Finite element analysis method for jacking of engine cover lock

Abstract

The invention discloses an engine cover lock jacking finite element analysis method, which comprises the following steps: performing finite element division on a spring axis, setting actual material attributes of a spring, and establishing a finite element model close to the actual state of the spring. And the rigidity checking problem caused by direct grid division of the spring entity is avoided, and the working process of the spring can be completely and effectively simulated, so that the jacking process of the engine cover is more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular relates to a finite element analysis method for hood lock lifting. Background Art

[0002] In the process of implementing the present invention, the inventors found that the prior art has at least the following problems:

[0003] The lifting performance of the hair cover directly affects the user experience. The hair cover is mainly lifted by the hair cover lock. The most important component in the hair cover lock is a coil spring. Since the coil spring theoretically follows Hooke's law, that is, within a certain range, the elastic force is proportional to the compression or extension of the spring, the spring is usually replaced by a 1D unit defined by a displacement-force curve in finite element simulation. This method stipulates that the spring can only move linearly along the directions defined by the two endpoints, ignoring other aspects of the spring. However, the actual spring movement is more complicated, and various external interference factors will force the spring movement to deviate from the theoretically defined state.

[0004] A spring is a mechanical part that uses elasticity to work. Parts made of elastic materials deform under external force and return to their original shape after the external force is removed. Springs are widely used in production and life, and are generally made of spring steel. There are many types of springs. According to their shapes, they mainly include helical springs, scroll springs, leaf springs, special-shaped springs, etc. Helical springs are generally used in automobile hood locks and other parts.

[0005] There are currently two main spring simulation methods in the finite element field. One is to use Hooke's law to simplify the spring into an elastic 1D unit, with its stiffness defined by force and displacement curves. This type of spring is easy to establish, but the details of the spring movement are seriously lost. The other is to directly divide the 3D grid using the spring's physical data, and then assign unit properties and materials. The spring stiffness generated in this way is greatly affected by the unit size, and repeated calibration is required to obtain a more accurate spring stiffness, and the modeling efficiency is too low.

[0006] CN112241568A-A finite element-based engine hood opening and closing durability fatigue analysis method discloses a finite element-based engine hood opening and closing durability fatigue analysis method, which imports the engine hood, engine hood related accessories and white body data that matches the engine hood into the software to establish a model; obtains the time domain stress results generated during the engine hood opening and closing process; imports the time domain stress results into the software model to cyclically simulate the engine hood opening and closing process to achieve a preset number of simulations and obtain various damage values; and is unable to solve the above-mentioned technical problems. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a finite element analysis method for the lifting of a hair cover lock, which not only retains the spiral structure of the spring, but also avoids the stiffness verification problem caused by directly dividing the spring entity into grids. The working process of the spring can be completely and effectively simulated, thereby more accurately simulating the process of lifting the hair cover.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a finite element analysis method for the lifting of the hair cover lock,

[0009] The cover system includes a cover body and a cover lock; the cover lock includes a lock housing and a spring;

[0010] The modeling process includes the modeling of the cover body and the process of locking the cover.

[0011] The steps of establishing the spring model are:

[0012] 1) Import the CAD model of the spring into the CAE software;

[0013] 2) Find two parallel spiral lines on the contours at both ends of the spring diameter and delete the spring entity;

[0014] 3) Using the two parallel helical lines found in step 2) to generate the helical axis of the spring;

[0015] 4) Perform finite element division on the spring spiral axis obtained in step 3) to generate 1D beam elements;

[0016] 5) Set the actual material and properties of the spring to the 1D beam element generated in step 4);

[0017] 6) Setting a ballast condition for the spring model obtained in step 5) to check the stiffness;

[0018] 7) providing a guide column to the spring obtained in step 6);

[0019] 8) Use the pressure plate to load the spring to the lock closed position;

[0020] 9) Release the spring and the hair cover will be lifted up under the action of the spring force.

[0021] In the above step 1), the spring is in a free state.

[0022] The modeling process of the hair cover body is as follows:

[0023] a) Import the digital model of the cover body;

[0024] b) obtaining a mesh model of the hair cover;

[0025] c) assigning corresponding properties and materials to the hair cover body;

[0026] d) Establishing the connection status of the cover body;

[0027] e) There is a set of hinge mechanisms in the cover body, which allows the cover to rotate during opening, so revolute (rotating hinge) is used for modeling.

[0028] In the above step a), the parts that do not need to be modeled are cleaned up in the digital model of the cover body.

[0029] In the above step b), the sheet metal of the hair cover body is extracted and then batchmesh is performed to obtain a mesh model of the hair cover.

[0030] In the above step c), corresponding properties and materials are assigned to each component in the cover body according to the EBOM (Bill of Materials).

[0031] In the above step d), according to the actual connection state of the hair cover body, a corresponding connection method is established in the grid model, and the hemming is sewn.

[0032] The modeling process of the lock housing is the same as that of the cover body.

[0033] One of the above technical solutions has the following advantages or beneficial effects: it not only retains the spiral structure of the spring, but also avoids the stiffness verification problem caused by directly dividing the spring entity into grids. It can completely and effectively simulate the working process of the spring, thereby more accurately modeling the process of the cover lifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a principle diagram of the finite element analysis method for lifting the hair cover lock provided in an embodiment of the present invention;

[0035] Figure 2 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0036] Figure 3 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0037] Figure 4 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0038] Figure 5 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0039] Figure 6 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0040] Figure 7 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock;

[0041] Figure 8 for Figure 1 Schematic diagram of the finite element analysis method for the hood lock; DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Embodiment 1

[0044] See also Figures 1 to 8 A finite element analysis method for lifting a hood lock, the hood system includes a hood body and a hood lock; the hood lock includes a lock shell and a spring; the modeling process includes the modeling of the hood body and the hood lock process.

[0045] The modeling process of the hood body is as follows: a) import the digital model of the hood body; b) obtain the mesh model of the hood; c) assign corresponding properties and materials to the hood body; d) establish the connection state of the hood body; e) there is a set of hinge mechanisms in the hood body, and the hood can rotate during the opening process, so revolute is used for modeling.

[0046] In the above step a), the parts that do not need to be modeled are cleaned up in the digital model of the cover body.

[0047] In the above step b), the sheet metal of the hood body is extracted and then batch meshed. (This step can obtain a better mesh model of the hood, which is mainly manifested in the high quality of the single-piece mesh and the good conformity of the part characteristics after meshing.)

[0048] In step c) above, the corresponding properties and materials are assigned to each component in the body of the cover according to the EBOM. (After being assigned properties and material parameters, the mesh in the component can participate in finite element mechanics calculations.)

[0049] In the above step d), according to the actual connection state of the hair cover body, the corresponding connection method is established in the grid model, and the hem is sewn. (This step connects each component piece into a movable mechanism, which can move accordingly under the action of external load.)

[0050] The modeling process of the lock shell is the same as that of the cover body.

[0051] The steps to build the spring model are:

[0052] 1) Import the CAD model of the spring into the CAE software; (This step is to facilitate CAE-related model operation and processing.)

[0053] 2) Find two parallel spiral lines on the contours at both ends of the spring diameter and delete the spring entity; (This step can quickly and accurately find the spiral axis from the spring entity.)

[0054] 3) Use the two parallel helical lines found in step 2) to generate the helical axis of the spring; (same as step 2)

[0055] 4) Perform finite element division on the spring spiral axis obtained in step 3) to generate 1D beam elements; (Based on the finite element concept, the spring axis is finite elementized to simulate the spring performance.)

[0056] 5) Set the actual material and properties of the spring to the 1D beam element generated in step 4); (This step assigns the 1D beam element properties and parameters, and the 1D beam element can perform mechanical calculations.)

[0057] 6) Set the ballast condition for the spring model obtained in step 5) and check the stiffness; (This step is used to benchmark the actual spring stiffness to determine the rationality of the spring unit division.)

[0058] 7) Set a guide column for the spring obtained in step 6); (This step is to simulate the actual working condition of the spring to prevent the spring from becoming unstable and flying out.)

[0059] 8) Use the pressure plate to load the spring to the lock closed position; (This step is to make the spring reach the preloaded state, which is consistent with the actual state)

[0060] 9) Release the spring and the hair cover will be lifted up under the action of the spring force.

[0061] In the above step 1), the spring is in a free state.

[0062] The present invention is based on finite element modeling software, which divides the spring axis into finite elements and assigns the actual material and properties of the spring to the finite element unit. In this way, a finite element spring model close to the actual state of the spring is generated through the actual structure and parameters of the spring itself.

[0063] This method divides the spring axis into finite elements, sets the actual material properties of the spring, and establishes a finite element model that is close to the actual state of the spring. This method not only retains the spiral structure of the spring, but also avoids the stiffness verification problem caused by directly dividing the spring entity into grids. It can completely and effectively simulate the working process of the spring, thereby more accurately modeling the process of the cover lifting.

[0064] This method performs 1D unit division on the extracted spring axis, so that the number of spring unit data is small, and the stiffness is not easily affected by the unit size and the stiffness is stable.

[0065] After adopting the above scheme, the spiral structure of the spring is retained and the stiffness verification problem caused by directly dividing the spring entity into grids is avoided. The working process of the spring can be fully and effectively simulated, thereby more accurately modeling the process of the cover lifting.

[0066] Embodiment 2

[0067] A finite element analysis method for the lifting of a hood lock. Since the hood system mainly includes two parts: the hood body and the hood lock, the following briefly describes its modeling process. The hood body is modeled as follows:

[0068] 1. Import the digital model of the hood body and clean up the standard parts and other parts that do not need to be modeled; 2. Extract the surface of the sheet metal parts of the hood body, and then perform batchmesh to obtain the mesh model of the hood; 3. According to EBOM, assign corresponding properties and materials to each component in the hood body; 4. According to the actual connection status of the hood body, establish the corresponding connection method in the mesh model and sew the edge; 5. There is a set of hinge mechanisms in the hood body, which can rotate during the opening process. Revolute is used for modeling, such as Figure 1 As shown in the figure, the model of the hair cover body is now established. Figure 2 shown.

[0069] The cover lock includes a lock shell and a spring, wherein the spring is a key component. The main body modeling methods of the shell and the cover are the same and will not be repeated.

[0070] The specific steps to establish the spring model are:

[0071] 1. Import the digital model of the spring in the free state, and find two parallel spiral lines on the outer contour at both ends of the spring diameter; 2. The two parallel spiral lines on the outer contour of the spring found in step 1 can quickly generate the spiral axis of the spring; 3. Perform finite element division on the spiral axis of the spring obtained in step 2 to generate a 1D beam unit; 4. Set the actual material and properties of the spring for the 1D beam unit generated in step 3; 5. Set the ballasting condition for the spring model obtained in step 4, check the stiffness, and adjust the size of the 1D beam unit of the spring; 6. Set a guide column for the spring obtained in step 5. This structure is used to guide the spring pre-loading process; 7. Use a pressure plate to pressurize the spring to the locked position; 8. Release the spring, and the cover is lifted up by the spring elastic force.

[0072] The present invention is based on finite element modeling software, which divides the spring axis into finite elements and assigns the actual material and properties of the spring to the finite element unit. In this way, a finite element spring model close to the actual state of the spring is generated through the actual structure and parameters of the spring itself.

[0073] Embodiment 3

[0074] The basic assumption of this method is that the axis of the spring is a helical line, which is similar to the spiral structure of the spring. If the axis of the spring is divided by finite element, it can not only ensure the spiral structure of the spring, but also simplify the stiffness calibration work brought by the entity division mesh. The modeling speed is improved, and the stiffness of the model is not easily affected by the mesh size, and the stiffness is stable.

[0075] A finite element analysis method for the lifting of a hair cover lock, the specific steps of establishing a spring model are:

[0076] 1. Import the CAD model of the spring into the CAE software. At this time, the spring is in a free state, such as Figure 3 ;

[0077] 2. Find two parallel spiral lines on the contours at both ends of the spring diameter and delete the spring entity, such as Figure 4 As shown;

[0078] 3. Use the two parallel helical lines found in step 2 to generate the helical axis of the spring, such as Figure 5 As shown;

[0079] 4. Perform finite element division on the spring spiral axis obtained in step 3 to generate 1D beam elements, such as Figure 6 As shown;

[0080] 5. Set the actual material and properties of the spring to the 1D beam element generated in step 4;

[0081] 6. Set a pressure plate and a guide column for the spring model obtained in step 4 and make contact. The pressure plate and the guide column are used as the preload of the spring, such as Figure 7 ;

[0082] 7. After preloading is completed, the pressure plate and guide column no longer work, and the spring is released to lift the cover.

[0083] The following demonstrates the relationship between spring stiffness and element size:

[0084] like Figure 8 , adjust the size of the spring unit respectively, measure the stiffness value of the spring, and obtain the following data, such as

[0085] Table 1:

[0086] Spring unit size (mm) Spring stiffness (N / mm) 1 1.33 3 1.39 5 1.39

[0087] It can be seen from Table 1 that when the spring unit size is in the range of (1mm, 5mm), the spring stiffness remains basically unchanged. Therefore, the stiffness of the spring is little affected by the unit size and the stiffness is stable.

[0088] The present invention is based on finite element modeling software, which divides the spring axis into finite elements and assigns the actual material and properties of the spring to the finite element unit. In this way, a finite element spring model close to the actual state of the spring is generated through the actual structure and parameters of the spring itself.

[0089] This method divides the spring axis into finite elements, sets the actual material properties of the spring, and establishes a finite element model that is close to the actual state of the spring. This method not only retains the spiral structure of the spring, but also avoids the stiffness verification problem caused by directly dividing the spring entity into grids. It can completely and effectively simulate the working process of the spring, thereby more accurately modeling the process of the cover lifting.

[0090] This method performs 1D unit division on the extracted spring axis, so that the number of spring unit data is small, and the stiffness is not easily affected by the unit size and the stiffness is stable.

[0091] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0092] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0093] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A finite element analysis method for a hair cover lock, characterized in that: The cover system includes a cover body and a cover lock; the cover lock includes a lock housing and a spring; The modeling process includes the modeling of the cover body and the process of locking the cover.

2. The finite element analysis method for the hood lock lifting according to claim 1, characterized in that: The steps of establishing the spring model are: 1) Import the CAD model of the spring into the CAE software; 2) Find two parallel spiral lines on the contours at both ends of the spring diameter and delete the spring entity; 3) Using the two parallel helical lines found in step 2) to generate the helical axis of the spring; 4) Perform finite element division on the spring spiral axis obtained in step 3) to generate 1D beam elements; 5) Set the actual material and properties of the spring to the 1D beam element generated in step 4); 6) Setting a ballast condition for the spring model obtained in step 5) to check the stiffness; 7) providing a guide column to the spring obtained in step 6); 8) Use the pressure plate to load the spring to the lock closed position; 9) Release the spring and the hair cover will be lifted up under the action of the spring force.

3. The finite element analysis method for the hood lock lifting according to claim 2, characterized in that: In the above step 1), the spring is in a free state.

4. The finite element analysis method for the hood lock lifting as claimed in claim 3, characterized in that: The modeling process of the hair cover body is as follows: a) Import the digital model of the cover body; b) obtaining a mesh model of the hair cover; c) assigning corresponding properties and materials to the hair cover body; d) Establishing the connection status of the cover body; e) There is a set of hinge mechanisms in the cover body, and the cover can rotate during the opening process, so a rotating hinge is used for modeling.

5. The finite element analysis method for the hood lock lifting according to claim 4, characterized in that: In the above step a), the parts that do not need to be modeled are cleaned up in the digital model of the cover body.

6. The finite element analysis method for the hood lock lifting according to claim 5, characterized in that: In the above step b), the sheet metal of the hair cover body is extracted and then subjected to mesh batch processing to obtain a mesh model of the hair cover.

7. The finite element analysis method for the hood lock lifting according to claim 6, characterized in that: In the above step c), corresponding properties and materials are assigned to various components in the cover body according to the bill of materials.

8. The finite element analysis method for the hood lock lifting according to claim 7, characterized in that: In the above step d), according to the actual connection state of the hair cover body, a corresponding connection method is established in the grid model, and the hemming is sewn.

9. The finite element analysis method for the hood lock lifting according to claim 8, characterized in that: The modeling process of the lock housing is the same as that of the cover body.

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