A vehicle body stiffness analysis method based on vehicle load

Abstract

The application discloses a vehicle body rigidity analysis method based on vehicle load, which comprises the following steps: S1, establishing a finite element grid model; S2, loading point processing; S3, load application; S4, load step establishment; S5, submitting calculation; S6, post-processing analysis, and evaluating the analysis result. The application defines the loading according to the design axle load, and the vehicle body deformation state is consistent with the actual state; the overall rigidity and local position deformation are comprehensively evaluated, so that the evaluation of the traditional single rigidity value is avoided; and the overall rigidity index can reflect the performance requirement of the designed vehicle model.

Description

Technical Field

[0001] This invention relates to a method for analyzing vehicle body stiffness, and more specifically, to a method for analyzing vehicle body stiffness based on vehicle load. Background Technology

[0002] Body stiffness is an important basic performance of automobiles, which has a significant impact on vehicle handling, NVH performance, strength and durability. In the development of traditional fuel vehicles, body stiffness is generally maximized through structural optimization design while meeting weight and cost targets.

[0003] With the advent of electric vehicles, the distribution of weight on the vehicle body has changed significantly, such as the arrangement of the power battery pack and motor. Therefore, designing the vehicle body frame stiffness to meet the specific requirements of electric vehicles has become crucial. Current early-stage designs typically involve benchmarking the stiffness performance of competing products through analysis or testing, and then using this as a basis for design.

[0004] Existing methods for analyzing vehicle body torsional stiffness involve: building a finite element model of the vehicle body or a test bench; constraining the mounting points of the front bumper beam and rear shock absorber; applying a fixed torque to the mounting points of the front shock absorber (regardless of vehicle model); analyzing or testing to extract the deformation and torsional angles at the measurement points of the left and right longitudinal beams of the vehicle body; and finally calculating the torsional stiffness value of the vehicle body using the torque and torsional angle, and using this to evaluate the stiffness performance of the vehicle body.

[0005] However, existing technologies have the following drawbacks:

[0006] 1. It does not differentiate between vehicle models and applies a fixed torque, which is seriously inconsistent with the actual stress state of the vehicle body.

[0007] 2. The calculated torsional stiffness value of the vehicle body can only reflect an overall state, and the assessment of the stiffness of the local structural parts of the vehicle body is lacking.

[0008] 3. Body stiffness is not directly related to the actual performance requirements of the designed vehicle model. Different vehicle models have vastly different stiffness performance requirements, which is one of the key issues in defining body stiffness targets. Summary of the Invention

[0009] One objective of this invention is to provide a new technical solution for a vehicle body stiffness analysis method based on vehicle load, in order to solve the problems mentioned in the background art.

[0010] According to a first aspect of the present invention, a method for analyzing vehicle body stiffness based on vehicle load is provided, comprising the following steps:

[0011] S1, Establish the finite element mesh model;

[0012] S2, Load point processing;

[0013] S3, load applied;

[0014] S4, load step establishment;

[0015] S5, Submit calculation;

[0016] S6. Post-analysis processing and evaluation of the analysis results.

[0017] Optionally, according to the vehicle body stiffness analysis method based on the whole vehicle load of the present invention, in step S1, a finite element mesh model is established based on the three-dimensional CAD model of the body-in-white, and the material property connections are defined according to the linear analysis type.

[0018] Optionally, according to the vehicle body stiffness analysis method based on vehicle load of the present invention, in S2, the hard points of the front and rear shock absorbers are the main points, the mounting bolt holes of the front and rear shock absorbers are the slave points, the connection is established by using rbe2 rigid elements, and the hard points of the front and rear shock absorbers are the loading points.

[0019] Optionally, according to the vehicle body stiffness analysis method based on the whole vehicle load of the present invention, in S3, the torque load is converted according to the design axle load, and the maximum torque value is applied uniformly before and after.

[0020] Optionally, according to the vehicle body stiffness analysis method based on the whole vehicle load of the present invention, in S4, the load is defined according to the converted load value, the Load Step is set to select the established load in the Load option, the calculation control is selected to use the linear static analysis method and inertial release, and the displacement of the output loading point is set.

[0021] Optionally, according to the vehicle body stiffness analysis method based on whole vehicle load of the present invention, in step S5, the established finite element model is saved as a *.BDF file and submitted to MSC NASTRAN software for calculation.

[0022] Optionally, according to the vehicle body stiffness analysis method based on the whole vehicle load of the present invention, in S6, the analysis results are opened using post-processing software, and the longitudinal beam deformation torsion angle A, the diagonal deformation B of the engine compartment, passenger compartment and rear luggage compartment, and the diagonal deformation C of the front door opening, rear door opening and tailgate opening are output.

[0023] Optionally, according to the vehicle body stiffness analysis method based on vehicle load of the present invention, in step S6, the evaluation index is as follows:

[0024] ① Diagonal deformation in key local areas and diagonal deformation of doorways;

[0025] ② Overall stiffness, the stiffness K is defined as:

[0026] K=T / A,

[0027] Where T is the applied torque, T=24700Nm.

[0028] The beneficial effects of the technical solution of this invention are as follows:

[0029] 1. Loading is performed according to the design axle load definition, and the vehicle body deformation state is consistent with the actual deformation.

[0030] 2. By comprehensively evaluating overall stiffness and local deformation, the traditional evaluation based on a single stiffness value is avoided;

[0031] 3. The overall stiffness index can reflect the performance requirements of the designed vehicle model.

[0032] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0034] Figure 1 This is a schematic diagram of the body-in-white model disclosed in this invention. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0038] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] This invention provides a new technical solution for a vehicle body stiffness analysis method based on vehicle load, in order to solve the problems mentioned in the background art.

[0040] According to a first aspect of the present invention, a method for analyzing vehicle body stiffness based on vehicle load is provided, comprising the following steps:

[0041] S1, Establish the finite element mesh model;

[0042] S2, Load point processing;

[0043] S3, load applied;

[0044] S4, load step establishment;

[0045] S5, Submit calculation;

[0046] S6. Post-analysis processing and evaluation of the analysis results.

[0047] like Figure 1 As shown, in S1, a finite element mesh model is established based on the three-dimensional CAD model of the white body, and the material property connections are defined according to the linear analysis type.

[0048] Furthermore, in S2, the hard points of the front and rear shock absorbers are the main points, and the mounting bolt holes of the front and rear shock absorbers are the secondary points. The connection is established using rbe2 rigid units, and the hard points of the front and rear shock absorbers are used as loading points.

[0049] Furthermore, in step S3, the torque load is converted according to the design axle load, and the maximum torque value is applied uniformly before and after the conversion, as shown in Table 1:

[0050] Table 1 Loading

[0051]

[0052] Furthermore, in S4, the load is defined according to the converted load value, the Load Step is set, the load is selected in the Load option, the calculation control is selected as linear static analysis method and inertial release, and the displacement of the output loading point is set.

[0053] Furthermore, in step S5, the established finite element model is saved as a *.BDF file and submitted to the MSCNASTRAN software for calculation.

[0054] Furthermore, in S6, the analysis results are opened using post-processing software, and the longitudinal beam deformation torsion angle A, the diagonal deformation B of the cabin, passenger compartment, and rear luggage compartment, and the diagonal deformation C of the front door opening, rear door opening, and tail door opening are output.

[0055] Furthermore, in S6, the evaluation indicators are as follows:

[0056] ① Diagonal deformation in key local areas and diagonal deformation of doorways;

[0057] ② Overall stiffness, the stiffness K is defined as:

[0058] K=T / A,

[0059] Where T is the applied torque, T=24700Nm.

[0060] By comprehensively examining the vehicle body rigidity performance through the above evaluation indicators, and after a certain period of development and accumulation, the assessment targets will be effectively defined according to the vehicle model positioning in the later stages.

[0061] By combining the deformation of key local areas and the deformation of doorways, areas that need optimization can be effectively identified, and weak areas can be strengthened to effectively ensure the stiffness performance requirements of different locations. This avoids using a single overall stiffness value as the optimization target and ignoring weak areas.

[0062] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for analyzing vehicle body stiffness based on whole vehicle load, characterized in that, Includes the following steps: S1, Establish the finite element mesh model; S2, Loading point processing, in which the hard points of the front and rear shock absorbers are the main points, and the mounting bolt holes of the front and rear shock absorbers are the slave points. The connection is established using the rbe2 rigid element, and the hard points of the front and rear shock absorbers are used as loading points. S3, load application, wherein the torque load is converted according to the design axle load, and the maximum torque value is applied uniformly before and after. The Z-direction load of the left front shock absorber is positive 12350N, the Z-direction load of the right front shock absorber is negative 12350N, the Z-direction load of the left rear shock absorber is negative 9500N, and the Z-direction load of the right rear shock absorber is positive 9500N. S4, load step establishment; S5, Submit calculation; S6. Post-analysis processing and evaluation of the analysis results.

2. The method for analyzing vehicle body stiffness based on whole vehicle load according to claim 1, characterized in that, In S1, a finite element mesh model is established based on the three-dimensional CAD model of the body-in-white, and the material property connections are defined according to the linear analysis type.

3. The method for analyzing vehicle body stiffness based on whole vehicle load according to claim 1, characterized in that, In S4, the load is defined according to the converted load value, the Load Step is set, the load is selected in the Load option, the calculation control is selected as linear static analysis method and inertial release, and the displacement of the output loading point is set.

4. The method for analyzing vehicle body stiffness based on whole vehicle load according to claim 1, characterized in that, In step S5, the established finite element model is saved as a *.BDF file and submitted to the MSC NASTRAN software for calculation.

5. The method for analyzing vehicle body stiffness based on whole vehicle load according to claim 1, characterized in that, In S6, the analysis results are opened using post-processing software, and the longitudinal beam deformation torsion angle A, the diagonal deformation B of the cabin, passenger compartment, and rear luggage compartment, and the diagonal deformation C of the front door opening, rear door opening, and tail door opening are output.

6. The method for analyzing vehicle body stiffness based on whole vehicle load according to claim 1, characterized in that, In S6, the evaluation indicators are as follows: Key local diagonal deformation and doorway diagonal deformation; overall stiffness, stiffness K is defined as: K=T / A, Where T is the applied torque, T=24700Nm.

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