A Theoretical Model for Calculating Vibration Characteristics of A Kind of Driver Seat with Air Spring and MR Damper

2011 ◽  
Vol 141 ◽  
pp. 8-14 ◽  
Author(s):  
Xing Xing Zhu ◽  
Si Hong Zhu
Keyword(s):  
Mr Damper ◽  
Damping Coefficient ◽  
Orifice Diameter ◽  
Equivalent Stiffness ◽  
Air Spring ◽  
Seat Suspension ◽  
Study Results ◽  
Stiffness And Damping Coefficient ◽  
Mr Damping ◽  
Stiffness And Damping

In order to further reduce the vibration transmitted from vehicle to driver, a new model of driver scissors linkage seat suspension was put forward, in which an air spring with auxiliary chamber and a MR damper are between the face and floor of the seat. The motion differential equation of this seat suspension system was established and the theoretical computing formulation of it’s equivalent vertical stiffness, equivalent damping coefficient, natural frequency and damping rate were deduced. Besides, taking HY-Z04 scissors linkage seat, SK37-6 air spring of ContiTech and RD-1005-3 MR damper of LORD as an example, the equivalent stiffness and damping coefficient in different conditions of the air spring pressure, the sprung mass, the orifice diameter and MR damping were computed and analyzed. The study results show that the air spring pressure, the sprung mass, the orifice diameter and MR damping all have obvious influence on the equivalent stiffness and damping coefficient, so the seat comfort can be improved by changing the air spring pressure, the orifice diameter and MR damping according to driver’s weight and road condition.

scholarly journals Active Control Method Based on Equivalent Stiffness and Damping Coefficient for an Electromagnetic Isolation System

2020 ◽  
Vol 10 (22) ◽  
pp. 7953
Author(s):  
Lei Zhang ◽  
Xiangtao Zhuan
Keyword(s):  
Control Method ◽  
Dynamic Performance ◽  
Damping Coefficient ◽  
Stiffness Coefficient ◽  
Equivalent Stiffness ◽  
Isolation System ◽  
Performance Indexes ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Active Control Method

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.

Study on Dynamics Characteristics of SINS Damping System in Shock Environment

2013 ◽  
Vol 397-400 ◽  
pp. 355-358
Author(s):  
Xia Qing Tang ◽  
Jun Qiang Gao ◽  
Li Bin Guo ◽  
Huan Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimal Design ◽  
Vibration Isolation ◽  
Damping Coefficient ◽  
Shock Environment ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Element Method

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.

scholarly journals Vibrational Interaction of Two Rotors with Friction Coupling

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
H. Larsson ◽  
K. Farhang
Keyword(s):  
Lumped Parameter Model ◽  
Equivalent Stiffness ◽  
Stick Slip ◽  
Lumped Parameter ◽  
Disk Friction ◽  
Axial Behavior ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Two Parameter ◽  
Very High

A lumped parameter model is presented for studying the dynamic interaction between two disks in relative rotational motion and in friction contact. The contact elastic and dissipative characteristics are represented by equivalent stiffness and damping coefficient in the axial as well as torsional direction. The formulation accounts for the coupling between the axial and angular motions by viewing the contact normal force a result of axial behavior of the system. The model is used to investigate stick-slip behavior of a two-disk friction system. In this effort the friction coefficient is represented as an exponentially decaying function of relative angular velocity, varying from its static value at zero relative velocity to its kinetic value at very high velocities. This investigation results in the establishment of critical curve defining two-parameter regions: one in which stick-slip occurs and that in which stick-slip does not occur. Moreover, the onset and termination of stick-slip, when it occurs, are related to the highest component frequency in the system. It is found that stick-slip starts at a period nearly equal to that of the highest component frequency and terminates at a period almost three times that of the highest component frequency.

Vibration of Elevator Cables With Small Bending Stiffness

2002 ◽  
Author(s):  
W. D. Zhu ◽  
G. Y. Xu
Keyword(s):  
Boundary Conditions ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Lateral Vibration ◽  
Approximate Methods ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Optimal Stiffness

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.

Experimental study on dynamic performance of typical nonballasted track systems using a full-scale test rig

2016 ◽  
Vol 231 (4) ◽  
pp. 470-481 ◽  
Author(s):  
Mingze Wang ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Wanming Zhai
Keyword(s):  
Experimental Study ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Full Scale ◽  
Damping Coefficient ◽  
Full Scale Test ◽  
Test Rig ◽  
Scale Test ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

This paper presents an experimental study on dynamic performance of China Railway Track System (CRTS) series track systems using a full-scale test rig. The test rig has been constructed based on 55.17 m long full-scale nonballasted tracks composed of four typical CRTS track elements in high-speed railways. First, the dynamic characteristics of different nonballasted tracks are investigated by conducting wheel-drop tests, where a wheel-drop testing vehicle with a dropping wheelset is devised to provide the wheel-drop load. The vibration levels of different track systems are assessed by the root-mean-square acceleration per one-third octave band, and the vibration transmission characteristics of the CRTS series tracks are evaluated by transfer functions. Further, a mathematical track model is used to extract the dynamic stiffness and damping coefficient of the four types of nonballasted track systems based on the wheel–rail impact response. The vibration characteristics, the dynamic stiffness, and damping coefficient of different nonballasted track systems under various wheel-drop heights are compared and discussed in detail.

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