A commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method

Abstract

The present invention discloses a commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method, including: using 3D software to build a model; importing Hypermesh software to perform interference testing and improvement; completing the meshing of cab components; setting various parameters; using Lsdyna software to perform cab A-pillar impact simulation analysis, importing the simulation analysis result file into Hyperview software, and outputting a curve of the distance between the steering wheel and seat base monitoring points over the impact time; at the moment when the distance between the monitoring points is minimum, importing the cab maximum deformation model into Hypermesh, then importing a dummy model into the cab deformation model, measuring the minimum distance between the steering wheel, steering column, and the dummy model; comparing the two minimum distances to determine the occupant survival space evaluation index. The present invention fully considers the impact of material elastic deformation on occupant survival space and quantifies it, making the evaluation more accurate and facilitating the comparison and optimization of different solutions.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile collision safety, and in particular to a method for simulating and analyzing the impact of an A-pillar on a commercial vehicle cab and evaluating the occupant survival space. Background Art

[0002] The crash safety performance of commercial vehicle cabs not only impacts the overall vehicle quality but also directly affects the health and safety of drivers and passengers. A-pillar impact safety is a key evaluation indicator for commercial vehicle cab crash safety and has become a crucial component of commercial vehicle development and design. Cabin A-pillar impact tests or finite element simulations are conducted in accordance with the technical requirements of GB 26512-2021, "Occupant Protection in Commercial Vehicle Cabs." A collision block is used to impact the cab with the A-pillar. After the cab deformation stabilizes, a percentile dummy is placed in the cab to verify contact or interference between the cab's inelastic components and the dummy's body parts. This is used to assess the occupant's survival space. A-pillar impacts often cause the steering column and steering wheel to move, intruding into the occupant's survival space and endangering their health. However, cab structures are primarily made of steel. During an impact, the cab typically undergoes elastic and plastic deformation, reaching maximum deformation. Elastic deformation then recovers, reducing overall cab deformation and reaching a stable deformation state. Therefore, the current commercial vehicle cab A-pillar impact safety performance analysis and occupant survival space evaluation methods do not take into account the impact of material elastic deformation on occupant survival space, and do not evaluate occupant survival space at maximum deformation, resulting in an inaccurate evaluation of occupant production space. At the same time, the occupant survival space evaluation method does not quantify parameters, which is not convenient for comparing and further optimizing the cab A-pillar impact performance and occupant survival space. Therefore, in response to the above problems, the present invention proposes a commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method. By performing a simulation analysis of the cab A-pillar impact test, the distance between the monitoring points on the steering wheel and the seat base is monitored as the impact time changes. When the distance between the monitoring points reaches the minimum, the occupant survival space is evaluated. The minimum distance between the steering wheel and the steering column and the dummy model is used as the occupant survival space evaluation index. This method is more consistent with the actual process of the cab A-pillar impact and effectively solves the non-quantification problem of the existing evaluation method. Summary of the Invention

[0003] In response to the problems existing in the existing commercial vehicle cab A-pillar impact safety performance analysis and occupant survival space evaluation methods, the present invention proposes a commercial vehicle cab A-pillar impact safety performance analysis and occupant survival space evaluation method. The method considers the influence of the elastic deformation of the cab material on the occupant survival space. During the cab impact process, the dummy model is introduced at the moment when the distance between the steering wheel and the seat base monitoring point is minimum. At the same time, in order to quantify the occupant space evaluation index, the minimum distance between the cab steering wheel and steering column and the dummy is measured respectively, and the minimum distance between the two is selected as the occupant space evaluation index.

[0004] In order to achieve the above objectives, the technical solution of the present invention is: a commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method, characterized by the specific steps of:

[0005] Step 1: Use 3D software to build a 3D model of the entire cab based on the actual cab or design requirements. Create a 3D model of the impact block and dummy model according to the technical requirements of the regulatory standard GB 26512-2021 "Occupant Protection in Commercial Vehicle Cabs";

[0006] Step 2: Import the established 3D models of the cab and impact block into Hypermesh software to check whether there is interference between the components. If there is interference, the interference parts need to be confirmed and improved;

[0007] Step 3: Divide the cab components into meshes, and select meshes of different sizes according to the deformation size of different areas;

[0008] Step 4: Set the thickness parameters of each component and the mechanical properties of different materials according to the parts BOM table, and perform component penetration inspection. If there is penetration, the penetration site needs to be confirmed and improved;

[0009] Step 5: According to the actual manufacturing process or process documents of the cab components, set the connection relationship of the cab components, the contact relationship between the impact block and the cab, and the cab components, the cab constraints and the impact block motion parameters, and the cab impact simulation analysis control card parameters;

[0010] Step 6: Import the data from Hypermesh into Lsdyna software to perform a simulation analysis of the cab A-pillar impact. After the analysis is completed, use Hyperview software to read the Lsdyna simulation analysis result file, select points A and B on the steering wheel and the cab seat base respectively, and output the time-varying curve of the distance between point A and point B;

[0011] Step 7: When the distance between point A and point B is minimum, import the cab deformation model into Hypermesh software, then import the dummy model into the cab deformation model, and measure the minimum distance between the steering wheel, steering column and the dummy model;

[0012] Step 8: Compare the minimum distance between the steering wheel, steering column and the dummy model to determine the occupant survival space evaluation index.

[0013] Furthermore, in Step 2, after the three-dimensional models of the cab and the impact block are imported into the Hypermesh software, the positional relationship between the two meets the technical requirements of the regulatory standard GB 26512-2021 "Protection of Occupants in Commercial Vehicle Cabs";

[0014] Furthermore, in Step 3, when dividing the mesh, the mesh size of the A-pillar, front panel, side panel, roof, and instrument panel with large deformation is set to 5-10 mm, and the mesh size of the rear panel and floor with small deformation is set to 10-20 mm.

[0015] Furthermore, in Step 4, the material mechanical properties include material density, elastic modulus, Poisson's ratio, tangent modulus, yield strength, and stress-strain curve;

[0016] Furthermore, stress-strain curves of different materials of cab components are obtained through experiments.

[0017] Furthermore, in Step 5, the connection relationship between components includes spot welding, seam welding, bolts, gluing, and hinges.

[0018] Furthermore, the spot welding includes two-layer welding spots and three-layer welding spots.

[0019] Furthermore, in Step 5, when the impact block is set to contact the cab, the surface of the impact block is set as the main contact surface, and the entire cab is set as the secondary contact surface.

[0020] Furthermore, in Step 5, the bolt holes connecting the cab suspension seat and the vehicle frame are constrained to be fully constrained, and the upper end of the swing arm of the impact block constrains the five degrees of freedom in directions other than the impact rotation direction.

[0021] Furthermore, in Step 5, the motion parameters of the impact block include the rotation center coordinates and the initial angular velocity.

[0022] Furthermore, the initial angular velocity is calculated according to the following formula:

[0023]

[0024] Wherein, L is the distance from the center of rotation of the impact block to the center of the impact block, E is the impact energy of the impact block, and m is the mass of the impact block.

[0025] Furthermore, in Step 5, the cab impact simulation analysis control card is set to include hourglass setting, impact time, time step, unit control setting, and file output control.

[0026] Furthermore, in Step 7, the dummy model is imported into the cab deformation model, and the "H" point of the dummy model is aligned with the "R" point of the cab seat.

[0027] Furthermore, in Step 8, the occupant survival space evaluation index I =min( d 1, d 2), where d 1 is the minimum distance between the steering wheel and the dummy, 7, d 2 is the minimum distance between the steering column and the dummy 8.

[0028] The evaluation of the occupant survival space includes: when the occupant survival space evaluation index I When ≤0, the occupant survival space is unqualified. I >0, I The larger the value, the larger the occupant survival space and the better the cab A-pillar impact safety performance.

[0029] Compared with the prior art, the present invention has the following advantages.

[0030] (1) A method for simulating and analyzing the impact of the A-pillar on the cab of a commercial vehicle and evaluating the occupant survival space is proposed. By simulating and analyzing the impact test of the A-pillar on the cab, the distance between the monitoring points on the steering wheel and the seat base is monitored as the impact time changes. When the distance between the monitoring points reaches the minimum, the occupant survival space is evaluated. This effectively avoids the problem of the existing method causing the occupant survival space to be too large due to not considering the elastic deformation of the material.

[0031] (2) The minimum distance between the steering wheel and steering column and the dummy model is used as the evaluation index of the occupant survival space, which effectively solves the non-quantification problem of the existing evaluation method and is conducive to the comparison and optimization of the cab A-pillar impact safety performance and the occupant survival space.

[0032] (3) Compared with the experimental method to examine and verify the collision safety performance of the cab A-pillar and the occupant survival space, this method avoids the actual vehicle processing and manufacturing and destructive testing, and is simpler to operate, more efficient and less costly. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art or ordinary technicians, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a flow chart of a commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method provided by the present invention.

[0035] Figure 2 Finite element model for commercial vehicle cab A-pillar impact simulation analysis.

[0036] Figure 3 For the dummy model.

[0037] Figure 4 Points A and B are selected on the cab.

[0038] Figure 5 Schematic diagram of occupant survival space evaluation indicators.

[0039] Figure 6 Schematic diagram of occupant survival space evaluation indicators. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of this application without making creative efforts should fall within the scope of protection of this application.

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0042] A commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method includes the following specific steps:

[0043] Step 1: Based on the actual cab or design requirements, use 3D software UG to create an accurate 3D model of the cab and the entire vehicle. Create a 3D model of the impact block and dummy model according to the technical requirements of the regulatory standard GB 26512-2021 "Occupant Protection in Commercial Vehicle Cabs";

[0044] Step 2: Import the established 3D models of the cab and impact block into Hypermesh software. The positional relationship between the two is set according to the technical requirements of the regulatory standard GB 26512-2021, "Occupant Protection in Commercial Vehicle Cabs." Check for interference between components. If so, identify and refine the interfering areas.

[0045] Step 3: Mesh the cab components, selecting different mesh sizes based on the deformation of different areas. Set the mesh size to 5mm for areas with larger deformation, such as the A-pillar, front panel, side panel, roof, and instrument panel, and 10mm for areas with smaller deformation, such as the rear panel and floor.

[0046] Step 4: According to the parts BOM, set the thickness parameters of each component and the density, elastic modulus, Poisson's ratio, tangent modulus, yield strength, stress-strain curve and other performance parameters of different materials. The stress-strain curves of different materials for cab components are obtained through experiments. Then, perform a penetration inspection on the components. If penetration is found, confirm the penetration location and make improvements.

[0047] Step 5: According to the actual manufacturing process or process documents of the cab parts, set the connection relationships of the cab parts such as spot welding, seam welding, bolts, adhesives, hinges, etc. Set the contact relationship between the impact block and the cab and cab parts, set the surface of the impact block as the main contact surface, and set the cab as a slave contact surface. Constrain the bolt holes connecting the cab suspension seat and the frame to full constraints, and constrain the upper end of the impact block swing arm to the other five degrees of freedom in the direction except the impact rotation direction. The motion parameters of the impact block include the coordinates of the center of rotation and the initial angular velocity. The magnitude of the initial angular velocity is calculated according to the following formula:

[0048]

[0049] Wherein, L is the distance from the center of rotation of the impact block to the center of the impact block, E is the impact energy of the impact block, and m is the mass of the impact block.

[0050] Set up the cab impact simulation analysis control card, including hourglass settings, impact time, time step, unit control settings, file output control, etc.

[0051] Step 6: Import the data in Hypermesh into Lsdyna software to perform a simulation analysis of the cab A-pillar impact. After the analysis is completed, use Hyperview software to read the Lsdyna simulation analysis result file, select points A and B on the steering wheel and the cab seat base respectively, and output the distance change curve between point A and point B over time. At 0ms of the impact, the distance between points A and B is the largest. As the impact block hits the cab A-pillar, the cab steering column and steering wheel deform toward the cab seat side, and the distance between points A and B gradually decreases until 180ms, when the distance between points A and B reaches the minimum. At this time, the cab produces elastic deformation and plastic deformation, reaching the maximum deformation moment. As the impact block ends its contact with the cab, the cab resumes its elastic deformation, and the deformation of the cab decreases, until the cab reaches a stable deformation state at 360ms.

[0052] Step 7: At the moment when the distance between point A and point B is minimum, that is, at 180ms, the cab deformation model is imported into the Hypermesh software. The traditional analysis method is to import the cab deformation model into the Hypermesh software at the end of the simulation analysis, that is, at the moment when the cab is stably deformed at 360ms, to evaluate the occupant space. At 360ms, the distance between points A and B in the cab increases by 30.197mm compared to 180ms. At this time, evaluating the occupant survival space will result in a result that the occupant survival space is too large. At 180ms, the distance between points A and B in the cab is minimum. At this time, the deformation of the steering wheel and steering column is the largest, reducing the occupant survival space. It is more reasonable to evaluate the occupant survival space at this time. When evaluating the occupant survival space, the dummy model is imported into the deformation model of the cab at 180ms, and the "H" point of the dummy model is overlapped with the "R" point of the cab seat. The minimum distance between the steering wheel and the dummy model is measured. d 1=16mm, the minimum distance between the steering column and the dummy model knee is d 2=31mm;

[0053] Step 8: Compare the minimum distance between the steering wheel, steering column and the dummy model d 1 and d 2, determine the evaluation index of occupant survival space I =min( d 1, d 2) = 16mm, when comparing A-pillar impact performance and occupant survival space between different structural schemes or different cabs, I The larger the value, the larger the occupant survival space is, and the better the cab A-pillar impact safety performance is. When optimizing the cab A-pillar impact performance, the occupant survival space evaluation index can be used d 1 is used as the optimization target to optimize the cab structural parameters.

[0054] The above is a detailed introduction to the commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method, characterized in that: The specific steps are: Step 1: Use 3D software to build a 3D model of the entire cab based on the actual cab or design requirements. Create a 3D model of the impact block and dummy model according to the technical requirements of the regulatory standard GB 26512-2021 "Occupant Protection in Commercial Vehicle Cabs"; Step 2: Import the established 3D models of the cab and impact block into Hypermesh software to check whether there is interference between the components. If there is interference, the interference parts need to be confirmed and improved; Step 3: Divide the cab components into meshes, and select meshes of different sizes according to the deformation size of different areas; Step 4: Set the thickness parameters and mechanical properties of each component according to the parts BOM, and perform component penetration inspection. If penetration is found, confirm and improve the penetration location. Step 5: According to the actual manufacturing process or process documents of the cab components, set the connection relationship of the cab components, the contact relationship between the impact block and the cab, and the cab components, the cab constraints and impact block motion parameters, and the cab impact simulation analysis control card parameters. Step 6: Import the data from Hypermesh into Lsdyna software to perform a simulation analysis of the cab A-pillar impact. After the analysis is completed, use Hyperview software to read the Lsdyna simulation analysis result file, select points A and B on the steering wheel and the cab seat base respectively, and output the time-varying curve of the distance between point A and point B; Step 7: When the distance between point A and point B is minimum, import the cab deformation model into Hypermesh software, then import the dummy model into the cab deformation model, and measure the minimum distance between the steering wheel, steering column and the dummy model; Step 8: Compare the minimum distance between the steering wheel, steering column and the dummy model to determine the occupant survival space evaluation index.

2. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1 is characterized by: In Step 2, after the three-dimensional models of the cab and the impact block are imported into the Hypermesh software, the positional relationship between the two meets the technical requirements of the regulatory standard GB 26512-2021 "Protection of Occupants in Commercial Vehicle Cabs".

3. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1 is characterized by: In Step 3, when dividing the mesh, the mesh size of the A-pillar, front panel, side panel, top cover, and instrument panel with large deformation is 5-10 mm, and the mesh size of the rear panel and floor with small deformation is 10-20 mm.

4. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 4, the material mechanical properties include material density, elastic modulus, Poisson's ratio, tangent modulus, yield strength, and stress-strain curve.

5. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 4 is characterized by: The stress-strain curves of different materials of cab components are obtained through experiments.

6. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 5, the connection relationship between components includes spot welding, seam welding, bolts, gluing, and hinges.

7. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 6, characterized in that: Spot welding includes two-layer welds and three-layer welds.

8. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1 is characterized by: In Step 5, when the impact block is set to contact the cab, the surface of the impact block is set as the main contact surface, and the entire cab is set as the secondary contact surface.

9. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 5, the bolt holes connecting the cab suspension seat and the vehicle frame are constrained to be fully constrained, and the upper end of the swing arm of the impact block is constrained in the other five directions except the impact rotation direction.

10. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 5, the motion parameters of the impact block include the rotation center coordinates and the initial angular velocity.

11. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 10, characterized in that: The initial angular velocity is calculated according to the following formula: Wherein, L is the distance from the center of rotation of the impact block to the center of the impact block, E is the impact energy of the impact block, and m is the mass of the impact block.

12. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 5, the cab impact simulation analysis control card is set up including hourglass setting, impact time, time step, unit control setting, and file output control.

13. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 7, the dummy model is imported into the cab deformation model, and the "H" point of the dummy model is aligned with the "R" point of the cab seat.

14. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 1, characterized in that: In Step 8, the occupant survival space evaluation index I =min( d 1, d 2), where d 1 is the minimum distance between the steering wheel and the dummy, d 2 is the minimum distance between the steering column and the dummy.

15. The commercial vehicle cab A-pillar impact simulation analysis and occupant survival space evaluation method according to claim 14, characterized in that: When the occupant survival space evaluation index I When ≤0, the occupant survival space is unqualified. I >0, I The larger the value, the larger the occupant survival space and the better the cab A-pillar impact safety performance.

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