A simplified method for automobile collision model and a method for developing its collision performance

Abstract

The present invention provides a method for simplifying a car collision model, which includes: establishing a whole vehicle finite element model, selecting units behind the B-pillar except tires as non-deformation zone units; calculating the attribute parameters of the non-deformation zone units, replacing the non-deformation zone units with concentrated mass points according to the attribute parameters, and assigning the same attribute parameters to the concentrated mass points; connecting the concentrated mass points with the replacement sections of the circumferential edges of the corresponding non-deformation zone units on the whole vehicle finite element model, replacing the non-deformation zone units with concentrated mass points, connecting the concentrated mass points with the replacement sections of the circumferential edges and the rear tires, thereby obtaining a collision finite element model. The present invention only simplifies the non-deformation zone at the rear of the model, ensuring that the center of mass, mass, and inertia of the concentrated mass points before and after simplification remain consistent under the action of gravity, and by increasing the time step, improving the calculation efficiency without reducing the accuracy, and shortening the development cycle of the car collision performance.

Description

Technical Field

[0001] The invention relates to the technical field of automobile collision, and in particular to a method for simplifying an automobile collision model and a method for developing its collision performance. Background Art

[0002] The field of automobile collision safety is an important field of automobile development, and collision safety simulation optimization is an important technical means to study automobile collision safety. Although this technology is currently very effective in reducing the collision performance development cycle, it still has the problem of too many calculation units in the finite element model of the frontal collision vehicle and a long time consumption. To solve the above problems, some operators use beam models instead of finite element models for calculation. Although this method has high calculation efficiency, its accuracy is greatly different from the original finite element model. Summary of the invention

[0003] In view of this, it is necessary to provide a method for simplifying the automobile collision model and a method for developing its collision performance, which can improve the calculation efficiency while ensuring the calculation accuracy.

[0004] The present invention provides a method for simplifying a vehicle collision model, comprising:

[0005] Establish the finite element model of the whole vehicle, and select the elements behind the B-pillar except the tires as the non-deformation zone elements;

[0006] Calculating the attribute parameters of the unit in the non-deformation zone, wherein the attribute parameters include the coordinates of the center of mass, mass and inertia;

[0007] According to the attribute parameters, the non-deformation zone unit is replaced with a concentrated mass point, and the concentrated mass point is given the same attribute parameters;

[0008] The concentrated mass point is connected to the replacement section of the circumferential edge of the non-deformation zone unit on the finite element model of the whole vehicle, the non-deformation zone unit is replaced by the concentrated mass point, and the concentrated mass point is connected to the replacement section of the circumferential edge and the rear tire to obtain a simplified collision finite element model.

[0009] In one embodiment, the concentrated mass point is connected to the replacement section via a rigid unit.

[0010] In one embodiment, the replacement section includes a section behind the B-pillar of the vehicle.

[0011] In one embodiment, the non-deformation zone elements include all elements behind the B-pillar in the finite element model of the whole vehicle except for the tires.

[0012] In one embodiment, the concentrated mass point is located at the centroid coordinates.

[0013] The present invention provides a method for developing collision performance using the above-mentioned vehicle collision model simplification method, comprising:

[0014] Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the whole vehicle finite element model, and draw and output the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the whole vehicle finite element model;

[0015] Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the single-side B-pillar of the collision finite element model, and draw and output the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the single-side B-pillar of the collision finite element model;

[0016] According to the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar of the whole vehicle collision finite element model and the collision finite element model, the rationality of the simplification of the collision finite element model is verified.

[0017] In one embodiment, in the step of calculating and outputting the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar of the whole vehicle collision finite element model and the collision finite element model, the calculation is performed using an increased calculation time step.

[0018] In one embodiment, after verifying the rationality of the simplification of the collision finite element model according to the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar of the collision finite element model and the whole vehicle collision finite element model, the method further includes:

[0019] According to the verification results of the rationality of the model simplification, the collision performance is developed through the frontal collision finite element model to determine the optimal development plan for the collision performance.

[0020] In summary, the present invention retains the complete structure of the front part of the finite element model of the whole vehicle and the rear tire model during the model simplification process, and only simplifies the non-deformed area at the rear of the model, thereby ensuring that the center of mass, mass, and inertia of the non-deformed area unit before simplification and the concentrated mass point after simplification are consistent under the action of gravity, and by increasing the time step, the calculation efficiency is greatly improved without reducing the accuracy, thereby shortening the development cycle of the vehicle collision performance.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1The figure shows a schematic structural diagram of a finite element model of a whole vehicle before simplification in the method for simplifying a vehicle collision model provided by the present invention;

[0023] Figure 2 Shown Figure 1 Schematic diagram of the structure of the unit in the non-deformation zone;

[0024] Figure 3 The figure shows a schematic structural diagram of a simplified collision finite element model in the method for simplifying a vehicle collision model provided by the present invention;

[0025] Figure 4 Shown Figure 3 Schematic diagram of the structure of the connection between the replaced concentrated mass point and the replaced section through the rigid unit;

[0026] Figure 5 The figure shows a principle block diagram of a method for simplifying a car collision model provided by the present invention and a method for developing collision performance using a collision finite element model obtained by the simplified method;

[0027] Figure 6 The left B-pillar acceleration-time curves of the full vehicle finite element model and the half vehicle simplified model are shown;

[0028] Figure 7 The acceleration-displacement curves of the left B-pillar of the full vehicle finite element model and the simplified half vehicle model are shown;

[0029] Figure 8 Shown are the deformation energy-displacement curves of the left B-pillar of the full vehicle finite element model and the simplified half vehicle model. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the present invention is described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0031] like Figures 1 to 8 As shown, the present invention provides a method for simplifying a car collision model, which comprises:

[0032] A finite element model 1 of the whole vehicle is established, and the unit behind the B-pillar 7 except the tire is selected as the non-deformation zone unit 2;

[0033] Calculating the attribute parameters of the non-deformation zone unit 2, wherein the attribute parameters include the coordinates of the center of mass, mass and inertia;

[0034] According to the attribute parameters, the non-deformation zone unit 2 is replaced by the concentrated mass point 3, and the concentrated mass point 3 is given the same attribute parameters;

[0035] Connect the concentrated mass point 3 with the replacement section 4 on the circumferential edge of the non-deformation zone unit 2 on the whole vehicle finite element model 1, replace the non-deformation zone unit 2 with the concentrated mass point 3, connect the concentrated mass point 3 with the replacement section 4 on the circumferential edge and the rear tire, so as to obtain a simplified collision finite element model 5.

[0036] Specifically, when the present invention simplifies the whole vehicle finite element model 1 into a collision finite element model 5, the concentrated mass point 3 is connected to the replacement section 4 and the rear tire through the rigid unit 6, and the mass, moment of inertia, and center of mass coordinates before and after simplification remain unchanged; more specifically, the replacement section 4 in the present invention includes the section behind the B-pillar 7 of the whole vehicle, and correspondingly, the non-deformation zone unit 2 includes all units behind the B-pillar 7 in the finite element model 1 of the whole vehicle except the rear tire.

[0037] In the present invention, the attribute parameters of the non-deformation zone unit 2 include centroid coordinates, mass and inertia. Specifically, the present invention determines the density of the material according to the material of the whole vehicle, calculates the volume of the sheet metal according to the unit size, and calculates the corresponding mass according to the formula: mass = density x volume. At the same time, the computer simulation software also determines the centroid coordinates and inertia of the non-deformation zone unit 2 according to the program set in the computer simulation software to collect the centroid coordinates and inertia of the non-deformation zone unit 2, and sets the replaced concentrated mass point 3 at the centroid coordinates of the non-deformation zone unit 2, and gives the concentrated mass point 3 the same mass and inertia (the mass and inertia of the concentrated mass point 3 are the same as the calculated mass and inertia of the non-deformation zone unit 2), thereby constructing a simplified collision finite element model 5 and optimizing the mesh quality in the original non-deformation zone unit 2. Preferably, the centroid coordinates of the non-deformation zone unit 2 of the present invention can be directly calculated by computer simulation software, and the inertia of the non-deformation zone unit 2 can be directly measured by the inertia measurement module in the computer simulation software. Specifically, the inertia measurement module can use the formula Calculated.

[0038] Furthermore, the method for developing collision performance using the collision finite element model 5 obtained by the simplified method described above includes:

[0039] Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the sensor below the left B-pillar of the whole vehicle finite element model 1, and draw and output the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the whole vehicle finite element model 1;

[0040] Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the sensor below the single-side B-pillar 7 of the collision finite element model 5, and draw the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the single-side B-pillar 7 of the output collision finite element model 5;

[0041] According to the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the sensor under the left B-pillar of the whole vehicle collision finite element model 1 and the sensor under the single-side B-pillar 7 of the collision finite element model 5, the rationality of the simplification of the collision finite element model 5 is verified.

[0042] In the steps of calculating and outputting the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the sensor below the single-side B-pillar 7 of the whole vehicle collision finite element model 1 and the collision finite element model 5, the present invention uses an increased calculation time step for calculation.

[0043] After verifying the rationality of the simplification of the collision finite element model 5 according to the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar 7 of the whole vehicle collision finite element model 1 and the collision finite element model 5, the present invention further includes:

[0044] According to the verification results of the rationality of the model simplification, the collision performance is developed through the frontal collision finite element model 5 to determine the optimal development plan for the collision performance.

[0045] In a specific embodiment of the present invention, computer simulation software is used to verify the rationality of the collision finite element model 5 according to the acceleration-time curve, the acceleration-displacement curve, and the energy-displacement curve, and to determine the optimal solution. That is, by simplifying the whole vehicle finite element model 1 through the simplification method provided by the present invention, a simplified half-vehicle model with the same accuracy as the whole vehicle finite element model 1 can be obtained, which can save half of the calculation time under the premise of the same calculation resources, thereby shortening the development cycle of the frontal collision performance.

[0046] Specifically, if Figure 5 As shown, the present invention simplifies the vehicle finite element model 1 into a collision finite element model 5, and uses the collision finite element model 5 to perform a collision performance development method, which is detailed as follows:

[0047] Step S1: Establish the finite element model of the vehicle frontal collision, as shown in the attached figure. Figure 1 ;

[0048] Step S2: Select all units behind the B-pillar 7 except the tire as the non-deformation zone unit 2, and calculate the centroid coordinates, mass and inertia of the non-deformation zone unit 2, as shown in the attached figure. Figure 2 ;

[0049] Step S3: Establish a concentrated mass point 3 at the mass center coordinates of the non-deformation zone unit 2, and assign the mass and inertia information of the non-deformation zone unit 2 to the concentrated mass point 3 to ensure that the mass center coordinates, mass, and inertia of the concentrated mass point model are consistent with those of the non-deformation zone unit model. Figure 3 ;

[0050] Step S4: Replace the non-deformation zone unit 2 with the concentrated mass point 3, optimize the non-physical quality of the non-deformation zone unit 2, and reduce the number of calculation units. Figure 4 ;

[0051] Step S5: connecting the concentrated mass point 3 of the non-deformation zone unit 2 and the replacement section 4 (including the section behind the B-pillar 7 and the rear tire) through the rigid unit 6 to obtain a simplified frontal collision finite element model 5;

[0052] Step S6: increasing the time step so that the increase in non-physical mass before and after simplification is the same, and using a computer simulation software program to measure and output specific values ​​of acceleration, time, displacement, and deformation energy;

[0053] Step S7: Output the acceleration-time, acceleration-displacement, and deformation energy-displacement curves of the vehicle finite element model 1 and the collision finite element model 5 (all the rear parts of the left B-pillar of the simplified half-vehicle model except the tire) according to the computer simulation software, and compare the acceleration peak time, acceleration peak, vehicle crushing amount, and total energy absorbed by the collision as evaluation indicators of the model simplification to verify the rationality of the model simplification, as shown in the attached figure. Figure 6-8 ;

[0054] Step S8: Based on the verification results of the rationality of the model simplification, the collision performance is developed through the frontal collision finite element model 5. The stiffness matching of the front force transmission components of the vehicle body with different plate thicknesses, different materials, and different shape characteristics is carried out. Under the premise of the same development progress, the number of calculation cases that can be tried is twice the original. After the optimal solution is confirmed, the solution is updated to the vehicle model to confirm the effect.

[0055] The present invention can reduce the calculation time of the whole vehicle frontal collision finite element model 5 and shorten the development cycle of the whole vehicle collision performance.

[0056] In summary, the present invention builds a finite element model of the whole vehicle, selects and calculates the centroid coordinates, mass, and inertia of the non-deformation zone unit, establishes a concentrated mass point at the centroid coordinates of the non-deformation zone unit, and gives the concentrated mass point the mass and inertia information of the non-deformation zone unit, replaces the non-deformation zone unit with the concentrated mass point, optimizes the non-physical mass of this part, and thus reduces the number of calculation units; and because the present invention retains the complete structure of the front part of the finite element model of the whole vehicle and the rear tire model during the model simplification process, only the non-deformation area at the rear of the model is simplified, ensuring that the center of mass, mass, and inertia of the non-deformation zone unit before optimization and the simplified concentrated mass point remain consistent under the action of gravity, and by increasing the time step without reducing the accuracy, the calculation efficiency is greatly improved, thereby shortening the development cycle of the vehicle collision performance.

[0057] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for simplifying a car collision model, characterized in that: include: A finite element model of the entire vehicle is established (1), and the elements behind the B-pillar (7) except the tires are selected as the non-deformation zone elements (2); Calculating the attribute parameters of the non-deformation zone unit (2), wherein the attribute parameters include the coordinates of the center of mass, mass and inertia; According to the attribute parameters, the non-deformation zone unit (2) is replaced by a concentrated mass point (3), and the concentrated mass point (3) is given the same attribute parameters; The concentrated mass point (3) is connected to the replacement section (4) of the circumferential edge of the non-deformation zone unit (2) on the finite element model (1) of the whole vehicle, the non-deformation zone unit (2) is replaced by the concentrated mass point (3), and the concentrated mass point (3) is connected to the replacement section (4) of the circumferential edge and the rear tire, thereby obtaining a collision finite element model (5).

2. The method for simplifying the automobile collision model according to claim 1, characterized in that: The concentrated mass point (3) is connected to the replacement section (4) and the rear tire via a rigid unit (6).

3. The method for simplifying the automobile collision model according to claim 2, characterized in that: The replacement section (4) includes a section behind the B-pillar (7) of the entire vehicle.

4. The method for simplifying the automobile collision model according to claim 1, characterized in that: The non-deformation zone unit (2) includes all units behind the B-pillar (7) in the whole vehicle finite element model (1) except the rear tire.

5. The method for simplifying the automobile collision model according to claim 1, characterized in that: The concentrated mass point (3) is located at the mass center coordinates.

6. A method for developing collision performance using the vehicle collision model simplification method according to any one of claims 1 to 5, characterized in that: include: Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the sensor below the left B-pillar of the whole vehicle finite element model (1), and draw and output the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the whole vehicle finite element model (1); Measure the specific values ​​of acceleration, time, displacement, and deformation energy of the sensor below the left B-pillar of the simplified collision finite element model (5), and draw and output the acceleration-time curve, acceleration-displacement curve, and energy-displacement curve of the simplified vehicle finite element model (5); According to the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar (7) of the whole vehicle collision finite element model (1) and the simplified collision finite element model (5), the acceleration peak time, acceleration peak, whole vehicle crushing amount and total energy absorbed by the collision are compared to verify the rationality of the simplification of the collision finite element model (5).

7. The method for developing crash performance according to claim 6, characterized in that: In the step of calculating and outputting the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of a single-side B-pillar (7) of a whole vehicle collision finite element model (1) and a simplified collision finite element model (5), the calculation is performed using an increased calculation time step.

8. The method for developing crash performance according to claim 6, characterized in that: After verifying the rationality of the simplification of the collision finite element model (5) based on the acceleration-time curve, acceleration-displacement curve and energy-displacement curve of the single-side B-pillar (7) of the whole vehicle collision finite element model (1) and the collision finite element model (5), the method further includes: According to the verification results of the rationality of the model simplification, the collision performance is developed through the frontal collision finite element model (5) to determine the optimal development plan for the collision performance.

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