| The mechanical elastic wheel(MEW)is a new non-pneumatic elastic safety wheel,which elastic outer ring and the rigid hub is connected together by the hinges.The MEW can realize the basic function of traditional pneumatic tire,in additional,the problems such as stinging,puncturing and blasting damage have been avoided.Thus,the MEW is greatly satisfied with requirements of safe service for the special vehicles.The dynamic characteristic of the wheel is the basis of vehicle dynamics analysis and research,and the good dynamic characteristic is the key factor of the design of wheel,which directly affects the steering performance of the whole vehicle.In this paper,the theoretical and experimental research on the buffer damping performance and its influencing factors of the MEW are carried out,the main research contents are follows:1.According to the structural characteristics of the mechanical elastic wheel,the characteristics of load deformation,the rolling radius and the vibration transfer path are analyzed.The mechanical models of rolling resistance,the driving,the braking of the wheel are established under the condition of the steady state,and the improved elastic foundation ring model is established based on the form of the buffer damping.The stiffness and damping of the compression and tension region are equivalent,which provides a reference for the theoretical and simulation analysis of the vibration characteristics of the MEW.2.The improved elastic foundation closed circle curved beam model and the hinges model are established based on the load deformation characteristics of the MEW.The influencing factors of the static and dynamic stiffness of the MEW are analyzed qualitatively,and the analytical results are verified by the finite element method and the static and dynamic loading tests.The influencing factors of the radial stiffness of the MEW were parametric analyzed,and the radial stiffness characteristics of MEW and pneumatic tire are compared and analyzed.Based on the static and dynamic stiffness analysis results,the nonlinear analytical model of the stiffness and damping of the MEW are established.3.Based on the theory of elastic foundation ring,the MEW is modeled as a ring on elastic foundations(REF)with only in-plane vibration,the vibration modes of the wheel are predicted,and the prediction results are verified by the modal test.The finite element model of the MEW is established according to the model of ring supported on elastic foundation.The modal frequencies and mode shapes of the MEW under different conditions can be obtained,and the calculated modal parameters are compared with the experimental modal parameters of the MEW.The vibration characteristics of the MEW and the pneumatic tire are compared and analyzed by the modal test.Finally,according to the evaluation index of the contribution of the vibration transfer path,the vibration transfer characteristics of the MEW are studied.4.The influence of elastic wheel laminated structure on the vibration characteristics of the MEW is studied by the finite element analysis method,in the condition that the rim structure has been unchanged.The influence of the rim structure and external conditions on the vibration modes of MEW is studied using the theoretical analysis and modal test,under this circumstance that the laminated structure of elastic wheel has been unchanged.The influence of the non-uniformity of the wheel on the vibration characteristics is studied by the modal test.And the effect of the radial stiffness of the MEW on the vibration transfer characteristics is analyzed,which provides guidance for the optimization design of the wheel structure.5.The effective road input and the steady enveloping characteristics at low speed are studied using the flexible roller contact model and nonlinear finite element model,and it shows that the MEW has the significant characteristics of enveloping the cleat,reducing impact and prolonging the time of impact.The vertical mechanical properties of the MEW under the effect of obstacles are studied using the finite element analysis method,and the analysis results are verified by the tire loading test.The MEW-enveloping characteristics while traversing the three different cross-section obstacles at low speed are investigated by the nonlinear finite element model and the bench testing.The vertical and longitudinal dynamic mechanical response while traversing different obstacles are illustrated,and the influence of load,radial stiffness and types of cleats on enveloping characteristics are analyzed.The results showed that the MEW has the typical enveloping characteristics under the certain load.Finally,the running test of obstacle performance of the MEW is carried out,the rolling mechanism model of MEW is verified.The obstacle performance of MEW is analyzed using the mechanical model of obstacle and real vehicle test,and the enveloping characteristics of the MEW when climbing is analyzed.The results showed that the MEW has good obstacle crossing and enveloping performance. |
PDF Full Text Request