Automobile door opening and closing durability analysis method based on multi-body dynamics and finite element, electronic equipment and medium

Abstract

The invention discloses an automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements, electronic equipment and a medium. The method comprises the following steps: establishing an automobile finite element model; establishing an automobile multi-body dynamic model based on the automobile finite element model, and calculating a time domain load result in an automobile door opening and closing process; calculating a stress result of the automobile door under the action of a unit load based on the automobile finite element model; and calculating a fatigue damage value of the vehicle door, and evaluating the fatigue damage value. According to the automobile door opening and closing durability analysis method, the efficient characteristic of multi-body dynamics analysis and the accurate characteristic of finite element analysis are combined, the fatigue life of metal plates and welding spots can be rapidly and accurately predicted, the automobile door development period is shortened, and the development cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and more specifically, to an automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements, an electronic device and a medium. Background Art

[0002] Automobile doors are important subsystems of the entire vehicle, and the durability of opening and closing is its basic performance indicator. As the movable body part that is used most frequently by users, the doors should not have structural durability problems throughout the life cycle of the vehicle. Usually, the durability of the doors of private vehicles must reach 100,000 times, and for public vehicles, it may even be required to reach 200,000 times. If the durability of the opening and closing of the doors is not designed enough, it will cause sheet metal or weld cracking problems during the normal use cycle of the doors, causing the stiffness and strength of the doors to decrease, which will affect the safety performance of the entire vehicle. It will also induce other problems such as rust on the door sheet metal, abnormal door noise, and door failure, which will increase the cost of using the vehicle and affect the user experience and satisfaction.

[0003] In mainstream automobile R&D companies, the development of the durability of automobile door opening and closing is a very important task, which usually requires multiple rounds of digital prototype simulation analysis and real prototype test verification. The usual simulation analysis method is based on display dynamics, using LS-DYNA software or the Explicit module of ABAQUS software to simulate the door closing process, obtain the stress and strain results of the door and surrounding body structural parts, and then import the analysis results into fatigue analysis software (such as FEMFAT or NCODE, etc.) to perform opening and closing durability fatigue analysis and predict the fatigue life of sheet metal and welds. Improve the structure that does not meet the life standard to avoid design risks.

[0004] The advantages of the above method are that the simulation analysis is of high accuracy and that it can simulate the effects of the body, door, hinge, door lock, sealing strip, buffer block, opening and closing speed, etc. on the durability of the door opening and closing. The disadvantages are that the analysis efficiency is low and the analysis cycle is long. The main reasons are: 1) The display dynamics model takes a long time to debug. Before the formal analysis, the display dynamics model needs to be debugged repeatedly to ensure that the lock hook can be locked smoothly when the door is closed and the door can be closed normally. It is also necessary to control the proportion of non-physical energy such as hourglass energy and slip energy not to be too high, otherwise it will affect the accuracy of the results; 2) The display dynamics model takes a long time to calculate. In order to obtain results with good robustness and stability, it is necessary to simulate the smaller structures such as sealing strips, buffer blocks and hood lock cores with a solid grid of 1-2mm size during modeling, which makes the minimum grid size in the model small. When calculating the model, the display solver will adjust the automatic time increment to a very small value, and the solution speed will be very slow, resulting in a very long time required for model calculation.

[0005] Usually, the cycle of a round of door opening and closing durability simulation analysis based on the above method is 6 weeks. As the development cycle of automobile products gradually shortens, the current door opening and closing durability simulation analysis cycle can no longer adapt to the gradually accelerated pace of automobile product development. It is necessary to propose an analysis method with higher efficiency, shorter cycle, and accuracy that can guide engineering practice for the development and design of automobile door opening and closing durability performance. Therefore, it is necessary to develop a method, electronic equipment and medium for automobile door opening and closing durability analysis based on multi-body dynamics and finite elements.

[0006] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0007] The present invention proposes a durability analysis method for opening and closing of automobile doors, an electronic device and a medium based on multi-body dynamics and finite elements, which can combine the high efficiency characteristics of multi-body dynamics analysis with the precise characteristics of finite element analysis, and can quickly and accurately predict the fatigue life of sheet metal and welds, thereby shortening the door development cycle and reducing development costs.

[0008] In a first aspect, an embodiment of the present disclosure provides a method for analyzing the opening and closing durability of a vehicle door based on multi-body dynamics and finite elements, comprising:

[0009] Establish a finite element model of the vehicle;

[0010] A multi-body dynamics model of the vehicle is established based on the vehicle finite element model, and the time domain load results of the door opening and closing process are calculated;

[0011] Calculating stress results of the door under unit load based on the automobile finite element model;

[0012] The fatigue damage value of the vehicle door is calculated and the fatigue damage value is evaluated.

[0013] Preferably, establishing a finite element model of a vehicle includes:

[0014] Establish finite element mesh models of the body-in-white and door assembly, and assign material properties;

[0015] Establish finite element models of the lock body, lock hook and internal structure, and assign material properties;

[0016] Establish a counterweight model for door accessories, where the door accessories are simulated by mass units;

[0017] Establish simplified models of door seals, buffer blocks and water cuts;

[0018] The above model is the automobile finite element model.

[0019] Preferably, a vehicle multi-body dynamics model is established based on the vehicle finite element model, and the time domain load results of the door opening and closing process are calculated, including:

[0020] The automobile finite element model is flexibly processed, converted into a file in mnf format, and imported into multi-body dynamics software;

[0021] Load the connection relationship between automobile parts, and set constraints and loading for the automobile multi-body dynamics model;

[0022] The multi-body dynamics model of the vehicle is solved and calculated to obtain the time domain load results of the door opening and closing process.

[0023] Preferably, the automobile multi-body dynamics model is:

[0024]

[0025] Among them, Φ is the constraint equation of the position coordinate matrix q, Φ q is the Jacobian matrix of the constraint equation, and λ is the Lagrange multiplier.

[0026] Preferably, calculating the stress result of the door under the unit load based on the automobile finite element model includes:

[0027] Converting the welds in the finite element model of the vehicle into welds in a FEMFAT format;

[0028] A unit load is applied to the converted finite element model of the car, and the stress results of the car door under the unit load are calculated by structural statics.

[0029] Preferably, the structural statics are:

[0030] [K]{x}={F}

[0031] Where [K] is the stiffness matrix, {x} is the displacement vector, and {F} is the force vector.

[0032] Preferably, calculate the fatigue damage value of the door sheet metal and welds

[0033] Associating the stress result with the time domain load result;

[0034] Set the material SN curve and fatigue analysis parameters to obtain the fatigue damage value of the door during single opening and closing;

[0035] According to the fatigue damage value of the door during a single opening and closing, it is linearly amplified according to the number of opening and closing times required by the development to obtain the fatigue damage value of the door during the entire life design cycle.

[0036] Preferably, evaluating the fatigue damage value includes:

[0037] The fatigue damage value of the car door is compared with the preset target value. If it is lower than the target value, it is considered to meet the requirements. If it is higher than the target value, it is considered that the fatigue performance requirements are not met. The vehicle structure is optimized and re-analyzed until the fatigue performance of the car door meets the target requirements.

[0038] In a second aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0039] A memory storing executable instructions;

[0040] A processor runs the executable instructions in the memory to implement the automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements.

[0041] In a third aspect, an embodiment of the present disclosure further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements.

[0042] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0044] Figure 1 A flowchart showing the steps of a method for analyzing the opening and closing durability of a vehicle door based on multi-body dynamics and finite elements according to an embodiment of the present invention is shown.

[0045] Figure 2 A schematic diagram of a finite element model of a vehicle body and a door assembly according to an embodiment of the present invention is shown.

[0046] Figure 3 A schematic diagram of a finite element model of a door lock body and a lock inner structure according to an embodiment of the present invention is shown.

[0047] Figure 4A schematic diagram of a multi-body dynamics model for durability analysis of an automobile door opening and closing according to an embodiment of the present invention is shown.

[0048] Figure 5 FIG. 4 is a schematic diagram showing a FEMFAT solder joint model according to an embodiment of the present invention.

[0049] Figure 6 A schematic diagram of a vehicle door finite element model of a unit load according to an embodiment of the present invention is shown.

[0050] Figure 7 A schematic diagram of a cloud diagram of the opening and closing durability damage results of a car door sheet metal and welding points according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0052] To facilitate understanding of the solutions and effects of the embodiments of the present invention, three specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0053] Example 1

[0054] Figure 1 A flowchart showing the steps of a method for analyzing the opening and closing durability of a vehicle door based on multi-body dynamics and finite elements according to an embodiment of the present invention is shown.

[0055] like Figure 1 As shown in the figure, the automobile door opening and closing durability analysis method based on multi-body dynamics and finite element includes:

[0056] Step 101, establishing a finite element model of a car;

[0057] Step 102, establishing a multi-body dynamics model of the vehicle based on the finite element model of the vehicle, and calculating the time domain load results of the door opening and closing process;

[0058] Step 103, calculating the stress result of the door under the unit load based on the automobile finite element model;

[0059] Step 104, calculating the fatigue damage value of the vehicle door and evaluating the fatigue damage value.

[0060] In one example, building a finite element model of a car involves:

[0061] Establish finite element mesh models of the body-in-white and door assembly, and assign material properties;

[0062] Establish finite element models of the lock body, lock hook and internal structure, and assign material properties;

[0063] Establish a counterweight model for door accessories, where the door accessories are simulated by mass units;

[0064] Establish simplified models of door seals, buffer blocks and water cuts;

[0065] The above model is the automobile finite element model.

[0066] In one example, a multi-body dynamics model of a car is established based on the finite element model of the car, and the time domain load results of the door opening and closing process are calculated, including:

[0067] The automobile finite element model is flexibly processed, converted into an mnf format file, and imported into the multi-body dynamics software;

[0068] Load the connection relationship between automobile parts, and set constraints and loading for the automobile multi-body dynamics model;

[0069] The multi-body dynamics model of the vehicle is solved and calculated to obtain the time domain load results of the door opening and closing process.

[0070] In an example, a car multibody dynamics model is:

[0071]

[0072] Among them, Φ is the constraint equation of the position coordinate matrix q, Φ q is the Jacobian matrix of the constraint equation, and λ is the Lagrange multiplier.

[0073] In one example, the stress results of a car door under a unit load are calculated based on the car finite element model, including:

[0074] Convert the welds in the finite element model of the vehicle into the FEMFAT format;

[0075] A unit load is applied to the converted finite element model of the car, and the stress results of the car door under the unit load are calculated by structural statics.

[0076] In one example, the structural statics are:

[0077] [K]{x}={F}

[0078] Where [K] is the stiffness matrix, {x} is the displacement vector, and {F} is the force vector.

[0079] In one example, fatigue damage values ​​of door panels and welds are calculated.

[0080] Correlate stress results with time domain load results;

[0081] Set the material SN curve and fatigue analysis parameters to obtain the fatigue damage value of the door during single opening and closing;

[0082] According to the fatigue damage value of the door during a single opening and closing, it is linearly amplified according to the number of opening and closing times required by the development to obtain the fatigue damage value of the door during the entire life design cycle.

[0083] In one example, evaluating fatigue damage value includes:

[0084] The fatigue damage value of the car door is compared with the preset target value. If it is lower than the target value, it is considered to meet the requirements. If it is higher than the target value, it is considered that the fatigue performance requirements are not met. The vehicle structure is optimized and re-analyzed until the fatigue performance of the car door meets the target requirements.

[0085] Figure 2 A schematic diagram of a finite element model of a vehicle body and a door assembly according to an embodiment of the present invention is shown.

[0086] Figure 3 A schematic diagram of a finite element model of a door lock body and a lock inner structure according to an embodiment of the present invention is shown.

[0087] Specifically, a finite element model including the body-in-white and the door assembly is established. First, a finite element mesh model of the body-in-white and the door assembly (including sheet metal, glass, hinges, etc.) is established, such as Figure 2 As shown in the figure, the material properties are assigned. The size of the 2D mesh unit such as sheet metal in the model is 8mm, and the size of the 3D mesh unit such as hinge is 3mm. The connection between the components is simulated as follows: the welds, welds and adhesives are simulated using REB3-HEXA-REB3 units, the bolts are simulated using RBE2 units, and the hinge shafts are simulated using RBE2-CBAR-RBE2 units. Furthermore, the finite element model of the lock body, lock hook and internal structures such as ratchet, pawl, buffer block, etc. is established. Figure 3As shown in the figure, these structures are simulated by 3D units with a mesh size of 2 mm and given material properties. It should be noted that door locks are usually universal parts, and different models will use the same door lock. Therefore, in order to improve modeling efficiency, if the door lock is determined to be a legacy part, the existing finite element model can be used directly. Further, the counterweight model of the door accessories is established. Since the door accessories are not examined, the inertial force generated by the mass of the accessories is mainly simulated. In order to reduce the calculation scale and provide analysis efficiency, the door accessories are simulated by mass units, and the connection points between the mass units and the doors are connected by RBE2 units. The exterior trim, exterior rearview mirrors, door handles, window frame trim strips, interior guard plates, speakers, glass lifting devices, etc. in the door accessories are simulated in the above manner. Finally, a simplified model of the door seal, buffer block and water cut is established. Since these parts are all directly force-bearing components, the above-mentioned mass unit simulation method is no longer applicable. In the existing methods, these parts are usually simulated with 3D units of 2mm in size. Although this method is more accurate, it takes a long time to model and increase the scale of the model grid and the analysis and calculation cycle. The present invention simplifies the door seal, inner water cut and outer water cut into spring units of 100mm each, and sets the spring stiffness according to the CLD curve. The advantage of this simulation is that it can improve the modeling efficiency by more than 90% while ensuring that the accuracy meets the engineering requirements.

[0088] Figure 4 A schematic diagram of a multi-body dynamics model for durability analysis of an automobile door opening and closing according to an embodiment of the present invention is shown.

[0089] Establish a multi-body dynamics model including the body in white, doors and door locks, such as Figure 4 As shown, the time domain load results of the door opening and closing process are calculated and output. First, the finite element model of the car is flexibly processed, converted into a file in mnf format, and imported into the multi-body dynamics software ADMAS. According to the connection relationship between the various components, the body, door, hinge, lock body and other components are connected through fixed joints, rotating joints, and moving joints. The reset spring between the ratchet, pawl and lock body inside the lock body structure is established, and the corresponding stiffness value is assigned to establish the contact relationship between the ratchet, pawl, lock body and lock hook.

[0090] Constraints and loading settings are made for the multi-body dynamics model. All degrees of freedom of the body section are constrained; a 1g gravity field is applied in the Z direction, and then after the door is opened to a certain angle, different instantaneous forces are applied to the door handle to make the instantaneous linear velocity of the door lock outer panel flange position reach the preset requirements, such as 1.5m / s.

[0091] In ADAMS software, the multi-body dynamics model is solved and calculated, and the time domain load results of the door during the opening and closing process are exported in the software post-processing.

[0092] The multibody dynamics model is expressed as:

[0093]

[0094] Among them, Φ is the constraint equation of the position coordinate matrix q, Φ q is the Jacobian matrix of the constraint equation, and λ is the Lagrange multiplier. This type of model is called the Euler-Lagrange equations. It has a large number of equations, but the coefficient matrix is ​​sparse, which is suitable for the computer to automatically establish a unified model for processing. By discretizing the dynamic equations of the system through numerical integration methods, we can obtain the equivalent information of the position, velocity, and acceleration of the system at different time steps, and then obtain the time domain load results. Commonly used numerical integration methods include the Euler method, the Longo-Kutta method, etc.

[0095] Compared with the long debugging and solution cycle of the display dynamics model in the prior art, the debugging and solution cycle of the multi-body dynamics model will be greatly shortened, thereby greatly improving the analysis efficiency of the present invention.

[0096] Figure 5 FIG. 4 is a schematic diagram showing a FEMFAT solder joint model according to an embodiment of the present invention.

[0097] Figure 6 A schematic diagram of a vehicle door finite element model of a unit load according to an embodiment of the present invention is shown.

[0098] Calculate and output the stress results of the car door under unit load.

[0099] Import the finite element model of the door assembly into ANSA or FEMFAT software and convert the welds into FEMFAT format welds, such as Figure 5 As shown. It should be noted that the vehicle body and lock assembly do not need to participate in the above model building. Then, the converted door finite element model is imported into the pre-processing software, and the inertia release method is used. Unit loads are applied along the six degrees of freedom in the hinges, door locks, sealing strips, buffer blocks and other positions. An analysis step is set for the unit load in each single direction to complete the analysis model setting, as shown in the figure below. Figure 6As shown. If the hinge contains 2 unit principal points, the door lock contains 1 unit principal point, the sealing strip contains 50 unit principal points, and the buffer block contains 1 unit principal point, then a total of 54×6=324 analysis steps need to be established. In addition, the order of analysis steps in the model should be completely consistent with the load order output by the multi-body dynamics solution. The above finite element model is solved and calculated using Nastran software, and the OP2 file containing the stress results is exported. Structural statics can be described using the following mathematical model:

[0100] [K]{x}={F}

[0101] Among them, [K] is the stiffness matrix, {x} is the displacement vector, and {F} is the force vector. By solving the above equations, the displacement of the nodes in the finite element model is obtained, and then the strain of the nodes in the finite element model and the stress value of the unit are obtained.

[0102] Figure 7 A schematic diagram of a cloud diagram of the opening and closing durability damage results of a car door sheet metal and welding points according to an embodiment of the present invention is shown.

[0103] like Figure 7 As shown, the fatigue damage values ​​of the door sheet metal and welds are calculated and output, and the damage values ​​are evaluated to determine whether the door design meets the opening and closing durability performance requirements. If not, it is necessary to optimize the design and re-analyze.

[0104] Firstly, the time domain load results during the door opening and closing process, the finite element model of the door assembly after the weld point conversion, and the calculated OP2 file containing the stress results are imported into the FEMAT software to complete the association between the stress results and the time domain load.

[0105] Then, in the FEMFAT software, set the material SN curve and fatigue analysis parameters, including weld calculation parameters, surface coefficient, average stress treatment, etc. After completing the settings, submit the software for calculation to obtain the fatigue damage value of the door sheet metal and weld during a single opening and closing.

[0106] The stress field obtained by applying a unit static load to the finite element model of the car door is the stress influence factor of each load component. The dynamic stress time history of the structure can be obtained by multiplying and superimposing the stress influence factor with the corresponding load time history. Assuming that the finite element model of the car door considers the loads of m nodes (including the sealing strip, hinge, lock, buffer block position, etc.), the stress field σ(x, t) of the car door under the dynamic load that changes with time t can be calculated as follows:

[0107]

[0108] σ ij(x) represents the stress field of the door under the unit load in the jth direction at the i-th node, F ij (t) represents the time history of the load in the jth direction of the ith node during the loading process, and x represents the position coordinate.

[0109] Fatigue problems are caused by stress cycle changes. The damage caused by each stress cycle can be calculated using the material life curve (SN curve). The SN curve depicts the corresponding relationship between the material's stress amplitude and the number of loading times. In addition to being related to the characteristics of the material itself, it is also affected by stress gradient, surface roughness, surface processing technology, average stress treatment method, etc.

[0110] The SN curve of the material is obtained based on the constant amplitude loading test. However, the door is subjected to stress that varies with time, and the amplitude of a cycle is difficult to determine. Therefore, it is necessary to select a suitable cycle counting method to convert the complex variable amplitude loading history into a series of discrete simple constant amplitude loading history. In fatigue analysis, the rain flow method is usually used to count cycles and reconstruct the stress time history as the input for fatigue damage calculation.

[0111] Currently, the Miner linear cumulative damage criterion is widely used in the automotive industry for fatigue damage calculation. The Miner criterion states that when a material is subjected to stress that changes over time, its total damage is the sum of the damage values ​​caused by each single stress cycle. When the total damage reaches 1, fatigue failure occurs.

[0112] During loading, it is assumed that the material undergoes σ1, σ2, ...σ f In this way, there are f loading cycles with different stress levels, and the fatigue life under various stress levels is N1, N2, ... N f The number of cycles under various stress levels is n1, n2, ... n f , then the total loss value D is

[0113]

[0114] By adopting the above method, the fatigue loss value of the structure of the door during a single opening and closing process can be obtained.

[0115] According to the fatigue damage results of the door sheet metal and welds under single opening and closing conditions, the fatigue damage value of the door over the entire life design cycle is obtained by linearly amplifying the opening and closing times required by the development.

[0116] The fatigue damage value of the car door is compared with the preset target value. If it is lower than the target value, it is considered to meet the requirements. If it is higher than the target value, it is considered that the fatigue performance requirements are not met and the structure needs to be optimized and re-analyzed until the fatigue performance of the car door meets the target requirements.

[0117] The present invention combines the high efficiency characteristics of multi-body dynamics analysis with the precise characteristics of finite element analysis to provide a method for analyzing the durability of automobile door opening and closing that can quickly and accurately predict the fatigue risk of sheet metal and welds. The analysis efficiency is improved by more than 80%, and the analysis cycle can be shortened from the original 6 weeks to 1 week, thereby improving development efficiency and shortening the development cycle. The method of the present invention can avoid the risk of cracking of sheet metal and welds in the door structure, effectively saving the design change costs caused by door fatigue problems, and the simulation results show that they are basically consistent with the results of the door opening and closing durability bench test. The CAE simulation results can feedback the results of the bench test. Therefore, the two rounds of development tests and one round of verification tests in traditional development can be compressed into only one round of verification tests, reducing the test cost by 400,000, the prototype cost by 800,000, and the test cycle from 3 months to 1 month.

[0118] Example 2

[0119] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; a processor running the executable instructions in the memory to implement the above-mentioned automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements.

[0120] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0121] The memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0122] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0123] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present disclosure.

[0124] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0125] Example 3

[0126] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements is implemented.

[0127] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of each embodiment of the present disclosure are executed.

[0128] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0129] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0130] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for analyzing the opening and closing durability of automobile doors based on multi-body dynamics and finite elements, characterized in that: include: Establish a finite element model of the vehicle; A multi-body dynamics model of the vehicle is established based on the vehicle finite element model, and the time domain load results of the door opening and closing process are calculated; Calculating stress results of the door under unit load based on the automobile finite element model; The fatigue damage value of the vehicle door is calculated and the fatigue damage value is evaluated.

2. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 1, wherein: Building a finite element model of a car includes: Establish finite element mesh models of the body-in-white and door assembly, and assign material properties; Establish finite element models of the lock body, lock hook and internal structure, and assign material properties; Establish a counterweight model for door accessories, where the door accessories are simulated by mass units; Establish simplified models of door seals, buffer blocks and water cuts; The above model is the automobile finite element model.

3. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 1, wherein: The multi-body dynamics model of the vehicle is established based on the finite element model of the vehicle, and the time domain load results of the door opening and closing process are calculated, including: The automobile finite element model is flexibly processed, converted into a file in mnf format, and imported into multi-body dynamics software; Load the connection relationship between automobile parts, and set constraints and loading for the automobile multi-body dynamics model; The multi-body dynamics model of the vehicle is solved and calculated to obtain the time domain load results of the door opening and closing process.

4. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 3, wherein: The automobile multi-body dynamics model is: Among them, Φ is the constraint equation of the position coordinate matrix q, Φ q is the Jacobian matrix of the constraint equation, and λ is the Lagrange multiplier.

5. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 1, wherein: The stress results of the door under unit load calculated based on the automobile finite element model include: Converting the welds in the finite element model of the vehicle into welds in a FEMFAT format; A unit load is applied to the converted finite element model of the car, and the stress results of the car door under the unit load are calculated by structural statics.

6. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 5, wherein: The structural statics are: [K]{x}={F} Where [K] is the stiffness matrix, {x} is the displacement vector, and {F} is the force vector.

7. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 1, wherein: Calculate fatigue damage values ​​of door sheet metal and welds Associating the stress result with the time domain load result; Set the material SN curve and fatigue analysis parameters to obtain the fatigue damage value of the door during single opening and closing; According to the fatigue damage value of the door during a single opening and closing, it is linearly amplified according to the number of opening and closing times required by the development to obtain the fatigue damage value of the door during the entire life design cycle.

8. The automobile door opening and closing durability analysis method based on multi-body dynamics and finite element analysis according to claim 1, wherein: The evaluation of the fatigue damage value includes: The fatigue damage value of the car door is compared with the preset target value. If it is lower than the target value, it is considered to meet the requirements. If it is higher than the target value, it is considered that the fatigue performance requirements are not met. The vehicle structure is optimized and re-analyzed until the fatigue performance of the car door meets the target requirements.

9. An electronic device, characterized in that: The electronic device comprises: A memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the automobile door opening and closing durability analysis method based on multi-body dynamics and finite elements as described in any one of claims 1 to 8.

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