Rubber stress relaxation test method and system suitable for finite element simulation
Data obtained through tensile and compression tests are preprocessed and fitted to generate stress relaxation curves. This solves the problem of insufficient adaptability of existing rubber stress relaxation test methods in finite element simulation, achieves high-precision parameter transfer, and improves simulation accuracy and design efficiency.
Patent Information
- Application Number
- CN202511617702.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-02-27
AI Technical Summary
Existing rubber stress relaxation test methods are not well adapted to finite element simulation, resulting in poor simulation accuracy and an inability to accurately assess the failure risk of tires after long-term use.
This paper provides a testing method and system that combines a specific test procedure with standardized data processing. Data is obtained through tensile and compression tests, preprocessed and fitted to generate stress relaxation curves, and relaxation time and relaxation modulus are extracted and input into finite element simulation software.
It achieves high-precision and high-reliability parameter transfer from physical experiments to simulation models, improves the prediction accuracy of finite element simulation, reduces human error, and enhances the precision and efficiency of tire structure design and material development.
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Figure CN121583370A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of mechanical property testing of rubber materials, and in particular to a rubber stress relaxation test testing method and system suitable for finite element simulation. BACKGROUND
[0002] As a core load-bearing component of commercial vehicles, truck and bus radial (TBR) tires are subjected to complex working conditions for a long time, and their performance reliability is crucial. These working conditions include dynamic load impact (such as road bumps during high-speed driving), continuous static load compression (such as tire shoulder compression when fully loaded), and wide temperature range environmental changes (-30℃ to 60℃). Under this background, the stress relaxation characteristics of rubber materials at key positions of the tire (such as the tread, sidewall, and cushion layer) become a core factor determining its durability. Stress relaxation characteristics directly determine the tire's resistance to shoulder separation cracking, resistance to tread separation, and long-term dimensional stability, and are the key to achieving a service life of more than 500,000 kilometers.
[0003] Currently, there are domestic and international standards such as GB / T 1685-2018 and ISO 815-1:2019 for testing the stress relaxation characteristics of rubber. However, these standard methods have obvious problems in terms of adaptability when serving the finite element simulation of TBR tires. Specifically, the finite element simulation of TBR tires needs to simulate extreme dynamic scenarios such as emergency braking (longitudinal sliding) and sharp turning (lateral deflection), which requires inputting parameters that accurately characterize the viscoelastic behavior of rubber, such as relaxation time and relaxation modulus. However, the original stress-time curves output by existing standard test methods are usually not preprocessed according to the simulation requirements. If such unprocessed raw data is directly input into the Prony series model in finite element simulation software (such as Abaqus), the model parameters will be distorted, which will significantly increase the prediction error of tire body deformation, and ultimately make it impossible to accurately assess the failure risks such as tire wear and bulging after long-term use, thereby restricting the precision and efficiency of tire structure design and material research and development. SUMMARY
[0004] To solve the technical problems of insufficient simulation adaptability of existing rubber stress relaxation test testing methods and lack of data preprocessing leading to poor finite element simulation accuracy in the background art, the present application provides a testing method and system that combines a specific test procedure with standardized data processing, achieving high-precision and high-reliability parameter transfer from physical testing to simulation models.
[0005] The first aspect of the present application provides a rubber stress relaxation test testing method suitable for finite element simulation, comprising: obtaining tensile relaxation test data and compression relaxation test data of a rubber sample; Preprocessing the tensile relaxation test data and the compression relaxation test data to obtain preprocessed stress-time data; Based on the preprocessed stress-time data, curve fitting is performed to generate a stress relaxation curve; Using a viscoelastic model to perform fitting analysis on the stress relaxation curve to extract relaxation time and relaxation modulus for characterizing the viscoelastic behavior of the rubber material; The relaxation time and relaxation modulus are input into a finite element simulation software for tire performance simulation.
[0006] Further, the obtaining of the tensile relaxation test data of the rubber sample includes: A standard dumbbell-shaped rubber sample is prepared; The dumbbell-shaped rubber sample is stretched to a first preset elongation rate on a tensile testing machine at a preset stretching speed; Under constant temperature conditions, the first preset elongation rate is maintained for a first preset duration, and the stress-time data during stretching is recorded; The stretching and maintaining steps are repeated at least twice, and the stress relaxation data of the last cycle are taken as the tensile relaxation test data.
[0007] Further, the obtaining of the compression relaxation test data of the rubber sample includes: A standard cylindrical rubber sample is prepared; The standard cylindrical rubber sample is compressed to a second preset compression amount on a dynamic mechanical analyzer at a preset compression speed; Under constant temperature conditions, the second preset compression amount is maintained for a second preset duration, and the stress-time data during compression is recorded; The compression and maintaining steps are repeated at least twice, and the stress relaxation data of the last cycle are taken as the tensile relaxation test data.
[0008] Further, the preprocessing of the tensile relaxation test data and the compression relaxation test data includes: Obtaining the stress relaxation data of the last cycle in the tensile relaxation test data and the compression relaxation test data; The stress relaxation data of the last cycle is smoothed and outliers are removed to obtain stress-time data after eliminating the stress softening effect.
[0009] Further, the fitting analysis of the stress relaxation curve using a viscoelastic model includes: Obtaining the stress relaxation curve; Using a Prony series form viscoelastic model to fit the stress relaxation curve, the formula of the Prony series form viscoelastic model is: ; wherein, represents the stress or strain response of a material over time t , is the initial elastic modulus, is the relaxation modulus, is the relaxation time, is the loading frequency, is the phase angle; by a fitting procedure, the relaxation modulus and the relaxation time in the Prony series form of the viscoelastic model are solved.
[0010] Further, the first preset elongation and the second preset compression amount are selected within a typical strain range of a rubber material.
[0011] A second aspect of the present application provides a rubber stress relaxation test testing system suitable for finite element simulation, comprising: a data acquisition module configured to acquire tensile relaxation test data and compression relaxation test data of a rubber sample; a data preprocessing module configured to preprocess the tensile relaxation test data and the compression relaxation test data to obtain preprocessed stress-time data; a curve fitting module configured to perform curve fitting based on the preprocessed stress-time data to generate a stress relaxation curve; a parameter extraction module configured to perform fitting analysis on the stress relaxation curve using a viscoelastic model to extract relaxation time and relaxation modulus for characterizing the viscoelastic behavior of the rubber material; a data output module configured to input the relaxation time and the relaxation modulus into a finite element simulation software for tire performance simulation.
[0012] A third aspect of the present application provides an electronic device comprising a memory, a processor, and a program stored on the memory and running on the processor, wherein the processor implements the steps of the rubber stress relaxation test testing method suitable for finite element simulation according to the first aspect of the present application when executing the program.
[0013] A fourth aspect of the present application provides a computer readable storage medium having a program stored thereon, wherein the program is executed by a processor to implement the steps of the rubber stress relaxation test testing method suitable for finite element simulation according to the first aspect of the present application.
[0014] The fifth aspect of the present application provides a computer program product comprising software code, wherein the programs in the software code perform the steps in the rubber stress relaxation test method suitable for finite element simulation as described in the first aspect of the present application.
[0015] Compared with the prior art, the rubber stress relaxation test method and system suitable for finite element simulation provided by the present application has the following beneficial effects: (1) In view of the technical problem that the existing test does not eliminate the stress softening effect, resulting in distortion of the simulation input parameters, the present application actively performs multiple strain cycles and selects data after the material response tends to be stable for subsequent analysis, effectively eliminating the influence of initial stress softening on long-term relaxation behavior, thereby realizing the technical effect that the relaxation modulus and relaxation time parameters obtained can better represent the steady-state viscoelastic behavior of the material, and providing pure and accurate input data for finite element simulation.
[0016] (2) In view of the technical problem that the single test mode in the prior art cannot comprehensively reflect the complex stress state of the tire, the present application combines the two basic mechanical modes of tension and compression to construct more comprehensive material constitutive information, thereby realizing more complete characterization of the viscoelastic response of the tire when subjected to combined tension and compression loads in actual working conditions, and significantly improving the technical effect of improving the prediction accuracy of the finite element model under multi-axial stress state.
[0017] (3) The present application uses a Prony series form viscoelastic model for fitting analysis, directly uses the Prony series model widely supported by the finite element software as a data analysis tool, establishes a direct and standardized conversion path from the original test data to the simulation model parameters, thereby realizing the technical effect of greatly improving the research and development efficiency and reducing the human error and precision loss in the parameter conversion process. BRIEF DESCRIPTION OF DRAWINGS
[0018] The drawings accompanying the specification of the present disclosure serve to provide a further understanding of the present disclosure, and the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an improper limitation on the present disclosure.
[0019] Figure 1 is a method flowchart provided by the first embodiment of the present application; Figure 2 is a curve of the change of the stress relaxation of a sample with time under 20% strain in a certain rubber tensile relaxation test provided by the first embodiment of the present application; Figure 3 is a curve of the change of the stress relaxation of a sample with time under 20% strain in a certain rubber compression relaxation test provided by the first embodiment of the present application; Figure 4 is a schematic diagram of the interval of the stress relaxation curve that needs to be fitted provided by the first embodiment of the present application; Figure 5 is a system architecture diagram provided by the second embodiment of the present application. DETAILED DESCRIPTION
[0020] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
[0021] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.
[0022] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0023] All data acquisition of the present embodiment is based on the compliance with laws and regulations and user consent, and the legal application of data.
[0024] Term explanation: 1. Stress relaxation: refers to the phenomenon that the internal stress of a material gradually decreases over time under the condition of maintaining a constant strain.
[0025] 2. Stress softening effect: also known as Mullins effect, refers to the phenomenon that the stress response of a material such as rubber is lower than the first loading when it is loaded to the same strain again after experiencing the first or first few loading-unloading cycles.
[0026] 3. Prony series: a mathematical model widely used in viscoelastic mechanics, which describes the stress relaxation or creep behavior of a material through the superposition of a series of exponential decay terms.
[0027] 4. Relaxation modulus: in models such as Prony series, refers to the proportionality coefficient of each relaxation process to the overall stiffness of the material, and is one of the key parameters to characterize the viscoelastic behavior of the material.
[0028] 5. Relaxation time: in viscoelastic models, a time constant that characterizes the speed of a certain relaxation process within the material. The relaxation time spectrum can reflect the transition characteristics of the material from instantaneous elastic response to long-term equilibrium state.
[0029] Embodiment one As Figure 1 The embodiment provides a rubber stress relaxation test test method suitable for finite element simulation, and the method comprises the following steps: obtaining tensile relaxation test data and compression relaxation test data of a rubber sample; preprocessing the tensile relaxation test data and the compression relaxation test data to obtain preprocessed stress-time data; based on the preprocessed stress-time data, curve fitting is performed to generate a stress relaxation curve; the stress relaxation curve is fitted and analyzed by using a viscoelastic model, and relaxation time and relaxation modulus for characterizing the viscoelastic behavior of the rubber material are extracted; the relaxation time and the relaxation modulus are input into a finite element simulation software for tire performance simulation.
[0030] The rubber stress relaxation test test method provided by the application firstly obtains the original response data of the material under the tensile and compression modes through physical test; then, the special preprocessing module is used to eliminate the interference factors (such as stress softening) in the test process; then, the processed data is fitted into a continuous relaxation curve by using a mathematical tool; finally, the direct input parameters required by the simulation software are accurately calculated from the curve by using the algorithm matched with the standard simulation model (Prony series) in the field. The scheme solves the problem of disconnection between test and simulation through standardization and standardization, and ensures the accuracy and reliability of the simulation input parameters.
[0031] Specifically, the tensile relaxation test data of the rubber sample comprises: a standard dumbbell-shaped rubber sample is prepared; the dumbbell-shaped rubber sample is stretched to a first preset elongation rate on a tensile testing machine at a preset stretching speed; under constant temperature conditions, the first preset elongation rate is maintained for a first preset time period, and the stress-time data in the stretching process is recorded; the stretching and maintaining steps are repeated at least twice, and the stress relaxation data of the last cycle are taken as the tensile relaxation test data.
[0032] Specifically, the compression relaxation test data of the rubber sample comprises: a standard cylindrical rubber sample is prepared; the standard cylindrical rubber sample is compressed to a second preset compression amount on a dynamic mechanical analyzer at a preset compression speed; under constant temperature conditions, the second preset compression amount is maintained for a second preset time period, and the stress-time data in the compression process is recorded; The compression and maintaining steps are repeated at least twice, and stress relaxation data of the last cycle is taken as the tensile relaxation test data.
[0033] The rubber material will undergo irreversible stress softening in the first deformation, and through multiple cycles, the material response tends to a stable and repeatable state, ensuring that the obtained data excludes the interference of initial history effects. This improves the consistency, stability and simulation applicability of the test data.
[0034] Specifically, the preprocessing of the tensile relaxation test data and the compression relaxation test data comprises: Obtaining stress relaxation data of the last cycle in the tensile relaxation test data and the compression relaxation test data; Smoothing and outlier rejection are performed on the stress relaxation data of the last cycle to obtain stress-time data after eliminating the stress softening effect.
[0035] It is explicitly specified to use the stress relaxation data of the last cycle as the effective data source, which is based on the material science cognition that the stress softening effect is basically eliminated after multiple cycles. The subsequent smoothing and outlier rejection is to use digital signal processing algorithms (such as moving average method, median filtering method, etc.) to suppress the inevitable random noise and accidental errors in the test process. The technical effect of extracting the intrinsic signal that best represents the true viscoelasticity of the material from the original data is achieved, which is a key step to improve the accuracy of subsequent parameter extraction.
[0036] Specifically, the fitting analysis of the stress relaxation curve using the viscoelastic model comprises: Obtaining the stress relaxation curve; Fitting the stress relaxation curve using a Prony series form viscoelastic model, the formula of the Prony series form viscoelastic model is: ; Wherein, represents the stress or strain response of the material at time t , is the initial elastic modulus, is the relaxation modulus, is the relaxation time, is the load frequency, is the phase angle; Through the fitting process, the relaxation modulus and the relaxation time in the Prony series form viscoelastic model are solved.
[0037] Prony series is a classical model to approximate the relaxation behavior of viscoelastic materials by superposition of multiple exponential decay terms, each of which contains a relaxation modulus (G , representing the contribution size of the relaxation process) and a relaxation time (τ , representing the speed of the relaxation process). By fitting algorithms such as least squares, the Prony series theoretical curve is maximally approximated to the stress relaxation curve fitted by experimental data, so as to inversely derive a series of and parameters. The continuous test curve is converted into a discrete set of viscoelastic parameters that can be directly identified and calculated by the finite element software.
[0038] Specifically, the first preset elongation and the second preset compression amount are selected within a typical strain range of the rubber material.
[0039] The rubber material may exhibit different mechanical behaviors at different strain levels. Selection within a typical strain range of the rubber material means that the preset strain should cover the main strain interval (e.g. 20%-40%) experienced by the key parts of the tire in actual use. Ensuring that the test conditions are associated with the actual working conditions makes the extracted material parameters have higher representativeness and prediction accuracy in the target simulation application.
[0040] Figure 2 A typical curve of stress change with relaxation time of a sample at 20% strain in a specific tensile relaxation test is shown. The curve intuitively shows the process of stress decay over time and is the basis for subsequent data fitting.
[0041] Figure 3 A typical curve of stress change with relaxation time of a sample at 20% strain in a specific compression relaxation test is shown. Compared with the tensile curve, the relaxation behavior of the material under different stress modes can be observed.
[0042] Figure 4 The key data interval that needs to be mathematically fitted on the generated stress relaxation curve is shown. Correctly selecting the fitting interval is an important step to ensure that the extracted Prony series parameters accurately reflect the long-term relaxation behavior of the material.
[0043] In a specific embodiment, the present application adopts the following technical solutions: 1. Tensile relaxation test 1.1 Set the vulcanization temperature to 150°C, high-temperature vulcanize the rubber compound, and make a dumbbell-shaped sample.
[0044] 1.2 Install the sample on the clamps of the tensile testing machine, and adjust the tensile machine to run at a speed of 30 mm / min.
[0045] 1.3 The sample is stretched to a sample length of 20% elongation, within 1% of the elongation, and the stress versus time data during the rubber tensile is recorded.
[0046] 1.4 The sample is fixed at 20% elongation for 300s under constant temperature, and the stress versus time data during the rubber stress relaxation is recorded.
[0047] 1.5 The steps 1.3 and 1.4 are repeated for 3 times, and the tensile force F0 used to stretch to 20% elongation and the tensile force Ft after 300s are recorded.
[0048] 2. Compression relaxation test 2.1 The rubber compound is high temperature cured at 150°C, and cylindrical samples with diameter of 18mm and thickness of 7mm are prepared.
[0049] 2.2 The sample is mounted on the grips of a dynamic mechanical analyzer, and the sample is compressed at a speed of 20mm / min.
[0050] 2.3 The sample is compressed to a sample thickness of 20% compression, within 1% of the compression, and the pressure versus time data during the rubber compression is recorded.
[0051] 2.4 The sample is fixed at 20% compression for 300s under constant temperature, and the pressure versus time data during the rubber stress relaxation is recorded. 2.5 The step 2.3 is repeated for 3 times, and the pressure F0 used to compress to 20% compression and the pressure Ft after 300s are recorded.
[0052] 3. Data processing and parameter extraction 3.1 For the data of tensile relaxation test and compression relaxation test, due to the stress softening effect of the rubber material, the data of the stress relaxation stage in the third cycle test process are taken and fitted to generate the stress relaxation curve.
[0053] 3.2 The stress relaxation curve generated in 3.1 is analyzed by using a suitable mathematical model, and the relaxation time and relaxation modulus of the material are calculated. In the process of finite element simulation analysis, the Prony series model is generally used to define the viscoelastic parameters of the rubber material, and the model formula is described as ; In the formula: represents the stress or strain response of the material at time t , is the initial elastic modulus, is the relaxation modulus, for the relaxation time, for the load frequency, for the phase angle.
[0054] Further, the type of the test sample in 1.1 is generally a standard sample in GB / T 528-2009.
[0055] Further, the number of test samples in 1.1 and 2.1 is generally 3-5.
[0056] Further, in order to control the stability of the deformation process of the dumbbell-shaped sample, the tensile testing machine in 1.2 should be a small deformation tensile testing machine, and the operating speed of the tensile testing machine is generally controlled to be below 50 mm / min, and the minimum effective force range of the tensile testing machine should be less than 1 N.
[0057] Further, in order to control the force measurement accuracy during the relaxation process of the cylindrical sample, the maximum force range of the dynamic mechanical analyzer in 2.2 should be greater than 1000 N.
[0058] Further, the temperature set in 1.4 and 2.4 can be room temperature conditions, or fixed temperature conditions according to the performance requirements of the rubber.
[0059] Further, the number of strain cycles of the sample in 1.5 and 2.5 should be at least twice, so as to eliminate the stress softening effect of the rubber material.
[0060] Further, the elongation / compression amount of the sample can be determined according to actual needs, and is generally 20%-40% of the length of the sample.
[0061] The present application significantly improves the calculation accuracy of the tire finite element model in simulating dynamic and steady-state conditions by accurately obtaining key parameters such as Prony series representing the viscoelastic behavior of the rubber compound, thereby more accurately predicting the tire's side slip, longitudinal slip, roll and stable over-bump performance, providing reliable data support and simulation basis for optimizing the carcass structure design, improving material utilization efficiency and predicting the tire's full life cycle performance, effectively shortening the development cycle and reducing test costs.
[0062] Embodiment two As Figure 5 The present embodiment provides a rubber stress relaxation test test system suitable for finite element simulation, comprising: a data acquisition module for acquiring tensile relaxation test data and compression relaxation test data of a rubber sample; a data preprocessing module for preprocessing the tensile relaxation test data and compression relaxation test data to obtain preprocessed stress-time data; a curve fitting module for generating a stress relaxation curve based on the preprocessed stress-time data. a parameter extraction module configured to perform a fitting analysis on the stress relaxation curve by using a viscoelastic model to extract a relaxation time and a relaxation modulus for characterizing the viscoelastic behavior of the rubber material; a data output module configured to input the relaxation time and the relaxation modulus into a finite element simulation software for tire performance simulation.
[0063] Embodiment three Embodiment three of the present application provides an electronic device.
[0064] An electronic device includes a memory, a processor, and a program stored in the memory and running on the processor, and the processor implements the steps in the rubber stress relaxation test method suitable for finite element simulation as described in embodiment one of the present application when executing the program.
[0065] The detailed steps are the same as the rubber stress relaxation test method suitable for finite element simulation provided in embodiment one, and will not be repeated here.
[0066] Embodiment four Embodiment four of the present application provides a computer readable storage medium.
[0067] A computer readable storage medium has a program stored thereon, and the program implements the steps in the rubber stress relaxation test method suitable for finite element simulation as described in embodiment one of the present application when executed by a processor.
[0068] The detailed steps are the same as the rubber stress relaxation test method suitable for finite element simulation provided in embodiment one, and will not be repeated here.
[0069] Embodiment five Embodiment five of the present application provides a computer program product.
[0070] A computer program product includes software code, and the program in the software code implements the steps in the rubber stress relaxation test method suitable for finite element simulation as described in embodiment one of the present application.
[0071] The detailed steps are the same as the rubber stress relaxation test method suitable for finite element simulation provided in embodiment one, and will not be repeated here.
[0072] Those skilled in the art will appreciate that embodiments of the present application can be readily used as software, hardware, or a combination of software and hardware. In a software embodiment, the methods can be tangibly embodied in a machine-readable storage medium having stored thereon instructions that can be used to program a computer to perform any of the methods. The software implementation can be initialized by loading and executing a set of instructions arranged to perform one of the methods into the computer's memory. Alternatively, hard-wired circuitry can be used in place of, or in combination with, software instructions. Thus, the
[0073] The present application is described in reference to the flow diagrams and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing device, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams.
[0074] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams.
[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams. Figure 1 one or more functions specified in one or more of the flow diagrams and / or block diagrams.
[0076] While preferred embodiments of the application have been described, modifications and variations can be apparent to those skilled in the art once aware of the general underlying concepts. Accordingly, the appended claims are intended to embrace all such modifications and variations as fall within the scope of the application.
[0077] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Thus, it is intended that the present application encompass such modifications and changes as fall within the scope of the claims and their equivalents.
[0078] The above only shows the preferred embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A rubber stress relaxation test method suitable for finite element simulation, characterized in that, include: Obtain tensile relaxation test data and compression relaxation test data of rubber specimens; The tensile relaxation test data and compression relaxation test data are preprocessed to obtain preprocessed stress-time data; Based on the preprocessed stress-time data, curve fitting is performed to generate a stress relaxation curve; The stress relaxation curve was fitted and analyzed using a viscoelastic model to extract the relaxation time and relaxation modulus, which characterize the viscoelastic behavior of the rubber material. The relaxation time and relaxation modulus are input into finite element simulation software for tire performance simulation.
2. The method as described in claim 1, characterized in that, The tensile relaxation test data of the rubber specimens obtained include: Prepare standard dumbbell-shaped rubber samples; On a tensile testing machine, the dumbbell-shaped rubber specimen is stretched to a first preset elongation at a preset tensile speed; Under constant temperature conditions, the first preset elongation rate is maintained for a first preset time, and stress-time data during the stretching process is recorded; Repeat the stretching and holding steps at least twice, and take the stress relaxation data from the last cycle as the tensile relaxation test data.
3. The method as described in claim 1, characterized in that, Obtaining data from compression relaxation tests on rubber samples includes: Prepare standard cylindrical rubber samples; On a dynamic thermomechanical analyzer, the standard cylindrical rubber sample is compressed to a second preset compression amount at a preset compression rate. Under constant temperature conditions, the second preset compression amount is maintained for a second preset duration, and stress-time data during the compression process is recorded; Repeat the compression and holding steps at least twice, and take the stress relaxation data from the last cycle as the tensile relaxation test data.
4. The method as described in claim 1, characterized in that, Preprocessing of the tensile relaxation test data and compression relaxation test data includes: Obtain the stress relaxation data of the last cycle from the tensile relaxation test data and the compression relaxation test data; The stress relaxation data from the last cycle is smoothed and outliers are removed to obtain stress-time data after eliminating the stress softening effect.
5. The method as described in claim 1, characterized in that, The fitting analysis of the stress relaxation curve using a viscoelastic model includes: Obtain the stress relaxation curve; The stress relaxation curve was fitted using a viscoelastic model in Prony series form, and the formula for the viscoelastic model in Prony series form is as follows: ； in, Indicates the material in time t Stress or strain response under stress, The initial elastic modulus, For relaxation modulus, For relaxation time, For the load frequency, The phase angle; The relaxation modulus in the viscoelastic model of the Prony series form is obtained through a fitting process. and relaxation time .
6. The method as described in claim 2 or 3, characterized in that, The first preset elongation and the second preset compression are selected within the typical strain range of the rubber material.
7. A rubber stress relaxation test system suitable for finite element simulation, characterized in that, include: The data acquisition module is used to acquire tensile relaxation test data and compression relaxation test data of rubber samples; The data preprocessing module is used to preprocess the tensile relaxation test data and the compression relaxation test data to obtain preprocessed stress-time data; The curve fitting module is used to perform curve fitting based on the preprocessed stress-time data to generate a stress relaxation curve. The parameter extraction module is used to fit and analyze the stress relaxation curve using a viscoelastic model, and extract the relaxation time and relaxation modulus to characterize the viscoelastic behavior of the rubber material. The data output module is used to input the relaxation time and relaxation modulus into the finite element simulation software for tire performance simulation.
8. A rubber stress relaxation test apparatus suitable for finite element simulation, characterized in that, The device includes a memory and a processor; the memory is used to store a computer program; the processor is used to implement, when executing the computer program, the rubber stress relaxation test method applicable to finite element simulation as described in any one of claims 1 to 6.
9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the rubber stress relaxation test method applicable to finite element simulation as described in any one of claims 1 to 6.
10. A computer program product, comprising software code, characterized in that, The program in the software code executes the steps of the rubber stress relaxation test method applicable to finite element simulation as described in any one of claims 1 to 6.