Commercial vehicle rivet strength analysis method and system
By establishing a detailed solid model of the rivet and the connected parts and applying axial preload, combined with multi-condition calculations, the accuracy problem of rivet strength analysis in commercial vehicles was solved, and the reliability assessment and optimized design of rivet connections were realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XUZHOU XCMG AUTOMOTIVE TECHNOLOGY CO LTD
- Filing Date
- 2026-01-13
- Publication Date
- 2026-05-15
AI Technical Summary
In the existing technology, the tensile and shear stress distribution of commercial vehicle rivets cannot be accurately assessed during the overall vehicle strength analysis, leading to rivet breakage and failure, especially at critical connection positions such as leaf spring brackets and longitudinal beams.
By establishing a detailed solid model of the rivet and the connected parts, defining the contact relationship and applying axial preload, and combining multiple working conditions for calculation, the shear and tensile strength of the rivet can be accurately quantified.
It improves the accuracy and prediction precision of rivet strength analysis, enables systematic evaluation of vehicle connection reliability under various working conditions, provides a reliable basis for the optimized design of connected parts, and quickly identifies the cause of failure and provides optimization solutions.
Smart Images
Figure CN122046785A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method and system for analyzing the strength of rivets in commercial vehicles, belonging to the technical field of vehicle rivet strength analysis. Background Technology
[0002] Riveting is the primary method of connecting frames in commercial vehicles. Rivets are the critical path for force transmission between structural components, and their strength directly determines the integrity of the structure and the reliability of force transmission. Currently, when analyzing the strength of the entire vehicle, rivets are not modeled using solid elements, but rather using 1D beam elements. This makes it impossible to obtain accurate tensile and shear stress distributions for the rivets. Furthermore, since the connection points of the connected components are all rigid, the stress error of the connected components is relatively large, making it impossible to accurately evaluate the strength of the rivets. As a result, rivet breakage failures frequently occur in actual use, especially in some critical locations, such as rivets connecting leaf spring brackets and longitudinal beams. Summary of the Invention
[0003] The purpose of this invention is to provide a method and system for analyzing the strength of rivets in commercial vehicles. By establishing a detailed solid model of the rivet and the connected parts, defining the contact relationship and applying axial preload, and then combining calculations under multiple working conditions, the shear and tensile strength of the rivet can be accurately quantified and evaluated, providing a reliable basis for the optimized design of the connected parts.
[0004] To achieve the above objectives, the present invention is implemented using the following technical solution.
[0005] On the one hand, the present invention provides a method for analyzing the strength of rivets in commercial vehicles, comprising the following steps:
[0006] S1. Establish a finite element model of the whole vehicle. For the rivet connection to be analyzed, model the rivet and the connected parts using hexahedral solid elements of preset size.
[0007] S2. Establish a contact relationship between the rivet and the connected parts;
[0008] S3. Apply axial preload to the rivet, set boundary conditions under different typical working conditions, and calculate the shear stress, tensile stress of the rivet and the stress of the connected parts in the connection area.
[0009] S4. Based on the calculated stress, the strength of the rivet is comprehensively evaluated.
[0010] Optionally, in step S1, the mesh nodes at the corresponding connection holes on the connected parts are the same in number and aligned with each other in spatial position.
[0011] The number and circumferential distribution of the mesh nodes on the outer surface of the rivet rod are consistent with the mesh nodes on the inner surface of the hole wall of the connected part.
[0012] Optionally, in step S1, for large connected parts, a 3D hexahedral solid element coupled with a 2D shell element is used for modeling, and the connection is achieved by transitioning the mesh size, so as to reduce the number of meshes in the overall model.
[0013] Optionally, in step S2, establishing a contact relationship between the rivet and the connected parts includes:
[0014] A contact relationship is established between the rivet head and the connected parts, as well as between the rivet shank and the hole wall of the connected parts.
[0015] Optionally, in step S3, the formula for calculating the axial preload is:
[0016] ;
[0017] Among them, the target stress of the rivet rod , The yield strength of the rivet material, and the cross-sectional area of the rivet shank. d is the diameter of the rivet.
[0018] Optionally, in step S3, the typical operating conditions include at least one of the following: bending condition, turning condition, braking condition, and torsion condition.
[0019] Optionally, in step S4, a comprehensive evaluation of the rivet strength is performed, including:
[0020] Evaluation of rivet shear strength: If the shear stress of the rivet is less than its allowable shear stress, then the shear strength of the rivet is deemed to meet the requirements.
[0021] Evaluation of rivet tensile strength: If the tensile stress of the rivet is less than its allowable tensile stress, then the tensile strength of the rivet is deemed to meet the requirements;
[0022] Evaluation of the strength of the connected parts: If the stress in the connection area of the connected parts is less than the yield strength of its material, then the strength of the connected parts is determined to meet the requirements.
[0023] Optionally, the rivet connection strength is deemed qualified only if all three evaluation criteria—rivet shear strength, rivet tensile strength, and strength of the connected parts—meet the requirements.
[0024] Secondly, the present invention provides a commercial vehicle rivet strength analysis system, comprising:
[0025] The model building module is used to build a finite element model of the whole vehicle. For the rivet connection to be analyzed, the rivet and the connected parts are modeled using hexahedral solid elements of preset size.
[0026] The contact relationship definition module is used to establish a contact relationship between the rivet and the connected parts;
[0027] The loading and solving module is used to apply axial preload to the rivet, set boundary conditions under different typical working conditions, and calculate the shear stress, tensile stress of the rivet and the stress of the connected parts in the connection area.
[0028] The strength evaluation module is used to comprehensively evaluate the strength of the rivet based on the calculated stress.
[0029] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:
[0030] This invention performs refined modeling and contact analysis on rivets and connected components at critical locations, revealing the stress state at the rivet connection more realistically and improving prediction accuracy. By applying axial preload, the influence of assembly processes is incorporated into the analysis, making the simulation results closer to the mechanical state of the actual product. By setting boundary conditions under different operating conditions, this invention can systematically evaluate the connection reliability of vehicles under various conditions, providing a comprehensive and accurate assessment. It can precisely quantify the shear and tensile strength of rivets and provide a reliable basis for the optimized design of connected components. Furthermore, for rivets that have failed in the market, it can quickly identify the cause of failure, provide optimization solutions, and achieve problem closure. The use of a 3D mesh coupled with a 2D mesh method ensures a low overall mesh count and high computational efficiency. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the commercial vehicle rivet strength analysis method provided in an embodiment of the present invention;
[0032] Figure 2 This is a schematic diagram of the overall vehicle frame model provided in an embodiment of the present invention;
[0033] Figure 3 This is a schematic diagram of a partial treatment of a key rivet connection provided in an embodiment of the present invention.
[0034] Among them: 1. Rivets; 2. Frame longitudinal beams; 3. Frame crossbeams; 4. Front leaf spring fixing end brackets. Detailed Implementation
[0035] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.
[0036] Example 1
[0037] This embodiment introduces a method for analyzing the strength of rivets in commercial vehicles. Based on engineering experience and rivet failure issues in the market, a strength analysis is performed on the connecting rivets between the front leaf spring fixing bracket and the longitudinal beam of the frame during the development of a light truck. Figure 1 As shown, the specific steps are as follows:
[0038] S1. Finite element modeling of the entire vehicle:
[0039] like Figure 2 and Figure 3 As shown, a finite element model of the entire vehicle is established. This example uses common finite element modeling software in this field for analysis. In the vehicle model, the riveted connection areas of the front leaf spring fixing bracket 4, the frame longitudinal beam 2, and the frame cross beam 3 are modeled in detail. These areas are all divided using hexahedral solid elements with an average size of 2mm. During modeling, it is ensured that the front leaf spring fixing bracket 4 and the corresponding rivet holes on the frame have the same number of network nodes, and the node positions correspond one-to-one to ensure the accuracy of subsequent contact calculations.
[0040] For the main structural parts such as longitudinal beams and transverse beams, which are far from the connection area, 2D shell elements with an average size of 10mm are used for modeling to control the model's scale. Between the refined solid region and the main shell element region, 3D hexahedral elements are coupled with 2D shell elements, and the connection is achieved through a smooth transition in mesh size. This transitions the mesh size from 2mm solid elements to an average 10mm shell element, thereby significantly reducing the number of elements in the overall model and improving computational efficiency while maintaining the computational accuracy in critical areas.
[0041] Rivet 1 is also modeled using hexahedral solid elements with an element size of approximately 2mm. During modeling, the number and circumferential distribution of the mesh nodes on the outer surface of the rivet shank are consistent with and correspond to the mesh nodes on the inner surface of the rivet hole wall on the front leaf spring fixing end bracket and the frame, so as to accurately simulate the actual geometric state of the rivet being upset and bulging into the hole wall after cold riveting.
[0042] S2. Definition of contact relationship:
[0043] Two key contact relationships are established in the finite element model, specifically including:
[0044] Establish surface-to-surface contact between the rivet head and the frame and the front leaf spring fixing end bracket.
[0045] A surface-to-surface contact is established between the outer surface of the rivet shank and the wall of the rivet hole.
[0046] The contact properties are set to frictional contact to simulate force transmission and possible relative slippage between the connected components (the longitudinal / crossbeams of the frame and the front leaf spring fixed end bracket).
[0047] S3. Applying axial preload to the rivets and setting the working conditions:
[0048] The rivet material is ML15, and its yield strength is... 225 MPa
[0049] In cold riveting, the axial preload of the rivet mainly comes from the axial flow of the material and the elastic recovery of the connected parts during the riveting process. In engineering practice, its size is indirectly obtained by controlling the size of the rivet head and appropriate plastic deformation. Generally speaking, after cold riveting, the tensile stress generated in the rivet shank is about 50% of its yield strength.
[0050] The target stress of the rivet rod is: =112.5 MPa; rivet diameter d=10 mm, its cross-sectional area ;
[0051] Axial preload of a single rivet: .
[0052] The preload is applied as an initial load to the cross section of the rivet shank.
[0053] Set the boundary conditions and loads for the following four typical load conditions:
[0054] Bending condition: Simulates a fully loaded static state.
[0055] Turning condition: Simulates the lateral inertial force generated when turning at a certain speed under full load.
[0056] Braking condition: Simulates the longitudinal inertial force generated during emergency braking.
[0057] Torsional load condition: Simulates the torsional load generated on the vehicle frame when one wheel of the vehicle passes over a raised obstacle.
[0058] After setting the load and boundary conditions, submit the calculation to obtain the shear stress, tensile stress of the rivet, and the stress around the connecting hole of the front leaf spring bracket and the cross / longitudinal beams of the frame under each working condition.
[0059] S4. Strength Evaluation:
[0060] The intensity is evaluated from the following three dimensions:
[0061] Rivet shear strength evaluation: The maximum shear stress of the rivet under torsion condition was found to be 89 MPa, while the allowable shear stress of the rivet material is 80 MPa. Therefore, it is determined that the shear strength of the rivet does not meet the requirements.
[0062] Rivet tensile strength evaluation: The maximum tensile stress of the rivet under all working conditions is lower than its allowable tensile stress, and the tensile strength meets the requirements.
[0063] Strength evaluation of connected components: The stress values at the maximum stress points of the front leaf spring bracket and the cross / longitudinal beams of the frame are all lower than the yield strength of their materials, and the static strength meets the requirements.
[0064] Based on the above three-dimensional evaluation, the rivet shear strength at this connection point is relatively weak. It is advisable to consider replacing it with a rivet with higher shear performance or optimizing the connection design.
[0065] Example 2
[0066] Based on the same inventive concept as Embodiment 1, this embodiment introduces a commercial vehicle rivet strength analysis system, including:
[0067] The model building module is used to build a finite element model of the whole vehicle. For the rivet connection to be analyzed, the rivet and the connected parts are modeled using hexahedral solid elements of preset size.
[0068] The contact relationship definition module is used to establish a contact relationship between the rivet and the connected parts;
[0069] The loading and solving module is used to apply axial preload to the rivet, set boundary conditions under different typical working conditions, and calculate the shear stress, tensile stress of the rivet and the stress of the connected parts in the connection area.
[0070] The strength evaluation module is used to comprehensively evaluate the strength of the rivet based on the calculated stress.
[0071] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 1, and will not be repeated here.
[0072] In summary, this invention performs refined modeling and contact analysis on rivets and connected components at critical locations, more realistically revealing the stress state at the rivet connection and improving prediction accuracy. By applying axial preload, the influence of assembly processes is incorporated into the analysis, making the simulation results closer to the mechanical state of the actual product. By setting boundary conditions under different operating conditions, this invention can systematically evaluate the connection reliability of vehicles under various conditions, providing a comprehensive and accurate assessment. It can precisely quantify the shear and tensile strength of rivets and provide a reliable basis for the optimized design of connected components. Furthermore, for rivets that have failed in the market, the cause of failure can be quickly identified, and optimization solutions can be provided, achieving problem closure. The use of a 3D mesh coupled with a 2D mesh method ensures that the overall mesh count of the model is not excessive, guaranteeing high computational efficiency.
[0073] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.
Claims
1. A method for analyzing the strength of rivets used in commercial vehicles, characterized in that, Includes the following steps: S1. Establish a finite element model of the whole vehicle. For the rivet connection to be analyzed, model the rivet and the connected parts using hexahedral solid elements of preset size. S2. Establish a contact relationship between the rivet and the connected parts; S3. Apply axial preload to the rivet, set boundary conditions under different typical working conditions, and calculate the shear stress, tensile stress of the rivet and the stress of the connected parts in the connection area. S4. Based on the calculated stress, the strength of the rivet is comprehensively evaluated.
2. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S1, the mesh nodes at the corresponding connection holes on the connected parts are the same in number and aligned with each other in spatial position. The number and circumferential distribution of the mesh nodes on the outer surface of the rivet rod are consistent with the mesh nodes on the inner surface of the hole wall of the connected part.
3. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S1, for large connected parts, 3D hexahedral solid elements and 2D shell elements are coupled to model them, and the connection is achieved by transitioning the mesh size to reduce the number of meshes in the overall model.
4. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S2, establishing a contact relationship between the rivet and the connected parts includes: A contact relationship is established between the rivet head and the connected parts, as well as between the rivet shank and the hole wall of the connected parts.
5. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S3, the formula for calculating the axial preload is: ； Among them, the target stress of the rivet rod , The yield strength of the rivet material, and the cross-sectional area of the rivet shank. d is the diameter of the rivet.
6. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S3, the typical operating conditions include at least one of the following: bending condition, turning condition, braking condition, and torsion condition.
7. The method for analyzing the strength of commercial vehicle rivets according to claim 1, characterized in that, In step S4, a comprehensive evaluation of the rivet strength is performed, including: Evaluation of rivet shear strength: If the shear stress of the rivet is less than its allowable shear stress, then the shear strength of the rivet is deemed to meet the requirements. Evaluation of rivet tensile strength: If the tensile stress of the rivet is less than its allowable tensile stress, then the tensile strength of the rivet is deemed to meet the requirements; Evaluation of the strength of the connected parts: If the stress in the connection area of the connected parts is less than the yield strength of its material, then the strength of the connected parts is determined to meet the requirements.
8. The method for analyzing the strength of commercial vehicle rivets according to claim 7, characterized in that, The rivet connection strength is deemed qualified only if all three evaluation criteria—rivet shear strength, rivet tensile strength, and strength of the connected parts—meet the requirements.
9. A rivet strength analysis system for commercial vehicles, characterized in that, include: The model building module is used to build a finite element model of the whole vehicle. For the rivet connection to be analyzed, the rivet and the connected parts are modeled using hexahedral solid elements of preset size. The contact relationship definition module is used to establish a contact relationship between the rivet and the connected parts; The loading and solving module is used to apply axial preload to the rivet, set boundary conditions under different typical working conditions, and calculate the shear stress, tensile stress of the rivet and the stress of the connected parts in the connection area. The strength evaluation module is used to comprehensively evaluate the strength of the rivet based on the calculated stress.