Non-bearing body frame torsional strength analysis method and system

Abstract

The application provides a non-load-bearing vehicle body frame torsional strength analysis method and system, which comprises the following steps: constructing a finite element model of a frame of a measured vehicle type based on a three-dimensional model of the vehicle type, performing simulation analysis on the finite element model, and obtaining unit torsional angle stress data of the frame; obtaining torsional angle combination spectrum data of a frame rear cross beam on a combined road surface according to a real vehicle road test; grouping parts of the frame according to material properties, matching the torsional angle combination spectrum data with the finite element model of the frame to simulate a frame fatigue test; and calculating fatigue damage values of each part of the frame according to the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until it is determined that any part fails according to the fatigue damage values. The application can preliminarily verify the torsional strength of the frame in the early stage of design and development, has high test accuracy, provides a reliable basis for frame development, shortens the test cycle and cost, and improves the research and development efficiency.

Description

Technical Field

[0001] This invention relates to the field of vehicle reliability testing, and more specifically, to a method, system, electronic device, and storage medium for analyzing the torsional strength of a non-load-bearing vehicle frame. Background Technology

[0002] With the continued and stable development of the electric vehicle industry, vehicle body structures are increasingly trending towards modularity and platformization. Examples include Rivian's Skateboard chassis and the similar product launched by the domestic startup U Power. These vehicles are characterized by separate development of the body and chassis. Essentially, these are non-load-bearing bodies, relying primarily on the frame for load-bearing. The frame supports the weight of the body, allowing for separate production of the body and frame, and meeting the personalized needs of multiple body structures on the same frame platform. Furthermore, non-load-bearing bodies facilitate the placement and installation of larger battery components, better meeting the structural requirements of future electric vehicles.

[0003] Currently, non-load-bearing chassis are mainly used in off-road vehicles, pickup trucks, and other similar models. These chassis are characterized by high strength and good resistance to bumps. The uneven forces experienced by the four wheels during driving are entirely borne by the frame, requiring the frame to have high torsional resistance. At present, the torsional performance of the frame is mainly evaluated through bench tests. However, the loading conditions and the relationship between the load and actual road conditions are unclear, which cannot reflect the actual stress situation. Furthermore, bench tests have long cycles and high labor and testing costs. Therefore, there is an urgent need to establish a simulation evaluation method for the torsional strength of non-load-bearing chassis frames in electric vehicles. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a method, system, electronic device, and storage medium for analyzing the torsional strength of a non-load-bearing vehicle frame. It can preliminarily verify the torsional strength of the frame in the early stages of design and development, providing a reliable basis for frame development, shortening the test cycle and reducing costs, and improving R&D efficiency.

[0005] According to a first aspect of the present invention, a method for analyzing the torsional strength of a non-load-bearing vehicle frame is provided, comprising:

[0006] A finite element model of the vehicle frame is constructed based on the three-dimensional model of the vehicle being tested. The finite element model is then subjected to simulation analysis to obtain the stress data per unit torsional angle of the vehicle frame.

[0007] The combined torsional angle spectrum data of the rear crossbeam of the composite road frame were obtained based on actual vehicle road tests;

[0008] The components of the frame are grouped according to their material properties. The combined torsional angle spectrum data is matched with the finite element model of the frame to simulate frame fatigue testing. The fatigue damage value of each component of the frame is calculated based on the unit torsional angle stress data of the frame and the combined torsional angle spectrum data until any component is determined to have failed based on the fatigue damage value.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Optionally, constructing the finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested includes:

[0011] A mesh model is established based on the 3D model of the chassis assembly of the vehicle under test. For structures with uniform wall thickness and material thickness exceeding the thickness threshold, first-order hexahedral mesh elements are used for modeling. For structures with material thickness below the thickness threshold, 2D shell elements are used for modeling. For non-uniform material thickness and key castings that are rigidly connected to the chassis, second-order tetrahedral elements are used for modeling.

[0012] Optionally, the construction of the finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested further includes:

[0013] The components of the frame include a front bumper beam, a front crossbeam, a middle crossbeam, a rear crossbeam, a left longitudinal beam, and a right longitudinal beam. The front bumper beam, the front crossbeam, the middle crossbeam, and the rear crossbeam are arranged side by side in sequence according to the X-axis of the vehicle coordinate system. The left longitudinal beam and the right longitudinal beam are symmetrically arranged on both sides of the Y0 plane of the vehicle coordinate system and are respectively connected to the front bumper beam, the front crossbeam, the middle crossbeam, and the rear crossbeam.

[0014] The connection points of the left longitudinal beam, right longitudinal beam and front anti-collision beam, front crossbeam, middle crossbeam and rear crossbeam are constrained by the connection method of Rbe2-CBeam-Rbe2 unit respectively to simulate the bolt connection method of the connection points. The lap joint of each connection point is also simulated by establishing Rbe2 unit through node to node to simulate weld connection.

[0015] Assign mesh material properties to each component of the chassis.

[0016] Optionally, the simulation analysis of the finite element model to obtain the unit torsional stress data of the frame includes:

[0017] The six degrees of freedom of the nodes of the front anti-collision beam in the middle of the constrained frame located on the Y0 plane are restricted by the Rbe2 unit;

[0018] The center of the node located in the Y0 plane at the middle of the rear crossbeam is taken as the main node. The main node is subjected to a forced torsion angle of a unit angle around the X-axis, and the stress results of each component of the frame under the unit torsion angle are obtained.

[0019] Optionally, obtaining the combined torsional angle spectrum data of the rear crossbeam of the composite road frame based on actual vehicle road tests includes:

[0020] Based on the road conditions of the actual vehicle road test site, data collection standards were developed, and combined road surfaces including various reinforced bad roads were set up according to the data collection standards.

[0021] An angle measuring device is installed in the middle of the rear crossbeam of the actual vehicle frame. According to the accelerated road fatigue test standard, the actual vehicle fatigue test is carried out cyclically on the combined road surface. The torsional angle data of the rear crossbeam of the frame is collected through the angle measuring device during the test.

[0022] The torsion angle data with high consistency in each cycle are extracted as the torsion angle combination spectrum data of the actual vehicle test, and the torsion angle combination spectrum data is denoised.

[0023] Optionally, the step of grouping the frame components according to material properties, matching the torsional angle combination spectrum data with the finite element model of the frame to simulate frame fatigue testing; calculating the fatigue damage value of each frame component based on the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage value, includes:

[0024] Based on the mesh material properties, the various components of the frame are grouped, and the material fatigue properties of each component of the frame are set respectively.

[0025] The finite element model of the frame and the stress results of each component of the frame under a unit torsion angle are matched with the load of the torsion angle combination spectrum data. The finite element model of the frame is then cyclically operated according to the load of the torsion angle combination spectrum data to simulate the frame fatigue test.

[0026] Based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the frame under different stresses are calculated; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirements, the corresponding component is deemed to have failed.

[0027] Optionally, based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the frame under different stresses are calculated; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirement, the corresponding component is determined to have failed, including:

[0028] Based on the SN curve of the material, the cyclic fatigue life (Ni) of each component under different stresses (Si) is obtained. Using the following formula, it is determined that the fatigue damage value of any component does not meet the torsional strength requirement:

[0029] n1 / N1+n2 / N2+……+(ni-1) / (Ni-1)+ni / Ni≥1, i≥1;

[0030] Where i is a natural number greater than 1, ni is the actual number of cycles of a certain stress Si, and ni is obtained through the torsion angle combination spectrum data; ni / Ni is the fatigue damage value of the corresponding component when the actual number of cycles of a certain stress Si is ni;

[0031] When the actual number of cycles of a certain stress Si is ni, and the sum of the fatigue damage values ​​of any component is not less than 1, the corresponding component is determined to have failed.

[0032] According to a second aspect of the present invention, a torsional strength analysis system for a non-load-bearing vehicle frame is provided, comprising:

[0033] The model data acquisition module is used to construct a finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested, perform simulation analysis on the finite element model, and obtain the unit torsional stress data of the vehicle frame.

[0034] The real vehicle data acquisition module is used to acquire the torsional angle combination spectrum data of the rear crossbeam of the combined road frame based on real vehicle road tests;

[0035] The simulation test analysis module is used to group the components of the frame according to material properties, match the torsional angle combination spectrum data with the finite element model of the frame to simulate frame fatigue test; calculate the fatigue damage value of each component of the frame according to the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage value.

[0036] According to a third aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the processor is configured to execute a computer management program stored in the memory to implement the steps of the above-described method for analyzing the torsional strength of a non-load-bearing vehicle frame.

[0037] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which a computer management program is stored, wherein when executed by a processor, the computer management program implements the steps of the above-described method for analyzing the torsional strength of a non-load-bearing vehicle frame.

[0038] This invention provides a method, system, electronic device, and storage medium for analyzing the torsional strength of a non-load-bearing vehicle frame. It proposes a simulation-based evaluation method for assessing the torsional strength of a non-load-bearing vehicle frame. This method can preliminarily verify the torsional strength of the frame in the early stages of design and development, providing a reliable basis for frame development. By collecting measured torsional angles from actual vehicles for torsional strength analysis, it better reflects the actual operating conditions of users than existing constant-amplitude torsional fatigue durability tests, and has higher testing accuracy. The modeling process of this method is simple, the simulation efficiency is high, and it can quickly identify the risk locations of the frame's torsional performance. It can partially replace bench testing, shorten the testing cycle and cost, and improve R&D efficiency. Attached Figure Description

[0039] Figure 1 A flowchart of a non-load-bearing vehicle frame torsional strength analysis method provided by the present invention;

[0040] Figure 2 This is a schematic diagram of the frame structure for a non-load-bearing body.

[0041] Figure 3 This is a schematic diagram illustrating the stress calculation of the chassis under a unit torsion angle in a finite element model.

[0042] Figure 4 A schematic diagram of the torsion angle combination spectrum data collected from the actual vehicle test;

[0043] Figure 5 A block diagram of a non-load-bearing vehicle frame torsional strength analysis system provided by the present invention;

[0044] Figure 6 A schematic diagram of the hardware structure of a possible electronic device provided by the present invention;

[0045] Figure 7 This is a schematic diagram of the hardware structure of a possible computer-readable storage medium provided by the present invention.

[0046] The attached diagram lists the components represented by each number as follows:

[0047] 101. Front bumper beam, 102. Front crossbeam, 103. Middle crossbeam, 104. Rear crossbeam, 105. Left longitudinal beam, 106. Right longitudinal beam, a. Middle part of the front bumper beam, b. Middle part of the rear crossbeam. Detailed Implementation

[0048] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0049] Figure 1 A flowchart of a non-load-bearing vehicle frame torsional strength analysis method provided by the present invention is shown below. Figure 1As shown, the method includes:

[0050] S1. Construct a finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested, perform simulation analysis on the finite element model, and obtain the stress data of the unit torsional angle of the vehicle frame.

[0051] S2. Obtain the combined torsional angle spectrum data of the rear crossbeam of the composite road frame based on actual vehicle road tests;

[0052] S3. Group the components of the frame according to the material fatigue properties, match the torsional angle combination spectrum data with the finite element model of the frame to simulate the frame fatigue test; calculate the fatigue damage value of each component of the frame according to the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage value.

[0053] Understandably, given the deficiencies in the background technology, this invention proposes a method for analyzing the torsional strength of a non-load-bearing vehicle frame. This method can be used for simulation evaluation of the torsional strength of a non-load-bearing vehicle frame, preliminarily verifying the torsional strength of the frame in the early stages of design and development, and providing a reliable basis for frame development. By collecting actual vehicle torsion angles for torsional strength analysis, it better reflects the actual operating conditions of users than existing constant-amplitude torsion fatigue durability tests, and has higher test accuracy. The modeling process of this method is simple, the simulation efficiency is high, and it quickly identifies the risk locations of the frame's torsional performance. It can partially replace bench testing, shorten the testing cycle and cost, and improve R&D efficiency.

[0054] Based on the above technical solution, the following improvements can be made to this embodiment.

[0055] In one possible embodiment, constructing the finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested includes:

[0056] A mesh model was established based on the 3D model of the chassis assembly of the vehicle under test. Structures with uniform wall thickness and material thickness exceeding the thickness threshold were modeled using first-order hexahedral mesh elements; structures with material thickness below the thickness threshold were modeled using 2D shell elements; and non-uniform material thickness and critical castings rigidly connected to the chassis were modeled using second-order tetrahedral elements. In this embodiment, the thickness threshold was set to 5mm based on the actual parameters of the chassis.

[0057] Understandably, modeling different components of the chassis using different methods based on their material thicknesses results in a finite element model that more closely matches the actual structure of the chassis. This leads to higher accuracy and more precise calculations when determining the stress per unit torsional angle of the chassis.

[0058] In one possible embodiment, constructing the finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested further includes:

[0059] like Figure 2 As shown in the schematic diagram of the vehicle frame structure, the frame components include a front bumper beam 101, a front crossbeam 102, a middle crossbeam 103, a rear crossbeam 104, a left longitudinal beam 105, and a right longitudinal beam 106. The front bumper beam 101, front crossbeam 102, middle crossbeam 103, and rear crossbeam 104 are arranged side-by-side in sequence along the X-axis of the vehicle coordinate system (i.e., arranged sequentially from the front to the rear of the vehicle, with their longitudinal direction parallel to the Y-axis). The left longitudinal beam 105 and right longitudinal beam 106... It is said to be set on both sides of the Y0 plane of the whole vehicle coordinate system and connected to the front anti-collision beam 101, the front crossbeam 102, the middle crossbeam 103 and the rear crossbeam 104 respectively; for example, the left longitudinal beam 105 is connected to the left end of the front anti-collision beam 101, the left end of the front crossbeam 102, the left end of the middle crossbeam 103 and the left end of the rear crossbeam 104, and the right longitudinal beam 106 is connected to the right end of the front anti-collision beam 101, the right end of the front crossbeam 102, the right end of the middle crossbeam 103 and the right end of the rear crossbeam 104; here, left and right refer to the relative positions on the Y-axis with the whole vehicle coordinate system as the reference.

[0060] Based on finite element modeling software (such as Hypermesh), the connection points of the left longitudinal beam 105, right longitudinal beam 106, front anti-collision beam 101, front crossbeam 102, middle crossbeam 103, and rear crossbeam 104 are constrained by Rbe2-CBeam-Rbe2 element connection method. The bolt connection method of the connection points is simulated. At the lap joint of each connection point, Rbe2 elements are established through node-to-node connection to simulate weld connection. The rigid connection of each connection point is simulated by simulating bolt connection. The weld filling of each connection point is simulated by sharing nodes. The connection points are further constrained by six degrees of freedom to simulate a more reliable rigid connection of the real vehicle frame.

[0061] Then, mesh material properties are assigned to each component of the frame, including elasticity model, density, and Poisson's ratio.

[0062] It is understandable that in this embodiment, Rbe2 is a typical rigid constraint element in MPC (Multi-Point Constraints) elements, which can be used to constrain the six degrees of freedom of connection points; CBeam elements belong to the Beam bar element constraint method, which is often used in finite element calculations when the length dimension is greater than the dimensions in the other two directions and the direction is fixed as a straight line. By combining Beam bar elements with Rbe2 elements, it is ensured that all connection points between the various components of the frame are rigidly connected, so as to more accurately simulate the frame structure of the actual vehicle and improve the accuracy of subsequent unit torsional angle stress analysis based on the finite element model of the frame. Furthermore, setting mesh material properties for each component is beneficial for classifying and calculating the fatigue damage value of the frame in subsequent calculations, thereby improving the accuracy of frame fatigue analysis.

[0063] In one possible embodiment, the simulation analysis of the finite element model to obtain the unit torsional stress data of the frame includes:

[0064] The six degrees of freedom of the nodes of the front anti-collision beam a in the Y0 plane are constrained by the Rbe2 unit, and the connection mode of the nodes of the rear crossbeam b in the Y0 plane is restricted.

[0065] like Figure 3 As shown, the center of the node located in the Y0 plane at the middle part b of the rear crossbeam is taken as the main node. The main node is subjected to a forced torsion angle of a unit angle around the X-axis, and the stress results of each component of the frame under the unit torsion angle are obtained.

[0066] It is understandable that, such as Figure 3 As shown, for the established finite element model of the chassis, the six degrees of freedom of the nodes of the front bumper beam (a) located on the Y0 plane are constrained, and the nodes of the rear crossbeam (b) located on the Y0 plane are rigidly connected to restrict the overall displacement of the chassis during the test. With the chassis effectively fixed, a torque Rx around the X-axis is applied to the main node of the rear crossbeam (b) to simulate the chassis under different forced torsional angles. The stress per unit torsional angle (i.e., Rx = 1°) on each component of the chassis can be analyzed using simulation software (e.g., MSC.nastran). The stress results can be saved in OP2 format for later use.

[0067] In one possible embodiment, obtaining the combined torsional angle spectrum data of the rear crossbeam of the composite road frame based on actual vehicle road tests includes:

[0068] Based on the road conditions of the actual vehicle road test site, data collection standards were developed, and combined road surfaces including various reinforced bad roads were set up according to the data collection standards.

[0069] An angle measuring device is installed in the middle of the rear crossbeam of the actual vehicle frame. According to the accelerated road fatigue test standard, the actual vehicle fatigue test is carried out cyclically on the combined road surface. The torsional angle data of the rear crossbeam of the frame is collected through the angle measuring device during the test.

[0070] The torsion angle data with high consistency in each cycle are extracted as the torsion angle combination spectrum data of the actual vehicle test, and the torsion angle combination spectrum data is denoised.

[0071] Understandably, in this embodiment, a real-vehicle test is conducted according to the accelerated road fatigue test standard to obtain the rear crossbeam torsional angle combination spectrum data when conducting real-vehicle tests on various types of rough road surfaces. This rear crossbeam torsional angle combination spectrum data can at least determine the actual number of cycles of a certain stress experienced by each component within one test cycle. One set of torsional angle combination spectrum data is obtained for each test cycle. To obtain more accurate real-vehicle test data, torsional angle combination spectrum data with high consistency across multiple cycles is selected as the original data obtained from the test. Noise removal processing is then performed on the original data to remove noise points, resulting in more accurate torsional angle combination spectrum data.

[0072] More specifically, this embodiment uses a real vehicle test as an example. Data collection standards were established based on the road conditions of the test track. Taking a reinforced rough road at a certain test track as an example, a set of test cycle road test conditions was composed of disrepaired roads, large cobblestone roads, washboard roads, Belgian Type A roads, Belgian Type B roads, fish-scale pothole roads, and twisted roads, with a total length of 5km. According to the accelerated road fatigue test standard, meeting the 8000km rough road test requirements constitutes compliance with fatigue strength requirements. An angle sensor was installed at the middle position of the rear crossbeam of the chassis (consistent with the simulation analysis position in the finite element model of the chassis) according to the test requirements, with a sampling frequency of 500Hz. To ensure signal accuracy, signals were measured for three cycles, ensuring that the data collected in at least two of the cycles had good consistency.

[0073] Torsional angle combination spectra of the rear crossbeam of the vehicle frame were collected for different road surfaces. Signal denoising was performed using methods such as burr removal, drift correction, offset processing, and filtering. The obtained torsional angle combination spectrum data curves are shown below. Figure 4 As shown.

[0074] In one possible embodiment, the process of grouping the frame components according to material properties, matching the torsional angle combination spectrum data with the finite element model of the frame to simulate frame fatigue testing, and calculating the fatigue damage value of each frame component based on the unit torsional angle stress data of the frame and the torsional angle combination spectrum data until any component is determined to have failed based on the fatigue damage value includes:

[0075] Based on the mesh material properties, the various components of the frame are grouped, and the material fatigue properties of each component of the frame are set respectively.

[0076] The finite element model of the frame and the stress results of each component of the frame under a unit torsion angle are matched with the load of the torsion angle combination spectrum data. The finite element model of the frame is then cyclically operated according to the load of the torsion angle combination spectrum data to simulate the frame fatigue test.

[0077] Based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the frame under different stresses are calculated; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirements, the corresponding component is deemed to have failed.

[0078] It is understandable that different types of materials have different material fatigue properties. In this embodiment, the components are grouped according to their material properties so that fatigue damage values ​​can be calculated in groups during subsequent simulation of chassis fatigue tests. When any component fails, the entire chassis can be determined to have failed, thus improving the accuracy of chassis fatigue simulation tests.

[0079] Taking a specific operational procedure as an example, this embodiment uses the unit torsional stress calculated from the finite element model of the chassis and the torsional angle combination spectrum data obtained during actual vehicle testing. Based on the simulation analysis software LMSVirtual.lab, a fatigue analysis process is performed. The Full Featured Fatigue Analysis module is selected, and the OP2 result file containing the unit torsional stress is imported. The chassis components are grouped according to mesh material properties. The crossbeam torsional angle combination spectrum data is imported, and the loads of the finite element model and the torsional angle combination spectrum data are matched. The material fatigue properties of each component are set, and the fatigue damage value of the chassis is calculated according to Miner's linear fatigue cumulative damage theory. When the total fatigue damage value is not greater than 1, the torsional strength requirement is met. If the total fatigue damage value of any component is greater than or equal to 1, it indicates that the component no longer meets the torsional strength requirement, and the component fails. If any component of the chassis fails, the entire chassis no longer meets the torsional strength requirement, and the entire chassis fails.

[0080] In one possible embodiment, more specifically, the fatigue damage values ​​of each component of the frame under different stresses are calculated according to Miner's linear fatigue cumulative damage theory; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirement, the corresponding component is determined to have failed, including:

[0081] Based on the SN curve of the material, the cyclic fatigue life (Ni) of each component under different stresses (Si) is obtained. Using the following formula, it is determined that the fatigue damage value of any component does not meet the torsional strength requirement:

[0082] n1 / N1+n2 / N2+……+(ni-1) / (Ni-1)+ni / Ni≥1, i≥1;

[0083] Where i is a natural number greater than 1, ni is the actual number of cycles of a certain stress Si, and ni can be obtained through the torsion angle combination spectrum data; ni / Ni is the fatigue damage value of the corresponding component when the actual number of cycles of a certain stress Si is ni;

[0084] If a component operates under different stress levels, and the actual number of cycles for a certain stress Si is ni, a fatigue damage value ni / Ni will be generated. If the sum of the fatigue damage values ​​of any component is not less than 1, the corresponding component is considered to have failed.

[0085] Figure 5 A structural diagram of a non-load-bearing vehicle frame torsional strength analysis system provided in an embodiment of the present invention is shown below. Figure 5 As shown, a non-load-bearing vehicle frame torsional strength analysis system includes a model data acquisition module, a real vehicle data acquisition module, and a simulation test analysis module, wherein:

[0086] The model data acquisition module is used to construct a finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested, perform simulation analysis on the finite element model, and obtain the unit torsional stress data of the vehicle frame.

[0087] The real vehicle data acquisition module is used to acquire the torsional angle combination spectrum data of the rear crossbeam of the combined road frame based on real vehicle road tests;

[0088] The simulation test analysis module is used to group the components of the frame according to material properties, match the torsional angle combination spectrum data with the finite element model of the frame to simulate frame fatigue test; calculate the fatigue damage value of each component of the frame according to the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage value.

[0089] It is understood that the non-load-bearing body frame torsional strength analysis system provided by the present invention corresponds to the non-load-bearing body frame torsional strength analysis method provided in the foregoing embodiments. The relevant technical features of the non-load-bearing body frame torsional strength analysis system can be referred to the relevant technical features of the non-load-bearing body frame torsional strength analysis method, and will not be repeated here.

[0090] Please see Figure 6 , Figure 6This is a schematic diagram illustrating an embodiment of the electronic device provided in this invention. For example... Figure 6 As shown, an embodiment of the present invention provides an electronic device, including a memory 610, a processor 620, and a computer program 611 stored in the memory 610 and executable on the processor 620. When the processor 620 executes the computer program 611, it performs the following steps:

[0091] A finite element model of the vehicle frame is constructed based on the three-dimensional model of the vehicle being tested. The finite element model is then subjected to simulation analysis to obtain the stress data per unit torsional angle of the vehicle frame.

[0092] The combined torsional angle spectrum data of the rear crossbeam of the composite road frame were obtained based on actual vehicle road tests;

[0093] The components of the frame are grouped according to their material properties. The combined torsional angle spectrum data is matched with the finite element model of the frame to simulate frame fatigue testing. The fatigue damage value of each component of the frame is calculated based on the unit torsional angle stress data of the frame and the combined torsional angle spectrum data until any component is determined to have failed based on the fatigue damage value.

[0094] Please see Figure 7 , Figure 7 This is a schematic diagram illustrating an embodiment of a computer-readable storage medium provided by the present invention. (See diagram below.) Figure 7 As shown, this embodiment provides a computer-readable storage medium 700, on which a computer program 711 is stored. When the computer program 711 is executed by a processor, it performs the following steps:

[0095] A finite element model of the vehicle frame is constructed based on the three-dimensional model of the vehicle being tested. The finite element model is then subjected to simulation analysis to obtain the stress data per unit torsional angle of the vehicle frame.

[0096] The combined torsional angle spectrum data of the rear crossbeam of the composite road frame were obtained based on actual vehicle road tests;

[0097] The components of the frame are grouped according to their material properties. The combined torsional angle spectrum data is matched with the finite element model of the frame to simulate frame fatigue testing. The fatigue damage value of each component of the frame is calculated based on the unit torsional angle stress data of the frame and the combined torsional angle spectrum data until any component is determined to have failed based on the fatigue damage value.

[0098] This invention provides a method, system, and storage medium for analyzing the torsional strength of a non-load-bearing vehicle frame. It proposes a simulation-based evaluation method for assessing the torsional strength of a non-load-bearing vehicle frame. This method can preliminarily verify the torsional strength of the frame in the early stages of design and development, providing a reliable basis for frame development. By collecting measured torsional angles from actual vehicles for torsional strength analysis, it better reflects the actual operating conditions of users compared to existing constant-amplitude torsional fatigue durability tests, and has higher testing accuracy. The modeling process of this method is simple, the simulation efficiency is high, and it can quickly identify the risk locations of the frame's torsional performance. It can partially replace bench testing, shorten the testing cycle and cost, and improve R&D efficiency.

[0099] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0100] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0101] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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 computer, 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, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0102] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0103] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0104] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0105] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A non-load-bearing body frame torsional strength analysis method characterized by comprising: include: A finite element model of the vehicle frame is constructed based on the three-dimensional model of the vehicle being tested. The mesh material properties of each component of the frame in the finite element model are assigned. The finite element model is then subjected to simulation analysis to obtain the stress data per unit torsional angle of the frame. The time-series data of the torsion angle of the rear crossbeam of the composite road frame obtained from the actual vehicle road test is used as the torsion angle composite spectrum data. The chassis components are grouped according to material properties, and the torsional angle combination spectrum data is matched with the finite element model of the chassis to simulate chassis fatigue testing; fatigue damage values ​​of each chassis component are calculated based on the unit torsional angle stress data of the chassis and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage values; including: Based on the mesh material properties, the various components of the frame are grouped, and the material fatigue properties of each component of the frame are set respectively. The torsion angle combination spectrum data is used as a load, and load matching is performed with the finite element model of the frame and the stress results of each component of the frame under a unit torsion angle. The finite element model of the frame is then subjected to load cycling according to the torsion angle combination spectrum data to simulate frame fatigue test. Based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the frame under different stresses are calculated; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirements, the corresponding component is deemed to have failed.

2. The method of claim 1, wherein, The construction of a finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested includes: A mesh model is established based on the 3D model of the chassis assembly of the vehicle under test. For structures with uniform wall thickness and material thickness exceeding the thickness threshold, first-order hexahedral mesh elements are used for modeling. For structures with material thickness below the thickness threshold, 2D shell elements are used for modeling. For non-uniform material thickness and key castings that are rigidly connected to the chassis, second-order tetrahedral elements are used for modeling.

3. The method of claim 2, wherein, The construction of the finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested also includes: The components of the frame include a front bumper beam, a front crossbeam, a middle crossbeam, a rear crossbeam, a left longitudinal beam, and a right longitudinal beam. The front bumper beam, the front crossbeam, the middle crossbeam, and the rear crossbeam are arranged side by side in sequence according to the X-axis of the vehicle coordinate system. The left longitudinal beam and the right longitudinal beam are symmetrically arranged on both sides of the Y0 plane of the vehicle coordinate system and are respectively connected to the front bumper beam, the front crossbeam, the middle crossbeam, and the rear crossbeam. The connection points of the left longitudinal beam, right longitudinal beam and front anti-collision beam, front crossbeam, middle crossbeam and rear crossbeam are constrained by the connection method of Rbe2-CBeam-Rbe2 unit respectively to simulate the bolt connection method of the connection points. The lap joint of each connection point is also simulated by establishing Rbe2 unit through node to node to simulate weld connection. Assign mesh material properties to each component of the chassis.

4. The method of claim 3, wherein, The simulation analysis of the finite element model yields the unit torsional stress data of the chassis, including: The six degrees of freedom of the nodes of the front anti-collision beam in the middle of the constrained frame located on the Y0 plane are restricted by the Rbe2 unit; The center of the node located in the Y0 plane at the middle of the rear crossbeam is taken as the main node. The main node is subjected to a forced torsion angle of a unit angle around the X-axis, and the stress results of each component of the frame under the unit torsion angle are obtained.

5. The method of claim 4, wherein the method further comprises: The torsional angle combination spectrum data of the rear crossbeam of the composite road frame obtained from actual vehicle road tests includes: Based on the road conditions of the actual vehicle road test site, data collection standards were developed, and combined road surfaces including various reinforced bad roads were set up according to the data collection standards. An angle measuring device is installed in the middle of the rear crossbeam of the actual vehicle frame. According to the accelerated road fatigue test standard, the actual vehicle fatigue test is carried out cyclically on the combined road surface. The torsional angle data of the rear crossbeam of the frame is collected through the angle measuring device during the test. The torsion angle data with high consistency in each cycle are extracted as the torsion angle combination spectrum data of the actual vehicle test, and the torsion angle combination spectrum data is denoised.

6. The method of claim 5, wherein, Based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the chassis under different stresses are calculated. If the total fatigue damage value of any component does not meet the torsional strength requirement, the corresponding component is deemed to have failed, including: Based on the SN curve of the material, the cyclic fatigue life (Ni) of each component under different stresses (Si) is obtained. Using the following formula, it is determined that the fatigue damage value of any component does not meet the torsional strength requirement: n1 / N1+n2 / N2+……+(ni-1) / (Ni-1)+ni / Ni≥1, i≥1; Where i is a natural number greater than 1, ni is the actual number of cycles of a certain stress Si, and ni is obtained through the torsion angle combination spectrum data; ni / Ni is the fatigue damage value of the corresponding component when the actual number of cycles of a certain stress Si is ni; When the actual number of cycles of a certain stress Si is ni, and the sum of the fatigue damage values ​​of any component is not less than 1, the corresponding component is determined to have failed.

7. A non-load-bearing body frame torsional strength analysis system characterized by comprising: include: The model data acquisition module is used to construct a finite element model of the vehicle frame based on the three-dimensional model of the vehicle being tested, assign mesh material properties to each component of the frame in the finite element model, perform simulation analysis on the finite element model, and obtain the unit torsional angle stress data of the frame. The real vehicle data acquisition module is used to acquire time-series data of the torsion angle of the rear crossbeam of the combined road frame as a combination spectrum data based on the real vehicle road test. The simulation test analysis module is used to group the components of the frame according to material properties, match the torsional angle combination spectrum data with the finite element model of the frame to simulate frame fatigue testing; calculate the fatigue damage value of each component of the frame based on the unit torsional angle stress data of the frame and the torsional angle combination spectrum data, until any component is determined to have failed based on the fatigue damage value; including: Based on the mesh material properties, the various components of the frame are grouped, and the material fatigue properties of each component of the frame are set respectively. The torsion angle combination spectrum data is used as a load, and load matching is performed with the finite element model of the frame and the stress results of each component of the frame under a unit torsion angle. The finite element model of the frame is then subjected to load cycling according to the torsion angle combination spectrum data to simulate frame fatigue test. Based on Miner's linear fatigue cumulative damage theory, the fatigue damage values ​​of each component of the frame under different stresses are calculated; if the sum of the fatigue damage values ​​of any component does not meet the torsional strength requirements, the corresponding component is deemed to have failed.

8. An electronic device, comprising: It includes a memory and a processor, wherein the processor is used to execute computer management programs stored in the memory to implement the steps of the non-load-bearing body frame torsional strength analysis method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, It stores a computer management program, which, when executed by a processor, implements the steps of a non-load-bearing vehicle frame torsional strength analysis method as described in any one of claims 1-6.

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