Study On Vibration Analysis And Its Control Of Vehicle Body Sheet

The body is used to carry passengers and to provide a comfortable space, body structure vibration will directly affect the car’s feelings. Car body is mainly composed of the following parts:body structure, body panels, doors, body parts and body parts and accessories, etc. In which the majority of body panels are pressed into the surface of the sheet. These panels are seen due to thin and support span large, small stiffness, when being excited by the outside world, which will produce vibration and radiation noise due to vibration. So it is very significant to analyze and control the vibration of the thin plate.The vibration problem of the vehicle body plate structure is mostly regarded as low frequency and intermediate frequency excitation, high frequency according to the noise problem. The natural frequency of thin plate structure to avoid the excitation source frequency is the basic requirement of vibration control. In this paper, the structure of the thin plate structure is optimized to improve the modal frequency of the thin plate structure, in order to achieve the purpose of avoiding frequency. Because of the simple structure, low cost and easy installation, passive dynamic vibration absorber is easy to install and so on, which is often used as a method of vibration control. In this paper, the vibration absorbing effect of a single dynamic absorber and a distributed dynamic vibration absorber are analyzed, provide theoretical guidance and design method for vibration control of thin plate structure.In this thesis, firstly take simple supported rectangular thin plate as the research object, through the longitudinal and transverse direction of the sheet steel and its layout, longitudinal and transverse reinforcement and layout, as well as the change of the curvature of the thin plate, etc. Modal shapes and frequencies of various structural schemes are analyzed. It is found that the increase of the number of the reinforcement and the increase of the number of the reinforcement and the modal frequency of the thin plate is increased; the thin plate curvature increases, and the modal frequency of the thin plate increases. Taking the automobile roof as an example, it is found that there is a new local mode shape, but the whole modal frequency is improved.Based on the analysis of the domestic and foreign research on the dynamic vibration absorber and the theoretical research of the dynamic vibration absorber. For controlling the simply supported thin plate of a modal, based on optimal coherent and optimal damping formula, analysis of the single power ceiling exciter and distributed dynamic vibration absorber. In software HyperMesh to establish sheet model and the additional dynamic vibration absorber, using the displacement frequency response function evaluation of different free degree dynamic ceiling exciter of thin plate vibration system of vibration characteristics. It is found that the single dynamic absorber can achieve the effect of vibration absorption in a very narrow frequency band, and the distributed vibration absorber has the advantages of light weight and wide absorption frequency band.Taking the top cover of the vehicle body as the research object, the modal frequency of the vehicle is controlled by the maximum amplitude position of the 115Hz. In the maximum amplitude of the installation of a single vibration absorber and distributed vibration absorber, and the vibration absorption performance analysis, analysis and verification of dynamic vibration absorber in the body top of the vibration absorbing effect. The results show that the distributed dynamic vibration absorber has obvious vibration absorbing effect on the local vibration of automobile top cover, and the vibration frequency band is wider.