Design method of automobile front hood buffer block layout based on CAE simulation technology

Abstract

The present invention relates to a design method for the arrangement of a buffer block of a front hood of an automobile based on CAE simulation technology, including the steps of conducting simulation analysis of the overload closing strength of the front hood, judging whether the plastic deformation meets the design requirements, conducting dynamic simulation analysis of the slam closure of the front hood, judging whether the dynamic clearance value between the front hood and the surrounding structure meets the design requirements, conducting dynamic fatigue analysis of the front hood, judging whether the fatigue performance of the front hood meets the requirements of a reliability road test, and determining a buffer block arrangement scheme. The present invention uses CAE simulation technology to simulate the user's use conditions of the front hood of an automobile to reasonably arrange the position of the buffer block.

Description

Technical Field

[0001] The invention relates to a design method for arranging a buffer block of a front cover of an automobile, in particular to a design method for arranging a buffer block of a front cover of an automobile based on CAE simulation technology. Background Art

[0002] In order to reduce the vibration when the car is running or the front hood is closed, according to experience, the front hood design of the car is usually equipped with two sets of buffer blocks. The front buffer block is generally arranged at the front grille or the water tank cross beam, and the rear buffer block is arranged at the side beam of the water tank cross beam or the front finger beam. Only after the actual car is produced can it be checked whether the front hood will hit the fender and headlight when closed, and the position of the buffer block is adjusted according to the actual car evaluation results. This will not only greatly increase the rectification and verification cycle, but also incur rectification costs, which is not conducive to product development. Summary of the invention

[0003] The purpose of the present invention is to provide a design method for arranging a car front hood buffer block based on CAE simulation technology, using CAE simulation technology to simulate the user's use of the car front hood to reasonably arrange the position of the buffer block.

[0004] The design method of the automobile front cover buffer block arrangement based on CAE simulation technology of the present invention comprises the following steps:

[0005] Step 1: Conduct simulation analysis of the front cover overload closing strength

[0006] Constrain the six degrees of freedom of the front cover female hinge mounting hole and the Z-direction degree of freedom of the initial mounting position of the buffer block. Apply a locking load of 110% to 140% at the front cover lock position and then unload it to obtain the plastic deformation of the front cover edge under this working condition.

[0007] Step 2: Determine whether the plastic deformation meets the design requirements

[0008] Based on the design requirements, determine whether the plastic deformation obtained in step one is qualified. If qualified, obtain an initial position of the buffer block and proceed to step three. Otherwise, optimize the buffer block arrangement position according to the plastic deformation result and proceed to step one.

[0009] Step 3: Conduct dynamic simulation analysis of the front hood slamming shut

[0010] Half of the car body finite element model is intercepted, and the three degrees of freedom of the interception position XYZ are constrained. The front hood is raised by 3 to 7 mm, and the equivalent angular velocity of overload energy is applied to the lock. The gap value between the front hood and the surrounding structure during the closing process of the front hood is obtained through finite element analysis to examine whether there is dynamic interference between the front hood and the surrounding structure.

[0011] Step 4: Determine whether the dynamic clearance value between the front cover and the surrounding structure meets the design requirements

[0012] Based on the design requirements, determine whether there is dynamic interference between the front cover and the surrounding structure. If qualified, proceed to step five; otherwise, optimize the buffer block layout position according to the analysis results and proceed to step three.

[0013] Step 5: Conduct dynamic fatigue analysis of the front cover

[0014] Based on the forces and moments at the connection points between the front hood and the body, dynamic fatigue analysis of the front hood is carried out.

[0015] Step 6: Determine whether the fatigue performance of the front hood meets the reliability road test requirements

[0016] Based on the design requirements, determine whether the fatigue performance of the front hood is qualified. If qualified, proceed to step seven. If the optimized front hood structure can be qualified, also proceed to step seven. Otherwise, it is necessary to optimize the buffer block layout and proceed to step three.

[0017] Step 7: Determine the buffer block layout plan

[0018] Solidify the front cover buffer block layout position.

[0019] The method of the present invention can optimize and reasonably arrange the position of the automobile front hood buffer block in the early stage of product development and design, reducing the damage to the automobile front hood caused by vibration or impact. Compared with the existing empirical design method, it can avoid the problem of dynamic interference of the front hood closing in the tooling prototype stage due to unreasonable arrangement of the buffer block, as well as the problem of cracking in the reliability road test, thereby reducing the prototype rectification cycle and saving the cost of sample rectification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0021] The design method of automobile front hood buffer block layout based on CAE simulation technology includes the following steps:

[0022] Step 1: Conduct simulation analysis of the front cover overload closing strength

[0023] Constrain the six degrees of freedom of the front cover female hinge installation hole, the Z-direction degree of freedom of the initial installation position of the buffer block, apply a locking load of 110% (also 125% or 140%) at the front cover lock position, and then unload to obtain the plastic deformation of the front cover edge under this working condition. The locking load can be calculated by CAE analysis. Under the action of the gravity field, constrain the six degrees of freedom of the front cover female hinge installation hole, the Z-direction degree of freedom of the initial installation position of the buffer block, and apply the lock gap design value at the front cover lock buckle, thereby obtaining the constraint reaction force at the lock buckle, which is the locking load.

[0024] Step 2: Determine whether the plastic deformation meets the design requirements

[0025] Based on the design requirements, determine whether the plastic deformation obtained in step one is qualified. If qualified, obtain an initial position of the buffer block and proceed to step three. Otherwise, optimize the buffer block arrangement position according to the plastic deformation result and proceed to step one.

[0026] Step 3: Conduct dynamic simulation analysis of the front hood slamming shut

[0027] Half of the car body finite element model is intercepted, and the three degrees of freedom of the interception position XYZ are constrained. The front hood is raised by 3 to 7 mm, and the equivalent angular velocity of overload energy is applied to the lock. The gap value between the front hood and the surrounding structure during the closing process of the front hood is obtained through finite element analysis to examine whether there is dynamic interference between the front hood and the surrounding structure.

[0028] Step 4: Determine whether the dynamic clearance value between the front cover and the surrounding structure meets the design requirements

[0029] Based on the design requirements, determine whether there is dynamic interference between the front cover and the surrounding structure. If qualified, proceed to step five; otherwise, optimize the buffer block layout position according to the analysis results and proceed to step three.

[0030] Step 5: Conduct dynamic fatigue analysis of the front cover

[0031] Based on the virtual test field technology, the load at the connection point between the body and the chassis is decomposed, and the dynamic fatigue analysis of the body is carried out. At the same time, the force and moment of the connection point between the front hood and the body can be extracted; if the connection point between the front hood and the body has not been changed, the dynamic fatigue analysis of the front hood can be carried out based on the force and moment of the connection point between the front hood and the body to examine the fatigue performance of the front hood; if the connection point between the front hood and the body has been changed, it is necessary to re-carry out the dynamic fatigue analysis of the body to examine the fatigue performance of the front hood.

[0032] Step 6: Determine whether the fatigue performance of the front hood meets the reliability road test requirements

[0033] Based on the design requirements, determine whether the fatigue performance of the front hood is qualified. If qualified, proceed to step 7. If the optimized front hood structure is qualified, proceed to step 7. Otherwise, the buffer block layout position needs to be optimized and proceed to step 3.

[0034] Step 7: Determine the buffer block layout plan

[0035] The front cover buffer block layout position is solidified to end the design process.

Claims

1. A design method for the layout of a car front hood buffer block based on CAE simulation technology, characterized in that: The following steps are involved: Step 1: Conduct simulation analysis of the front cover overload closing strength Constrain the six degrees of freedom of the front cover female hinge installation hole and the Z-direction degree of freedom of the initial installation position of the buffer block, apply a locking load of 110% to 140% at the front cover lock position, and then unload, and obtain the plastic deformation of the front cover edge under this working condition; Step 2: Determine whether the plastic deformation meets the design requirements Based on the design requirements, determine whether the plastic deformation obtained in step 1 is qualified. If qualified, obtain an initial position of the buffer block and proceed to step 3. Otherwise, optimize the buffer block arrangement position according to the plastic deformation result and proceed to step 1. Step 3: Conduct dynamic simulation analysis of the front hood slamming shut Cut off half of the car body finite element model, constrain the three degrees of freedom of the cut position XYZ, lift the front hood by 3 to 7 mm, apply the equivalent angular velocity of overload energy at the lock, and obtain the gap value between the front hood and the surrounding structure during the closing process through finite element analysis to examine whether there is dynamic interference between the front hood and the surrounding structure; Step 4: Determine whether the dynamic clearance value between the front cover and the surrounding structure meets the design requirements Based on the design requirements, determine whether there is dynamic interference between the front cover and the surrounding structure. If qualified, proceed to step five; Otherwise, optimize the buffer block layout according to the analysis results and proceed to step 3; Step 5: Conduct dynamic fatigue analysis of the front cover Based on the forces and moments at the connection points between the front hood and the body, dynamic fatigue analysis of the front hood is carried out; Step 6: Determine whether the fatigue performance of the front hood meets the reliability road test requirements Based on the design requirements, determine whether the fatigue performance of the front hood is qualified. If qualified, proceed to step 7. If the optimized front hood structure is qualified, proceed to step 7. Otherwise, the buffer block layout position needs to be optimized and proceed to step 3. Step 7: Determine the buffer block layout plan Solidify the front cover buffer block layout position.

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