A load application method for a body-in-white bending stiffness simulation load application device

Abstract

The present invention discloses a load application method for a BIW bending stiffness simulation load application device, comprising a simulation rod for applying a load and a simulation plate fixedly connected to the bottom of the simulation rod through a one-dimensional connecting beam unit and used to transfer the load to the load application location of the BIW bending stiffness simulation test; at least one simulation plate is symmetrically connected to the left and right sides of the simulation rod. By utilizing the simulation loading device designed by the present invention, the BIW bending stiffness can be obtained simply, accurately and quickly, and the BIW bending stiffness performance can be accurately evaluated in the early stage of project development, thereby improving the BIW development efficiency, avoiding repeated modifications in the later physical stage due to inaccurate early performance evaluation, and saving development costs and time.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle testing, and in particular to a load applying method of a vehicle body-in-white bending stiffness simulation load applying device. Background Art

[0002] BIW stiffness is a key performance indicator for BIW, reflecting its ability to resist deformation. BIW stiffness is closely related to performance such as NVH, fatigue, and handling stability. Therefore, during the design phase, BIW stiffness must be maximized while maintaining weight control.

[0003] However, during the design phase, because the BIW wasn't physically produced, direct bending tests couldn't be performed on it. Simulation was required to assess the body's stiffness. Therefore, the results of this simulation should be consistent with those from actual bending tests to provide better design guidance.

[0004] Currently, the loading method for BIW bending stiffness simulation involves applying a simulated load to the sill beam, seat mounting point, or seat H-point. Actual BIW bending tests typically involve stacking sandbags at the loading points or applying loads to the loading points via a loading device. BIW bending simulations apply concentrated force to a single area or point, while actual BIW bending tests typically load a larger load-bearing area. Furthermore, there are discrepancies between the simulated and actual loading locations of the BIW, resulting in significant discrepancies between the BIW bending simulation and actual test results, impacting development work during the design phase. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned background technology and to provide a load application method for a body-in-white bending stiffness simulation load application device that ensures consistency between simulation test and actual test results and effectively improves simulation efficiency and accuracy.

[0006] To achieve this purpose, the body-in-white bending stiffness simulation load application device designed in the present invention includes a simulation rod for applying load and a simulation plate fixedly connected to the bottom of the simulation rod through a one-dimensional connecting beam unit and used to transfer the load to the load application point of the body-in-white bending stiffness simulation test; at least one simulation plate is symmetrically connected to the left and right sides of the simulation rod.

[0007] Furthermore, the simulation rod comprises a plurality of one-dimensional beam units arranged in the same direction and fixedly connected end to end to form an integrated structure.

[0008] Furthermore, the simulation plate includes at least two shell units symmetrically connected below the simulation rod.

[0009] Furthermore, the shell unit is composed of a plurality of grid units.

[0010] Furthermore, the shell unit is a regular polygonal structure with multiple vertices, and the vertices of the same shell unit are fixedly connected to a node of the one-dimensional beam unit on one side of the simulation rod through a one-dimensional connecting beam unit.

[0011] The load application method based on the above-mentioned body-in-white bending stiffness simulation load application device includes: importing the body-in-white bending stiffness simulation load application device into the body-in-white mesh model, setting the material properties of the body-in-white bending stiffness simulation load application device and the bending load loading position of the body-in-white bending stiffness simulation load application device on the body-in-white, applying a load to the body-in-white bending stiffness simulation load application device, and judging whether the body-in-white bending stiffness meets the requirements.

[0012] Furthermore, the method for setting the bending load loading position of the body-in-white bending stiffness simulation load applying device on the body-in-white is: two of the body-in-white bending stiffness simulation load applying devices are respectively set above the front and rear row seat sheet metals of the body-in-white, the simulation rods are arranged along the width direction of the body, the simulation panel is located directly above the seat sheet metal, and the distance L between the simulation panel and the seat sheet metal is set.

[0013] Furthermore, the distance L between the simulation panel and the seat sheet metal is 0.5t-t, where t is the thickness of the seat sheet metal.

[0014] Furthermore, applying the load to the BIW bending stiffness simulation load applying device includes: applying the load symmetrically along the height direction of the BIW at both end nodes of the simulation rod.

[0015] Furthermore, the method for determining whether the bending stiffness of the body-in-white meets the requirements is: calculating the bending stiffness of the body-in-white in a simulated bending test, comparing the bending stiffness of the body-in-white in a simulated bending test with a set value; if the bending stiffness of the body-in-white in the simulated bending test is not less than the set value, the bending stiffness of the body-in-white meets the requirements; otherwise, the bending stiffness of the body-in-white does not meet the requirements.

[0016] Furthermore, the calculation formula for the bending stiffness of the simulated bending test of the body-in-white is: K=F / d, wherein K is the bending stiffness of the simulated bending test of the body-in-white, F is the load applied to the body-in-white bending stiffness simulation load application device, and d is the maximum deformation of the body-in-white rocker beam in the body height direction.

[0017] The beneficial effects of the present invention are as follows: the present invention designs a load application device for simulation for the bending stiffness test of the body-in-white. By combining the simulation rod and the simulation plate, the device can ensure the size and direction of the load during loading, and has good calculation accuracy. The simulation loading device is consistent with the loading device structure used in the actual bending test of the body-in-white. By applying a -Z direction load at both ends of the simulation rod, the point-based simulation load is converted into a surface-based simulation load through the simulation plate, which corresponds to the surface-based loading method in the actual bending test of the body-in-white (such as piling sandbags on top of the seat sheet metal, etc.). The load application method based on the simulation loading device maintains good consistency with the actual bending test, solving the problem of inconsistent simulation and actual measurement results that plagues the initial design; at the same time, the simulation loading device model designed by the present invention can be directly reused after it is established, thereby improving the simulation efficiency. In summary, the simulation loading device designed by the present invention can be used to obtain the bending stiffness of the body-in-white simply, accurately and quickly, and can accurately evaluate the bending stiffness performance of the body-in-white in the early stage of project development, thereby improving the efficiency of the body-in-white development, avoiding repeated modifications in the later physical stage due to inaccurate early performance evaluation, and saving development costs and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A perspective view of a load application device for simulating bending stiffness of a body-in-white according to the present invention;

[0019] Figure 2 This is a front view of the load loading structure of the body-in-white bending stiffness simulation load application device of the present invention;

[0020] Among them, 1 is the simulated rod (1.1 is the one-dimensional beam element), 2 is the simulated plate (2.1 is the shell element), and 3 is the one-dimensional connecting beam element. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0022] like Figure 1As shown in FIG2 , the BIW bending stiffness simulation load application device designed by the present invention comprises a simulation rod 1 for applying a load and a simulation plate 2 fixedly connected to the bottom of the simulation rod 1 through a one-dimensional connecting beam unit 3 and used for transferring the load to the load application location of the BIW bending stiffness simulation test; at least one simulation plate 2 is symmetrically connected to the left and right sides of the simulation rod 1.

[0023] Example 1 of the simulation rod 1:

[0024] The simulation rod 1 comprises a plurality of one-dimensional beam elements 1.1 arranged in the same direction and fixedly connected end to end to form an integrated structure.

[0025] Example 1 of simulation board 2:

[0026] The simulation plate 2 includes at least two shell elements 2.1 symmetrically connected to the bottom of the simulation rod 1, and the shell element 2.1 is composed of multiple grid elements.

[0027] Example 2 of the simulation board 2:

[0028] Based on the above-mentioned embodiment 1 of the simulation panel 2, the shell element 2.1 is optimized as follows:

[0029] The shell element 2.1 is a regular polygonal structure with multiple vertices. The vertices of the same shell element 2.1 are fixedly connected to a node of the one-dimensional beam element 2.1 on one side of the simulation rod 1 through a one-dimensional connecting beam element 3.

[0030] Embodiment 1 of the load application method based on the above-mentioned body-in-white bending stiffness simulation load application device:

[0031] Import the BIW bending stiffness simulation load application device into the BIW mesh model, set the material properties of the BIW bending stiffness simulation load application device and the bending load loading position of the BIW bending stiffness simulation load application device on the BIW, apply the load to the BIW bending stiffness simulation load application device, and judge whether the BIW bending stiffness meets the requirements.

[0032] Embodiment 1 of the method for setting the bending load loading position of the body-in-white bending stiffness simulation load applying device on the body-in-white:

[0033] Two BIW bending stiffness simulation load application devices are respectively set above the front and rear seat sheet metals of the BIW. The simulation rod 1 is arranged along the width direction of the vehicle body, and the simulation panel 2 is located directly above the seat sheet metal. The distance L between the simulation panel 2 and the seat sheet metal is set. L is 0.5t, and t is the thickness of the seat sheet metal.

[0034] Example 1 of applying a load to a body-in-white bending stiffness simulation load applying device:

[0035] Loads are applied symmetrically along the height direction of the body-in-white at the nodes at both ends of the simulation rod 1.

[0036] Example 1 of the method for determining whether the bending stiffness of the body-in-white meets the requirements:

[0037] Calculate the bending stiffness of the body-in-white (BIW) in the simulated bending test, and compare the bending stiffness of the body-in-white (BIW) in the simulated bending test with a set value. If the bending stiffness of the body-in-white (BIW) in the simulated bending test is not less than the set value, the bending stiffness of the body-in-white (BIW) meets the requirements; otherwise, the bending stiffness of the body-in-white (BIW) does not meet the requirements. The calculation formula for the bending stiffness of the body-in-white (BIW) in the simulated bending test is: K = F / d, where K is the bending stiffness of the body-in-white (BIW) in the simulated bending test, F is the load applied to the BIW bending stiffness simulation load application device, and d is the maximum deformation of the BIW sill beam in the body height direction.

[0038] A specific embodiment of the vehicle body-in-white bending stiffness simulation load application device is described below.

[0039] like Figure 1 As shown in Figure 2, the present invention is a load-applying device for simulating the bending stiffness of a body-in-white (BIW) for computer simulation. A finite element model of the device is created on a computer and, in conjunction with a finite element model of the vehicle body, enables virtual simulation of the BIW's bending stiffness. Once created, the device can be stored on a computer medium and directly imported for use in developing different vehicle models.

[0040] The vehicle coordinate system is defined as follows: the X direction is the longitudinal direction of the vehicle, from the front to the rear; the Y direction is the lateral direction of the vehicle, from left to right; and the Z direction is the height direction of the vehicle, from bottom to top.

[0041] The structure of the load application device for BIW bending stiffness simulation is as follows: Figure 1 As shown in Figure 2, the device is a rigid loading beam structure composed of four one-dimensional beam elements 1.1, eight one-dimensional connecting beam elements 3, and two shell elements 2.1 (dividable into several grid elements), containing 13 main nodes and shell elements. The beam elements simulate rods in real objects, while the shell elements 2.1 simulate plates in real objects. Shell elements 2.1 are square. The one-dimensional beam elements 1.1 and the one-dimensional connecting beam elements 3 have the same structure, material, and dimensions. The device is bilaterally symmetrical (about the vehicle coordinate plane Y = 0). The midpoint of the simulated rod 1 is a symmetry point, located on the vehicle coordinate plane Y = 0. Constraining the degrees of freedom at this point limits the simulated loading device's translational degrees of freedom in the X and Y directions and its rotational degrees of freedom in the X, Y, and Z directions, ensuring that the simulated loading device only has displacement in the Z direction and no movement or rotation in other directions. The load applied by the simulated loading device to the vehicle body is bilaterally symmetrical, and the length and size of the device can be adjusted according to the vehicle model.

[0042] After determining the structure and dimensions of the simulation loading device, set its material properties. The simulation loading device designed in this invention has the same structure as the loading device used in actual BIW bending tests. If the BIW bending stiffness test device is standardized, the simulation loading model parameters can be assigned based on the actual panel thickness and crossbeam cross-sectional parameters of the BIW bending test device. If the BIW bending test device is not standardized, that is, if there are multiple bending test mechanisms and multiple test loading devices, the simulation model parameters can be assigned based on the BIW bending test device with the highest stiffness.

[0043] After determining the structure, size and material properties of the simulation loading device, the simulation loading device is used as follows: the device is imported into the body-in-white mesh model, and then two simulation loading devices are imported. The two simulation loading devices are placed on the front and rear seat sheet metals respectively. The distance between the bottom surface of the shell unit 2.1 of the simulation loading device and the body-in-white sheet metal is 0.5t (t is the thickness of the sheet metal under the shell unit 2.1), and the contact relationship between the shell unit 2.1 and the body sheet metal is established. The distance between the bottom surface of the shell unit 2.1 of the simulation loading device and the body-in-white sheet metal is set to 0.5t. When a -Z load is applied to the simulation loading device, the shell unit 2.1 will move downward and contact the body, avoiding the influence of the shell unit 2.1 itself on the body-in-white bending test, and ensuring that the test structure of the body-in-white bending simulation test is consistent with the test results of the actual bending test.

[0044] Calculation of the bending stiffness of the body in white. Figure 2 A -Z load is applied at the node shown, and the load is transferred to the shell unit 2.1 through the loading device, and then transferred to the body through the contact relationship between the shell unit 2.1 and the body, causing the body to deform. The maximum deformation of the door sill beam in the Z direction is measured by post-processing software. The bending stiffness of the body-in-white is calculated by the following formula: K = F / d. K-bending stiffness, F-load size, d-maximum deformation of the door sill in the Z direction. The bending stiffness of the simulated bending test of the body-in-white is compared with the set value. If the bending stiffness of the simulated bending test of the body-in-white is not less than the set value, the bending stiffness of the body-in-white meets the requirements, otherwise the bending stiffness of the body-in-white does not meet the requirements. The size of the simulated load F in the present invention can be set according to the load of the actual bending test of the body-in-white to ensure that the load value of the simulated panel 2 on the body seat sheet metal is the same as the load value received by the actual bending test of the body-in-white.

[0045] The present invention designs a load application device for simulation in the bending stiffness test of the body-in-white. By combining the simulation rod 1 with the simulation plate 2, the device can ensure the size and direction of the load during loading, and has good calculation accuracy. The simulation loading device is consistent with the loading device structure used in the actual bending test of the body-in-white. By applying a -Z direction load at both ends of the simulation rod 1, the point-based simulation load is formed into a surface-based simulation load through the simulation plate 2, which corresponds to the surface-based loading method in the actual bending test of the body-in-white (such as piling sandbags on top of the seat sheet metal, etc.). The load application method based on the simulation loading device maintains good consistency with the actual bending test, solving the problem of inconsistent simulation and actual measurement results that plagues the initial design; at the same time, the simulation loading device model designed by the present invention can be directly reused after it is established, thereby improving the simulation efficiency. In summary, the simulation loading device designed by the present invention can be used to obtain the bending stiffness of the body-in-white simply, accurately and quickly, and can accurately evaluate the bending stiffness performance of the body-in-white in the early stage of project development, thereby improving the development efficiency of the body-in-white, avoiding repeated modifications in the later physical stage due to inaccurate early performance evaluation, and saving development costs and time.

[0046] It should be noted that the description of the above technical solutions is exemplary, and this specification can be embodied in different forms and should not be interpreted as being limited to the technical solutions set forth herein. On the contrary, providing these descriptions will make the disclosure of the present invention thorough and complete, and will fully convey the scope disclosed in this specification to those skilled in the art. In addition, the technical solutions of the present invention are limited only by the scope of the claims. When using "including", "having" and "comprising" described in this specification, it may also have another part or other parts, and the terms used may generally be singular but may also represent plural forms.

[0047] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and is susceptible to numerous variations. Any simple modifications, equivalent variations, and modifications to the above embodiments based on the technical essence of the present invention shall be deemed to fall within the scope of protection of the present invention.

Claims

1. A load application method for a vehicle body in white bending stiffness simulation load application device, characterized by: The body-in-white bending stiffness simulation load application device comprises a simulation rod (1) for applying a load and a simulation plate (2) fixedly connected to the bottom of the simulation rod (1) via a one-dimensional connecting beam unit (3) and used to transfer the load to the load application location of the body-in-white bending stiffness simulation test; at least one simulation plate (2) is symmetrically connected to the left and right sides of the simulation rod (1); The load application method of the body-in-white bending stiffness simulation load application device comprises the following steps: importing the body-in-white bending stiffness simulation load application device into the body-in-white mesh model, setting the material properties of the body-in-white bending stiffness simulation load application device and the bending load loading position of the body-in-white bending stiffness simulation load application device on the body-in-white, applying a load to the body-in-white bending stiffness simulation load application device, and judging whether the body-in-white bending stiffness meets the requirements; the method for setting the bending load loading position of the body-in-white bending stiffness simulation load application device on the body-in-white is as follows: two body-in-white bending stiffness simulation load application devices are respectively arranged above the front and rear row seat sheet metals of the body-in-white, the simulation rod (1) is arranged along the width direction of the body, the simulation plate (2) is located directly above the seat sheet metal, and a distance L between the simulation plate (2) and the seat sheet metal is set; the distance L between the simulation plate (2) and the seat sheet metal is 0.5t —t, t is the thickness of the seat sheet metal; the simulation rod (1) includes a plurality of one-dimensional beam units (1.1) arranged in the same direction and fixedly connected end to end to form an integrated structure; the simulation panel (2) includes at least two shell units (2.1) symmetrically connected to the bottom of the simulation rod (1); the shell unit (2.1) is a regular polygonal structure with multiple vertices, and the vertices of the same shell unit (2.1) are fixedly connected to a node of the one-dimensional beam unit (1.1) on one side of the simulation rod (1) through a one-dimensional connecting beam unit (3); if the bending stiffness test device of the white body is unified, the specific parameters of the simulation loading model can be assigned according to the actual plate thickness of the white body bending test device and the cross-section parameters of the beam; if the white body bending test device is not unified, that is, there are multiple bending test mechanisms and multiple test loading devices, the specific parameters of the simulation model are assigned with reference to the white body bending test device with the largest stiffness.

2. The load application method of the vehicle body in white bending stiffness simulation load application device according to claim 1, characterized in that: The shell element (2.1) is composed of a plurality of mesh elements.

3. The load application method of the vehicle body in white bending stiffness simulation load application device according to claim 1, characterized in that: Applying a load to the body-in-white bending stiffness simulation load applying device comprises: applying a load symmetrically along the height direction of the body-in-white at the two end nodes of the simulation rod (1).

4. The load application method of the vehicle body in white bending stiffness simulation load application device according to claim 3, characterized in that: The method for determining whether the BIW bending stiffness meets the requirements is as follows: calculating the bending stiffness of the BIW in a simulated bending test, comparing the bending stiffness of the BIW in a simulated bending test with a set value, and if the bending stiffness of the BIW in a simulated bending test is not less than the set value, the BIW bending stiffness meets the requirements; otherwise, the BIW bending stiffness does not meet the requirements; The calculation formula for the bending stiffness of the body-in-white (BIW) in the simulated bending test is: K=F / d, where K is the bending stiffness of the body-in-white (BIW) in the simulated bending test, F is the load applied to the BIW bending stiffness simulation load application device, and d is the maximum deformation of the BIW rocker beam in the body height direction.

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