Research On Vibration Dynamic Characteristic Of Coach Based On Ground Roughness Excitation

Body and frame are main loaded parts of non-integrated structure of a bus,will bear the static and dynmic loads. So it is rather important for both its strength and dynamic characteristic design. The dynmic charaeteristic of the frame will aeffet the ride comofort, the contorl stability and the seucrity of thebus,and the relibaility of the components. And if the strength,espeeially the dynamic strength can't meet its requests, the frame may be destoryed. Therefore, dynamic response analysis of the body and frame can be evaluated not only on their own performances,but also on their travel stability and other performances, its result can also provide a theoretical basis for body and frame's structure.Taking the model analysis for the body and frame of bus model which based on CATIA make up by using he finite element method of calculation and analysis;Taking dynamics simulation in ADAMS;Taking transient response analysis of the body and frame by Hyperworks. In this thesis, the following works were mainly studied.First:The modal properties of the frame were analyzed through the FE method, and the first thirty natural frequencies and ten vibration modes were given. The modal analysis showed that the lower modal frequency of this frame was within the scope of the road excitation frequency, and this fact was not propitious for the vibration decreasing. The foreside of this frame was weak in stiffness and vulnerable to fatigue damages.Second:Taking dynamics simulation in ADAMS,found out those nodes which has the larger stress on flexible body,and received the variation curve along the time of those nodes belong to the frame and suspension's force and the moment at the same time, thus became the random load in transient response analysis.Third:Taking transient response analysis of the body and frame by Hypermesh, and found out the larger displacement and stress parts of the body and frame. To improve its structure and quantification offers a basis.Through a detail analysis of the results, we obtained the places of the bodyand frame of the lager displacement, stress and fatigue damage under thedynamic load,which can be privided a new way for a theoretical basis and the structural design.