A method and system for checking loading force in a chassis component bench durability test of an automobile

Abstract

The application relates to a loading force inspection method and system for a chassis part bench endurance test, a virtual model of a test sample, a clamp and a bench test loader is established according to a test working condition, test load is loaded on the virtual model, a virtual maximum principal strain value of a measuring point is obtained, and the virtual maximum principal strain value is used as a standard for subsequent judgment; then a strain gauge is attached to the test sample to perform an actual test, so as to obtain a real maximum principal strain value; the actual measured data and the standard are analyzed to verify whether the clamp and the bench test loader are abnormal, in addition, the method can judge whether the loading force is normal by setting the strain gauge to obtain the strain value of the measuring point, has the characteristics of low use cost, the strain gauge is directly pasted and can be clamped with the test sample, the loading force borne by the test sample in the endurance test can be monitored in real time, and the method is suitable for endurance test loading force inspection of different test samples.

Description

Technical Field

[0001] This application relates to the field of fatigue durability testing technology for automotive components, and in particular to a method and system for testing the loading force of a bench durability test for automotive chassis components. Background Technology

[0002] Fatigue durability is one of the most important performance characteristics of automobiles. The fatigue durability of automotive components is primarily verified through bench durability testing. The magnitude of the force applied to the test specimen during bench durability testing directly affects the fatigue life of the component. Therefore, the bench durability testing process must verify the actual loading force borne by the test specimen. The accuracy of the loading force in bench durability testing depends not only on the output force of the loader of the bench testing equipment but also on the accuracy of the clamping of the test specimen.

[0003] Currently, there are two methods for verifying the load output force of bench durability testing equipment: one is to measure it with a spring; the other is to measure it with a force sensor.

[0004] The spring measurement method involves connecting one end of a spring to the loader of the testing equipment via a clamp, fixing the other end to the clamp, applying a preset loading force to the spring, measuring the spring deformation, and then calculating the spring force based on the spring's stiffness value. This spring force represents the actual loading force of the testing equipment. However, this method has the following problems:

[0005] The spring-based measurement method requires specialized fixtures, and it's difficult to achieve perfect centering of the spring during loading. Furthermore, the measurement error for spring deformation is relatively large. Automotive component testing benches typically have high durability loads, easily exceeding the range of conventional springs, resulting in low measurement accuracy for this method. Additionally, this method can only verify the load output by the testing equipment before the test; it cannot achieve real-time monitoring of the load force, nor can it verify inaccuracies in the load force borne by the test specimen due to clamping issues.

[0006] The force sensor measurement method involves installing a force sensor on the loading device of the testing equipment and connecting the force sensor signal to a data acquisition system. When the testing equipment is loaded, the data signal collected by the force sensor is synchronously transmitted to the data acquisition system. The data acquisition system performs post-processing on the sampled signal to obtain the force value. However, the following problems exist:

[0007] The advantage of this method is its high measurement accuracy, but it is difficult to implement, requiring the design of specialized fixtures. Furthermore, the accuracy of the force sensor decreases after repeated disassembly and reassembly, and the replacement cost of the force sensor is high. This method can only verify the loading force output by the testing equipment, and cannot verify inaccuracies in the loading force borne by the test specimen due to clamping issues. Summary of the Invention

[0008] This application provides a method and system for testing the loading force of automotive chassis components on a bench for durability testing. This addresses the problems in related technologies where monitoring the loading force output by testing equipment requires the design of specialized fixtures, and the accuracy of force sensors decreases after repeated disassembly and assembly, resulting in high replacement costs and short service life.

[0009] Firstly, a method for testing the loading force in a bench durability test of automotive chassis components is provided, comprising:

[0010] A virtual model is constructed based on the test conditions, test specimens, fixtures, and bench test loaders.

[0011] Finite element analysis was performed on the virtual model to obtain the measurement point locations of the test specimen;

[0012] The virtual model is loaded with test loads to obtain the virtual maximum principal strain values ​​of all the measuring points, and the virtual maximum principal strain value of each measuring point is used as the specified parameter under the test conditions.

[0013] Based on the specified parameters and the actual parameters, verify whether there are any abnormalities in the loading force;

[0014] If everything is normal, proceed with the durability test; otherwise, suspend the durability test.

[0015] The true parameters are the true maximum principal strain values ​​of all the measuring points obtained when the test specimen, fixture, and bench test loader are subjected to the actual test under the test load and the test conditions.

[0016] In some embodiments, the actual parameters are obtained from actual strain gauges set on the measuring points of the test specimen;

[0017] Before performing a virtual test by loading the test load onto the virtual model, virtual strain gauges identical to the real strain gauges are established at the measuring points of the test specimen in the virtual model.

[0018] In some embodiments, based on the specified parameters and the actual parameters, verifying whether the loading force is abnormal includes the following steps:

[0019] Based on Formula 1, and the virtual maximum principal strain value and the actual maximum principal strain value of the measuring point, the first error value of each measuring point is obtained;

[0020] Compare the first error value of each measuring point with the first set value;

[0021] If the first error value of all measuring points is greater than the first set value, then the loading force is abnormal;

[0022] Otherwise, the loading force is normal.

[0023] In some embodiments, after pausing the durability test, an anomaly cause analysis step is performed:

[0024] Adjust the fixture or bench test loader according to the analysis results, and then obtain the new actual parameters; repeat the steps based on the specified parameters and the actual parameters to verify whether there are any abnormalities in the fixture and bench test loader until the loading force is normal.

[0025] The new true parameters are the true maximum principal strain values ​​of all the measured points obtained from the actual test after adjustment.

[0026] In some embodiments, the anomaly cause analysis step includes the following steps:

[0027] Obtain the ratio of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point, and calculate the average of multiple ratios;

[0028] Based on Formula 2, and the ratio of the mean to each measuring point, the second error value for each measuring point is obtained;

[0029] Compare the second error value of each measuring point with the second set value:

[0030] If the second error value of all measuring points is greater than the second set value, then the fixture is abnormal;

[0031] If the second error value of all measuring points is less than or equal to the second set value, then there is an abnormality in the bench test loader.

[0032] In some embodiments, a virtual model is constructed based on the test conditions, test specimens, fixtures, and bench test loaders, including the following steps:

[0033] Obtain modeling parameters; modeling parameters are the material properties and cross-sectional characteristics of the test specimen, fixture, and bench test loader; material properties include density, elastic modulus, and Poisson's ratio;

[0034] Based on the modeling parameters, establish the initial model of the test specimen, the initial model of the fixture, and the initial model of the bench test loader;

[0035] Obtain the assembly and constraint relationships of the test specimen, fixture, and bench test loader. Then, assemble and connect the initial models of the test specimen, fixture, and bench test loader according to the assembly and constraint relationships to form the model to be determined.

[0036] The boundary conditions of the model to be determined are set according to the test conditions to form the virtual model.

[0037] In some embodiments, defining the boundary conditions of the model to be determined according to the test conditions includes the following steps:

[0038] Apply full constraints to the unloaded fixture;

[0039] A unit force with the same loading direction as the test condition is applied to the loading end of the bench test loader, and constraints are applied to the loading point of the test specimen.

[0040] In some embodiments, finite element analysis is performed on the virtual model to obtain the measurement point locations of the test specimen, including the following steps:

[0041] Finite element analysis was performed on the test specimen of the virtual model to obtain the stress distribution diagram of the test specimen;

[0042] The location of the measuring points on the test specimen is determined based on the stress distribution diagram; the number of measuring points is not less than two.

[0043] Secondly, a bench durability testing system for automotive chassis components is provided, comprising:

[0044] The test component simulation module is used to construct a virtual model based on the test conditions, test specimen, fixture, and bench test loader, and to perform finite element analysis on the virtual model to obtain the measurement point positions of the test specimen; and to conduct virtual tests under test loads.

[0045] The test load input module is used to input test loads into the virtual model and the actual bench test loader;

[0046] The data acquisition module is used to acquire the virtual maximum principal strain values ​​of all the measuring points in the virtual model under the test load, and then use the virtual maximum principal strain value of each measuring point as a specified parameter under the test condition; and to acquire the real parameters; the real parameters are the real maximum principal strain values ​​of all the measuring points obtained when the test specimen, fixture and bench test loader are tested under the test load and the test condition.

[0047] The monitoring and analysis module is used to verify whether there is any abnormality in the loading force based on the specified parameters and the actual parameters; if it is normal, a durability test is conducted; otherwise, the durability test is suspended.

[0048] The display module is used to display the actual maximum principal strain value and the virtual maximum principal strain value, as well as to indicate whether there is any abnormality in the loading force.

[0049] In some embodiments, the data acquisition module includes a virtual strain gauge setting unit and a maximum principal strain value calculation unit;

[0050] The virtual strain gauge setting unit is used to set virtual strain gauges on the measuring points of the virtual model;

[0051] The maximum principal strain value calculation unit is used to obtain the virtual maximum principal strain value and the actual maximum principal strain value.

[0052] The beneficial effects of the technical solution provided in this application include:

[0053] This application provides a method and system for verifying the loading force in a bench durability test of automotive chassis components. A virtual model connecting the test specimen, fixture, and bench test loader is established based on the test conditions. This virtual model serves as the standard, and the measured points and the virtual maximum principal strain values ​​obtained from the test load are the criteria for subsequent judgment. Identical test specimens, fixtures, and bench test loaders are then connected according to the assembly relationship of the virtual model for actual testing. Strain gauges are attached to the measured points to obtain the true maximum principal strain values. Finally, analysis based on the true maximum principal strain values ​​and the standard verifies whether there are any abnormalities in the fixtures and bench test loaders. Furthermore, this method does not require additional complex loading force detection devices; it only needs to obtain the maximum principal strain value of the measured points by setting strain gauges. The maximum principal strain value is sufficient to determine whether the loading force is normal, without considering the direction of the strain gauge placement. It features simple operation and low cost, eliminating the need for specialized fixture design. Strain gauges can be directly attached and clamped together with the test specimen, enabling real-time monitoring of the loading force borne by the test specimen throughout the entire test process. Therefore, this solves the problems of requiring the design of special fixtures for monitoring the load output of the test equipment, and the high replacement cost and short service life caused by the decrease in accuracy of the force sensor after multiple disassembly and assembly.

[0054] In addition, by analyzing the actual maximum strain value and the virtual maximum strain value, it is possible to quickly identify whether the problem of inaccurate loading force on the test specimen is due to a problem with the test equipment or improper clamping of the test specimen. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 A flowchart for the loading force test of automotive chassis component bench durability testing provided in this application embodiment;

[0057] Figure 2 The test specimens provided in the embodiments of this application are schematic diagrams of the actual structure of the front control arm;

[0058] Figure 3A schematic diagram of a virtual model of a front control arm as the test specimen provided in the embodiments of this application;

[0059] Figure 4 A schematic diagram of strain measurement points of the front control arm as the test specimen in the embodiments provided in this application;

[0060] Figure 5 The schematic diagram showing the comparison of the virtual maximum principal strain and the real maximum principal strain before equipment adjustment when the test specimen in the embodiment of this application is a virtual front control arm;

[0061] Figure 6 This is a schematic diagram comparing the virtual maximum principal strain with the real maximum principal strain after equipment adjustment, when the test sample in the embodiment provided in this application is a virtual front control arm.

[0062] In the diagram: 1. Steering knuckle connection point; 2. Front connection point of the subframe; 3. Rear connection point of the subframe. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] This application provides a method and system for testing the loading force of automotive chassis components on a bench for durability testing. This addresses the problems in related technologies where monitoring the loading force output by testing equipment requires the design of specialized fixtures, and the accuracy of force sensors decreases after repeated disassembly and assembly, resulting in high replacement costs and short service life.

[0065] Please see Figure 1 A method for testing the loading force of a bench durability test for automotive chassis components, comprising:

[0066] Step 101: Construct a virtual model based on the test conditions, test specimens, fixtures, and bench test loaders;

[0067] Step 102: Perform finite element analysis on the virtual model to obtain the measurement point locations of the test specimen;

[0068] Step 103: Apply test loads to the virtual model to obtain the virtual maximum principal strain values ​​of all measuring points, and use the virtual maximum principal strain value of each measuring point as the specified parameter under the test conditions;

[0069] Step 104: Based on the specified parameters and the actual parameters, verify whether there is any abnormality in the loading force; the actual parameters are: the actual maximum principal strain values ​​of all measuring points obtained when the test specimen, fixture and bench test loader are tested under the test load and test conditions.

[0070] Step 105: If normal, conduct a durability test;

[0071] Step 106: If abnormal, suspend the durability test.

[0072] Because a virtual model connecting the test specimen, fixture, and bench test loader was established based on the test conditions, and this virtual model is used as a standard, the measured points and the virtual maximum principal strain values ​​obtained from the test load serve as the criteria for subsequent judgment. Then, identical test specimens, fixtures, and bench test loaders are connected according to the assembly relationship of the virtual model for actual testing. Strain gauges are attached to the measured points to obtain the true maximum principal strain values. Finally, based on the above measured strain data and the standard, the presence of any abnormalities in the fixture and bench test loader can be verified. Furthermore, this method does not require additional complex loading force detection devices; it only needs to obtain the strain values ​​at the measured points using strain gauges to determine whether the loading force is normal. It features simple operation and low cost, eliminating the need for specialized fixtures. Strain gauges can be directly attached and clamped together with the test specimen, enabling real-time monitoring of the loading force borne by the test specimen throughout the entire test process. Therefore, it solves the problems of requiring specialized fixtures for loading force monitoring of test equipment outputs, and the high replacement costs and short service life caused by the decrease in accuracy of force sensors after repeated disassembly and assembly.

[0073] It should be understood why the maximum principal strain value is used to determine whether the loading force is normal; the following explanation can be used as a reference:

[0074] Stress: When an object deforms due to external forces, internal forces arise between the different parts of the object to resist the external forces and attempt to restore the object to its original position after deformation. The internal force per unit area at a point on the interface under consideration is called stress.

[0075] This can be expressed as a formula: In the formula, σ represents stress, F represents external force, and A represents the area of ​​the force in the direction of the force.

[0076] Strain: When an object is subjected to an external force, it will undergo a certain deformation. The degree of deformation is called strain. When a material deforms, an internal reaction force equal in magnitude but opposite in direction to the external force is generated to resist the external force.

[0077] because but

[0078] The relationship between stress and strain is: σ=E*ε, where ε represents strain and E represents the elastic modulus of the material.

[0079] The direction and value of the maximum principal strain at any point on the plane are unique. The maximum principal strain force at the measuring point can be calculated using a 45° right-angle strain gauge. The pasting direction of the 45° right-angle strain gauge will not affect the calculation result of the maximum principal strain. Other types of strain gauges are also applicable.

[0080]

[0081] In the formula, ε 0° ε 45° and ε 90° This represents the strain values ​​at 0°, 45°, and 90° for a 45° right-angle strain gauge. ε represents the maximum principal strain.

[0082] During the experiment, the applied force is equivalent to an external force acting on the test specimen. Therefore, by detecting the stress on the test specimen using strain gauges, the application of the applied force on different test specimens can be reflected. In addition, the direction and value of the maximum principal strain at any point on the plane are unique. During the strain gauge installation process, it is not necessary to consider the influence of its installation angle. It is only necessary to ensure that the position of the strain gauge with respect to the measuring point is accurate, which improves the accuracy of subsequent calculations.

[0083] Furthermore, there are various ways to obtain stress changes. One method provided in this application is: the real parameters are obtained by real strain gauges set on the measuring points of the test specimen; before the virtual test is carried out by loading the test load onto the virtual model, virtual strain gauges identical to the real strain gauges are established on the measuring points of the test specimen in the virtual model; of course, this application does not exclude other ways to obtain strain values.

[0084] For step 101

[0085] In some preferred embodiments, a virtual model is constructed based on the test conditions, test specimens, fixtures, and bench test loaders, including the following steps:

[0086] Step 10101: Obtain modeling parameters; these parameters are the material properties and cross-sectional characteristics of the test specimen, fixture, and bench test loader; material properties include density, elastic modulus, and Poisson's ratio. Step 10102: Establish initial models for the test specimen, fixture, and bench test loader based on the modeling parameters. Step 10103: Obtain the assembly and constraint relationships of the test specimen, fixture, and bench test loader. Then, assemble and connect the initial models of the test specimen, fixture, and bench test loader according to these relationships to form the model to be determined. Step 10104: Set the boundary conditions of the model to be determined according to the test conditions to form a virtual model. In this step, full constraints are applied to the unloaded fixture. A unit force with the same loading direction as the test conditions is applied to the loading end of the bench test loader, and constraints are applied to the loading points of the test specimen. This ensures that the motion of the test specimen is consistent with the test conditions in the finite element analysis. Full constraints can be understood as fixing the installation point or installation form of the test specimen; refer to [reference needed]. Figure 3 .

[0087] For step 102

[0088] Finite element analysis is performed on the virtual model to obtain the measurement point locations of the test specimen, including the following steps:

[0089] Finite element analysis is performed on the virtual model of the test specimen to obtain the stress distribution diagram. The locations of the measuring points on the test specimen are determined based on the stress distribution diagram. There should be at least two measuring points, each located in a different area. The test specimen should have sufficient space to accommodate strain gauges at the measuring point locations, and the stress level should be high with a gentle stress gradient.

[0090] For step 104:

[0091] In some preferred embodiments, the verification of whether the loading force is abnormal, based on specified parameters and actual parameters, includes the following steps:

[0092] Based on Formula 1, and the virtual maximum principal strain value and the actual maximum principal strain value of the measuring point, the first error value of each measuring point is obtained; the first error value of each measuring point is compared with the first set value; Formula 1 is:

[0093]

[0094] If the first error value of all measuring points is greater than the first set value, then the loading force is abnormal;

[0095] Otherwise, the loading force is normal.

[0096] Furthermore, after determining that the loading force is abnormal, we need to clarify whether the abnormality is caused by the fixture or the bench test loader, and adjust the fixture or bench test loader to ensure the continuation of the test. Therefore, the following steps follow after step 106:

[0097] Step 107: After pausing the durability test, perform the anomaly cause analysis steps:

[0098] Step 108: Adjust the fixture or bench test loader according to the analysis results, and then obtain the new true parameters; repeat the steps based on the specified parameters and the true parameters to verify whether there are any abnormalities in the fixture and bench test loader until the loading force is normal; where the new true parameters are the true maximum principal strain values ​​of all measuring points obtained after the adjustment and the actual test.

[0099] Step 107, the abnormal cause analysis step, includes the following steps:

[0100] Step 10701: Obtain the ratio of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point, and calculate the average of multiple ratios; Step 10702: Based on Formula 2, and the average and the ratio of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point, obtain the second error value for each measuring point; Step 10703: Compare the second error value of each measuring point with the second set value: if the second error value of all measuring points is greater than the second set value, then the fixture is abnormal; if the second error value of all measuring points is less than or equal to the second set value, then the bench test loader is abnormal.

[0101] Formula 2 is:

[0102]

[0103] The formula for calculating the ratio is:

[0104]

[0105] This application also proposes a load force verification system for bench durability testing of automotive chassis components. This system, stored in a computer, can construct a virtual model based on test conditions, test specimens, fixtures, and bench test loaders for virtual testing. Additionally, it can acquire real data on test conditions, test specimens, fixtures, and bench test loaders under actual test conditions. This allows for real-time online acquisition of the actual load force during the bench durability testing of automotive chassis components, and verification of the actual load force, ensuring the accuracy of the test.

[0106] A bench durability testing system for automotive chassis components, characterized in that it comprises:

[0107] The test component simulation module is used to construct a virtual model based on the test conditions, test specimens, fixtures, and bench test loaders, and to perform finite element analysis on the virtual model to obtain the measurement point positions of the test specimens; and to conduct virtual tests under test loads.

[0108] The test load input module is used to input test loads into the virtual model and the actual bench test loaders.

[0109] The data acquisition module is used to acquire the virtual maximum principal strain values ​​of all measuring points in the virtual model under the test load, and then use the virtual maximum principal strain value of each measuring point as the specified parameter under the test conditions; and to acquire the real parameters; the real parameters are: the real maximum principal strain values ​​of all measuring points obtained when the test specimen, fixture and bench test loader are tested under the test load and test conditions.

[0110] The monitoring and analysis module is used to verify whether there are any abnormalities in the loading force based on the specified parameters and the actual parameters; if normal, a durability test is conducted; otherwise, the durability test is suspended.

[0111] The display module is used to display the actual maximum principal strain value, the virtual maximum principal strain value, and to indicate whether there are any abnormalities in the loading force.

[0112] Furthermore, the data acquisition module includes a virtual strain gauge setting unit and a maximum principal strain value calculation unit. The virtual strain gauge setting unit is used to set virtual strain gauges at the measuring points of the virtual model; the maximum principal strain value calculation unit is used to obtain the virtual maximum principal strain value and the actual maximum principal strain value. The calculation process can refer to the calculation formula for the maximum principal strain value mentioned above. The settings of the data acquisition module can realize the setting of virtual strain gauges at different measuring points for different specimens, thereby improving the versatility and flexibility of the system.

[0113] To illustrate the above methods in detail, the following example uses the test sample as the front control arm as a practical application, as shown in the following description and appendix. Figure 2-6 :

[0114] Obtain the material properties and cross-sectional characteristics of the front control arm, fixture, and bench test loader; the material properties include density, elastic modulus E, and Poisson's ratio μ; then, based on these, establish the initial models of the front control arm, fixture, and bench test loader in the automotive chassis component bench durability test loading force verification system to form a finite element mesh model.

[0115] The assembly and constraint relationships of the front control arm, fixture, and bench test loader were obtained. Then, based on these relationships, multiple finite element mesh models, including the initial models of the front control arm, fixture, and bench test loader, were assembled and connected to form the model to be determined. Bolt connections were simulated using rigid element RBE2, and bushings were simulated using rigid element RBE3+CBUSH elements. The steering knuckle connection point 1 of the front control arm, the front connection point 2 of the subframe, and the rear connection point 3 of the subframe were connected to the fixture. (Refer to...) Figure 2 ;

[0116] The boundary conditions of the model to be determined are set according to the test conditions to form a virtual model; the boundary conditions of the finite element model of the bench durability test of the front control arm are as follows: Figure 3 and Figure 2 As shown, one is a fixture base that is fully constrained and connected to the connection points of the front and rear subframes; the other is a unit force applied at the steering knuckle connection point in the plane defined by the connection points of the steering knuckle and the front and rear subframes, with the loading direction at 25° to the line connecting the front and rear subframes, and a vertical constraint applied at the loading point to ensure that the motion mode of the test specimen is consistent with that of the test conditions during the finite element analysis.

[0117] Finite element analysis was performed on the bench durability test of the front control arm to obtain the stress distribution map of the front control arm. Based on the space requirements for strain gauge arrangement, three locations with high stress levels and gentle stress gradient changes were selected as strain measurement points. Specific locations are as follows: Figure 4 The measuring points are shown as 1, 2, and 3.

[0118] In the test system for loading force verification of automotive chassis component bench durability testing, virtual strain gauges are established corresponding to the above three measuring points. Then, the test load of bench durability is applied to obtain the virtual maximum principal strain value of all measuring points. The virtual maximum principal strain value of each measuring point is used as the specified parameter under the test conditions. The test load of bench durability is the drive signal that drives the reciprocating motion of the bench durability test loader during the front control arm bench durability test.

[0119] The actual front control arm, fixture, and bench test loader are assembled and connected. Strain gauges are attached to the corresponding measuring points on the front control arm and connected to the automotive chassis component bench durability test loading force verification system to transmit detection signals. Then, the same test load is applied to conduct a real test, in which the real test and the virtual test are carried out simultaneously or asynchronously.

[0120] The data acquisition module of the vehicle chassis component bench durability test loading force verification system will collect the strain signals of strain gauges at each measuring point in real time and obtain the true maximum principal strain value of each measuring point.

[0121] Then, the monitoring and analysis module is used for analysis, and the virtual maximum principal strain signal and the actual maximum principal strain signal at each measuring point are displayed, such as... Figure 5 As shown. The error between the true maximum principal strain and the virtual maximum principal strain at the three measuring points was calculated, that is, the first error value between the true maximum principal strain and the virtual maximum principal strain at each measuring point. The first error values ​​of the three measuring points are 61%, 57%, and 60% respectively. The first error values ​​of the three measuring points all exceed the set threshold (first set value) by 20%. It is determined that the test loading force of the front control arm is inaccurate, and the test is suspended.

[0122] Further analysis was conducted to determine whether the problem stemmed from the loader of the bench test equipment or improper bench setup. A comparative analysis of the ratios of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point revealed ratios of 2.61, 2.42, and 2.55 for the three measuring points. The average strain ratio for the three measuring points was 2.53. The second error values ​​between the actual maximum principal strain value and the average value for each measuring point were 3.2%, 4.3%, and 1%, respectively. Since the second error value for each measuring point was within 10% of the set threshold (second set value), the problem was determined to be with the loader of the bench test equipment. After repairing and adjusting the test equipment, the test was restarted.

[0123] Then, the new virtual maximum principal strain signals and the true maximum principal strain signals for each measuring point are obtained, such as... Figure 6 As shown, the first error values ​​of the three measuring points are 8.8%, 6.4%, and 7.8%, which meet the set threshold requirements, indicating that the loading force borne by the front control arm during the test is correct.

[0124] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0125] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0126] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for testing the loading force in a bench durability test of automotive chassis components, characterized in that, It includes: A virtual model is constructed based on the test conditions, test specimen, fixture, and bench test loader. This step specifically includes the following steps: obtaining modeling parameters; the modeling parameters are the material properties and cross-sectional characteristics of the test specimen, fixture, and bench test loader; material properties include density, elastic modulus, and Poisson's ratio; establishing initial models of the test specimen, fixture, and bench test loader based on the modeling parameters; obtaining the assembly and constraint relationships of the test specimen, fixture, and bench test loader, and then assembling and connecting the initial models of the test specimen, fixture, and bench test loader according to the assembly and constraint relationships to form the model to be verified; setting the boundary conditions of the model to be verified according to the test conditions to form the virtual model. Finite element analysis was performed on the virtual model to obtain the measurement point locations of the test specimen; Before performing a virtual test by loading the test load onto the virtual model, virtual strain gauges identical to those on the real strain gauges are established at the measuring points of the test specimen in the virtual model. The virtual model is loaded with test loads to obtain the virtual maximum principal strain values ​​of all the measuring points, and the virtual maximum principal strain value of each measuring point is used as the specified parameter under the test conditions. Based on the specified parameters and the actual parameters, verify whether there are any abnormalities in the loading force; If normal, proceed with the durability test; otherwise, suspend the durability test. The true parameters are the true maximum principal strain values ​​obtained at all measuring points under the test load and test conditions during a real test of the test specimen, fixture, and bench test loader. These true parameters are obtained from true strain gauges installed at the measuring points of the test specimen. After suspending the durability test, perform the anomaly cause analysis procedure, which includes: Adjust the fixture or bench test loader according to the analysis results, and then obtain new true parameters; repeat the steps based on the specified parameters and the true parameters to verify whether there are any abnormalities in the fixture and bench test loader until the loading force is normal; wherein, the new true parameters are the true maximum principal strain values ​​of all the measuring points obtained after the adjustment and the actual test. The abnormality cause analysis steps include the following steps: obtaining the ratio of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point, and calculating the average of multiple ratios; based on Formula 2, and the ratio of the average to each measuring point, obtaining the second error value for each measuring point; comparing the second error value for each measuring point with a second set value: if the second error value of all measuring points is greater than the second set value, then the fixture is abnormal; if the second error value of all measuring points is less than or equal to the second set value, then the bench test loader is abnormal. Formula 2 is as follows: ; The formula for calculating the ratio in Formula 2 is as follows: .

2. The method for testing the loading force of automotive chassis component bench durability test as described in claim 1, characterized in that, Based on the specified parameters and the actual parameters, verify whether there is any abnormality in the loading force, including the following steps: Based on Formula 1, and the virtual maximum principal strain value and the actual maximum principal strain value of the measuring point, the first error value of each measuring point is obtained; Compare the first error value of each measuring point with the first set value; If the first error value of all measuring points is greater than the first set value, then the loading force is abnormal; Otherwise, the loading force is normal; Formula 1 is as follows: .

3. The method for testing the loading force of automotive chassis component bench durability test as described in claim 1, characterized in that, Define the boundary conditions of the model to be verified according to the test conditions, including the following steps: Apply full constraints to the unloaded fixture; A unit force with the same loading direction as the test condition is applied to the loading end of the bench test loader, and constraints are applied to the loading point of the test specimen.

4. The method for testing the loading force of automotive chassis component bench durability test as described in claim 1, characterized in that, The virtual model is subjected to finite element analysis to obtain the measurement point locations of the test specimen, including the following steps: Finite element analysis was performed on the test specimen of the virtual model to obtain the stress distribution diagram of the test specimen; The location of the measuring points on the test specimen is determined based on the stress distribution diagram; the number of measuring points is not less than two.

5. A load-bearing force testing system for automotive chassis component bench durability testing, characterized in that, It includes: The test component simulation module is used to construct a virtual model based on the test conditions, test specimens, fixtures and bench test loaders, and to perform finite element analysis on the virtual model to obtain the measurement point positions of the test specimens; And for conducting virtual tests under test loads; based on test conditions, test specimens, fixtures, and bench test loaders, a virtual model is constructed, including the following steps: obtaining modeling parameters; the modeling parameters are the material properties and cross-sectional characteristics of the test specimens, fixtures, and bench test loaders; the material properties include density, elastic modulus, and Poisson's ratio; establishing initial models of the test specimens, fixtures, and bench test loaders according to the modeling parameters; obtaining the assembly and constraint relationships of the test specimens, fixtures, and bench test loaders, and then assembling and connecting the initial models of the test specimens, fixtures, and bench test loaders according to the assembly and constraint relationships to form a model to be verified; setting the boundary conditions of the model to be verified according to the test conditions to form the virtual model; The test load input module is used to input test loads into the virtual model and the actual bench test loader; The data acquisition module is used to acquire the virtual maximum principal strain values ​​of all the measuring points in the virtual model under the test load, and then use the virtual maximum principal strain value of each measuring point as a specified parameter under the test condition; and to acquire the real parameters; the real parameters are the real maximum principal strain values ​​of all the measuring points obtained when the test specimen, fixture and bench test loader are subjected to a real test under the test load and the test condition; the real parameters are acquired by real strain gauges set on the measuring points of the test specimen. The monitoring and analysis module is used to verify whether there is any abnormality in the loading force based on the specified parameters and the actual parameters; if normal, a durability test is performed; otherwise, the durability test is paused; after pausing the durability test, an abnormality cause analysis step is executed, specifically including: adjusting the fixture or bench test loader according to the analysis results, and then obtaining new actual parameters; and repeating the step of verifying whether there is any abnormality in the fixture and bench test loader based on the specified parameters and the actual parameters until the loading force is normal; wherein, the new actual parameters are the true maximum principal strain values ​​of all the measuring points obtained after the adjustment and actual test. The abnormality cause analysis steps include the following steps: obtaining the ratio of the virtual maximum principal strain value to the actual maximum principal strain value at each measuring point, and calculating the average of multiple ratios; based on Formula 2, and the ratio of the average to each measuring point, obtaining the second error value for each measuring point; comparing the second error value for each measuring point with a second set value: if the second error value of all measuring points is greater than the second set value, then the fixture is abnormal; if the second error value of all measuring points is less than or equal to the second set value, then the bench test loader is abnormal. The display module is used to display the actual maximum principal strain value and the virtual maximum principal strain value, as well as to indicate whether there is any abnormality in the loading force.

6. The load testing system for automotive chassis component bench durability testing as described in claim 5, characterized in that: The data acquisition module includes a virtual strain gauge setting unit and a maximum principal strain value calculation unit; The virtual strain gauge setting unit is used to set virtual strain gauges on the measuring points of the virtual model; The maximum principal strain value calculation unit is used to obtain the virtual maximum principal strain value and the actual maximum principal strain value.

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