Computer simulation prediction method of in-car vibration and noise of car

Abstract

The invention aims to provide a computer simulation prediction method of the in-car vibration and noise of a car. The computer simulation prediction method comprises the following steps: A: calculating the reciprocating inertial force and the reciprocating inertial moment of a crank mechanism of an engine; B: according to the combustion pressure of the engine, calculating a moment generated by air pressure; C: processing engine load into frequency domain load according to orders; D: establishing an NVH (Noise Vibration and Harshness) finite element simulation model of a complete car, preliminarily judging the correctness of a model according to a modality, and loading the load onto an engine centroid in the model; E: calculating a response curve of the in-car vibration and noise, and comparing the response curve with a target value; F: according to the response curve of the in-car vibration and noise and the target value, finding a peak point which affects NVH performance to carry out contribution analysis; and G: according to a contribution analysis result, carrying out structure improvement to lower a noise or vibration peak. The computer simulation prediction method can predict and solve problems before manufacture cost is generated, a great quantity of cost is saved, and a development period is shortened.

Description

technical field [0001] The invention relates to the technical field of computer-aided engineering (CAE), in particular to a computer simulation prediction method for vibration and noise inside an automobile. Background technique [0002] The structural noise and vibration inside the passenger car caused by the engine excitation is the most important link affecting the comfort of the passenger car. To reduce this kind of vibration and noise, the method of test adjustment is generally adopted, that is, after the prototype vehicle is assembled, the noise and vibration inside the vehicle are measured. If the target requirements are exceeded, the vibration isolation system and the test methods used in the vehicle are checked. , which has two defects: firstly, even if parts with long-term molds such as car bodies are identified as having problems, they cannot be rectified; secondly, due to the limitation of test methods, the weakness analysis cannot be sufficient. [0003] The CA...

AI Technical Summary

Problems solved by technology

To reduce this kind of vibration and noise, the method of test adjustment is generally adopted, that is, after the prototype vehicle is assembled, the noise and vibration inside the vehicle are measured. If the target requirements are exceeded, the vibration isolation system and the test methods used in the vehicle are checked. , which has two defects: firstly, parts with long-term molds such as car bodies cannot be rectified even if they are identified as having problems; secondly, due to the limitation of test methods, the weakness analysis cannot be fully

[0003] The CAE simulation method can be used to solve the above defects, that is: through the simulation evaluation and rectification of the later "test" in the digital-analog stage, the problem can be predicted before the manufacturing cost occurs, so as to avoid cost waste; through simulation tools, use The finite element method establishes the model of the whole vehicle, and uses the principles of mechanics, vibration, and acoustics to conduct sufficient research on any part to obtain the relationship between its local performance and overall performance, so as to obtain the impact of local performance on the overall performance , and finally know which part of the defect in the overall performance is caused by, and the effect of the physical test method on the physical prototype is limited to verification, which is not conducive to fully analyzing the problem in essence, so CAE simulation technically makes up for this defect

[0004] However, the CAE simulation methods currently used are mostly limited to the unit excitation load or the acceleration load at the mount, and cannot predict the final problem from the perspective of actual vehicle performance.

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