Investigation On Vibration Energy Transfer Characteristics Of Beam Structures In Ladder Frame Chassis

In the process of improving vehicle driving comfort,vibration problems can not be got around.As the main part of the body-on-frame,the vibration characteristics of the frame greatly affect the vibration characteristics of the vehicle.The frame is composed of multi-section coupling thin-walled beam structure,which carries different componets and bears various loads,so the transmission ways of vibration energy in the frame are diverse.That makes it difficult to model and analyze the essence of vibration transmission in frame and describe it quantitately,the study of the transmission law of vibration energy in the frame structure is helpful to realize the artificial control of vibration.Starting from this difficulty,this paper takes the typical beam structure of side beam frame as the research object,and discusses the influence of concentrated mass on the dynamic behaviors of beam structure,the propagation law of elastic wave in Y-shaped bifurcated coupled beam,and the vibration power flow characteristics of thin-walled beam.The vibration control and the law of vibration energy propagation of beam structure are emphatically studied.and the details are as follows:(1)The kinetic and potential energy of concentrated mass and boundary constraints is considered are considered,and the motion equation of the overhanging beam under the influence of concentrated mass under bending excitation is derived.The influence of load type and mass block on forced vibration response of overhanging beams is studied,and the suppression effect of mass block applied in different ways on dynamic response of overhanging beams is emphatically studied.(2)The propagation law of bending wave in Y-shaped bifurcated beam is derived from the elastic wave perspective,and the vibration energy conversion law at the Y-shaped bifurcated interface of the semi-infinite coupling beam is obtained.Considering the influence of bifurcation Angle,geometric parameters of the branch beam and application mode of concentrated mass,the energy conversion law and transfer efficiency of the finite coupled beam in the frequency domain are studied.(3)The governing equations of forced vibration are obtained by considering the axial vibration,bending vibration and torsional vibration caused by harmonic excitation.The power flow of structural sound intensity method is introduced to study the propagation law of vibration energy in thin-walled rectangular beam(4)The vibration energy transfer law of a certain ladder frame chassis was studied by power flow method,and the difference of power flow at response points before and after applying concentrated mass was compared.Through sensitivity analysis,the influence of dimension parameters of side sill and cross sill on natural frequencies of ladder frame chassis is obtained,and the dimension optimization direction is proposed.The related work in this paper studies the vibration phenomenon of beam structure from the perspective of energy transfer,which provides a certain theoretical basis for suppression or influence to vibration of beam structure applied concentrated mass,and helps to further improve the NVH performance of automobile body structure.