CN117216865A - Subframe modal calculation finite element modeling method, subframe modal calculation finite element modeling device, terminal and storage medium - Google Patents

Abstract

The application belongs to the technical field of automobiles, and particularly relates to a subframe modal calculation finite element modeling method, a subframe modal calculation finite element modeling device, a subframe modal calculation terminal and a storage medium. The method comprises the following steps: step one, preparing a three-dimensional mould of a subframe; step two, establishing a subframe finite element model, dividing a finite element grid and checking the finite element grid; step three, carrying out attribute assignment; setting model boundary conditions; fifthly, submitting modal calculation and setting constraint modal parameter solving; and step six, outputting a result. The application provides a reliable and effective modeling and analysis means for the modal calculation of the auxiliary frame, and provides guidance in the whole vehicle development stage.

Description

Subframe modal calculation finite element modeling method, subframe modal calculation finite element modeling device, terminal and storage medium

Technical Field

The application belongs to the technical field of automobiles, and particularly relates to a subframe modal calculation finite element modeling method, a subframe modal calculation finite element modeling device, a subframe modal calculation terminal and a storage medium.

Background

The subjective feeling and experience of the NVH performance of the passenger car to the customer are more and more prominent, so that the NVH performance control is very important to the main stream host factory in China, development indexes of all levels are formulated in the early stage of product development, and forward control development is carried out on the NVH performance.

The auxiliary frame is an important part of a suspension of the passenger car, is an important pivot which is arranged on the car body after each part of the suspension is formed into a suspension system, and is a necessary path for road surface excitation to a response path in the car. The auxiliary frame of the passenger car is divided into a front auxiliary frame and a rear auxiliary frame, the front auxiliary frame and the rear auxiliary frame are independently connected with each control arm of the suspension and the car body, the rear auxiliary frame is fixed on the car body through bushing suspension, the front auxiliary frame and the car body are fixed on the car body through bushing suspension or bolts, the auxiliary frame has more modes, and in the whole car system, the modes of the auxiliary frame can resonate with the suspension system, the transmission system and the car body system, so that the response NVH problem is caused. The mode characteristics of the auxiliary frame in the assembled state cannot be reflected by the result obtained by the traditional free mode calculation, and the limitation is mainly two points, namely, the rigid mode of the auxiliary frame is calculated, and the free mode of the elastomer obtained by calculation is inconsistent with the mode of the elastomer in the assembled state. According to the application, through carrying out parameterization treatment on the connection mode of the auxiliary frame and the vehicle body, a novel auxiliary frame mode calculation method is invented, the auxiliary frame mode performance can be estimated according to the calculation result, and the method has important engineering practice significance.

For a long time, the calculation of the auxiliary frame mode is mainly free mode calculation or constraint mode calculation, rigid body mode of the auxiliary frame cannot be identified, the calculated elastic body mode cannot reflect the auxiliary frame state in the whole vehicle state, more research on CAE analysis of the auxiliary frame at home and abroad is carried out, and the finite element modeling method of the auxiliary frame is not specified in the public literature.

Disclosure of Invention

In order to solve the problems, the application provides a finite element modeling method, a finite element modeling device, a finite element modeling terminal and a finite element storage medium for modal calculation of a sub-frame of a passenger car, which simulate the rigidity of a connection point of the sub-frame and a car body and provide reasonable and simplified structure and parameters.

The technical scheme of the application is as follows in combination with the accompanying drawings:

in a first aspect, an embodiment of the present application provides a method for modeling a subframe modality calculation finite element, including the steps of:

step one, preparing a three-dimensional mould of a subframe;

step two, establishing a subframe finite element model, dividing a finite element grid and checking the finite element grid;

step three, carrying out attribute assignment;

setting model boundary conditions;

fifthly, submitting modal calculation and setting constraint modal parameter solving;

and step six, outputting a result.

Further, the specific method of the first step is as follows:

11 Acquiring three-dimensional geometric detailed parameters of the auxiliary frame;

12 Acquiring subframe material parameters.

Further, in the step 12), the subframe material parameters include a material brand, a material elastic modulus E, a material poisson's ratio μ, and a material density ρ.

Further, the specific method in the second step is as follows:

the auxiliary frame for plate welding adopts quadrilateral and triangular mixed shell units for modeling, and the auxiliary frame for casting adopts tetrahedron or hexahedral solid units for modeling;

the finite element mesh used for modeling needs to meet the following requirements:

the tetrahedral second order unit and the hexahedral first order unit satisfy the following requirements:

1) Dividing at least 2 layers of units in the thickness direction of the split piece, wherein the unit size is 3mm, and the maximum unit size is less than 6mm;

2) 95% of the units have an aspect ratio <5, not satisfying a maximum of < 10;

3) 95% of the units have a warpage angle <7 DEG, and do not satisfy a maximum of < 10 DEG;

4) 95% of the cell twist angle is <30 °, and the maximum of the cell is not less than 45 °;

5) 95% of the unit cone angles are more than 80%, and the minimum unit cone angle is not more than 60%;

the quadrilateral unit meets the following requirements:

1) The number of quadrilateral units is more than 95%, and the number of triangular units is less than 5%;

2) The unit size is recommended to be 3mm, and the maximum unit size is less than 6mm;

3) 95% of units have a warpage angle <7 DEG, and all units have a warpage angle < 10 DEG;

4) 95% of the units have an aspect ratio <5 and all units have an aspect ratio < 7;

5) 95% cell twist angle <30 °, all cell twist angle < 40 °;

6) 95% of the unit jacobian sides are less than 0.7, and all the unit jacobian sides are less than 0.3;

7) 95% of unit taper is less than 0.7, and all unit taper is less than 0.8;

8) 95% of the maximum angles of the units are less than 120 DEG, and the maximum angles of the units are less than 135 DEG.

Further, the specific method in the third step is as follows:

31 Aiming at the auxiliary frame of the plate welding type, the welding seam connection adopts shell unit connection, and the attribute of the connected shell unit is consistent with that of the main part;

32 Checking the finite element model; the method comprises the following steps:

321 Checking geometric cleaning information, wherein the finite element model does not contain geometric information such as lines, planes and the like;

322 Checking the internal unit connection of the part;

323 Checking for the presence of repeat units;

324 Checking the material properties of the parts;

325 Checking the quality and other information of the part, wherein the difference between the quality and the information of the part is within 3 percent from a geometric sample in three-dimensional modeling software.

33 Material name, two-dimensional cell thickness, young's modulus, poisson's ratio, and density should be given to the grid cells, and material name, young's modulus, poisson's ratio, and density should be given to the solid cells;

34 A rigid connection unit for connecting the auxiliary frame with the vehicle body is established, a cylindrical geometric center formed by the upper end face, the lower end face and the inner circle is taken as a main node, and all nodes on the inner surface are connected to be taken as slave nodes;

35 A spring unit is established between the connection point of the auxiliary frame and the vehicle body, one end of the spring unit is connected with the main node of the established rigid unit, and the other end of the spring unit is used for restraining 6 degrees of freedom in directions

36 Spring element attribute assignment; when the auxiliary frame is connected with the vehicle body through a bushing, the stiffness of the spring unit adopts dynamic stiffness corresponding to 100Hz of the bushing; when the auxiliary frame is connected with the vehicle body through bolts, the rigidity of the spring unit adopts equivalent dynamic rigidity of a vehicle body connecting point.

Further, the specific method of the fourth step is as follows:

the calculation range is set to extract modal parameters within 0-500 Hz, and the displacement is set to be an output parameter.

Further, the specific method in the sixth step is as follows:

the mode frequency and mode shape within 500Hz are extracted, and the mode frequency and mode shape are listed.

In a second aspect, an embodiment of the present application further provides a device for defining an expansion parameter of an internal structure of a battery cell, including:

the preparation module is used for preparing a three-dimensional mould of the auxiliary frame;

the building model module is used for building a subframe finite element model, carrying out finite element mesh division and checking finite element meshes;

the attribute assignment module is used for carrying out attribute assignment;

the setting module is used for setting model boundary conditions;

the calculation module is used for submitting modal calculation and setting constraint modal parameter solution;

and the output module is used for outputting the result.

In a third aspect, a terminal is provided, including:

one or more processors;

a memory for storing the one or more processor-executable instructions;

wherein the one or more processors are configured to:

the method according to the first aspect of the embodiment of the application is performed.

In a fourth aspect, a non-transitory computer readable storage medium is provided, which when executed by a processor of a terminal, enables the terminal to perform the method according to the first aspect of the embodiments of the application.

In a fifth aspect, an application product is provided, which when running at a terminal causes the terminal to perform the method according to the first aspect of the embodiments of the application.

The beneficial effects of the application are as follows:

1) The application simplifies the structure and models the connection of the auxiliary frame body and the auxiliary frame with the vehicle body in a parameterized manner, and provides a reliable and effective modeling and analyzing means for the modal calculation of the auxiliary frame;

2) The application gives a reasonable and simplified scheme, simulates the modal characteristics of the auxiliary frame in the equipment state, and provides guidance in the whole vehicle development stage;

3) The application only provides one modeling method, and does not compare the subsequent calculation result with the test result.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method for modeling finite element for subframe modal calculation according to the present application;

FIG. 2 is a schematic illustration of a shell element weld joint;

FIG. 3 is a schematic diagram of a subframe modal computing finite element modeling apparatus;

fig. 4 is a schematic block diagram of a terminal structure.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.

Example 1

Fig. 1 is a flowchart of a subframe modal calculation finite element modeling method according to an embodiment of the present application, where the embodiment is applicable to subframe modal calculation finite element modeling, and the method may be performed by a subframe modal calculation finite element modeling apparatus according to an embodiment of the present application, and the apparatus may be implemented in a software and/or hardware manner.

S1, acquiring three-dimensional geometric detailed parameters of the auxiliary frame.

S2, acquiring auxiliary frame material parameters, wherein main information comprises material marks, material elastic modulus E, material Poisson ratio mu and material density rho, and the main information is specifically shown in a reference table 1.

Table 1 list of material parameters

S3, establishing a finite element model of the auxiliary frame, wherein the plate welding auxiliary frame is modeled by adopting a quadrilateral and triangular mixed shell unit, and the casting auxiliary frame is modeled by adopting a tetrahedron or hexahedral solid unit. The finite element mesh needs to meet the following requirements:

3.1 tetrahedral second order units and hexahedral first order units should meet the following requirements:

1) Dividing at least 2 layers of units in the thickness direction of the split piece, wherein the recommended unit size is 3mm, and the maximum unit size is less than 6mm;

2) 95% of the units have an aspect ratio <5, not satisfying a maximum of < 10;

3) 95% of the units have a warpage angle <7 DEG, and do not meet the maximum unit cell < 10 DEG;

4) 95% of the cell twist angle is <30 °, and the maximum of the cell is not less than 45 °;

5) 95% of the unit cone angles are more than 80%, and the minimum unit cone angle is not more than 60%.

3.2 quadrilateral units should meet the following requirements:

1) The number of quadrilateral units is more than 95%, and the number of triangular units is less than 5%;

2) The unit size is recommended to be 3mm, and the maximum unit size is less than 6mm;

3) 95% of units have a warpage angle <7 DEG, and all units have a warpage angle < 10 DEG;

4) 95% of the units have an aspect ratio <5 and all units have an aspect ratio < 7;

5) 95% cell twist angle <30 °, all cell twist angle < 40 °;

6) 95% of the unit jacobian sides are less than 0.7, and all the unit jacobian sides are less than 0.3;

7) 95% of unit taper is less than 0.7, and all unit taper is less than 0.8;

8) 95% of the maximum angles of the units are less than 120 DEG, and the maximum angles of the units are less than 135 DEG.

S4, referring to FIG. 2, aiming at the auxiliary frame of the plate welding type, the welding seam connection adopts shell unit connection, and the attribute of the connected shell unit is consistent with that of the main part.

S5, after grid modeling is completed, the finite element model is subjected to the following examination:

1) Checking geometric cleaning information, wherein the finite element model does not contain geometric information such as lines, planes and the like;

2) Checking the connection of internal units of the parts;

3) Checking whether a repeating unit exists;

4) Checking the material properties of the parts;

5) And checking information such as part quality and the like, wherein the information is within 3% different from a geometric sample in the three-dimensional modeling software.

S6, the grid unit is given a material name, a two-dimensional unit thickness, young 'S modulus, poisson' S ratio and density, and the solid unit is given a material name, young 'S modulus, poisson' S ratio and density.

And S7, establishing a rigid connection unit of the connection point of the auxiliary frame and the vehicle body, taking a cylindrical geometric center formed by the upper end face, the lower end face and the inner circle as a main node, and connecting all nodes on the inner surface as slave nodes.

And S8, establishing a spring unit between the auxiliary frame and the vehicle body connection point, wherein one end of the spring unit is connected with the main node of the rigid unit established in the step 5, and one end of the spring unit is constrained with 6 directional degrees of freedom.

S9, assigning the attribute of the spring unit. When the auxiliary frame is connected with the vehicle body through a bushing, the stiffness of the spring unit adopts dynamic stiffness corresponding to 100Hz of the bushing; when the auxiliary frame is connected with the vehicle body through bolts, the rigidity of the spring unit adopts equivalent dynamic rigidity of a vehicle body connecting point.

S10, setting a calculation range to extract modal parameters within 0-500 Hz, and setting displacement as an output parameter.

S11, outputting the completed finite element model into a file format required by solution software.

S12, submitting modal calculation, and setting constraint modal parameter solving.

S13, extracting the mode frequency and the mode shape within 500Hz, and listing the mode frequency and the mode shape.

In conclusion, the application provides a reliable and effective modeling and analysis means for the auxiliary frame modal calculation and provides guidance in the whole vehicle development stage by simplifying the structure and modeling the auxiliary frame body and the auxiliary frame and connecting the auxiliary frame with the vehicle body in a parameterized manner.

Example two

Referring to fig. 3, an apparatus for defining expansion parameters of an internal structure of a battery cell includes:

the preparation module is used for preparing a three-dimensional mould of the auxiliary frame;

the building model module is used for building a subframe finite element model, carrying out finite element mesh division and checking finite element meshes;

the attribute assignment module is used for carrying out attribute assignment;

the setting module is used for setting model boundary conditions;

the calculation module is used for submitting modal calculation and setting constraint modal parameter solution;

and the output module is used for outputting the result.

Example III

Fig. 4 is a block diagram of a terminal according to an embodiment of the present application, and the terminal may be a terminal according to the above embodiment. The terminal may be a portable mobile terminal such as: smart phone, tablet computer. Terminals may also be referred to by other names, user equipment, portable terminals, etc.

Generally, the terminal includes: a processor 301 and a memory 302.

Processor 301 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and the like. The processor 301 may be implemented in at least one hardware form of DSP (Digital Signal Processing ), FPGA (Field-Programmable Gate Array, field programmable gate array), PLA (Programmable Logic Array ). The processor 301 may also include a main processor, which is a processor for processing data in an awake state, also called a CPU (Central Processing Unit ), and a coprocessor; a coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 301 may integrate a GPU (Graphics Processing Unit, image processor) for rendering and drawing of content required to be displayed by the display screen. In some embodiments, the processor 301 may also include an AI (Artificial Intelligence ) processor for processing computing operations related to machine learning.

Memory 302 may include one or more computer-readable storage media, which may be tangible and non-transitory. Memory 302 may also include high-speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In some embodiments, a non-transitory computer readable storage medium in memory 302 is used to store at least one instruction for execution by processor 301 to implement a subframe modality calculation finite element modeling method provided in the present application.

In some embodiments, the terminal may further optionally include: a peripheral interface 303, and at least one peripheral. Specifically, the peripheral device includes: at least one of radio frequency circuitry 304, touch screen 305, camera 306, audio circuitry 307, positioning component 308, and power supply 309.

The peripheral interface 303 may be used to connect at least one Input/Output (I/O) related peripheral to the processor 301 and the memory 302. In some embodiments, processor 301, memory 302, and peripheral interface 303 are integrated on the same chip or circuit board; in some other embodiments, either or both of the processor 301, the memory 302, and the peripheral interface 303 may be implemented on separate chips or circuit boards, which is not limited in this embodiment.

The Radio Frequency circuit 304 is configured to receive and transmit RF (Radio Frequency) signals, also known as electromagnetic signals. The radio frequency circuitry 304 communicates with a communication network and other communication devices via electromagnetic signals. The radio frequency circuit 304 converts an electrical signal into an electromagnetic signal for transmission, or converts a received electromagnetic signal into an electrical signal. Optionally, the radio frequency circuit 304 includes: antenna systems, RF transceivers, one or more amplifiers, tuners, oscillators, digital signal processors, codec chipsets, subscriber identity module cards, and so forth. The radio frequency circuitry 304 may communicate with other terminals via at least one wireless communication protocol. The wireless communication protocol includes, but is not limited to: the world wide web, metropolitan area networks, intranets, generation mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and/or WiFi (Wireless Fidelity ) networks. In some embodiments, the radio frequency circuitry 304 may also include NFC (Near Field Communication ) related circuitry, which is not limiting of the application.

The touch display screen 305 is used to display a UI (User Interface). The UI may include graphics, text, icons, video, and any combination thereof. The touch screen 305 also has the ability to collect touch signals at or above the surface of the touch screen 305. The touch signal may be input as a control signal to the processor 301 for processing. The touch screen 305 is used to provide virtual buttons and/or virtual keyboards, also known as soft buttons and/or soft keyboards. In some embodiments, the touch display 305 may be one, providing a front panel of the terminal; in other embodiments, the touch display screen 305 may be at least two, respectively disposed on different surfaces of the terminal or in a folded design; in still other embodiments, the touch display 305 may be a flexible display disposed on a curved surface or a folded surface of the terminal. Even more, the touch display screen 305 may be arranged in an irregular pattern that is not rectangular, i.e., a shaped screen. The touch display 305 may be made of LCD (Liquid Crystal Display ), OLED (Organic Light-Emitting Diode) or other materials.

The camera assembly 306 is used to capture images or video. Optionally, the camera assembly 306 includes a front camera and a rear camera. In general, a front camera is used for realizing video call or self-photographing, and a rear camera is used for realizing photographing of pictures or videos. In some embodiments, the number of the rear cameras is at least two, and the rear cameras are any one of a main camera, a depth camera and a wide-angle camera, so as to realize fusion of the main camera and the depth camera to realize a background blurring function, and fusion of the main camera and the wide-angle camera to realize a panoramic shooting function and a Virtual Reality (VR) shooting function. In some embodiments, camera assembly 306 may also include a flash. The flash lamp can be a single-color temperature flash lamp or a double-color temperature flash lamp. The dual-color temperature flash lamp refers to a combination of a warm light flash lamp and a cold light flash lamp, and can be used for light compensation under different color temperatures.

The audio circuit 307 is used to provide an audio interface between the user and the terminal. The audio circuit 307 may include a microphone and a speaker. The microphone is used for collecting sound waves of users and environments, converting the sound waves into electric signals, and inputting the electric signals to the processor 301 for processing, or inputting the electric signals to the radio frequency circuit 304 for voice communication. For the purpose of stereo acquisition or noise reduction, a plurality of microphones can be respectively arranged at different parts of the terminal. The microphone may also be an array microphone or an omni-directional pickup microphone. The speaker is used to convert electrical signals from the processor 301 or the radio frequency circuit 304 into sound waves. The speaker may be a conventional thin film speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, not only the electric signal can be converted into a sound wave audible to humans, but also the electric signal can be converted into a sound wave inaudible to humans for ranging and other purposes. In some embodiments, the audio circuit 307 may also include a headphone jack.

The location component 308 is used to locate the current geographic location of the terminal to enable navigation or LBS (Location Based Service, location-based services). The positioning component 308 may be a positioning component based on the United states GPS (Global Positioning System ), the Beidou system of China, or the Galileo system of Russia.

The power supply 309 is used to power the various components in the terminal. The power source 309 may be alternating current, direct current, disposable or rechargeable. When the power source 309 comprises a rechargeable battery, the rechargeable battery may be a wired rechargeable battery or a wireless rechargeable battery. The wired rechargeable battery is a battery charged through a wired line, and the wireless rechargeable battery is a battery charged through a wireless coil. The rechargeable battery may also be used to support fast charge technology.

Those skilled in the art will appreciate that the structure shown in fig. 4 is not limiting of the terminal and may include more or fewer components than shown, or may combine certain components, or may employ a different arrangement of components.

Example IV

In an exemplary embodiment, a computer readable storage medium is also provided, on which a computer program is stored, which program, when being executed by a processor, implements a subframe modality calculation finite element modeling method as provided by all inventive embodiments of the present application.

Any combination of one or more computer readable media may be employed. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).

Example five

In an exemplary embodiment, an application program product is also provided that includes one or more instructions executable by the processor 301 of the above apparatus to perform one of the subframe modality calculation finite element modeling methods described above.

Although embodiments of the present application have been disclosed above, they are not limited to the use listed in the description and modes of implementation. It can be applied to various fields suitable for the present application. Additional modifications will readily occur to those skilled in the art. Therefore, the application is not to be limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.

Claims (10)

1. The modeling method for the finite element calculation of the subframe mode is characterized by comprising the following steps of:

step one, preparing a three-dimensional mould of a subframe;

step two, establishing a subframe finite element model, dividing a finite element grid and checking the finite element grid;

step three, carrying out attribute assignment;

setting model boundary conditions;

fifthly, submitting modal calculation and setting constraint modal parameter solving;

and step six, outputting a result.

2. The method for modeling a subframe modality calculation finite element according to claim 1, wherein the specific method of the first step is as follows:

11 Acquiring three-dimensional geometric detailed parameters of the auxiliary frame;

12 Acquiring subframe material parameters.

3. A method of modeling a subframe modal calculation finite element as claimed in claim 2, wherein in step 12), the subframe material parameters include the material brand, the material elastic modulus E, the material poisson's ratio μ, and the material density ρ.

4. The method for modeling a subframe modality calculation finite element according to claim 1, wherein the specific method in the second step is as follows:

the auxiliary frame for plate welding adopts quadrilateral and triangular mixed shell units for modeling, and the auxiliary frame for casting adopts tetrahedron or hexahedral solid units for modeling;

the finite element mesh used for modeling needs to meet the following requirements:

the tetrahedral second order unit and the hexahedral first order unit satisfy the following requirements:

1) Dividing at least 2 layers of units in the thickness direction of the split piece, wherein the unit size is 3mm, and the maximum unit size is less than 6mm;

2) 95% of the units have an aspect ratio <5, not satisfying a maximum of < 10;

3) 95% of the units have a warpage angle <7 DEG, and do not satisfy a maximum of < 10 DEG;

4) 95% of the cell twist angle is <30 °, and the maximum of the cell is not less than 45 °;

5) 95% of the unit cone angles are more than 80%, and the minimum unit cone angle is not more than 60%;

the quadrilateral unit meets the following requirements:

1) The number of quadrilateral units is more than 95%, and the number of triangular units is less than 5%;

2) The unit size is recommended to be 3mm, and the maximum unit size is less than 6mm;

3) 95% of units have a warpage angle <7 DEG, and all units have a warpage angle < 10 DEG;

4) 95% of the units have an aspect ratio <5 and all units have an aspect ratio < 7;

5) 95% cell twist angle <30 °, all cell twist angle < 40 °;

6) 95% of the unit jacobian sides are less than 0.7, and all the unit jacobian sides are less than 0.3;

7) 95% of unit taper is less than 0.7, and all unit taper is less than 0.8;

8) 95% of the maximum angles of the units are less than 120 DEG, and the maximum angles of the units are less than 135 DEG.

5. The subframe modal computing finite element modeling method according to claim 1, wherein the specific method in the third step is as follows:

31 Aiming at the auxiliary frame of the plate welding type, the welding seam connection adopts shell unit connection, and the attribute of the connected shell unit is consistent with that of the main part;

32 Checking the finite element model; the method comprises the following steps:

321 Checking geometric cleaning information, wherein the finite element model does not contain geometric information such as lines, planes and the like;

322 Checking the internal unit connection of the part;

323 Checking for the presence of repeat units;

324 Checking the material properties of the parts;

325 Checking the quality and other information of the part, wherein the difference between the quality and the information of the part is within 3 percent from a geometric sample in three-dimensional modeling software.

33 Material name, two-dimensional cell thickness, young's modulus, poisson's ratio, and density should be given to the grid cells, and material name, young's modulus, poisson's ratio, and density should be given to the solid cells;

34 A rigid connection unit for connecting the auxiliary frame with the vehicle body is established, a cylindrical geometric center formed by the upper end face, the lower end face and the inner circle is taken as a main node, and all nodes on the inner surface are connected to be taken as slave nodes;

35 A spring unit is established between the auxiliary frame and the connection point of the vehicle body, one end of the spring unit is connected with the main node of the established rigid unit, and the other end of the spring unit is constrained with 6 directional degrees of freedom;

36 Spring element attribute assignment; when the auxiliary frame is connected with the vehicle body through a bushing, the stiffness of the spring unit adopts dynamic stiffness corresponding to 100Hz of the bushing; when the auxiliary frame is connected with the vehicle body through bolts, the rigidity of the spring unit adopts equivalent dynamic rigidity of a vehicle body connecting point.

6. The subframe modal calculation finite element modeling method according to claim 1, wherein the specific method of the fourth step is as follows:

the calculation range is set to extract modal parameters within 0-500 Hz, and the displacement is set to be an output parameter.

7. The subframe modal calculation finite element modeling method according to claim 1, wherein the specific method of the step six is as follows:

the mode frequency and mode shape within 500Hz are extracted, and the mode frequency and mode shape are listed.

8. A cell internal structure expansion parameter defining device, comprising:

the preparation module is used for preparing a three-dimensional mould of the auxiliary frame;

the building model module is used for building a subframe finite element model, carrying out finite element mesh division and checking finite element meshes;

the attribute assignment module is used for carrying out attribute assignment;

the setting module is used for setting model boundary conditions;

the calculation module is used for submitting modal calculation and setting constraint modal parameter solution;

and the output module is used for outputting the result.

9. A terminal, comprising:

one or more processors;

a memory for storing the one or more processor-executable instructions;

wherein the one or more processors are configured to:

a subframe modality calculation finite element modeling method as claimed in any one of claims 1 to 7.

10. A non-transitory computer readable storage medium, characterized in that instructions in the storage medium, when executed by a processor of a terminal, enable the terminal to perform a subframe modality calculation finite element modeling method as claimed in any one of claims 1 to 7.