STUDY ON THE VERTICAL STIFFNESS AND DAMPING COEFFICIENT OF TRACTOR TIRE USING SEMI-EMPIRICAL MODEL

Author(s):  
Đỗ Minh Cường ◽  
Zhu shi Hong ◽  
Đinh Vương Hùng ◽  
Nguyễn Thị Ngọc

An experiment was conducted to determine the vertical stiffness and damping characteristics of tractor tires for the aim of simulation and design of the tractor suspension system. Three kinds of tractor tires were selected to measure vertical stiffness and damping coefficient by using Free-Vibration Logarithm Decay Method at five levels of tire inflation pressures and two tire loads. The results show that, for all kinds of tire, the stiffness was linearly increased by increasing tire inflation pressure whereas the damping coefficient decreased when tire inflation pressure increased. The stiffness and damping coefficient of tractor tires also depend on the tire size, the structure of tires as front tire or rear tire. Additionally, the damping coefficient shows the increasing trend while the increase in tire stiffness is not clear by increasing tire load. The results also reveal that the appropriate distribution of tire load, tire inflation pressure and tire size can change significantly the tire stiffness and damping coefficient to control tractor vibration. Keywords: Tire stiffness; Damping coefficient; Tractor tire; Tire inflation pressure.

2013 ◽  
Vol 397-400 ◽  
pp. 355-358
Author(s):  
Xia Qing Tang ◽  
Jun Qiang Gao ◽  
Li Bin Guo ◽  
Huan Zhang

Dynamics characteristics of SINS damping system in shock environment were analyzed by finite element method, as the deformation of dampers may leads to the accuracy loss of SINS. In addition, the influence of absorber stiffness and damping coefficient on dynamics characteristics were studied. The results indicate that the decoupling of vibrations is significant for the accuracy of SINS. However, considering the almost impossible of completely decoupled vibrations, its necessary to carry out an optimal design of the absorber stiffness and damping coefficient to maintain the accuracy of SINS while meeting the requirement of vibration isolation.


Author(s):  
V. H. Saran ◽  
V. K. Goel

In this paper, a laboratory technique for determination of rolling dynamic stiffness and damping coefficients of small-sized, bias-ply tyres has been discussed. The effect of normal load, inflation pressure and speed on four different tyres has been reported. The results show similar trends to those reported by other investigators.


2020 ◽  
Vol 10 (22) ◽  
pp. 7953
Author(s):  
Lei Zhang ◽  
Xiangtao Zhuan

For improving the performance of an electromagnetic isolation system with reasonable parameters and avoid the parameter tuning problem of a PID controller, an active control method is put forward based on equivalent stiffness and damping coefficient. In this paper, the range of equivalent stiffness coefficient and damping coefficient of the electromagnetic force are calculated based on the required range of dynamic performance indexes. According to the nonlinear expression between electromagnetic force and coil current and gap, the relationships between the coil current and equivalent stiffness coefficient and damping coefficient are established. Then, the equivalent stiffness coefficient and damping coefficient can be satisfied by the controlled current in different gaps for meeting the required dynamic performance indexes. For reducing the maximum overshoot and the number of oscillations of the system, the active control method with the piecewise equivalent stiffness and damping coefficient is proposed based on the piecewise control strategy to realize the variable control parameters of the isolation system. Simulation and experimental results verify that the control method based on the equivalent stiffness and damping coefficient can obtain the desired dynamic performance indexes and the proposed control method with the piecewise strategy can not only reduce the setting time of the system, but also ensure the stability of the system.


Author(s):  
W. D. Zhu ◽  
G. Y. Xu

The effects of bending stiffness and boundary conditions on the lateral vibration of the stationary and moving hoist cables are investigated. The role of the trial functions in the approximate methods is examined. The optimal stiffness and damping coefficient of the suspension of the car against its guide rails are identified for the moving cable.


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