Laboratory method and system for evaluating impact resistance of passenger car tire, storage medium and software product

Abstract

The invention relates to the technical field of tire detection, in particular to a laboratory method, a system, a storage medium and a software product for evaluating the impact resistance of a passenger car tire. According to the method, on an existing tire strength testing machine, force-displacement data real-time collection and curve fitting in the tire pressing process are achieved by installing a standard wedge block and integrating a high-speed data collection system, and the minimum damage energy and the impact resistance factor are calculated. The device adopts a modular design, is convenient to disassemble and assemble quickly, has multiple shutdown criteria, and ensures that the test is safe and reliable. The device can truly simulate the stress condition when the tire impacts the curb, is accurate in test result and good in repeatability, and is suitable for tire research and development and quality evaluation.

Description

Technical Field

[0001] The present invention relates to the field of tire testing technology, and in particular to a laboratory method, system, storage medium and software product for evaluating the impact resistance performance of passenger car tires. Background Art

[0002] When a passenger car travels over a speed bump, a pothole, or hits a curb, the tire sidewall and rim are subjected to instantaneous compression. If the local strain exceeds the tire carcass limit, failures such as bulging, air leakage, and even car cord breakage can occur, seriously threatening driving safety. To evaluate a tire's ability to withstand such impacts, the industry uses both real-vehicle tests (such as the pothole and curb tests) and indoor tests. For example, the real-vehicle method, as described in a Chinese invention patent (publication number: CN115266430A), requires a dedicated test track and is subject to random environmental interference. This method is costly, time-consuming, and results in high data dispersion.

[0003] Among laboratory methods, the US SAE J1981 "Road Hazard Impact Test for Wheel and Tire Assemblies" proposed the pendulum method, which was subsequently translated into the national standard GB / T 30195-2013 "Test Method for Impact Resistance of Motor Vehicle Tires." In recent years, this standard has been further upgraded to GB / T 30195-2023 "Test Method for Impact Resistance of Motor Vehicle Tires - Pendulum Method." The core of these standards involves impacting the tire-rim assembly with a pendulum with increasing potential energy until the tire is damaged. The potential energy of the pendulum at the time of damage is used as the minimum destructive energy of the tire, thereby evaluating the tire's resistance to impact bulging. This method is bulky, the inertia of the pendulum mechanism is difficult to precisely adjust, and it primarily simulates instantaneous impacts, failing to replicate the gradual stretching and rupture of the tire carcass ply when continuously pressed by a wedge-shaped foreign object. Furthermore, this method can easily cause irreversible damage to the wheel rim when testing some low-section, high-strength tires.

[0004] Another type of ASTM F414 "plunger penetration" test uses a hemispherical plunger to slowly penetrate the tread to measure the energy absorbed by complete penetration. It is used to measure the tread rubber-cord bonding strength, but does not take into account the sidewall compression-bending behavior, and therefore cannot reflect the failure mechanism when the tire hits the curb.

[0005] The strength / bead-unseating test, durability test, and high-speed resistance test specified in the U.S. Federal Motor Vehicle Safety Standard FMVSS No. 109 mainly focus on indicators such as crown tensile strength and bead dislocation resistance, and also do not cover the comprehensive damage energy characterization in the tire-curb squeeze scenario.

[0006] In summary, existing indoor testing methods focus on either instantaneous impact or vertical penetration, making it difficult to simultaneously (1) simulate the actual force pattern of the tire sidewall under continuous compression by a wedge-shaped roadblock; (2) record the entire force-displacement process at a high sampling rate and obtain the minimum destructive energy through curve integration; and (3) easily integrate on a general tire strength testing machine with multiple safety shutdown protections. Therefore, the industry urgently needs an improved experimental method and supporting equipment that can be quickly assembled and disassembled on the existing strength testing platform, accurately measure, and safely evaluate the impact resistance performance of tires. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a laboratory method for evaluating the impact resistance of passenger car tires. This method is compatible with the original equipment strength and bead unseating tests, reduces repeated investment in equipment, and can effectively identify and calculate the minimum destructive energy of the tire caused by extrusion damage, thereby calculating the tire impact resistance factor, which can be used for the impact resistance performance of the tire.

[0008] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0009] A laboratory method for evaluating the impact resistance of passenger car tires comprises the following steps:

[0010] 1) On the loading platform of a conventional tire strength tester, a standard wedge block is fixed using a quickly removable modular fixture.

[0011] 2) Assembling the tire-rim assembly on the testing machine and starting loading at a preset inflation pressure and radial loading speed;

[0012] 3) Use a data acquisition system with a sampling frequency of not less than 200 Hz to synchronously record the real-time radial force F, displacement x and loading speed;

[0013] 4) When the real-time radial force satisfies 0N<F≤50N, the displacement at that moment is set as zero point;

[0014] 5) Loading is automatically terminated by the programmable logic controller (PLC) based on any of the following conditions:

[0015] a. Tire leakage detected;

[0016] b. The force value at three consecutive sampling points decreases and the cumulative decrease is ≥250N;

[0017] c. Displacement limit X obtained by segmented fitting of the real-time curve of arrival force and displacement limt , the fitting formula is as follows:

[0018] F=k1x,x≤k3,

[0019]

[0020] X limt =k4-k5;

[0021] Where F is the real-time radial force in N; x is the real-time displacement in mm; k1, k2, k3, and k4 are fitting parameters; and k5 is the safety threshold.

[0022] d. The real-time force value reaches 80% of the full scale of the force sensor;

[0023] 6) Record the stop displacement X s , calculate the minimum destructive energy according to the following formula:

[0024] E=k1X s 2 / 2000+k2(k3-X s ) / 1000+k2(k3-k4) / 1000×ln[(k4-X s ) / (k4-k3)];

[0025] 7) According to the formula f=E / Li·(H / 80) 2.5 D / 200 is used to calculate the tire impact resistance factor f, where Li is the load index, H is the nominal section height, and D is the outer diameter;

[0026] 8) Output the measured and fitted Fx curves and the f value.

[0027] Preferably, the data acquisition frequency is 200 Hz-1000 Hz.

[0028] Preferably, the wedge-shaped block is a triangular prism with an isosceles trapezoidal bottom surface.

[0029] Preferably, the safety threshold k5 has a value range of 0.5 mm to 1.5 mm and can be set by the user in the software interface.

[0030] Preferably, the test parameters, real-time data and calculation results are automatically archived by the host computer software and a report file is generated.

[0031] Furthermore, the present invention also provides a tire impact resistance performance evaluation system for implementing the method, comprising:

[0032] a. A tire strength testing machine, with a standard wedge-shaped fixture mounted on the loading platform for quick detachable connection;

[0033] b. Force-displacement high-speed data acquisition module with a sampling frequency of ≥200Hz, including NI module, displacement PCI acquisition card and Profinet communication interface;

[0034] c. A PLC controller communicating with the data acquisition module for executing the stop criteria of step 5 in real time and driving the servo loading mechanism;

[0035] d. The host computer software is used to input test parameters such as tire specifications, loading speed, and air pressure, call the PLC and acquisition module, complete data fitting, calculate energy and impact resistance factors, and output reports.

[0036] Preferably, the data acquisition module has a resolution of 16 bits or more and supports multi-channel parallel sampling with a synchronous clock error of ≤1μs; and / or the PLC has an online curve fitting operation unit that can update k1-k4 in each sampling cycle and refresh X in real time. limt and / or, the wedge block fixture adopts a dovetail groove and a positioning pin dual positioning structure, so that the replacement time between the wedge block and other conventional strength / unstrap tooling does not exceed 10min.

[0037] Furthermore, the present invention also provides a computer-readable storage medium having a computer program or instruction stored thereon, which implements the method when the computer program or instruction is executed by a processor.

[0038] Furthermore, the present invention also provides a computer program product, comprising a computer program or instructions, which implement the method when executed by a processor.

[0039] The present invention has the following technical effects due to the adoption of the above technical solution:

[0040] 1. Multifunctional integration and reduced equipment investment: By adding a quickly removable modular wedge block fixture to the existing tire strength testing machine, the same equipment can complete conventional strength / bead unseat tests and impact resistance tests, avoiding the repeated investment in purchasing a pendulum machine or a dedicated wedge block machine, and is expected to save 90% of the experimental equipment costs.

[0041] 2. High reproducibility of real working conditions: The wedge block of the present invention can realistically simulate the force path of continuous squeezing and shearing of the sidewall when a vehicle crosses a curb. Compared with a single impact of a pendulum or vertical penetration of a plunger, it is more consistent with the failure mechanism of the cord layer gradually stretching and rupturing.

[0042] 3. Full-process energy evaluation, more objective results: Synchronous force-displacement data is collected at 200Hz or above and segmented curves are fitted in real time to obtain the minimum destructive energy E at the moment of shutdown. The impact resistance factor f is then normalized by combining the load index Li, section height H, and outer diameter D. This eliminates the interference of tire specification differences on the results and improves the lateral comparability between tires of different sizes and structures.

[0043] 4. Repeatability and accuracy are significantly improved: Curve fitting predicts displacement limit Xlimt The machine automatically shuts down to avoid secondary damage caused by overvoltage. Measured data show that the coefficient of variation (CV) between samples has dropped from 5.8% of the pendulum method to 2.5%, significantly reducing the discreteness of the test results.

[0044] 5. Multiple safety protections to prevent equipment and rim failure: PLC synchronously monitors four thresholds: air leakage, sudden drop in force, fitting displacement limit, and 80% of the sensor range. If any of these is triggered, the machine will stop immediately.

[0045] In summary, the present invention, through the use of structurally optimized standard wedge blocks and real-time curve energy analysis methods, achieves a passenger car tire impact resistance performance test with lower cost, more realistic working conditions, more stable results, and a higher safety factor, providing a more scientific and reliable evaluation method for tire design optimization and regulatory comparison. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 : Schematic diagram of a tire strength testing machine equipped with wedge blocks.

[0047] Figure 2 : Schematic diagram of the modular tooling installation of the loading platform.

[0048] Figure 3 : Measured and fitted load-displacement curves. DETAILED DESCRIPTION

[0049] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0050] The main technical solutions of the method and device of the present invention are as follows:

[0051] 1. Add a modular tooling 2 with a safe, stable and fast detachable structure to the existing tire strength testing machine 1, see attached Figure 1 To the attached Figure 2 .

[0052] 2. New high-speed data acquisition system: Integrates NI acquisition modules, displacement PCI high-speed acquisition cards, and Profinet acquisition cards to achieve real-time high-speed sampling of vertical force and displacement velocity (frequency ≥ 200 Hz), accurately capturing instantaneous changes in the force-displacement curve.

[0053] 3. Develop an independent software system whose software interface can input information such as tire specifications, tire outer diameter, test pressure, loading speed, etc.

[0054] 4. Install the tire-rim assembly and apply radial force to the tire. The point where the wedge block begins to contact the tire (0N<radial force≤50N) is defined as the zero point of displacement.

[0055] 5. PLC real-time control system to automatically determine the conditions for stopping loading, including:

[0056] (1) Tire leak;

[0057] (2) The failure point occurs (judgment condition: at least three consecutive data points with decreasing force values, and the total force difference ≥ 250N);

[0058] (3) Displacement limit X obtained by segmented fitting of the real-time curve of arrival force and displacement limt , the fitting formula is as follows:

[0059] F=k1x,x≤k3 Formula 1

[0060]

[0061] X limt =k4-k5 formula 3

[0062] Where F is the real-time radial force, in N; x is the real-time displacement, in mm;

[0063] k1, k2, k3, k4 are fitting parameters; k5 is the safety threshold;

[0064] (4) The radial force reaches 80% of the maximum range of the force sensor.

[0065] 6. Record the displacement Xs when the test stops, and output the relationship curve between the actual applied load and displacement, as well as the relationship curve between the fitted load and displacement, see Figure 3 .

[0066] 7. Calculate the minimum tire destructive energy E by integrating the curve fitting formula (unit: J).

[0067]

[0068] 8. Calculate the tire impact resistance factor f with reference to GB / T30195-2023 "Test method for impact resistance of passenger car tires - pendulum method".

[0069]

[0070] Where Li is the tire load index; H is the nominal section height of the tire; and D is the outer diameter of the tire.

[0071] Test example: Passenger car tire impact resistance test

[0072] 1. Test items and sample description

[0073] To verify the effectiveness of the proposed solution, a 225 / 50R18 99H passenger car tire was selected as the test object. The tire was inflated to 230 kPa according to the manufacturer's recommended pressure and assembled with an 18-inch steel rim to form a complete tire-rim assembly.

[0074] 2. Test equipment and configuration

[0075] A tire strength testing machine with a load capacity of 100kN. The workbench has dovetail grooves and locating pin holes reserved.

[0076] The standard wedge block designed by the present invention can be clamped within 10 minutes via the positioning pin and the countersunk bolt.

[0077] The high-speed data acquisition system includes NI modules, displacement PCI cards and Profinet interfaces, and the sampling frequency is set to 200 Hz.

[0078] The PLC control program has four built-in shutdown criteria: ① air leakage detection; ② the force value drops for three consecutive points and the cumulative drop is ≥ 250N; ③ the real-time fitting displacement reaches X limt ; ④The force value reaches 80% of the full scale of the sensor.

[0079] 3. Experimental steps

[0080] Zeroing: When the top of the wedge block just contacts the tread and the radial force F does not exceed 50N, the instantaneous displacement is defined as 0mm.

[0081] Loading: Servo motor at 50mm min -1 The workbench is driven to move at a speed of 1000 rpm, and the tire tread is continuously squeezed by the wedges.

[0082] Real-time fitting: The data acquisition system records a set of F–x data every 0.005s; the PLC uses piecewise function in the background

[0083] F=k1x (when x≤k3)

[0084] F=k1x+k2(x-k3) / (k4-x)(when x>k3)

[0085] Perform online least squares fitting and update parameters k1–k4 and displacement limit X in real time limt =k4-k5.

[0086] Stop judgment: When the displacement reaches 83.137mm, the force value is monitored to drop for three consecutive points and the total drop is 37514.20-37072.61=441.59N. If the drop is ≥250N, the PLC will immediately trigger the shutdown; at this time, the stop displacement X is recorded. s =83.253mm.

[0087] Data preservation: The system automatically generates original curves, fitting curves and test reports, and archives them in the database.

[0088] 4. Results and calculations

[0089] Key Data

[0090] Displacement x / mm Measured force F / N <![CDATA[Fitting force F fit / N]]> error / % 0 0 0 0 4.015 601.21 612.35 -1.85％ 8.001 1263.29 1220.28 3.40％ 12.000 1846.38 1830.20 0.88％ 16.091 2398.32 2454.14 -2.33％ 20.034 3013.16 3055.51 -1.41％ 24.008 3686.85 3661.61 0.68％ 28.015 4242.90 4272.75 -0.70％ 31.986 4880.59 4878.39 0.05％ 36.025 5527.77 5494.40 0.60％ 39.999 6155.95 6100.50 0.90％ 43.974 6786.80 6706.75 1.18％ 47.932 7369.78 7310.41 0.81％ 51.947 7952.34 7922.77 0.37％ 55.946 8498.10 8532.68 -0.41％ 59.960 9017.78 9144.88 -1.41％ 63.923 9656.96 9749.30 -0.96％ 67.918 11403.35 11345.58 0.51％ 71.916 14568.55 14641.06 -0.50％ 75.915 19284.01 19339.30 -0.29％ 79.858 26836.71 26784.77 0.19％ 83.137 37514.20 38049.86 -1.43％ 83.169 37089.72 38202.90 -3.00％ 83.201 37089.72 38357.12 -3.42％ 83.253 37072.61 38610.28 -4.15％

[0091] Fitting parameters: k1 = 152.5 N·mm -1 , k2=11994N, k3=66.0mm, k4=91.2mm, R 2 =0.9998.

[0092] According to the formula:

[0093]

[0094] The calculated minimum destruction energy is E≈669.96J.

[0095] The nominal section height of the tire is H = 0.5 × 225 mm ≈ 112.5 mm, the outer diameter is D ≈ 685 mm, and the load index is Li = 99.

[0096] Substitute the above parameters into:

[0097]

[0098] The impact resistance factor f≈54.35 is obtained.

[0099] 5. Technical effect verification

[0100] index Method of the present invention GB / T30195 pendulum method (control) CV between samples (n=5) 2.5％ 5.8％ Single tire test time <1h 4h Energy calculation method Curve integral Pendulum potential energy Is the equipment damaged? no no

[0101] High fitting consistency: The average error is approximately 1%, and the goodness of fit is as high as 99.98%, confirming that real-time segmented fitting can accurately reconstruct the entire loading process;

[0102] Improved repeatability: The coefficient of variation was reduced from 5.8% of the pendulum method to 2.5%, significantly reducing discreteness;

[0103] Improved efficiency: The turnover time of a single tire is shortened by more than 75%, and R&D iterations are faster.

[0104] To ensure the safety of the equipment, no damage occurred to the wedge block and test rim during the test.

[0105] In summary, the present invention fully demonstrates that the present invention can quickly, accurately and safely evaluate the impact resistance of passenger car tires on a universal strength test platform through standard wedge blocks and real-time curve energy analysis, and its test efficiency and data reliability are significantly better than existing methods such as pendulum impact.

[0106] The above is a description of the embodiments of the present invention. The above description of the disclosed embodiments will enable professionals in the field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laboratory method for evaluating the impact resistance of passenger car tires, characterized in that: The following steps are involved: 1) On the loading platform of a conventional tire strength tester, a standard wedge block is fixed using a quickly removable modular fixture. 2) Assembling the tire-rim assembly on the testing machine and starting loading at a preset inflation pressure and radial loading speed; 3) Use a data acquisition system with a sampling frequency of not less than 200 Hz to synchronously record the real-time radial force F, displacement x and loading speed; 4) When the real-time radial force satisfies 0N<F≤50N, the displacement at that moment is set as zero point; 5) Loading is automatically terminated by the programmable logic controller (PLC) based on any of the following conditions: a. Tire leakage detected; b. The force value at three consecutive sampling points decreases and the cumulative decrease is ≥250N; c. Displacement limit X obtained by segmented fitting of the real-time curve of arrival force and displacement limt , the fitting formula is as follows: F=k1x,x≤k3, X limt =k4-k5; Where F is the real-time radial force in N; x is the real-time displacement in mm; k1, k2, k3, and k4 are fitting parameters; and k5 is the safety threshold. d. The real-time force value reaches 80% of the full scale of the force sensor; 6) Record the stop displacement X s , calculate the minimum destructive energy according to the following formula: E=k1X s 2 / 2000+k2(k3-X s ) / 1000+k2(k3-k4) / 1000×ln[(k4-X s ) / (k4-k3)]; 7) According to the formula f=E / Li·(H / 80) 2.5 D / 200 is used to calculate the tire impact resistance factor f, where Li is the load index, H is the nominal section height, and D is the outer diameter; 8) Output the measured and fitted Fx curves and the f value.

2. The method according to claim 1, characterized in that The data acquisition frequency is 200 Hz–1000 Hz.

3. The method according to claim 1, characterized in that The wedge-shaped block is a triangular pyramid with an isosceles trapezoidal bottom surface.

4. The method according to claim 1, wherein The safety threshold k5 has a value range of 0.5 mm to 1.5 mm and can be set by the user in the software interface.

5. The method according to claim 1, wherein The test parameters, real-time data and calculation results are automatically archived and generated into report files through the host computer software.

6. A tire impact resistance performance evaluation system for implementing the method according to any one of claims 1 to 5, characterized in that: include: a. A tire strength testing machine, with a standard wedge-shaped fixture mounted on the loading platform for quick detachable connection; b. Force-displacement high-speed data acquisition module with a sampling frequency of ≥200Hz, including NI module, displacement PCI acquisition card and Profinet communication interface; c. A PLC controller communicating with the data acquisition module for executing the stop criterion of step 5 of claim 1 in real time and driving the servo loading mechanism; d. The host computer software is used to input test parameters such as tire specifications, loading speed, and air pressure, call the PLC and acquisition module, complete data fitting, calculate energy and impact resistance factors, and output reports.

7. The system according to claim 6, characterized in that The data acquisition module has a resolution of 16 bits or more and supports multi-channel parallel sampling with a synchronous clock error of ≤1μs; and / or the PLC has an online curve fitting operation unit that can update k1-k4 in each sampling cycle and refresh X in real time. limt .

8. The system according to claim 6, wherein: The wedge block fixture adopts a dual positioning structure of dovetail groove and positioning pin, so that the replacement time between the wedge block and other conventional strength / knockout tooling does not exceed 10 minutes.

9. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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