scholarly journals Vibration Control and Cost-Effectiveness Evaluation of Cable-Stayed Bridges with Semi-Active Control System

2005 ◽  
Vol 9 (4) ◽  
pp. 43-54 ◽  
Author(s):  
G. Nelson ◽  
R. Rajamani ◽  
A. Gastineau ◽  
A. Schultz ◽  
S. Wojtkiewicz

The fatigue life of a bridge can be extended by fifty years just by reducing the peak strain levels it experiences by 33%. This paper utilizes a dynamic model of the Cedar Avenue tied arch steel bridge in Minnesota to investigate active control technologies for peak strain reduction. Simulations show that the use of passive structural modification devices such as stiffeners and dampers is inadequate to reduce the key resonant peaks in the frequency response of the bridge. Both active and semi-active vibration control strategies are then pursued. Active vibration control can effectively reduce all resonant peaks of interest, but is practically difficult to implement on a bridge due to power, size, and cost considerations. Semi-active control with a variable orifice damper in which the damping coefficient is changed in real-time using bridge vibration feedback can be practically implemented. Simulation results show that the proposed semi-active control system can reduce many of the resonant peaks of interest, but is unable to reduce the response at one key resonant frequency. Further analysis reveals that the location of the actuator on the bridge chosen for the semi-active controller is inappropriate for controlling the specific resonant frequency of issue. By modifying the actuator location, it would be possible to obtain control of all bridge resonant frequencies with the semi-active control system.


2021 ◽  
Vol 11 (1) ◽  
pp. 49-52
Author(s):  
K. Sumanth Ratna ◽  
C. Daniel ◽  
Anshika Ram ◽  
B. Siva Kumar Yadav ◽  
G. Hemalatha

Abstract In this paper, a vibration control system with magnetorheological (MR) damper investigation is reviewed. At first a MR damper is investigated analytically using various finite element method software and the performance is investigated using experimental. The MR Dampers are designed and modelled for a scaled down setup. The application is in seismic resistance of buildings, automobile, physical and biological. Finally, the damper is investigated using various technique and methods used to study the performance is reviewed. This device reduces the vibration in both active and semi active control system effectively.


Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda

We propose a semi-active vibration control method of structural systems based on the output emulation approach. In the output emulation approach, the semi-active control law is obtained so that the controlled output signal of the semi-active control system is similar to that of the reference active control system. The reference active control system is a virtual control system employing the actuator for vibration control and achieves the ideal control performance. Because the constraints of the semi-active control comes from the inherent dissipative characteristics of semi-active control devices a certain amount of the error of the controlled output signals between the semi-active and its reference active control system is unavoidable. To realize the semi-active control system based on the output emulation approach, i.e., the semi-active control system whose controlled output signal is similar to that of the reference active control system, the semi-active control law in the present study is obtained for minimizing an error function related to the controlled output. The error function is defined as a quadratic function on the output signal of the error between the semi-active and its reference active control systems and the Lyapunov matrix. The control characteristics of the reference active control law and free parameters in the Lyapunov matrix are searched with a boot-strap optimization algorithm for the optimal semi-active control system. Some simulation results are shown to claim the effectiveness.


2020 ◽  
Author(s):  
Daniel Rooney ◽  
Mathew Roseman ◽  
Charles Shotridge ◽  
Jeffrey Aschenbrenner ◽  
Sanjay Jayaram

Author(s):  
A.V. NEMENKO ◽  
M.M. NIKITIN

The transformation of a spherical concave mirror into a parabolic one with the help of elastic bending deformations is considered. The magnitude and direction of the load, which creates the necessary bend for transforming the mirror with the given parameters, are determined. Uneven material removal during machining is replaced by the bend of an optically accurate spherical surface already obtained. The application of the results to the creation of an active control system for the shaping of the surface of a paraboloid of rotation is considered. The proposed finishing technology is aimed at solving the problem of guaranteed obtaining optically accurate surface of a parabolic mirror.


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