal force change is expressed as N in the initial linear segment of the longitudinal force-displacement curve. This represents the corresponding longitudinal displacement change, in mm; this stiffness parameter comprehensively reflects the coupling effect of tire structural stiffness, rubber material properties, and contact surface stiffness.

[0081] S6, perform comprehensive friction performance index calculation This indicator takes into account the effects of multi-stage loading characteristics, contact surface condition, environmental conditions, and the dynamic stiffness of the tire-contact surface system.

[0082] The calculation formula is:

[0083] ;

[0084] in, This is a comprehensive friction performance index, dimensionless. β is the multi-stage dynamic weighted friction coefficient, dimensionless; β is the contact surface state coupling coefficient, dimensionless; γ is the environmental condition correction factor, dimensionless; δ is the tire-contact surface system dynamic stiffness coupling coefficient, dimensionless.

[0085] Multi-stage dynamic weighted friction coefficient This model provides a fundamental assessment of tire friction performance; the contact surface state coupling coefficient β corrects for the influence of different contact surface conditions on friction performance; the environmental condition correction factor γ eliminates measurement errors caused by temperature and humidity fluctuations; and the tire-contact surface system dynamic stiffness coupling coefficient δ introduces the coupling relationship between tire structural characteristics and friction performance. The product of these four factors constitutes a comprehensive quantitative description of tire friction performance. This multiplicative coupling model... A multi-dimensional, nonlinear quantitative description of frictional properties was achieved, in which the β coefficient adopted a three-level multiplication structure to finely characterize the synergistic attenuation effect of the contact surface material, microstructure, and coating.

[0086] Under typical conditions, ∈[0.5,0.9], β∈[0.3,1.3], γ∈[0.9,1.1], δ∈[0.9,1.2], ∈[0.4,1.0].

[0087] S7, Friction Performance Stability Index Calculation: To evaluate the repeatability and stability of tire friction performance, after the multi-stage loading in S1, the tire is unloaded to zero load and then reloaded to the standard test load. Repeat this independent loading process 4 times, denoted as the number of repeated measurements n=4. n is distinguished from the stage number i of the previous multi-stage loading. Record 4 data points. Longitudinal force-displacement curves under each loading condition; calculation of frictional performance stability index. This index is calculated based on the variation of the friction coefficient measured in each repeated loading process.

[0088] ;

[0089] in, Let be the stage friction coefficient calculated for the j-th loading stage, which is dimensionless; where j = 1, 2, 3, 4. The friction coefficient is the average value of n repeated measurements, and is dimensionless. n represents the number of times the loading is repeated, n=4;

[0090] Stage friction coefficient The calculation formula is:

[0091] ;

[0092] in, The peak longitudinal force on the longitudinal force-displacement curve during the j-th loading stage is expressed in N; where The standard radial test load set for the test.

[0093] Friction performance stability index This reflects the repeatability of tire friction performance under the same load conditions. The smaller the value, the more stable the tire friction performance, the better the measurement repeatability, and the better the uniformity of tire structure and materials; The higher the value, the greater the fluctuation in tire friction performance, which is related to uneven tire structure, such as belt layer misalignment, uneven vulcanization of rubber materials, or changes in the contact surface state.

[0094] S8, conduct a comprehensive performance rating assessment.

[0095] Based on comprehensive friction performance indicators and friction performance stability index The tire friction performance is comprehensively evaluated, and the comprehensive performance score P is calculated using the following formula:

[0096] ;

[0097] Where P is the overall performance score, which is dimensionless and ranges from 0 to 1; This is the friction performance weighting coefficient, dimensionless, with a value ranging from 0.6 to 0.8; This is a stability weighting coefficient, dimensionless, ranging from 0.2 to 0.4, and satisfies... , As a stability benchmark value, =0.01, used for normalization.

[0098] Based on the overall performance rating P, tire friction performance is classified into the following levels:

[0099] When P ≥ 0.85, it is rated as excellent, indicating that the tire has excellent friction performance and good stability;

[0100] When 0.70≤P<0.85, it is rated as good, indicating that the tire has good friction performance and stability;

[0101] When 0.55≤P<0.70, it is rated as medium, indicating that the tire's friction performance and stability are average, meeting basic usage requirements;

[0102] When P < 0.55, the rating is poor, indicating that the tire's friction performance or stability is significantly insufficient, requiring improvements in design or manufacturing processes. By coupling friction level and stability through a nonlinear function, a four-level rating standard (Excellent / Good / Average / Poor) is formed. This dual-index weighted fusion method provides a more comprehensive dimension for tire quality evaluation.

[0103] S9 saves the raw data, intermediate calculation parameters, and final results collected during the test. The saved data includes: longitudinal force-displacement curves for each stage, peak longitudinal force for each stage, multi-stage dynamic weighted friction coefficient, components of the contact surface state coupling coefficient, components of the environmental condition correction factor, dynamic stiffness data, comprehensive friction performance indicators, friction performance stability index, comprehensive performance score, and performance level evaluation results. A test report is generated, including: a description of the test conditions, contact surface type and condition, ambient temperature and humidity, test load and air pressure, test process records, calculation formulas and parameter values, a summary of calculation results, and a performance level evaluation conclusion.

[0104] The tires were tested according to the simulated scenarios of the comprehensive testing machine.

[0105] Test code Contact surface type Contact surface state Remark Q37-KD Composite cement surface dry Q37-KW Composite cement surface waterlogging Q37-KS Composite cement surface sand and gravel Q37-LD Composite 8K mirror steel plate dry Q37-LW Composite 8K mirror steel plate waterlogging Simulated ice surface Q37-LS Composite 8K mirror steel plate sand and gravel Q37-MD Composite smooth cement board dry Q37-MW Composite smooth cement board waterlogging Q37-MS Composite smooth cement board sand and gravel Q37-ND Composite asphalt board dry Q37-NW Composite asphalt board waterlogging Q37-NS Composite asphalt board sand and gravel

[0106] Figure 5 If the curve has no peak during the data acquisition process, the data set is invalid, and the data results of other adjacent loads are used for calculation.

[0107] Example 1

[0108] A 12R22.5 radial truck tire was selected as the test object. The test contact surface was made of composite cement board. The ambient temperature T was 25℃, the ambient relative humidity RH was 50%, the arithmetic mean roughness Ra of the contact surface was 100μm, and the test was conducted in a dry state, i.e., the water film thickness was [not specified]. 0mm, thickness of sand and gravel cover layer 0mm. Set standard radial load. The value is 29400 N, calculated by multiplying the 3000 kg test load by the acceleration due to gravity. Conversion.

[0109] S1, according to The target load is set at 29400N, and a four-stage incremental load increase scheme is adopted. The first stage target load is 19600N, which is... The reduction of 9800N is determined; the target load for the second stage is 24500N, determined by... The reduction of 4900N is determined; the target load for the third stage is 29400N, i.e. The target load for the fourth stage is 34300N, which is... The load was determined to be 4900N. The load was applied radially at a rate of 50 mm / min to the target load at each stage. After holding the load for 5 seconds at each stage, the test bench was moved along the X-axis at a speed of 50 mm / min, and the longitudinal force-displacement curves for each stage were measured. Considering that the typical friction coefficient of a heavy-duty radial tire on a dry composite cement pavement ranges from 0.65 to 0.75, the peak longitudinal forces were extracted as follows: Stage 1 =12740N, corresponding to a friction coefficient of 0.65 in the second stage; =16660N, corresponding to a friction coefficient of 0.68 in the third stage; =20580N, corresponding to a friction coefficient of 0.70 in the fourth stage; =22000N, corresponding to a friction coefficient of 0.64. This value is within the typical upper limit range of dry road surface friction performance, which is consistent with the physical law that tires tend to stabilize after break-in.

[0110] S2, Set weighting coefficients =0.8, =0.9, =1.0, =1.1, summation =3.8, calculate the numerator: 0.8 × 12740 = 10192 N, 0.9 × 16660 = 14994 N, 1.0 × 20580 = 20580 N, 1.1 × 22000 = 24200 N, summing them up to 69966 N. Calculate the denominator: 29400 × 3.8 = 111720 N. Multi-stage dynamic weighted friction coefficient. =69966 / 111720=0.6263, take 0.626.

[0111] S3 is a correction factor for the contact surface material of composite cement surfaces. Set to 1.0; roughness sensitivity coefficient k is set to 0.1, and the reference roughness is... =100μm, surface roughness correction factor =1+0.1×(100-100) / 100=1.0; Water film thickness influence coefficient Take 0.2 but =0mm, Sand and gravel cover influence coefficient Take 0.1 but =0mm, pollutant cover correction factor =1-0.2×0-0.1×0=1.0. The coupling coefficient of the contact surface state β=1.0×1.0×1.0=1.0.

[0112] S4, temperature sensitivity coefficient λ is taken as -0.006 Reference temperature T_0 = 23℃, temperature correction factor =1+(-0.006)×(25-23)=1-0.012=0.988; Humidity influence coefficient η is taken as 0.08, and the reference humidity is... =40%, Humidity Correction Factor =1-0.08×(50-40) / 100=1-0.008=0.992; Environmental condition correction factor γ=0.988×0.992=0.9801, take 0.980.

[0113] S5, record the slope of the initial linear segment of the longitudinal force-displacement curve, and measure the dynamic stiffness of the first stage. =380N / mm, second stage =390N / mm, third stage =400N / mm, fourth stage =410 N / mm. Average dynamic stiffness across multiple stages. =(380+390+400+410) / 4=1580 / 4=395N / mm. Take the baseline dynamic stiffness. =400 N / mm, stiffness coupling index ξ=0.4, dynamic stiffness coupling coefficient of tire-contact surface system Taking the natural logarithm of 0.9875 gives -0.01258, multiplying it by 0.4 gives -0.00503, and taking the exponent gives 0.9950, so δ=0.995.

[0114] S6, comprehensive friction performance index =0.626×1.0×0.980×0.995, approximately equal to 0.610. This value is within the typical range [0.4, 1.0], indicating that the tire's overall friction level under standard cement dry conditions is in the upper-middle range.

[0115] After completing the multi-stage loading in S1 (S7), the load was unloaded to zero. The load was then independently applied to the standard radial load of 29400N four times. The number of repeated measurements was recorded as n=4. The peak longitudinal forces measured were: 20500N for the first time, 20600N for the second, 20580N for the third, and 20400N for the fourth. The friction coefficients for each stage were calculated. : =20500 / 29400=0.6973, =20600 / 29400=0.7007, =20580 / 29400=0.7000, =20400 / 29400=0.6939.

[0116] average value =(0.6973+0.7007+0.7000+0.6939) / 4=2.7919 / 4=0.6980;

[0117] Calculate the square of each deviation: (0.6973-0.6980) 2 =0.00000049, (0.7007-0.6980) 2 =0.00000729,

[0118] (0.7000-0.6980) 2 =0.00000400, (0.6939-0.6980) 2 =0.00001681.

[0119] The sum of squares of the deviations is 0.00002859. Dividing by (n-1)=3 gives 0.00000953. Taking the square root yields the friction performance stability index. =0.00309.

[0120] S8, taking the friction performance weighting coefficient =0.7, stability weighting coefficient =0.3, and satisfies Stability benchmark value =0.01, calculate the stability score. =1 / (1+0.00309 / 0.01)=1 / 1.309=0.7640.

[0121] Overall performance score

[0122] P = 0.7 × 0.61 + 0.3 × 0.764 = 0.427 + 0.229 = 0.656. According to the scoring criteria, 0.55 ≤ 0.656 < 0.70. The tire's friction performance is rated as medium, indicating that the tire's friction performance and stability are average, meeting basic usage requirements but with room for improvement.

[0123] S9, the four-stage peak longitudinal forces of 12740N, 16660N, 20580N, and 22000N, and various intermediate calculation parameters (weighting coefficients) are included. =0.8, =0.9, =1.0, =1.1, contact surface state coupling coefficient β=1.0, temperature correction factor 0.988, humidity correction factor 0.992, dynamic stiffness to The friction coefficients were 380, 390, 400, and 410 N / mm, respectively, with repeated measurements ranging from 0.6939 to 0.7007, and the final result was a multi-stage dynamically weighted friction coefficient. =0.626, contact surface state coupling coefficient β=1.0, environmental condition correction factor γ=0.980, dynamic stiffness coupling coefficient δ=0.995, comprehensive friction performance index =0.610, frictional stability index =0.00309, comprehensive performance score P=0.656, performance level medium) saved to the test database. A test report is generated. Test conditions are: composite cement board in dry state, ambient temperature 25℃, ambient humidity 50%, standard radial load 29400N, four-stage loading sequence 19600N to 34300N; the values ​​of each calculation formula and parameter are... Sequence, β components, λ, η, ξ, etc.; the calculation results are summarized as follows: =0.610、 =0.00309, P=0.656; the performance rating conclusion is intermediate.

[0124] As can be seen from the above embodiments, the method of the present invention can systematically and comprehensively evaluate the friction performance of tires under different contact surface conditions and environmental conditions. The evaluation results have high accuracy and reliability, providing an effective technical means for tire design optimization and quality control.

[0125] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A comprehensive evaluation method for tire friction performance based on multi-factor coupling, characterized in that, include: S1, conduct a multi-stage progressive load test on the tire and collect data on the relationship between longitudinal force and longitudinal displacement at each stage; S2, Based on the longitudinal force data of each stage, the multi-stage dynamic weighted friction coefficient is calculated using an increasing weighting coefficient; S3, determine the contact surface state coupling coefficient based on the material properties, surface roughness and contaminant coverage of the contact surface; S4, calculate the environmental condition correction factor based on the ambient temperature and relative humidity of the test environment; S5. Determine the dynamic stiffness coupling coefficient of the tire-contact surface system based on the slope of the initial linear segment of the longitudinal force-longitudinal displacement relationship curve. S6. Calculate the comprehensive friction performance index based on the multi-stage dynamic weighted friction coefficient, contact surface state coupling coefficient, environmental condition correction factor, and dynamic stiffness coupling coefficient. S7, the friction performance stability index is calculated through repeated loading tests; S8. Based on the comprehensive friction performance index and friction performance stability index, the tire friction performance is comprehensively rated.

2. The multi-factor coupled comprehensive evaluation method for tire friction performance according to claim 1, characterized in that, S1 includes: setting a four-stage incremental loading sequence based on a standard radial load, and recording the peak longitudinal force at each stage, wherein the loading sequence dynamically adjusts the stage load difference and termination displacement according to the tire specifications and test load.

3. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, S2 includes: setting a weighted coefficient sequence that increases with the number of loading cycles, and performing a weighted average of the longitudinal force peak values ​​at each stage to reflect the characteristics of the tire tending to a stable friction state after break-in.

4. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, The S3 includes: determining a basic correction value based on the material type of the contact surface, performing roughness correction based on the deviation between the surface roughness and the reference roughness, and performing pollutant attenuation correction in combination with the thickness of the water film and sand cover, and obtaining the contact surface state coupling coefficient through multi-level multiplication.

5. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, The S4 includes: calculating a temperature correction factor based on the deviation between the test temperature and the reference temperature, calculating a humidity correction factor based on the deviation between the test humidity and the reference humidity, and obtaining an environmental condition correction factor by multiplying the two.

6. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, S5 includes: calculating the average value of dynamic stiffness during multi-stage loading, and obtaining the dynamic stiffness coupling coefficient by power function mapping based on the ratio of the average value to the reference dynamic stiffness.

7. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, S6 includes: multiplying and coupling the multi-stage dynamic weighted friction coefficient, contact surface state coupling coefficient, environmental condition correction factor and dynamic stiffness coupling coefficient to obtain a comprehensive friction performance index that considers multiple factors such as time sequence characteristics, contact surface state, environmental conditions and structural stiffness.

8. The comprehensive evaluation method for tire friction performance based on multi-factor coupling according to claim 1, characterized in that, S7 includes: performing multiple repeated loadings after the multi-stage loading is completed, calculating the stage friction coefficient based on the peak longitudinal force of each repeated loading, and calculating the friction performance stability index by statistical dispersion.

9. A computer system, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to implement the comprehensive evaluation method for tire friction performance applied to multi-factor coupling as described in any one of claims 1 to 8 when executing the executable instructions.

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