Vibration Analysis And Floor Optimization Of A Passenger Car

This article topic comes from an automobile company. As part of a passenger car vibration and noise reduction , the study was carried .The study content of this article is relate vehicle road test ,build FEM model of passenger cars body, body calculating modal analysis ,morphology optimization and so on . In this paper, based a passenger car, the study was carried out .Firstly the road test was carried base on the national standard GB/718697-2002. The acceleration signal of key part was tasted at the idle and constant velocity condition, and the vibration of vehicle was evaluated subjectively at constant velocity condition. Than the acceleration signal was processed by LMS Test.Lab software and the weak part of floor vibration was found.Secondly, base on the geometric model, body finite element model was established by geometry model predigested mesh, mesh quality checks and simulation of connections. Free modal and constraint modal was calculated by the software of Nastran. The result was demonstrated by HyperView, one of most professional post-processing environment. The modal parameters were extracted, than modal test was carried out and the modal parameter was identified by the software of LMS Test. Lab. By comparing the calculation modal and experimental modal, proves that finite element model has sufficient credibility.Finally, base on the finite element modal, the topography optimization was carried out at the weak region of floor vibration. Analysis and evaluate the effect, by comparison of the modal analysis results between the before optimization and the after optimization. The results prove that the method of topography optimization based on modal analysis is vary effective to improve the vibration characteristics of floor.Final conclusion: the finite element model verified by test modal analysis is credible, it can be used to Structural optimization analysis. The method of topography Optimization based on modal analysis is vary effective to improve the vibration characteristics of Sheet Metal.