Method, device and equipment for evaluating assembly deformation of automobile back door and storage medium

Abstract

The invention discloses an evaluation method, device and equipment for assembly deformation of an automobile back door and a storage medium, and relates to the technical field of simulation analysis, the method comprises the steps that a back door finite element model is established according to back door design data, and the back door finite element model comprises connection relations and physical attributes of sheet metal parts, glass, hinges and accessories; applying constraint conditions and loads in a closed state in the back door finite element model, wherein the loads comprise contact area pressure intensity, compression force, support rod force and gravity; obtaining a displacement cloud picture of the back door outer plate based on the constraint condition and the load; and according to the displacement cloud picture, screening a sunken deformation area of the back door outer plate, and according to a preset strategy, carrying out deformation evaluation on the sunken deformation area. According to the method, the accuracy of deformation of the back door during simulation assembly is improved by quantitatively evaluating the sinking degree of the sinking area.

Description

Technical Field

[0001] The present application relates to the technical field of simulation analysis, and in particular to a method, device, equipment and storage medium for evaluating the assembly deformation of a car tailgate. Background Art

[0002] In recent years, the growing popularity of MPVs (Multi-Purpose Vehicles) and SUVs (Sport Utility Vehicles) in the automotive market has significantly increased consumer acceptance and recognition of larger vehicles. This trend has prompted major automakers to adopt larger vehicle designs to meet market demand for space and comfort. However, this pursuit of larger sizes comes with increasingly stringent requirements for lightweighting, posing greater challenges to vehicle structural design.

[0003] In particular, in the design of automotive tailgates, as their size continues to increase, the planar surface area of ​​the tailgate outer panel increases accordingly, while the material thickness gradually decreases, resulting in a decrease in panel stiffness while maintaining the same structural design. To ensure the tailgate outer panel's dent resistance, traditional design methods often bend and extend the inner panel to form support legs, which are then connected to the outer panel with structural adhesive to enhance the outer panel's support. However, due to the inherently weak stiffness of the outer panel, when the tailgate is assembled and closed, the outer edge of the inner panel is squeezed by elastic components such as buffer blocks and sealing strips, causing the outer edge of the outer panel to slightly lift toward the opening direction. At the same time, the middle of the inner panel cannot lift due to the locking constraint at the latch installation. As a result, the support leg connecting the middle of the inner panel to the outer panel lifts less than the outer edge, creating a discrepancy. When this discrepancy reaches a certain level, a visually noticeable dent may form at the support leg in the middle of the outer panel, affecting the vehicle's exterior quality. In the prior art, although there are methods for controlling the appearance gap between the door and the body by calculating the door sealing reaction force and reaction torque, these methods mainly focus on the gap matching between the door and the body, and do not deeply involve the problem of appearance deformation of the tailgate itself after assembly.

[0004] Therefore, during the design phase of a car's tailgate, how to accurately assess and prevent appearance deformation problems that may occur after assembly has become a technical challenge that needs to be solved urgently. Summary of the Invention

[0005] The main purpose of this application is to provide a method, device, equipment and storage medium for evaluating the assembly deformation of a car tailgate, aiming to solve the technical problem of how to accurately evaluate and prevent the appearance deformation that may occur after assembly during the design stage of the car tailgate.

[0006] To achieve the above objectives, the present application proposes a method for evaluating the assembly deformation of a car tailgate, the method comprising:

[0007] Establishing a tailgate finite element model based on the tailgate design data, wherein the tailgate finite element model includes the connection relationship and physical properties of the sheet metal parts, glass, hinges, and accessories;

[0008] Applying constraints and loads in the closed state to the tailgate finite element model, wherein the loads include contact area pressure, compression force, support rod force, and gravity;

[0009] Obtaining a displacement nephogram of the back door outer panel based on the constraint conditions and the load;

[0010] The concave deformation area of ​​the back door outer panel is screened according to the displacement cloud map, and the deformation evaluation of the concave deformation area is performed according to a preset strategy.

[0011] In one embodiment, the step of establishing a finite element model of the back door according to the back door design data includes:

[0012] Obtain the sheet metal data, glass data, hinge data and accessory center of mass coordinates of the back door according to the back door design data;

[0013] Using the first unit and the second unit to mesh the sheet metal data, the glass data, and the hinge data to obtain mesh models of the sheet metal, the glass, and the hinge;

[0014] Establishing a mass point unit according to the coordinates of the center of mass of the accessory, and connecting the mass point unit to the tailgate sheet metal mounting point through a load unit to simulate the connection relationship between the accessory and the tailgate;

[0015] A tailgate finite element model is established based on the mesh models of the sheet metal, glass, hinges, and the connection relationship between the accessories and the tailgate.

[0016] In one embodiment, the step of applying constraints and loads in the closed state to the tailgate finite element model comprises:

[0017] Importing sealing strip data into the tailgate finite element model;

[0018] Obtaining a contact area according to the sealing strip data, and obtaining the contact area, the contact area length, and the sealing strip reaction force in a closed state through the contact area;

[0019] The contact area pressure is calculated according to the contact area area, the contact area length and the sealing strip reaction force, and the contact area pressure is loaded to the contact area.

[0020] In one embodiment, the step of screening the concave deformation area of ​​the back door outer panel according to the displacement cloud map includes:

[0021] Obtaining a target area where the back door outer panel and the inner panel are bonded via the support structure;

[0022] Obtaining a target displacement cloud map based on the displacement cloud map and the target area, and obtaining a minimum displacement through the target displacement cloud map, wherein the minimum displacement is the minimum displacement of the target area;

[0023] The concave deformation area of ​​the back door outer panel is determined according to the target displacement cloud map and the minimum displacement.

[0024] In one embodiment, the step of determining the concave deformation area of ​​the back door outer panel according to the target displacement cloud map and the minimum displacement includes:

[0025] Obtaining the current region and the region cloud type where the target displacement is located according to the target displacement cloud map and the minimum displacement;

[0026] When the current area is the middle and the area cloud map type is a concave cloud map, the target area is determined to be a concave deformation area of ​​the back door outer panel.

[0027] In one embodiment, the step of performing deformation assessment on the concave deformation area according to a preset strategy includes:

[0028] Expanding the concave deformation area according to a preset strategy to obtain a complete concave deformation area;

[0029] Extracting grid node coordinates and displacement data of the complete concave deformation area;

[0030] Calculating a concave range according to the grid node coordinates, wherein the concave range is the maximum distance between the grid node coordinates;

[0031] Calculating a depression depth based on the displacement data, wherein the depression depth is a maximum difference between the displacement data and a minimum displacement value in the depression area;

[0032] Calculating a curvature mutation degree based on the grid node coordinates, wherein the curvature mutation degree is the maximum value of the curvature difference between adjacent grid nodes;

[0033] When the concave range is greater than a preset width threshold, the concave depth is greater than a preset depth threshold, and the curvature mutation degree is greater than a preset curvature threshold, the concave deformation area is determined to be an appearance defect that needs to be optimized.

[0034] In one embodiment, the step of calculating the curvature mutation degree based on the grid node coordinates includes:

[0035] Calculate the coordinate vectors and step lengths of two adjacent nodes according to the grid node coordinates;

[0036] Calculating a first-order derivative and a second-order derivative based on the coordinate vector and the step size;

[0037] Calculating a node curvature based on the first-order derivative and the second-order derivative;

[0038] All adjacent nodes in the grid node coordinates are traversed to obtain node curvature differences, and the maximum curvature difference among the node curvature differences is used as the curvature mutation degree.

[0039] In addition, to achieve the above-mentioned purpose, the present application also proposes a device for evaluating the assembly deformation of a car tailgate, the device comprising:

[0040] A model building module, configured to build a finite element model of the tailgate based on the tailgate design data, wherein the finite element model of the tailgate includes connection relationships and physical properties of sheet metal parts, glass, hinges, and accessories;

[0041] a load simulation module for applying constraints and loads in the closed state to the tailgate finite element model, wherein the loads include contact area pressure, compression force, support rod force, and gravity;

[0042] a displacement calculation module, configured to obtain a displacement cloud diagram of the back door outer panel based on the constraint conditions and the load;

[0043] The dent assessment module is used to screen the dent deformation area of ​​the back door outer panel according to the displacement cloud map, and perform deformation assessment on the dent deformation area according to a preset strategy.

[0044] In addition, to achieve the above-mentioned purpose, the present application also proposes an evaluation device for the assembly deformation of a car tailgate, which includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the computer program is configured to implement the steps of the method for evaluating the assembly deformation of a car tailgate as described above.

[0045] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium and stores a computer program. When the computer program is executed by a processor, the steps of the method for evaluating the assembly deformation of a car tailgate are implemented as described above.

[0046] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the steps of the method for evaluating the assembly deformation of a car tailgate as described above.

[0047] The present application provides a method for evaluating the assembly deformation of a car's rear tailgate, and the method of the present application includes: establishing a rear tailgate finite element model based on the rear tailgate design data, the rear tailgate finite element model including the connection relationship and physical properties of sheet metal parts, glass, hinges and accessories; applying constraints and loads in the closed state to the rear tailgate finite element model, the loads including contact area pressure, compression force, strut force and gravity; obtaining a displacement cloud map of the rear tailgate outer panel based on the constraints and the loads; screening the concave deformation area of ​​the rear tailgate outer panel based on the displacement cloud map, and performing deformation evaluation on the concave deformation area according to a preset strategy. In summary, the present application uses finite element simulation modeling technology to simulate the stress conditions of the rear tailgate in the closed state after assembly, accurately reproduce the deformation of the rear tailgate outer panel, and further quantitatively evaluate the degree of concavity of the concave area, thereby identifying and resolving potential appearance deformation risks in advance during the design stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 A schematic flow chart of a first embodiment of the method for evaluating the assembly deformation of a rear door of an automobile provided by the present application;

[0051] Figure 2 This is a schematic diagram of loading of a tailgate constraint in an embodiment of a method for evaluating the assembly deformation of a car tailgate of the present application;

[0052] Figure 3 This is a displacement cloud diagram of the tailgate outer panel in accordance with an embodiment of the method for evaluating the assembly deformation of a tailgate of an automobile according to the present application;

[0053] Figure 4 A flowchart illustrating a second embodiment of the method for evaluating the assembly deformation of a vehicle tailgate of the present application;

[0054] Figure 5 This is a diagram of the area where the outer panel and the inner panel of the rear door are bonded via a support structure in one embodiment of the method for evaluating the assembly deformation of the rear door of an automobile of the present application;

[0055] Figure 6 A displacement cloud diagram showing the minimum displacement in the middle of the target area in an embodiment of the automobile tailgate assembly deformation evaluation method of the present application;

[0056] Figure 7 A displacement cloud diagram showing the minimum displacement at the edge of the target area in an embodiment of the automobile tailgate assembly deformation evaluation method of the present application;

[0057] Figure 8 A flowchart illustrating a third embodiment of the method for evaluating the assembly deformation of a rear door of an automobile according to the present invention;

[0058] Figure 9 This is a displacement nephogram showing an enlarged concave deformation area in an embodiment of a method for evaluating assembly deformation of a rear door of an automobile according to the present application;

[0059] Figure 10 A schematic diagram of the concave range of the concave area in an embodiment of the method for evaluating the assembly deformation of a rear door of an automobile of the present application;

[0060] Figure 11 A schematic diagram of the depth of a recessed area in an embodiment of a method for evaluating assembly deformation of a rear door of an automobile according to the present application;

[0061] Figure 12 This is a flowchart of judging the appearance defects of the tailgate outer panel in accordance with an embodiment of the method for evaluating the assembly deformation of the tailgate of an automobile according to the present application;

[0062] Figure 13 This is a schematic diagram of the module structure of the device for evaluating the assembly deformation of a car tailgate according to an embodiment of the present application;

[0063] Figure 14 Schematic diagram of the device structure of the hardware operating environment involved in the method for evaluating the assembly deformation of a car tailgate in an embodiment of the present application.

[0064] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0065] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended to limit the present application.

[0066] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0067] The main solution of the embodiment of the present application is: establishing a tailgate finite element model based on the tailgate design data, the tailgate finite element model includes the connection relationship and physical properties of sheet metal parts, glass, hinges and accessories; applying constraints and loads in the closed state to the tailgate finite element model, the loads including contact area pressure, compression force, support rod force and gravity; obtaining the displacement cloud map of the tailgate outer panel based on the constraints and the loads; screening the concave deformation area of ​​the tailgate outer panel according to the displacement cloud map, and performing deformation evaluation on the concave deformation area according to a preset strategy.

[0068] In recent years, with the continued rise in popularity of MPVs and SUVs in the automotive market, consumer acceptance and recognition of larger vehicles has significantly increased. This trend has prompted major automakers to adopt larger vehicle designs to meet market demand for space and comfort. However, this pursuit of larger sizes also comes with increasingly stringent requirements for lightweighting, posing greater challenges to vehicle structural design.

[0069] In particular, in the design of automotive tailgates, as their size continues to increase, the planar surface area of ​​the tailgate outer panel increases accordingly, while the material thickness gradually decreases, resulting in a decrease in panel stiffness while maintaining the same structural design. To ensure the tailgate outer panel's dent resistance, traditional design methods often bend and extend the inner panel to form support legs, which are then connected to the outer panel with structural adhesive to enhance the outer panel's support. However, due to the inherently weak stiffness of the outer panel, when the tailgate is assembled and closed, the outer edge of the inner panel is squeezed by elastic components such as buffer blocks and sealing strips, causing the outer edge of the outer panel to slightly lift toward the opening direction. At the same time, the middle of the inner panel cannot lift due to the locking constraint at the latch installation. As a result, the support leg connecting the middle of the inner panel to the outer panel lifts less than the outer edge, creating a discrepancy. When this discrepancy reaches a certain level, a visually noticeable dent may form at the support leg in the middle of the outer panel, affecting the vehicle's exterior quality. While existing methods exist for controlling the apparent clearance between the door and the body by calculating the door's sealing reaction force and reaction torque, these methods primarily focus on matching the clearance between the door and the body and do not delve into the issue of post-assembly deformation of the tailgate itself. Therefore, accurately assessing and preventing potential post-assembly deformation has become a pressing technical challenge during the tailgate design phase.

[0070] This application uses finite element simulation modeling technology to simulate the stress conditions of the tailgate in the closed state after assembly, accurately reproduce the deformation of the tailgate outer panel, and further quantitatively evaluate the degree of depression in the depressed area, so as to identify and resolve potential risks of appearance deformation in advance during the design stage.

[0071] It should be noted that the execution subject of this embodiment can be a system for evaluating automobile tailgate assembly deformation, or a computing service device with data processing, network communication, and program execution capabilities, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of performing the above-mentioned automobile tailgate assembly deformation evaluation function, and this embodiment is not specifically limited to these. The following uses the automobile tailgate assembly deformation evaluation system as an example to illustrate this embodiment and the following embodiments.

[0072] Based on this, the embodiment of the present application provides a method for evaluating the deformation of the rear door assembly of an automobile, referring to Figure 1 , Figure 1 This is a flow chart of a first embodiment of a method for evaluating assembly deformation of a vehicle tailgate of the present application.

[0073] In this embodiment, the method for evaluating the assembly deformation of a car tailgate includes steps S10 to S40:

[0074] Step S10: establishing a tailgate finite element model according to the tailgate design data, wherein the tailgate finite element model includes the connection relationship and physical properties of the sheet metal parts, glass, hinges and accessories.

[0075] It should be noted that the tailgate finite element model refers to a mathematical model established through the finite element method, which can simulate the stress and deformation of each component of the tailgate when it is closed. Specifically, in this step, the system will import the model data of the sheet metal and glass of the tailgate of this model into the simulation software, mesh it, and set the attribute values ​​and material information of each component. Then, the components are connected, and welding points, adhesives, welds and bolts are simulated, and hinge kinematic pairs are established at the hinges. Finally, mass point units are established for accessories such as the trim on the tailgate, and connected to the tailgate sheet metal mounting points through flexible units (i.e., RBE3 units).

[0076] In a feasible implementation manner, the step S10 specifically includes:

[0077] Step S101: Obtaining the sheet metal data, glass data, hinge data, and accessory centroid coordinates of the tailgate according to the tailgate design data.

[0078] It should be noted that in this step, the system will use CAD software or other automotive design tools to extract the geometric shape, size and position information of the sheet metal, glass, and hinges from the tailgate design drawings or 3D models, and record the center of mass coordinates of all accessories.

[0079] Additionally, it should be noted that tailgate design data refers to all information generated during the tailgate design phase, including its geometry, dimensions, location, and material properties. Accessory centroid coordinates refer to the location of accessories (such as trim panels and latches) within the tailgate coordinate system, typically expressed as the coordinates of the center of mass (i.e., center of gravity).

[0080] Step S102: using the first unit and the second unit to perform mesh division on the sheet metal data, the glass data, and the hinge data to obtain mesh models of the sheet metal, the glass, and the hinge.

[0081] It should be noted that in this step, the system selects appropriate 2D and 3D elements based on the geometry and stress characteristics of the sheet metal, glass, and hinges, meshes the sheet metal, glass, and hinges, and generates the corresponding mesh model. For example, 2D shell elements are used for meshing the sheet metal, 2D elements are also used for the glass (considering the thinness of the glass, it can be simplified to a 2D model), and 3D solid elements are used for meshing the hinges. The mesh model after meshing accurately reflects the geometry and stress characteristics of each component.

[0082] In addition, it should be noted that the first unit refers to a 2D unit, which is usually a two-dimensional finite element unit used to simulate thin plate structures (such as sheet metal and glass). The first unit is a 3D unit, which is a three-dimensional finite element unit used to simulate three-dimensional solid structures (such as hinges).

[0083] Step S103: establishing a mass point unit according to the coordinates of the center of mass of the accessory, and connecting the mass point unit to the tailgate sheet metal mounting point via a load unit to simulate the connection relationship between the accessory and the tailgate.

[0084] It should be noted that in this step, the system creates a mass point unit in the pre-processing software based on the accessory's center of mass coordinates to simulate the accessory's mass. A load unit (such as an RBE3 unit) is then used to connect the mass point unit to the tailgate's mounting point, simulating the actual connection between the accessory and the tailgate.

[0085] Additionally, it should be noted that mass point elements are finite element elements used to simulate objects with mass but no specific geometric shape (such as accessories). Load cells are finite element elements used to connect different components and transfer loads, accurately simulating the connection relationship between components and the load transfer path.

[0086] Step S104: establishing a tailgate finite element model based on the mesh models of the sheet metal, glass, hinges, and the connection relationship between the accessories and the tailgate.

[0087] It should be noted that the system integrates the generated mesh models of the sheet metal, glass, hinges, and the connections between the accessories and the tailgate, and uses pre-processing software or specialized modeling tools to create a complete tailgate finite element model. It should be understood that this tailgate finite element model is a digital model that includes all the main components of the tailgate (sheet metal, glass, hinges, and accessories), their connections, and their physical properties.

[0088] Step S20: applying constraints and loads in the closed state to the tailgate finite element model, wherein the loads include contact area pressure, compression force, support rod force, and gravity.

[0089] It should be noted that if Figure 2 As shown, Figure 2 The figure is a schematic diagram of the loading of the tailgate constraint. Specifically, in this step, the system will (1) import the 3D data of the sealing strip, compare and identify the contact area between the sealing strip and the inner panel of the tailgate, measure the area and length of the contact area, and calculate the pressure required to be applied to the contact area in combination with the reaction force of the sealing strip in the closed state, and load the pressure to the contact area; (2) import the 3D data of the buffer block and the limit block, compare and identify their installation area on the inner panel, use the rigid unit (i.e., RIGID unit) to capture the installation area, and load the compression force of the buffer block and the limit block in the closed state to the main node of the unit; (3) import the 3D data of the strut, and apply the strut force to the strut installation point on the inner panel along the strut direction; (4) apply 1G gravity to the tailgate to simulate the natural deformation of the tailgate under the action of gravity when the tailgate is closed; (5) constrain all degrees of freedom at the tailgate hinge and body fixing point to simulate the body fixing effect on the tailgate; and apply the tailgate constraint around the hinge opening direction at the tailgate lock to simulate the state where the tailgate cannot be opened after being locked.

[0090] It's understood that contact area pressure refers to the pressure exerted on the back door inner panel by the sealing strip under pressure. Its magnitude is related to the sealing strip's reaction force and the area and length of the contact area. Compression force refers to the force exerted on the back door inner panel by the buffer block and stop block under pressure, and its direction is perpendicular to the mounting surface. Strut force refers to the force exerted by the strut on the back door, and its direction is along the strut.

[0091] In a feasible implementation manner, the step S20 specifically includes:

[0092] Step S201: Importing sealing strip data into the tailgate finite element model.

[0093] It should be noted that the sealing strip data refers to the 3D geometry, dimensions, and position of the sealing strip, and this data is usually stored in the form of a CAD file. Specifically, the system uses pre-processing software or specialized CAD tools to import the 3D data model of the sealing strip into the established finite element model of the tailgate.

[0094] Step S202: obtaining a contact area according to the sealing strip data, and obtaining the contact area area, the contact area length, and the sealing strip reaction force in the closed state through the contact area.

[0095] It should be noted that in this step, the system identifies the contact area between the sealing strip and the back door inner panel based on a data comparison of the sealing strip. The system then uses the software's built-in measurement function to obtain the area and length of the contact area. Finally, based on the pre-set material properties of the sealing strip, the system calculates the reaction force generated by the sealing strip in the closed state (typically the reaction force generated per 100mm of the sealing strip length).

[0096] Step S203: Calculating the contact area pressure according to the contact area area, the contact area length, and the sealing strip reaction force, and loading the contact area pressure to the contact area.

[0097] It should be noted that in this step, the system calculates the pressure P that needs to be applied to the contact area based on the area A and length L of the contact area, combined with the reaction force F of the sealing strip in the closed state. The calculation method is shown in Formula 1:

[0098]

[0099] Where P is the pressure required to be applied to the sealing strip contact area, in N / mm²; F is the reaction force per 100 mm of the sealing strip when the door is closed, in N / mm; L is the length of the sealing strip in contact with the door when the door is closed, in mm; and A is the contact area between the sealing strip and the door when the door is closed, in mm².

[0100] It can be understood that this step simulates the upward pressure on the inner panel generated by the sealing strip being compressed by applying the calculated pressure to the contact area between the sealing strip and the inner panel of the back door in the closed state.

[0101] Step S30: obtaining a displacement nephogram of the back door outer panel based on the constraint conditions and the load.

[0102] It should be noted that if Figure 3 As shown, Figure 3 This is a schematic diagram of the displacement contour of the rear door outer panel. A displacement contour is a graphical representation of the deformation of various parts of the rear door outer panel, obtained through finite element calculation. The colors or values ​​in the contour represent the amount of deformation at different locations. In this step, the system submits the rear door finite element model constructed in the previous step to the static calculation software for calculation. After the calculation is complete, the rear door deformation results are imported into the post-processing software to read the displacement contour of the rear door outer panel.

[0103] It can be understood that the displacement cloud map can intuitively show the deformation of the back door outer panel in the closed state, providing a basis for subsequent screening of concave deformation areas.

[0104] Step S40: screening the concave deformation area of ​​the back door outer panel according to the displacement cloud map, and performing deformation evaluation on the concave deformation area according to a preset strategy.

[0105] It should be noted that the "deformed area" refers to the localized indentation caused by uneven force on the tailgate outer panel when closed. The preset strategy refers to the criteria and method for determining the eligibility of the deformed area based on parameters such as the indentation range, depth, and degree of curvature change.

[0106] It's understood that in this step, the system uses the displacement cloud map to screen all areas where the back door outer panel is bonded to the inner panel via the support structure. It then selects these areas to read the displacement, extracts the minimum displacement within the selected area, and determines whether the area is a concave deformation area based on the location of the minimum displacement. The system then quantitatively evaluates the concave deformation area, determining whether the area is qualified based on parameters such as the concave range, concave depth, and degree of curvature change.

[0107] The present embodiment provides a method for evaluating the assembly deformation of a car's rear tailgate. The method of the present embodiment includes: establishing a finite element model of the rear tailgate based on the rear tailgate design data, wherein the finite element model of the rear tailgate includes the connection relationship and physical properties of sheet metal parts, glass, hinges, and accessories; applying constraints and loads in the closed state to the finite element model of the rear tailgate, wherein the loads include contact area pressure, compression force, strut force, and gravity; obtaining a displacement cloud map of the rear tailgate outer panel based on the constraints and the loads; screening the concave deformation area of ​​the rear tailgate outer panel based on the displacement cloud map, and performing deformation evaluation on the concave deformation area according to a preset strategy. In summary, the present embodiment simulates the stress conditions of the rear tailgate in the closed state after assembly through finite element simulation modeling technology, accurately reproduces the deformation of the rear tailgate outer panel, and further quantitatively evaluates the degree of concavity of the concave area, thereby identifying and resolving potential risks of appearance deformation in advance during the design stage.

[0108] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above embodiment 1 can be referred to the above introduction and will not be described in detail later. Figure 4 , Figure 4 This is a flow chart of a second embodiment of the method for evaluating the assembly deformation of a rear tailgate of an automobile according to the present application. The steps of screening the concave deformation area of ​​the rear tailgate outer panel according to the displacement cloud map specifically include:

[0109] Step A10: Acquire a target area where the back door outer panel and the inner panel are bonded via a support structure.

[0110] It should be noted that the target area refers to the specific locations where the tailgate outer panel and inner panel are bonded together by support structures (such as support legs). In this step, the system uses the tailgate finite element model to determine the specific locations where the tailgate outer panel and inner panel are bonded together by support structures (such as support legs). These locations are key areas where the tailgate outer panel may dent and deform when closed.

[0111] Specifically, due to the weak rigidity of the outer panel itself, after the tailgate is assembled and closed, the outer edge of the inner panel will be squeezed by elastic components such as buffer blocks and sealing strips, driving the outer edge of the outer panel to lift in the opening direction. However, the lock installation point in the middle of the inner panel cannot be lifted due to the locking constraint, which results in the lifting amount of the support leg connecting the middle of the inner panel to the outer panel being less than the outer edge. When the lifting amount of the support leg in the middle of the outer panel is different from that of the outer edge to a certain extent, a visually perceptible concave area may be formed at that location. Therefore, the outer panel concave area will only appear where the support leg is bonded, as shown below. Figure 5 All areas where the back door outer panel is bonded to the inner panel through the supporting structure are screened out. Due to the symmetrical structure, there are a total of 5 target areas to be verified that meet the requirements in the given case.

[0112] Step A20: obtaining a target displacement cloud map based on the displacement cloud map and the target area, and obtaining a minimum displacement through the target displacement cloud map, where the minimum displacement is the minimum displacement of the target area.

[0113] It should be noted that in this step, the system uses the software's functionality to extract the minimum displacement value within the selected target area from the overall displacement cloud map. The target displacement cloud map refers to the displacement cloud map corresponding to the target area extracted from the overall displacement cloud map, which reflects the deformation of the target area in the closed state. The minimum displacement refers to the minimum displacement value within the target area in the target displacement cloud map, which represents the minimum deformation of the area in the closed state.

[0114] Step A30: determining the concave deformation area of ​​the back door outer panel according to the target displacement cloud map and the minimum displacement.

[0115] It should be noted that in this step, the system analyzes the location of the minimum displacement in the target displacement cloud map. The location of the minimum displacement is used to determine whether the target area is a concave deformation area. For example, if the minimum displacement occurs at the edge of the target area, it indicates that the area has not undergone concave deformation; if the minimum displacement occurs in the middle of the target area, it indicates that the area may have undergone concave deformation.

[0116] In a feasible implementation manner, the step A30 specifically includes:

[0117] Step A301: obtaining the current region where the target displacement is located and the region cloud type according to the target displacement cloud map and the minimum displacement.

[0118] It should be noted that in this step, the system will locate the current area of ​​the target area where the minimum displacement is located based on the target displacement cloud map. It can be understood that the current area refers to the specific location of the minimum displacement value in the target displacement cloud map, that is, the location within the selected target area (such as the edge or the middle).

[0119] In addition, it should be noted that the concave cloud map type refers to the appearance of the target area in the target displacement cloud map, which reflects the size and distribution of the displacement value through the depth of color or gradient changes. For example, a flat cloud map indicates that the displacement value is relatively uniform, while a concave cloud map indicates that the displacement value in this area is significantly lower than the surrounding area.

[0120] Step A302: When the current area is the middle and the regional cloud map type is a concave cloud map, determine that the target area is a concave deformation area of ​​the back door outer panel.

[0121] It should be noted that if Figure 6 As shown, in this step, the system will determine whether the current area is located in the middle of the target area and whether the area cloud type is a concave cloud. If both conditions are met, the system can determine that the target area is the concave deformation area of ​​the back door outer panel. It can be understood that, if Figure 7 As shown in FIG, if the current area is at the edge of the target area and the regional cloud map type is not a concave cloud map, the system determines that the target area has no concave deformation problem.

[0122] In this embodiment, by obtaining the target area where the tailgate outer panel and the inner panel are bonded through the supporting structure, and analyzing the minimum displacement and cloud type of the target area based on the displacement cloud map, the precise positioning of the sunken deformation area of ​​the tailgate outer panel is achieved, which solves the problem that traditional methods are difficult to accurately identify the sunken deformation area, and improves the ability to predict and evaluate the risk of sunken deformation in the design stage of the tailgate, thereby effectively avoiding the rectification costs caused by appearance defects in the actual vehicle in the later stage.

[0123] Based on the first and second embodiments of the present application, in the third embodiment of the present application, the same or similar contents as those in the first and second embodiments can be referred to above and will not be described in detail. Figure 8 , Figure 8 This is a flow chart of a third embodiment of the method for evaluating the assembly deformation of a rear door of an automobile according to the present application. The step of evaluating the deformation of the concave deformation area according to a preset strategy specifically includes:

[0124] Step B10: expanding the concave deformation area according to a preset strategy to obtain a complete concave deformation area.

[0125] It should be noted that in this step, the system will gradually expand the initially screened concave deformation area using tools in the post-processing software (such as region expansion and boundary tracking) according to a preset strategy until a complete concave deformation area containing all relevant deformed mesh nodes is obtained. The preset strategy refers to the rules or methods followed when expanding the concave deformation area, such as gradually expanding the area according to the displacement gradient or color depth until specific conditions are met (such as stable displacement values ​​and gentle color changes).

[0126] For example, Figure 9 As shown in , the system will gradually expand the displacement reading range of the concave deformation area until the complete concave area appears. Figure 9 As can be seen from the red boxes in the first three images, all three contain gaps. Therefore, the system continues to expand the concave deformation area to the last image, where a complete concave area cloud map can be seen. The area enclosed by the clear blue boundary line shown in the red circle is the complete concave deformation area.

[0127] Step B20: extracting the grid node coordinates and displacement data of the complete concave deformation area.

[0128] It should be noted that in this step, the system extracts the coordinates and displacement data of all relevant mesh nodes from the complete concave deformation area. This data will be used for subsequent calculations and analysis. Furthermore, it should be noted that mesh node coordinates refer to the specific location of each mesh node in three-dimensional space, typically expressed in the form of (x, y, z). Displacement data refers to the displacement of each mesh node under the action of force, reflecting the degree of deformation at that node.

[0129] Step B30: Calculating a concave range according to the grid node coordinates, where the concave range is the maximum distance between the grid node coordinates.

[0130] It should be noted that the concave range refers to the maximum distance between all grid nodes in the concave deformation area, which reflects the spatial size of the concave deformation. Figure 10 As shown, in this step, the system extracts the grid node coordinate data, calculates the distance between each grid node, and finds the value with the largest distance, which is the concave range D (mm).

[0131] Step B40: Calculating the depression depth according to the displacement data, where the depression depth is the maximum difference between the displacement data and the minimum displacement value in the depression area.

[0132] It should be noted that the depth of the concave refers to the maximum difference between the displacement values ​​of the grid nodes that enclose the concave area and the minimum displacement value of the area, which reflects the depth of the concave deformation. Specifically, Figure 11 As shown, the system extracts the displacement values ​​of all grid nodes that form the concave area in the displacement data and the minimum displacement value in the concave area, and calculates the difference between these displacement values ​​and the minimum displacement value in the middle of the area. The largest difference is defined as the concave depth H (mm) of the concave area.

[0133] Step B50: Calculating the curvature mutation degree based on the grid node coordinates, where the curvature mutation degree is the maximum value of the curvature difference between adjacent grid nodes.

[0134] It should be noted that the curvature mutation degree refers to the maximum value of the curvature difference between adjacent grid nodes in the concave area, which reflects the smoothness and irregularity of the surface of the concave deformation area. In this step, the system calculates the curvature of each node using the grid node coordinates, and then calculates the curvature difference between adjacent nodes, and sets the maximum difference in the curvature difference as the curvature mutation degree Δk max .

[0135] Step B60: When the concave range is greater than a preset width threshold, the concave depth is greater than a preset depth threshold, and the curvature mutation degree is greater than a preset curvature threshold, the concave deformation area is determined to be an appearance defect that needs to be optimized.

[0136] It should be noted that if Figure 12 As shown, the system compares the calculated concave range, concave depth, and curvature mutation with the preset width, depth, and curvature thresholds, respectively. If all three conditions are met: the concave range is greater than the preset width threshold, the concave depth is greater than the preset depth threshold, and the curvature mutation is greater than the preset curvature threshold, the concave deformation area is determined to be an appearance defect requiring improvement. This means that the tailgate structure or assembly force needs to be optimized and adjusted. The above verification steps are repeated until the appearance requirements are met. If any of these conditions are not met, the concave deformation area is considered qualified and is not a visible concave deformation area.

[0137] In addition, it should be noted that the preset width threshold, preset depth threshold and preset curvature threshold refer to the threshold standards used when determining whether the concave deformation area is an appearance defect that needs to be optimized. These thresholds are determined based on factors such as different car types and different tailgate appearance quality standards.

[0138] In a feasible implementation manner, the step B50 specifically includes:

[0139] Step B501: Calculate the coordinate vectors and step lengths of two adjacent nodes based on the grid node coordinates.

[0140] It should be noted that a coordinate vector is a collection of objects with magnitude and direction, representing the relative position of a point or shape in space. The system determines the coordinate data values ​​(xi, yi, zi) for all mesh nodes within the complete concave deformation region, where i = 1, 2, ..., n, where n is the total number of nodes within the concave region. The step length between two nodes—the straight-line distance between them—is also calculated, serving as the basis for subsequent numerical differentiation calculations.

[0141] Step B502: Calculate the first-order derivative and the second-order derivative according to the coordinate vector and the step size.

[0142] It should be noted that in this step, the system will calculate the first-order derivative (r i ′) and the second-order derivative (r i Specifically, for a node i, its first-order derivative can be approximated by the ratio of the coordinate vector difference between it and its adjacent nodes i-1 and i+1 to the step length; the second-order derivative can be approximated by the ratio of the first-order derivative difference between nodes i-1, i, and i+1 to the step length. Specifically, the calculation process is shown in Formula 2:

[0143]

[0144] Among them, r i =(x i ,y i ,z i ), is the coordinate vector of point i, r i and r i-1 is the coordinate vector of the adjacent nodes, and h is the step size.

[0145] Step B503: Calculate the node curvature according to the first-order derivative and the second-order derivative.

[0146] It should be noted that the node curvature is an important indicator for evaluating the surface smoothness of the concave deformation area, which reflects the degree of curvature at the node position. Specifically, the curvature K of the point i is calculated based on the first-order derivative and second-order derivative of the point i. i The process is shown in formula 3:

[0147]

[0148] Step B504: traverse all adjacent nodes in the grid node coordinates to obtain node curvature differences, and use the maximum curvature difference among the node curvature differences as the curvature mutation degree.

[0149] It should be noted that in this step, the system will traverse all adjacent grid nodes within the complete concave deformation area and calculate the curvature difference between them. Specifically, for each pair of adjacent nodes, the difference in their curvature is calculated to obtain the curvature difference, that is, Δk = |k i -k i-1 |. Then, find the maximum value Δk from all the calculated curvature differences max , which is the degree of curvature mutation.

[0150] It can be understood that the curvature mutation degree refers to the maximum value of the curvature difference between adjacent grid nodes in the concave deformation area, which reflects the irregularity and continuity of the surface of the concave deformation area.

[0151] In this embodiment, by expanding the sunken area, extracting grid node coordinates and displacement data, and calculating the sunken range, sunken depth, and curvature mutation degree, the problem that traditional methods are difficult to accurately assess the degree of sunken deformation is solved, thereby improving the accuracy and efficiency of appearance defect judgment and effectively avoiding the increase in rectification costs caused by the deformation and sunken tailgate of the actual vehicle in the later stage.

[0152] This application also provides an evaluation device for automobile tailgate assembly deformation, please refer to Figure 13 The vehicle tailgate assembly deformation assessment device comprises:

[0153] A model building module 10 is used to establish a tailgate finite element model based on the tailgate design data, wherein the tailgate finite element model includes the connection relationship and physical properties of the sheet metal parts, glass, hinges and accessories;

[0154] a load simulation module 20 for applying constraints and loads in the tailgate finite element model under the closed state, wherein the loads include contact area pressure, compression force, support rod force, and gravity;

[0155] a displacement calculation module 30, configured to obtain a displacement cloud diagram of the back door outer panel based on the constraint conditions and the load;

[0156] The dent assessment module 40 is configured to screen the dent deformation area of ​​the back door outer panel according to the displacement cloud map, and perform deformation assessment on the dent deformation area according to a preset strategy.

[0157] The vehicle tailgate assembly deformation assessment device provided in this application utilizes the vehicle tailgate assembly deformation assessment method described in the aforementioned embodiment, addressing the technical problem of accurately assessing and preventing post-assembly appearance deformation during the design phase of a vehicle tailgate. Compared to the prior art, the vehicle tailgate assembly deformation assessment device provided in this application achieves the same beneficial effects as the vehicle tailgate assembly deformation assessment method described in the aforementioned embodiment. Other technical features of the vehicle tailgate assembly deformation assessment device are the same as those disclosed in the aforementioned embodiment and are not further detailed here.

[0158] In one embodiment, the model building module 10 is also used to obtain the sheet metal data, glass data, hinge data and accessory center of mass coordinates of the back door based on the back door design data; use the first unit and the second unit to mesh the sheet metal data, the glass data and the hinge data to obtain a mesh model of the sheet metal, glass and hinge; establish a mass point unit according to the accessory center of mass coordinates, and connect the mass point unit to the back door sheet metal installation point through a load unit to simulate the connection relationship between the accessory and the back door; establish a back door finite element model based on the mesh model of the sheet metal, glass and hinge, and the connection relationship between the accessory and the back door.

[0159] In one embodiment, the load simulation module 20 is also used to import sealing strip data into the tailgate finite element model; obtain a contact area based on the sealing strip data, and obtain the contact area area, contact area length and sealing strip reaction force in the closed state through the contact area; calculate the contact area pressure based on the contact area area, the contact area length and the sealing strip reaction force, and load the contact area pressure to the contact area.

[0160] In one embodiment, the dent assessment module 40 is further used to obtain a target area where the back door outer panel and the inner panel are bonded by a support structure; obtain a target displacement cloud map based on the displacement cloud map and the target area, and obtain a minimum displacement through the target displacement cloud map, wherein the minimum displacement is the minimum displacement of the target area; and determine the dent deformation area of ​​the back door outer panel based on the target displacement cloud map and the minimum displacement.

[0161] In one embodiment, the dent assessment module 40 is further used to obtain the current area and the area cloud type of the target displacement based on the target displacement cloud map and the minimum displacement; when the current area is in the middle and the area cloud type is a dent cloud map, the target area is determined to be the dent deformation area of ​​the back door outer panel.

[0162] In one embodiment, the concave evaluation module 40 is further used to expand the concave deformation area according to a preset strategy to obtain a complete concave deformation area; extract the grid node coordinates and displacement data of the complete concave deformation area; calculate the concave range according to the grid node coordinates, wherein the concave range is the maximum distance between the grid node coordinates; calculate the concave depth according to the displacement data, wherein the concave depth is the maximum difference between the displacement data and the minimum displacement value in the concave area; calculate the curvature mutation degree based on the grid node coordinates, wherein the curvature mutation degree is the maximum value of the curvature difference between adjacent grid nodes; when the concave range is greater than a preset width threshold, the concave depth is greater than a preset depth threshold, and the curvature mutation degree is greater than a preset curvature threshold, the concave deformation area is determined to be an appearance defect that needs to be optimized.

[0163] In one embodiment, the sag assessment module 40 is further used to calculate the coordinate vector and step size of two adjacent nodes based on the grid node coordinates; calculate the first-order derivative and the second-order derivative based on the coordinate vector and the step size; calculate the node curvature based on the first-order derivative and the second-order derivative; traverse all adjacent nodes in the grid node coordinates to obtain node curvature differences, and use the maximum curvature difference among the node curvature differences as the degree of curvature mutation.

[0164] The present application provides a device for evaluating the assembly deformation of a vehicle tailgate. The device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for evaluating the assembly deformation of the vehicle tailgate in the first embodiment.

[0165] Reference below Figure 14 , which shows a schematic diagram of the structure of a device suitable for implementing the automobile tailgate assembly deformation assessment in accordance with an embodiment of the present application. The automobile tailgate assembly deformation assessment device in accordance with an embodiment of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 14 The illustrated device for evaluating the assembly deformation of a car tailgate is merely an example and should not limit the functions and scope of use of the embodiments of the present application.

[0166] like Figure 14As shown, the vehicle tailgate assembly deformation assessment device may include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes based on programs stored in a ROM (Read Only Memory) 1002 or programs loaded from a storage device 1003 into a RAM (Random Access Memory) 1004. RAM 1004 also stores various programs and data required for the operation of the vehicle tailgate assembly deformation assessment device. Processing device 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input device 1007 including, for example, a touch screen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output device 1008 including, for example, an LCD (Liquid Crystal Display), speaker, vibrator, etc.; storage device 1003 including, for example, a magnetic tape, hard disk, etc.; and communication device 1009. Communication device 1009 can allow the vehicle tailgate assembly deformation assessment device to communicate wirelessly or wired with other devices to exchange data. Although the figure shows a vehicle tailgate assembly deformation assessment device with various systems, it should be understood that not all of the illustrated systems are required to be implemented or present. More or fewer systems may alternatively be implemented or present.

[0167] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0168] The vehicle tailgate assembly deformation assessment device provided in this application utilizes the vehicle tailgate assembly deformation assessment method described in the aforementioned embodiment. This device can address the technical problem of accurately assessing and preventing potential post-assembly appearance deformation during the design phase of a vehicle tailgate. Compared to the prior art, the vehicle tailgate assembly deformation assessment device provided in this application offers the same beneficial effects as the vehicle tailgate assembly deformation assessment method described in the aforementioned embodiment. Other technical features of the vehicle tailgate assembly deformation assessment device are the same as those disclosed in the aforementioned embodiment and are not further detailed here.

[0169] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0170] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0171] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, a computer program) stored thereon, wherein the computer-readable program instructions are used to execute the method for evaluating the assembly deformation of a rear door of an automobile in the above-mentioned embodiment.

[0172] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, RAM (Random Access Memory), ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory or Flash memory), optical fiber, CD-ROM (CD-Read Only Memory, portable compact disk read-only memory), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0173] The computer-readable storage medium may be included in the vehicle tailgate assembly deformation evaluation device; or may exist independently without being assembled into the vehicle tailgate assembly deformation evaluation device.

[0174] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the evaluation device for the deformation of the rear tailgate assembly of an automobile, the evaluation device for the deformation of the rear tailgate assembly of an automobile: establishes a finite element model of the rear tailgate according to the design data of the rear tailgate, and the finite element model of the rear tailgate includes the connection relationship and physical properties of sheet metal parts, glass, hinges and accessories; applies constraints and loads in the closed state to the finite element model of the rear tailgate, and the loads include contact area pressure, compression force, strut force and gravity; obtains a displacement cloud map of the rear tailgate outer panel based on the constraints and the loads; screens the concave deformation area of ​​the rear tailgate outer panel according to the displacement cloud map, and performs deformation evaluation on the concave deformation area according to a preset strategy.

[0175] The computer program code for performing the operations of the present application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer can be connected to the user's computer through any type of network, including a LAN (Local Area Network) or a WAN (Wide Area Network), or can be connected to an external computer (e.g., using an Internet service provider to connect via the Internet).

[0176] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0177] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0178] The computer-readable storage medium provided in this application stores computer-readable program instructions (i.e., a computer program) for executing the aforementioned method for evaluating automobile tailgate assembly deformation. This computer-readable storage medium addresses the technical problem of accurately evaluating and preventing post-assembly appearance deformation of automobile tailgates during the design phase. Compared to the prior art, the computer-readable storage medium provided in this application offers the same beneficial effects as the method for evaluating automobile tailgate assembly deformation provided in the aforementioned embodiments, and therefore is not further elaborated upon here.

[0179] The present application also provides a computer program product, comprising a computer program, which implements the steps of the above-mentioned method for evaluating the assembly deformation of a rear door of an automobile when the computer program is executed by a processor.

[0180] The computer program product provided in this application can address the technical problem of accurately assessing and preventing possible post-assembly deformation of a vehicle's tailgate during its design phase. Compared to existing technologies, the computer program product provided in this application offers the same beneficial effects as the method for assessing tailgate assembly deformation provided in the aforementioned embodiments, and will not be further elaborated here.

[0181] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for evaluating the assembly deformation of a car back door, characterized in that: The method comprises: Establishing a tailgate finite element model based on the tailgate design data, wherein the tailgate finite element model includes the connection relationship and physical properties of the sheet metal parts, glass, hinges, and accessories; Applying constraints and loads in the closed state to the tailgate finite element model, wherein the loads include contact area pressure, compression force, support rod force, and gravity; Obtaining a displacement nephogram of the back door outer panel based on the constraint conditions and the load; The concave deformation area of ​​the back door outer panel is screened according to the displacement cloud map, and the deformation evaluation of the concave deformation area is performed according to a preset strategy.

2. The method according to claim 1, wherein The step of establishing a finite element model of the back door according to the back door design data comprises: Obtain the sheet metal data, glass data, hinge data and accessory center of mass coordinates of the back door according to the back door design data; Using the first unit and the second unit to mesh the sheet metal data, the glass data, and the hinge data to obtain mesh models of the sheet metal, the glass, and the hinge; Establishing a mass point unit according to the coordinates of the center of mass of the accessory, and connecting the mass point unit to the tailgate sheet metal mounting point through a load unit to simulate the connection relationship between the accessory and the tailgate; A tailgate finite element model is established based on the mesh models of the sheet metal, glass, hinges, and the connection relationship between the accessories and the tailgate.

3. The method according to claim 1, wherein The step of applying the constraint conditions and loads in the closed state to the tailgate finite element model comprises: Importing sealing strip data into the tailgate finite element model; Obtaining a contact area according to the sealing strip data, and obtaining the contact area, the contact area length, and the sealing strip reaction force in a closed state through the contact area; The contact area pressure is calculated according to the contact area area, the contact area length and the sealing strip reaction force, and the contact area pressure is loaded to the contact area.

4. The method according to claim 1, wherein The step of screening the concave deformation area of ​​the back door outer panel according to the displacement cloud map includes: Obtaining a target area where the back door outer panel and the inner panel are bonded via the support structure; Obtaining a target displacement cloud map based on the displacement cloud map and the target area, and obtaining a minimum displacement through the target displacement cloud map, wherein the minimum displacement is the minimum displacement of the target area; The concave deformation area of ​​the back door outer panel is determined according to the target displacement cloud map and the minimum displacement.

5. The method according to claim 4, wherein The step of determining the concave deformation area of ​​the back door outer panel according to the target displacement cloud map and the minimum displacement includes: Obtaining the current region and the region cloud type where the target displacement is located according to the target displacement cloud map and the minimum displacement; When the current area is the middle and the area cloud map type is a concave cloud map, the target area is determined to be a concave deformation area of ​​the back door outer panel.

6. The method according to claim 1, wherein The step of performing deformation assessment on the concave deformation area according to a preset strategy includes: Expanding the concave deformation area according to a preset strategy to obtain a complete concave deformation area; Extracting grid node coordinates and displacement data of the complete concave deformation area; Calculating a concave range according to the grid node coordinates, wherein the concave range is the maximum distance between the grid node coordinates; Calculating a depression depth based on the displacement data, wherein the depression depth is a maximum difference between the displacement data and a minimum displacement value in the depression area; Calculating a curvature mutation degree based on the grid node coordinates, wherein the curvature mutation degree is the maximum value of the curvature difference between adjacent grid nodes; When the concave range is greater than a preset width threshold, the concave depth is greater than a preset depth threshold, and the curvature mutation degree is greater than a preset curvature threshold, the concave deformation area is determined to be an appearance defect that needs to be optimized.

7. The method according to claim 6, wherein The step of calculating the curvature mutation degree based on the grid node coordinates includes: Calculate the coordinate vectors and step lengths of two adjacent nodes according to the grid node coordinates; Calculating a first-order derivative and a second-order derivative based on the coordinate vector and the step size; Calculating a node curvature based on the first-order derivative and the second-order derivative; All adjacent nodes in the grid node coordinates are traversed to obtain node curvature differences, and the maximum curvature difference among the node curvature differences is used as the curvature mutation degree.

8. An evaluation device for automobile tailgate assembly deformation, characterized in that: The device comprises: A model building module, configured to build a finite element model of the tailgate based on the tailgate design data, wherein the finite element model of the tailgate includes connection relationships and physical properties of sheet metal parts, glass, hinges, and accessories; a load simulation module for applying constraints and loads in the closed state to the tailgate finite element model, wherein the loads include contact area pressure, compression force, support rod force, and gravity; a displacement calculation module, configured to obtain a displacement cloud diagram of the back door outer panel based on the constraint conditions and the load; The dent assessment module is used to screen the dent deformation area of ​​the back door outer panel according to the displacement cloud map, and perform deformation assessment on the dent deformation area according to a preset strategy.

9. An evaluation device for automobile tailgate assembly deformation, characterized in that: The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the method for evaluating assembly deformation of a rear tailgate of an automobile according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the method for evaluating the assembly deformation of a rear tailgate of an automobile according to any one of claims 1 to 7 are implemented.

Images