Wheel fatigue evaluation methods, equipment and storage media

Abstract

This application provides a wheel fatigue evaluation method, device, and storage medium, relating to the field of automotive technology. The method includes: acquiring sampling data of vertical force and driving torque during vehicle operation and obtaining a two-dimensional load spectrum; acquiring the S-N curve of the wheel material based on stress and strain data obtained from a uniaxial tensile test; establishing a static strength finite element model and obtaining the stress and strain values ​​of the wheel; the static strength finite element model includes a solid element wheel model, a shell element tire model, and beam elements. The shell element tire model includes different tire regions divided according to the tire's position and area, with each tire region including corresponding preset elastic modulus parameters and preset Poisson's ratio parameters; and obtaining the wheel's fatigue safety factor based on the two-dimensional load spectrum, the S-N curve, and the wheel's stress and strain values. This application aims to solve the problem in existing technologies where the actual wheel conditions are not comprehensively considered, resulting in inaccurate wheel fatigue assessments.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and in particular to a method, device and storage medium for evaluating wheel fatigue. Background Technology

[0002] Wheels are crucial components of automobiles, and their safety and reliability are paramount. During operation, wheels endure a variety of complex dynamic loads, including bending, torsion, shearing, and impact. Prolonged exposure to cyclic loads, even those far below the wheel's maximum static load, can lead to cracks and fractures—the result of accumulated fatigue damage. Fatigue refers to the gradual damage and eventual fracture of materials or parts under continuous cyclic loading. High-cycle fatigue cracks are one of the main types of damage during wheel operation, typically causing direct wheel failure or inducing failure when subjected to impact loads within safe limits.

[0003] Currently, wheel fatigue calculation methods rely on finite element models established based on the radial fatigue, bending fatigue, and biaxial fatigue test methods specified in national standards, with corresponding boundary conditions and loads. However, these methods do not adequately consider the stress conditions experienced by the wheel during actual driving.

[0004] To address the aforementioned shortcomings, there is an urgent need for a method, equipment, and storage medium for evaluating wheel fatigue. Summary of the Invention

[0005] This application provides a wheel fatigue evaluation method, device, and storage medium to solve the problem that the existing technology does not fully consider the stress conditions of the wheel during actual driving and the obtained wheel fatigue degree is not accurate enough.

[0006] Firstly, this application provides a method for evaluating wheel fatigue, including:

[0007] Acquire sampling data of vertical force and driving torque during vehicle operation, and obtain a two-dimensional load spectrum of load frequency based on the sampling data;

[0008] The stress and strain values ​​are obtained based on the stress and strain test data, and the stress-strain curve is fitted to obtain the SN curve of the wheel material.

[0009] A static strength finite element model is established, and the stress and strain values ​​of the wheel are obtained based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and a Beam beam element for simulating the steel rim inside the tire. The shell element tire model is divided into different tire regions according to the tire's position and area. Each tire region includes a corresponding preset elastic modulus parameter and a preset Poisson's ratio parameter.

[0010] The fatigue safety factor of the wheel is obtained based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel.

[0011] In one possible design, the shell unit tire model includes a first bead region, a second bead region, a sidewall region, a shoulder region, and a tread region; wherein, the first bead region is the area in the bead with a thickness less than a preset thickness, and the second bead region is the area in the bead with a thickness not less than a preset thickness; the preset elastic modulus parameters corresponding to the first bead region, the second bead region, the sidewall region, the shoulder region, and the tread region increase sequentially in a stepwise manner.

[0012] In one possible design, after obtaining the stress and strain values ​​of the wheel, the method further includes:

[0013] The measured values ​​of the wheel's error index are obtained based on wheel pressure and deformation experiments; the simulated values ​​of the error index are obtained based on the static strength finite element model; wherein the wheel's error index includes the tire's deformation and the contact pressure between the tire and the rim under a fixed air pressure.

[0014] If the error between the measured calculated value and the simulation value is not less than 5%, change the preset elastic modulus parameter and the preset Poisson's ratio parameter corresponding to different tire regions within the preset value range until the error between the measured calculated value and the simulation value is less than 5%. Obtain the stress and strain values ​​of the wheel according to the static strength finite element model.

[0015] In one possible design, establishing a static strength finite element model and obtaining the stress and strain values ​​of the wheel based on the static strength finite element model includes:

[0016] A static strength finite element model is established based on the wheel entity; wherein, the static strength finite element model also includes fixed constraints; the fixed constraints are used to simulate bolt holes; based on the measured contact area between the tire and the ground, distributed coupling constraints are established at the tire contact point to simulate the effect of the ground on the tire; load data corresponding to the two-dimensional load spectrum are input at the control points of the distributed coupling constraints; and the stress and strain values ​​of the wheel are obtained based on the static strength finite element model.

[0017] In one possible design, obtaining a two-dimensional load spectrum of load frequencies based on the sampled data includes:

[0018] The average load, load amplitude, and load frequency are obtained by extracting the vertical force and driving torque within the preset load time series using the rainflow counting method.

[0019] The load amplitude is divided into N preset amplitude levels by non-equal intervals from smallest to largest based on the maximum and minimum values ​​of the load amplitude. The load mean is divided into M preset mean levels by equal intervals from smallest to largest based on the maximum and minimum values ​​of the load mean. The load frequency corresponding to the preset amplitude level minus the preset mean level is counted to obtain a two-dimensional load spectrum.

[0020] In one possible design, the two-dimensional load spectrum is obtained by statistically analyzing the load frequencies corresponding to the preset amplitude level and the preset mean level; including:

[0021] Based on the two-dimensional distribution model of the load mean and load amplitude, the frequency of each load cycle is statistically analyzed, and the statistical method is shown in the following formula:

[0022]

[0023] In the formula, n ij It is the load frequency that occurs simultaneously in both the amplitude range of the i-th load level and the mean range of the j-th load level, N. c is the total frequency of the load, and f is the probability density function of the two-dimensional joint distribution of the load mean and load amplitude.

[0024] In one possible design, obtaining the fatigue safety factor of the wheel based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel includes:

[0025] The fatigue safety factor of the wheel is obtained by processing the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel using the local stress-strain method.

[0026] Secondly, this application provides a wheel fatigue evaluation device, the device comprising:

[0027] The load spectrum module is used to acquire sampling data of vertical force and driving torque during vehicle operation, and to acquire a two-dimensional load spectrum of load frequency based on the sampling data.

[0028] The fitting module is used to obtain stress and strain data based on uniaxial tensile tests, and to fit the stress and strain data to obtain the SN curve of the wheel material according to the stress-strain curve;

[0029] The finite element analysis module is used to establish a static strength finite element model and obtain the stress and strain values ​​of the wheel based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and a Beam beam element for simulating the steel rim inside the tire. The shell element tire model is divided into different tire regions according to the tire's position and area. Each tire region includes a corresponding preset elastic modulus parameter and a preset Poisson's ratio parameter.

[0030] The fatigue analysis module is used to obtain the fatigue safety factor of the wheel based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel.

[0031] Thirdly, this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0032] The memory stores computer-executed instructions;

[0033] The processor executes the computer execution instructions stored in the memory to implement the above-described wheel fatigue evaluation method.

[0034] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the aforementioned wheel fatigue evaluation method.

[0035] This application provides a wheel fatigue evaluation method, device, and storage medium, comprising: establishing a static strength finite element model based on the wheel entity to obtain the stress and strain values ​​of the wheel, wherein the static strength finite element model includes a solid element wheel model, a shell element tire model, and Beam beam elements for simulating the internal steel rim of the tire; the shell element tire model includes different tire regions divided according to the tire's position and area, and each tire region includes corresponding preset elastic modulus parameters and preset Poisson's ratio parameters; obtaining the wheel's fatigue safety factor based on the two-dimensional load spectrum, SN curve, and the wheel's stress and strain values; achieving the following technical effects:

[0036] The static strength finite element model provided in this embodiment combines a solid element wheel model and a shell element tire model. The shell element tire model divides the shell element of the tire model into multiple regions according to the actual tire structure and tire deformation, and sets corresponding different elastic moduli and Poisson's ratios. The shell element tire model obtained in this way simplifies the parameters while fully considering the stress situation of the wheel during actual driving. The static strength finite element model provided in this embodiment can obtain more accurate and effective stress and strain values, thereby improving the accuracy of obtaining the fatigue safety factor of the wheel. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1A flowchart illustrating a wheel fatigue evaluation method provided in this application embodiment. Figure 1 ;

[0039] Figure 2 A flowchart illustrating a wheel fatigue evaluation method provided in this application embodiment. Figure 2 ;

[0040] Figure 3 A cross-sectional view of a wheel calculated using finite element methods, provided in an embodiment of this application;

[0041] Figure 4 A schematic diagram of a wheel pressure and deformation experiment provided in an embodiment of this application;

[0042] Figure 5 This is a schematic diagram of the structure of a wheel fatigue evaluation device provided in an embodiment of this application;

[0043] Figure 6 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application.

[0044] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0045] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of devices and methods consistent with some aspects of this application as detailed in the appended claims, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0046] It should be noted that, in the embodiments of this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0047] It should be noted that the terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0048] It should be noted that "at the time of..." in the embodiments of this application can be either at the instant when a certain situation occurs, or for a period of time after the occurrence of a certain situation. The embodiments of this application do not make specific limitations on this.

[0049] The following is a definition of the term:

[0050] The local stress-strain method, developed in the 1960s based on low-cycle fatigue, is used for calculating high- and low-cycle fatigue. It uses strain as a parameter related to low-cycle fatigue and facilitates complex calculations using computers based on stress-strain at strain concentration points and material fatigue test data. It is suitable for calculating fatigue safety factors under random loads. It transforms the nominal load spectrum of a part into a local stress-strain spectrum at the critical point of the part using the elastoplastic finite element method or other methods combined with the material's stress-strain curve. Then, it combines the material strain-life relationship at the critical point with the local stress-strain history processed using cyclic counting, rainflow counting, and effective counting methods for correction. Finally, based on the principle that damage to a part is equal under the same strain—that is, fatigue damage theory—the actual life of the part is obtained.

[0051] In existing technologies, wheel fatigue calculations are performed by establishing finite element models with corresponding boundary conditions and loads based on the radial fatigue, bending fatigue, and biaxial fatigue test methods specified in national standards. These methods, however, are based on the fatigue test methods specified in the standards and do not consider actual road load conditions. Furthermore, the results calculated using radial and bending fatigue test methods tend to be conservative and cannot reflect the actual stress on the wheel. The biaxial fatigue test calculation method requires applying 98 sets of load data when calculating the wheel's static strength, and each set of load data needs to be applied uniformly along the wheel's circumference 10-24 times when calculating wheel fatigue. This results in long calculation times, long evaluation cycles, and high evaluation costs. If a tire model is established, it includes models of the tire carcass, rim, and belt layers, requiring information such as the hyperelastic material parameters of the rubber. Obtaining these parameters requires specialized testing equipment and is time-consuming, making the modeling process complex and computationally intensive.

[0052] The above methods all have shortcomings in fatigue analysis of commercial vehicle wheels. One part is that they only follow the test methods specified in the standard and cannot take into account the actual road load. Another part requires the establishment of a complete tire model and input of hyperelastic parameters of rubber materials, which makes the calculation complex and time-consuming.

[0053] This application provides a wheel fatigue evaluation method, device, and storage medium. A static strength finite element model of the wheel is established, including a solid element wheel model, a shell element tire model, and a Beam element for simulating the internal steel rim of the tire. The simplified shell element tire model is a simplified calculation method in finite element calculations that uses a thin shell on the surface of a solid to replace the solid. The shell element is divided into different regions based on the actual structure and deformation of the tire. The established static strength finite element model fully considers the force exerted by the tire on the wheel, as well as the influence of load on the stress and strain values ​​obtained from the static strength finite element model. It simplifies parameter settings while emphasizing relevant effective data, simplifying the calculation process and improving the accuracy of the wheel's fatigue safety factor.

[0054] As an application scenario for this application, this application can be used for fatigue calculation of all commercial vehicle wheels, including steel, aluminum alloy and magnesium alloy wheels, as well as rim and spoke split wheels and rim and spoke integrated wheels.

[0055] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0056] Figure 1 A flowchart illustrating a wheel fatigue evaluation method provided in this application embodiment. Figure 1 ,like Figure 1 As shown, it includes:

[0057] S101. Acquire sampling data of vertical force and driving torque during vehicle operation, and obtain a two-dimensional load spectrum of load frequency based on the sampling data;

[0058] Specifically, the six-component force measuring instrument mainly measures the longitudinal force Fx, lateral force Fy, vertical force Fz, as well as the overturning torque Tx, driving torque Ty, and return torque Tz of the wheel. During the vehicle's operation, wheel fatigue damage mainly comes from the vertical load on the road surface and the engine's driving torque; therefore, the vertical force Fz and driving torque Ty are primarily analyzed and recorded.

[0059] S102. Obtain the stress and strain data based on the uniaxial tensile test, and fit the stress and strain data according to the stress-strain curve to obtain the SN curve of the wheel material.

[0060] Specifically, the stress and strain data of the material are recorded as the tensile force increases during the test, and a stress-strain curve is plotted. The stress-strain curve is then fitted into an SN curve with the number of failure loading cycles N as the abscissa and the stress amplitude S as the ordinate. The SN curve of the material is the basis for fatigue analysis.

[0061] S103. Establish a static strength finite element model and obtain the stress and strain values ​​of the wheel based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and a Beam beam element for simulating the steel rim inside the tire. The shell element tire model includes different tire regions divided according to the tire's position and area. Different tire regions include corresponding preset elastic modulus parameters and preset Poisson's ratio parameters.

[0062] Specifically, the tire's function is to transfer load to the rim and spokes; it is not the primary focus of wheel fatigue calculations and is therefore simplified in the calculations. Based on the actual tire structure and deformation, the shell unit tire model is divided into 5-8 regions (based on the actual conditions of the tread, shoulder, sidewall, and bead). Different regions of the tire are assigned different elastic moduli and Poisson's ratios.

[0063] S104. Obtain the fatigue safety factor of the wheel based on the two-dimensional load spectrum, SN curve, and the stress and strain values ​​of the wheel.

[0064] Specifically, the fatigue safety factor of the wheel can be obtained by processing the two-dimensional load spectrum, SN curve, and stress and strain values ​​of the wheel using the local stress-strain method, and the corresponding software can be called to perform the calculation.

[0065] This embodiment provides a wheel fatigue evaluation method. It establishes a static strength finite element model of the wheel to obtain its stress and strain values. The static strength finite element model includes a solid element wheel model, a shell element tire model, and Beam beam elements to simulate the internal steel rim of the tire. The shell element tire model is divided into different tire regions based on the tire's location and area. Each tire region includes corresponding preset elastic modulus parameters and preset Poisson's ratio parameters. The fatigue safety factor of the wheel is obtained based on the two-dimensional load spectrum, SN curve, and the wheel's stress and strain values. This achieves the following technical effects:

[0066] The static strength finite element model provided in this embodiment combines a solid element wheel model and a shell element tire model. The shell element tire model divides the shell element of the tire model into multiple regions according to the actual tire structure and tire deformation, and sets corresponding different elastic moduli and Poisson's ratios. The shell element tire model obtained in this way simplifies the parameters while fully considering the stress situation of the wheel during actual driving. The static strength finite element model provided in this embodiment can obtain more accurate and effective stress and strain values, thereby improving the accuracy of the fatigue safety factor of the wheel.

[0067] Figure 2 A flowchart illustrating a wheel fatigue evaluation method provided in this application embodiment. Figure 2 ;like Figure 2 As shown, the method includes:

[0068] S201. Acquire sampling data of vertical force and driving torque during vehicle operation;

[0069] Specifically, a load information database for wheel fatigue calculation is established, and the vertical force Fz and driving torque Ty are collected by the user using a six-component force measurement system based on typical road conditions at the test track.

[0070] Furthermore, after the load data is collected during the road load test at the test track, the collected data is processed by outlier screening, signal denoising, and low-radius load filtering.

[0071] S202. Extract the vertical force and driving torque within the preset load time series using the rainflow counting method to obtain the load mean, load amplitude, and load frequency; divide the load amplitude into N preset amplitude levels by non-equal intervals from smallest to largest based on the maximum and minimum values ​​of the load amplitude; divide the load mean into M preset mean levels by equal intervals from smallest to largest based on the maximum and minimum values ​​of the load mean; and calculate the load frequency corresponding to the preset amplitude level minus the preset mean level to obtain a two-dimensional load spectrum.

[0072] Specifically, the rainflow counting method is used to extract the cyclic load from the extrapolated road load using nCode GlyphWork software. The relationship between the mean and amplitude of the wheel load and its corresponding frequency is obtained. The load amplitude and mean can be divided into 8-20 levels (determined according to the specific load conditions, with N and M ranging from 8 to 20), and a two-dimensional load spectrum is established.

[0073] In a preferred embodiment, the load amplitude is divided into 8 levels based on the maximum and minimum values ​​of the load amplitude, and the division method for each level of amplitude interval is shown in the following formula:

[0074] I0 = A min ,I8=A max

[0075]

[0076] In the formula, A max and A min These are the maximum and minimum values ​​of the load amplitude, I. i-1 and I i These are the lower and upper limits of the i-th level mean interval, respectively, K i It is the length scaling factor of the i-th amplitude interval.

[0077] The load amplitude and mean are each divided into 8 levels, and the method for dividing the load mean is shown in the following formula:

[0078] I0 = M min ,I8=M max

[0079]

[0080] In the formula, M max and M min These are the maximum and minimum values ​​of the load mean, I. j-1 and I j These are the lower and upper limits of the j-th level mean interval, respectively.

[0081] Specifically, after classifying the load amplitude and load mean, it is necessary to statistically analyze the frequency of each load cycle based on the two-dimensional distribution model of the load mean and load amplitude. The statistical method is shown in the following formula:

[0082]

[0083] In the formula, n ij It is the load frequency that occurs simultaneously in both the amplitude range of the i-th load level and the mean range of the j-th load level, N. c Let f be the total frequency of loads, and let f be the probability density function of the two-dimensional joint distribution of the load mean and load amplitude. A two-dimensional load spectrum is established based on the above statistical methods.

[0084] Specifically, two-dimensional load spectra often use multiple tables, matrices, or graphs to represent the mean value of random loads, load amplitude, and their corresponding load frequencies.

[0085] S203. Obtain the stress and strain data based on the uniaxial tensile test, and fit the stress and strain data according to the stress-strain curve to obtain the SN curve of the wheel material.

[0086] Specifically, this step is similar to S102, and will not be repeated here.

[0087] S204. Establish a static strength finite element model; the static strength finite element model includes a solid element wheel model, a shell element tire model, and a Beam beam element used to simulate the internal steel ring of the tire; the shell element tire model includes a first bead region, a second bead region, a sidewall region, a shoulder region, and a tread region; wherein, the first bead region is the area in the bead with a thickness less than a preset thickness, and the second bead region is the area in the bead with a thickness not less than a preset thickness; the preset elastic modulus parameters corresponding to the first bead region, the second bead region, the sidewall region, the shoulder region, and the tread region increase sequentially in a stepwise manner.

[0088] Specifically, the shell element tire model is created by extracting its unpatterned outer contour surface, and the steel rim inside the tire model is simulated using Beam beam elements; fixed constraints are used at the bolt holes in the static strength finite element model.

[0089] Specifically, a static implicit algorithm analysis is employed, with equivalent boundary conditions and load application methods to those used in real experiments to ensure the accuracy of the simulation model. Static strength finite element models of commercial vehicle wheels and their matching tires are established using software such as Hypermesh.

[0090] Specifically, Figure 3 This is a cross-sectional view of the wheel provided in the finite element calculation of this embodiment; as shown. Figure 3 As shown, it includes wheel model 1, tire model (2-7) and fixed constraints at wheel bolt holes; the tire model extracts the outer contour surface without tread and uses shell elements; the tire model is divided into the first bead region 3, the second bead region 4, the sidewall region 5, the shoulder region 6 and the tread region 7, and the steel ring 2 is located at the tire bead part.

[0091] Specifically, the actual rubber structure of the first bead region 3 and the second bead region 4 is relatively soft, and the preset elastic modulus parameters corresponding to the first bead region 3 and the second bead region 4 are both less than 100 MPa; the tread region 7 has a small deformation, and the corresponding preset elastic modulus parameter is greater than 2000 MPa.

[0092] Specifically, the parameters increase sequentially in a stepwise manner: the preset elastic modulus parameter corresponding to the first bead region 3 < the preset elastic modulus parameter corresponding to the second bead region 4 < the preset elastic modulus parameter corresponding to the sidewall region 5 < the preset elastic modulus parameter corresponding to the shoulder region 6 < the preset elastic modulus parameter corresponding to the tread region 7.

[0093] Specifically, the steel rim 2 refers to 1-2 coils of steel wire in the tire's bead region, used to fix the sides of the tire body to maintain internal air pressure. In the finite element model, 1-2 beam elements are created to simulate the fixing effect of the steel rim. In the actual modeling process, the corresponding circumferential area of ​​the steel rim and tire model is set with shared nodes, without introducing additional degrees of freedom. The diameter of the beam elements is set according to the actual diameter of the steel rim in the tire. In this embodiment, 2 beam elements are used. The actual tire rim is made of 60 steel wires with a diameter of 0.8mm wound together, so the diameter of each beam element is set to 24mm. Although this method increases the number of elements, it can more realistically simulate the geometric and physical nonlinear properties of the cord-rubber material.

[0094] Furthermore, the wheel model, tire model, and rim model in the wheel finite element model also include parameters such as the corresponding material density input by the user;

[0095] Specifically, the preset Poisson's ratio parameters are the same for multiple different tire regions, which are used to adjust them in the subsequent step S206 according to the actual error.

[0096] S205. Based on the measured contact area between the tire and the ground, establish distributed coupling constraints at the tire contact point to simulate the effect of the ground on the tire; input the load data corresponding to the two-dimensional load spectrum at the control point of the distributed coupling constraint; obtain the stress and strain values ​​of the wheel based on the static strength finite element model.

[0097] Specifically, a distributed coupling constraint is established at the tire contact point to simulate the effect of the ground on the tire. The control point of the distributed coupling constraint is the tire contact point, and the slave node is the node on the mesh corresponding to the contact area between the tire and the ground. By inputting the load data corresponding to the two-dimensional load spectrum at the control point of the distributed coupling constraint, the static strength finite element model can further consider the influence of actual road load conditions on the stress and strain values ​​of the wheel. Then, the static strength of the wheel is calculated using finite element analysis software to obtain the stress and strain values ​​of the wheel.

[0098] Specifically, the load data are the wheel load average, load amplitude, and load frequency data obtained in steps S201-S202.

[0099] S206. Obtain the measured values ​​of the wheel error index based on the wheel pressure and deformation experiment; obtain the simulated values ​​of the error index based on the static strength finite element model; if the error between the measured calculated value and the simulated value is not less than 5%, change the preset elastic modulus parameter and preset Poisson's ratio parameter corresponding to different tire regions within the preset value range until the error between the measured calculated value and the simulated value is less than 5%; obtain the stress and strain values ​​of the wheel based on the static strength finite element model.

[0100] Specifically, the wheel's error indices include tire deformation and the contact pressure between the tire and rim under a fixed air pressure. The error indices are calculated by ensuring that both the deformation error and the contact pressure error are less than 5%, or if either one is not less than 5%. Within a preset value range, the preset elastic modulus parameters and preset Poisson's ratio parameters corresponding to different tire regions are changed, and the simulated values ​​of the error indices are obtained again and the error indices are calculated. This process continues until both the deformation error and the contact pressure error are determined to be less than 5%. Finally, the stress and strain values ​​of the wheel are obtained based on the static strength finite element model.

[0101] Furthermore, the measured value of the tire-rim contact pressure under fixed air pressure in the error index is obtained based on actual measurements and records;

[0102] Furthermore, the tire deformation amount in the error index is obtained based on actual measurements and calculations, and the test results are recorded, such as... Figure 4 This is a schematic diagram of wheel pressure and deformation provided in an embodiment of this application, as shown below. Figure 4 The test includes wheel pressure and deformation tests on the tire body 10 and the wheel 1; measuring the tire deformation under fixed air pressure with loads of 0, 15, 30, 45, 60 and 75 kN; obtaining the tire radius R, the distance Rm between the spoke opening edge and the ground, the tire width W, and the distances L1 and L2 between the tire and the two test stands when the test load is fixed; and calculating the axial or radial deformation of the tire based on the above parameters as the measured value of the deformation in this embodiment.

[0103] For example, when the test load is 75kN, the radial deformation of the tire is Rm. (0) -Rm (75) The deformation on the left side of the tire is L1. (0) -L1 (75) The deformation on the right side of the tire is L2. (0) -L2 (75) The value in parentheses is the load value applied during the test;

[0104] For example, the tire model is 12R22.5, and the tire inflation pressure is 1 MPa. When the test load is 75 kN, the radial deformation of the tire is 42 cm.

[0105] Specifically, the method for changing the preset elastic modulus parameters and preset Poisson's ratio parameters corresponding to different tire regions is to randomly change them within the preset value range or change them based on experience. The preset elastic modulus parameters still conform to the above-mentioned rule of sequential step-by-step increase after the change.

[0106] S207. Obtain the fatigue safety factor of the wheel based on the two-dimensional load spectrum, SN curve, and the stress and strain values ​​of the wheel.

[0107] Specifically, this step is similar to S104, and will not be repeated here.

[0108] The method provided in this application can achieve the following technical effects:

[0109] In the method provided in this embodiment, the static strength finite element model includes a solid element wheel model, a shell element tire model, a Beam beam element simulating the steel rim inside the tire, and fixed constraints. The shell element tire model divides the shell element of the tire model into multiple regions according to the actual tire structure and tire deformation, and sets corresponding different elastic moduli and Poisson's ratios. The shell element tire model obtained in this way simplifies the parameters while fully considering the stress situation of the wheel during actual driving, and can obtain more accurate and effective stress and strain values, thereby improving the accuracy of the fatigue safety factor of the wheel.

[0110] This embodiment provides relevant error indices for stress and strain values ​​as a feedback mechanism; these are used to adjust the preset elastic modulus parameters and Poisson's ratio parameters corresponding to different tire regions, in order to control the calculation error of the static strength finite element model and ensure the accuracy of its stress and strain value acquisition.

[0111] This embodiment establishes distributed coupling constraints for the tire model based on the tire model and the measured contact area. For the control points of the distributed coupling constraints, the corresponding load mean and load amplitude are input. The static strength finite element model used in this embodiment further considers actual road load conditions. The two-dimensional load spectrum, which uses the wheel load mean, load amplitude, and their corresponding frequency relationship, better reflects the actual stress condition of the wheel, resulting in more accurate and realistic calculation results. This allows for more precise stress and strain values ​​to be obtained based on the wheel's stress condition under different loads, improving the accuracy of the wheel's fatigue safety factor.

[0112] Compared to the existing method of simulating wheel fatigue conditions and calculating wheel fatigue using biaxial fatigue testing, which takes several days or even weeks, this invention's numerical simulation time is only 1-2 days, further shortening the product development cycle and reducing development and time costs.

[0113] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0114] It should be further noted that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0115] It should be understood that the above-described device embodiments are merely illustrative, and the device of this application can also be implemented in other ways. For example, the division of units / modules in the above embodiments is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units, modules, or components may be combined, or integrated into another system, or some features may be ignored or not executed.

[0116] In this embodiment of the invention, electronic devices or main control devices can be divided into functional modules according to the above method examples. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional module. It should be noted that the module division in this embodiment of the invention is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0117] Figure 5 This is a schematic diagram of the structure of a wheel fatigue evaluation device provided in an embodiment of this application; as shown. Figure 5 As shown, device 50 includes:

[0118] The load spectrum module 501 is used to acquire sampling data of vertical force and driving torque during vehicle operation, and to acquire a two-dimensional load spectrum of load frequency based on the sampling data.

[0119] Fitting module 502: Obtain stress and strain data based on uniaxial tensile test, and fit the stress and strain data according to the stress-strain curve to obtain the SN curve of the wheel material;

[0120] The finite element analysis module 503 is used to establish a static strength finite element model and obtain the stress and strain values ​​of the wheel based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and a Beam beam element for simulating the steel rim inside the tire. The shell element tire model is divided into different tire regions according to the tire's position and area. Different tire regions include corresponding preset elastic modulus parameters and preset Poisson's ratio parameters.

[0121] The fatigue analysis module 504 is used to obtain the fatigue safety factor of the wheel based on the two-dimensional load spectrum, SN curve, and the stress and strain values ​​of the wheel.

[0122] Furthermore, the shell unit tire model includes a first bead region, a second bead region, a sidewall region, a shoulder region, and a tread region; wherein, the first bead region is the area in the bead with a thickness less than a preset thickness, and the second bead region is the area in the bead with a thickness not less than a preset thickness; the preset elastic modulus parameters corresponding to the first bead region, the second bead region, the sidewall region, the shoulder region, and the tread region increase sequentially in a stepwise manner.

[0123] Furthermore, the finite element analysis module 503 is also specifically used for:

[0124] After obtaining the stress and strain values ​​of the wheel, the measured values ​​of the wheel error index are obtained based on the wheel pressure and deformation test parameters; the simulated values ​​of the error index are obtained based on the static strength finite element model; the wheel error index includes the tire deformation and the contact pressure between the tire and the rim under a fixed air pressure.

[0125] If the error between the measured calculated value and the simulation value is not less than 5%, change the preset elastic modulus parameter and preset Poisson's ratio parameter corresponding to different tire regions within the preset value range until the error between the measured calculated value and the simulation value is less than 5%. Obtain the stress and strain values ​​of the wheel based on the static strength finite element model.

[0126] Furthermore, the finite element analysis module 503 is also specifically used for:

[0127] A static strength finite element model is established based on the wheel entity. The static strength finite element model also includes fixed constraints. The fixed constraints are used to simulate bolt holes. Based on the measured contact area between the tire and the ground, distributed coupling constraints are established at the tire contact point to simulate the effect of the ground on the tire. The load data corresponding to the two-dimensional load spectrum are input at the control points of the distributed coupling constraints. The stress and strain values ​​of the wheel are obtained based on the static strength finite element model.

[0128] Furthermore, the load spectrum module 501 is specifically used for:

[0129] The vertical force and driving torque within a preset load time series are extracted using the rainflow counting method to obtain the load mean, load amplitude, and load frequency;

[0130] The load amplitude is divided into N preset amplitude levels by non-equal intervals from smallest to largest based on the maximum and minimum values ​​of the load amplitude. The load mean is divided into M preset mean levels by equal intervals from smallest to largest based on the maximum and minimum values ​​of the load mean. The load frequency corresponding to the preset amplitude level minus the preset mean level is counted to obtain a two-dimensional load spectrum.

[0131] Furthermore, the load spectrum module 501 is specifically used for:

[0132] The frequency of each load cycle is statistically analyzed based on a two-dimensional distribution model of the load mean and load amplitude, as shown in the following formula:

[0133]

[0134] In the formula, n ij It is the load frequency that occurs simultaneously in both the amplitude range of the i-th load level and the mean range of the j-th load level, N. c is the total frequency of the load, and f is the probability density function of the two-dimensional joint distribution of the load mean and load amplitude.

[0135] Furthermore, the fatigue analysis module 504 is specifically used for:

[0136] The fatigue safety factor of the wheel is obtained by processing data from the two-dimensional load spectrum, SN curve, and stress and strain values ​​of the wheel using the local stress-strain method.

[0137] The wheel fatigue evaluation device provided in this embodiment can perform the wheel fatigue evaluation method described above. Its implementation principle and technical effect are similar, and will not be described again in this embodiment.

[0138] In the aforementioned specific implementation of a wheel fatigue evaluation device, each module can be implemented as a processor. The processor can execute computer execution instructions stored in the memory, thereby enabling the processor to execute the aforementioned wheel fatigue evaluation method.

[0139] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 6 As shown, the electronic device 60 includes at least one processor 601 and a memory 602. The electronic device 60 also includes a communication component 603. The processor 601, memory 602, and communication component 603 are connected via a bus 604.

[0140] In the specific implementation process, at least one processor 601 executes computer execution instructions stored in memory 602, causing at least one processor 601 to execute a wheel fatigue evaluation method as executed by the above-mentioned electronic device.

[0141] The specific implementation process of processor 601 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0142] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0143] The memory may include high-speed RAM, and may also include non-volatile storage (NVM), such as at least one disk storage.

[0144] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0145] The above description of the functions implemented by electronic devices and main control devices has introduced the solutions provided by the embodiments of the present invention. It is understood that, in order to implement the above functions, the electronic device or main control device includes hardware structures and / or software modules corresponding to the execution of each function. By combining the units and algorithm steps of the various examples described in the embodiments of the present invention, the embodiments of the present invention can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the technical solutions of the embodiments of the present invention.

[0146] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the wheel fatigue evaluation method described above.

[0147] The aforementioned computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0148] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in an electronic device or a host device.

[0149] This application also provides a computer program product, comprising: a computer program stored in a readable storage medium, wherein at least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the electronic device to perform the scheme provided in any of the above embodiments.

[0150] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating wheel fatigue, characterized in that, include: Acquire sampling data of vertical force and driving torque during vehicle operation, and obtain a two-dimensional load spectrum of load frequency based on the sampling data; The stress and strain values ​​are obtained based on the stress and strain test data, and the stress-strain curve is fitted to obtain the SN curve of the wheel material. A static strength finite element model is established, and the stress and strain values ​​of the wheel are obtained based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and Beam elements for simulating the internal steel rim of the tire. The shell element tire model is divided into different tire regions according to the tire's position and area. Each tire region includes a corresponding preset elastic modulus parameter and a preset Poisson's ratio parameter. The shell element tire model includes a first bead region, a second bead region, a sidewall region, a shoulder region, and a tread region. The first bead region is the area within the bead with a thickness less than a preset thickness, and the second bead region is the area within the bead with a thickness not less than a preset thickness. The preset elastic modulus parameters corresponding to the first bead region, second bead region, sidewall region, shoulder region, and tread region increase sequentially in a stepwise manner. The fatigue safety factor of the wheel is obtained based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel.

2. The method according to claim 1, characterized in that, After obtaining the stress and strain values ​​of the wheel, the method further includes: The measured values ​​of the wheel's error index are obtained based on wheel pressure and deformation experiments; the simulated values ​​of the error index are obtained based on the static strength finite element model; wherein the wheel's error index includes the tire's deformation and the contact pressure between the tire and the rim under a fixed air pressure. If the error between the measured calculated value and the simulated value is not less than 5%, change the preset elastic modulus parameter and the preset Poisson's ratio parameter corresponding to different tire regions within the preset value range until the error between the measured calculated value and the simulated value is less than 5%. Obtain the stress and strain values ​​of the wheel according to the static strength finite element model.

3. The method according to claim 1, characterized in that, The process of establishing a static strength finite element model and obtaining the stress and strain values ​​of the wheel based on the static strength finite element model includes: A static strength finite element model is established based on the wheel entity; wherein, the static strength finite element model also includes fixed constraints; the fixed constraints are used to simulate bolt holes; based on the measured contact area between the tire and the ground, distributed coupling constraints are established at the tire contact point to simulate the effect of the ground on the tire; load data corresponding to the two-dimensional load spectrum are input at the control points of the distributed coupling constraints; and the stress and strain values ​​of the wheel are obtained based on the static strength finite element model.

4. The method according to claim 1, characterized in that, The step of obtaining the two-dimensional load spectrum of load frequencies based on the sampled data includes: The average load, load amplitude, and load frequency are obtained by extracting the vertical force and driving torque within the preset load time series using the rainflow counting method. The load amplitude is divided into N preset amplitude levels by non-equal intervals from smallest to largest based on the maximum and minimum values ​​of the load amplitude. The load mean is divided into M preset mean levels by equal intervals from smallest to largest based on the maximum and minimum values ​​of the load mean. The two-dimensional load spectrum is obtained by counting the load frequencies corresponding to the preset amplitude levels minus the preset mean levels.

5. The method according to claim 4, characterized in that, The two-dimensional load spectrum is obtained by statistically analyzing the load frequencies corresponding to the preset amplitude level and the preset mean level; including: Based on the two-dimensional distribution model of the load mean and load amplitude, the frequency of each load cycle is statistically analyzed, and the statistical method is shown in the following formula: In the formula, Is at the same time in the Level load amplitude range and the first Load frequency within the average load range of level load, It is the total frequency of the load. It is the probability density function of the two-dimensional joint distribution of the load mean and load amplitude.

6. The method according to claim 1, characterized in that, The process of obtaining the fatigue safety factor of the wheel based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel includes: The fatigue safety factor of the wheel is obtained by processing the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel using the local stress-strain method.

7. A wheel fatigue evaluation device, characterized in that, include: The load spectrum module is used to acquire sampling data of vertical force and driving torque during vehicle operation, and to acquire a two-dimensional load spectrum of load frequency based on the sampling data. The fitting module is used to obtain stress and strain data based on uniaxial tensile tests, and to fit the stress and strain data to obtain the SN curve of the wheel material according to the stress-strain curve; The finite element analysis module is used to establish a static strength finite element model and obtain the stress and strain values ​​of the wheel based on the static strength finite element model. The static strength finite element model includes a solid element wheel model, a shell element tire model, and Beam elements for simulating the internal steel rim of the tire. The shell element tire model is divided into different tire regions according to the tire's position and area. Each tire region includes a corresponding preset elastic modulus parameter and a preset Poisson's ratio parameter. The shell element tire model includes a first bead region, a second bead region, a sidewall region, a shoulder region, and a tread region. The first bead region is the area within the bead with a thickness less than a preset thickness, and the second bead region is the area within the bead with a thickness not less than a preset thickness. The preset elastic modulus parameters corresponding to the first bead region, second bead region, sidewall region, shoulder region, and tread region increase sequentially in a stepwise manner. The fatigue analysis module is used to obtain the fatigue safety factor of the wheel based on the two-dimensional load spectrum, the SN curve, and the stress and strain values ​​of the wheel.

8. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 6.

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