scholarly journals Optimal Design Criteria for Isolation Devices in Vibration Control

10.5772/9742 ◽  
2010 ◽  
Author(s):  
Sara Sgobba ◽  
Giuseppe Carlo
Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Akira Fukukita ◽  
Katsuaki Sunakoda

We address a simultaneous optimal design problem of a semi-active control law and design parameters in a vibration control device for civil structures. The Vibration Control Device (VCD) that is being developed by authors is used as the semi-active control device in the present paper. The VCD is composed of a mechanism of a ball screw with a flywheel for the inertial resistance force and an electric motor with an electric circuit for the damping resistance force. A new bang-bang type semi-active control law referred to as Inverse Lyapunov Approach is proposed as the semi-active control law. In the Inverse Lyapunov Approach the Lyapunov function is searched so that performance measures in structural vibration control are optimized in the premise of the bang-bang type semi-active control based on the Lyapunov function. The design parameters to determine the Lyapunov function and the design parameters of the VCD are optimized for the good performance of the semi-active control system. The Genetic Algorithm is employed for the optimal design.


2018 ◽  
Vol 57 (1) ◽  
pp. 134-159 ◽  
Author(s):  
Wei Liu ◽  
Hongwen He ◽  
Fengchun Sun ◽  
Hong Wang

2019 ◽  
Vol 25 (6) ◽  
pp. 1133-1147 ◽  
Author(s):  
Francielly Elizabeth de Castro Silva ◽  
Carlos Alberto Bavastri

Dynamic vibration absorbers are simple mechanical devices that are attached to a structure aiming at reducing vibration levels. Designing such devices for vibration control of mechanical systems using viscoelastic materials results in low costs, easy construction, and higher efficacy due to their ability to dissipate vibration energy. In this context, the present study aims at developing a methodology for an optimal design of a set of viscoelastic dynamic absorbers considering their natural frequencies, the positions to attach them onto the structure to be controlled, and the viscoelastic materials as variables to be optimized for different working temperatures. The optimal configuration is obtained by applying a hybrid optimization technique, which uses genetic algorithms (considering continuous and discrete variables in the same design vector) aiming at approximating the global minimum point and, subsequently, a nonlinear programming method (simplex based on the Nelder–Mead method) to perform a local search. An example of dynamic absorber design to reduce vibration levels in a one-degree-of-freedom (DOF) system and on a steel plate (multiple-DOFs) is presented. The results show the efficacy of the methodology for passive control of vibrations acting on a broadband of frequencies and different temperatures.


2019 ◽  
Vol 11 (10) ◽  
pp. 2801 ◽  
Author(s):  
Chao Wang ◽  
Weixing Shi

Slender steel footbridges suffer excessive human-induced vibrations due to their low damping nature and their frequency being located in the range of human-induced excitations. Tuned mass dampers (TMDs) are usually used to solve the serviceability problem of footbridges. A multiple TMD (MTMD) system, which consists of several TMDs with different frequencies, has a wide application in the vibration control of footbridges. An MTMD system with well-designed parameters will have a satisfactory effect for vibration control. This study firstly discusses the relationship between the acceleration dynamic amplification factor and important parameters of an MTMD system, i.e., the frequency bandwidth, TMD damping ratio, central frequency ratio, mass ratio and the number of TMDs. Then, the frequency bandwidth and damping ratio optimal formulas are proposed according to the parametric study. At last, an in-service slender footbridge is proposed as a case study. The footbridge is analyzed through a finite element model and an in situ test, and then, an MTMD system is designed based on the proposed optimal design formulas. The vibration control effect of the MTMD system is verified through a series of in situ comparison tests. Results show that under walking, running and jumping excitations with different frequency, the MTMD system always has an excellent vibration control effect. Under a crowd-induced excitation with the resonance frequency, the footbridge with an MTMD system can meet the acceleration limit requirement. It is also found that the analysis result agrees well with the in situ test.


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