Vibration Control of Jacket Platforms by DTMD System

2005 ◽  
Author(s):  
Dong Zhao ◽  
Rujian Ma ◽  
Weiqiang Wang ◽  
Dongmei Cai
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Frequency Ratio ◽  
Excitation Frequency ◽  
Fem Simulation ◽  
Mass Ratio ◽  
Control Effect ◽  
Theory Analysis ◽  
Additional Mass ◽  
Mass Damper

The turned mass damper (TMD) system has found extensive applications in vibration control nowadays. The main disadvantage of the system is to add additional mass to the structures. In order to make use of its merits and overcome its disadvantage, the developed turned mass damper (DTMD) vibration control system is studied in this paper. It uses the equipment set on the structure instead of additional mass to control the vibration of structures. The theory analysis shows that the frequency range is enlarged and the resonant band is reduced with the mass ratio increasing. The FEM simulation shows that the DTMD vibration control system could absorb more vibration energy when the frequency of the DTMD is near the excitation frequency. The platform has better vibration control effect when the mass ratio between 3.75 and 5 and when the frequency ratio is in the range of (0.3,0.35) and (0.35,0.5). The whole system, including the platform and the DTMD, has the smaller vibration response when the frequency ratio is between 0.5 and 2. The results of the simulation also showed that the DTMD is more effective in the vibration control for the jacket platforms.

scholarly journals Seismic Resistance and Parametric Study of Building under Control of Impulsive Semi-Active Mass Damper

2021 ◽  
Vol 11 (6) ◽  
pp. 2468
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
Frequency Ratio ◽  
Efficiency Index ◽  
Reduction Ratio ◽  
Seismic Resistance ◽  
Control Effect ◽  
Active Mass ◽  
High Rise ◽  
Mass Damper ◽  
Active Mass Damper ◽  
External Forces

When high-rise buildings are shaken due to external forces, the facilities of the building can be damaged. A Tuned Mass Damper (TMD) can resolve this issue, but the seismic resistance of TMD is exhausted due to the detuning effect. The Impulsive Semi-Active Mass Damper (ISAMD) is proposed with fast coupling and decoupling at the active joint between the mass and structure to overcome the detuning effect. The seismic proof effects of a high-rise building with TMD and ISAMD were compared. The numerical analysis results indicate that: (1) the reduction ratio of the maximum roof displacement response and the mean square root of the displacement reduction ratio of the building with the ISAMD were higher than 30% and 60%, respectively; (2) the sensitivity of the efficiency index to the frequency ratio of the ISAMD was very low, and detuning did not occur in the building with the ISAMD; (3) to achieve stable seismic resistance of the ISAMD, its frequency ratio should be between 2 and 4; (4) the amount of displacement of the control mass block of the ISAMD can be reduced by enhancing the stiffness of the auxiliary spring of the ISAMD; and (5) the proposed ISAMD has a stable control effect, regardless of the earthquake distance.

Vibration Control of Offshore Platforms Using a Wideband METMD System

2006 ◽  
Author(s):  
Dong Zhao ◽  
Rujian Ma ◽  
Dongmei Cai
Keyword(s):  
Vibration Control ◽  
Natural Frequency ◽  
Fem Simulation ◽  
Average Frequency ◽  
Offshore Platforms ◽  
Frequency Bandwidth ◽  
Wave Load ◽  
Control Effect ◽  
Exciting Frequency ◽  
Specific Frequency

A wideband multiple extended tuned mass dampers (METMD) system has been developed for reducing the multiple resonant responses of the platforms to all kinds of loads, such as earthquake, typhoon, tsunami and big ice load. This system is composed of several subsystems, each of which consists of one set of extended tuned mass damper (ETMD) unit covering a specific frequency bandwidth, and its average frequency is tuned to one of the first resonant frequencies of the platform. The offshore platform is simplified to a single degree-of-freedom (DOF) system to which a METMD subsystem (composed of m ETMDs) is attached and constitutes m+1 DOFs system. The total mass ratio of the METMD subsystem to the platform is 14% and the frequency ratio of the exciting frequency to the platform’s natural frequency varies in [0.5, 1.5]. The theory analysis shows that: 1) the platform has the better vibration control effect when the non-dimensional frequency bandwidth Ω, which is defined as the ratio of the frequency range to the controlled (target) platforms natural frequency, is in [0.35, 0.6]; 2) the damping coefficient ξ of ETMD systems is in [0.05, 0.15] and 3) the number of the ETMDs is 5 when Ω = 0.45 and ξ = 0.1. The FEM simulation shows that the METMD has a better vibration control effect on the mega-platforms’ vibration control under the random ocean wave load.

Theory and application of multi-mode vibration control systems

2012 ◽  
Vol 227 (1) ◽  
pp. 65-73
Author(s):  
Rujian Ma ◽  
Xiaobing Luo
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Parameter Optimization ◽  
Degree Of Freedom ◽  
Optimal Parameters ◽  
Control Effect ◽  
Mass Damper ◽  
Mode Vibration ◽  
Multi Mode ◽  
Dynamic Magnification Factor

The theoretical analysis of vibration control of multiple-degree-of-freedom structures with multi-mode vibration control systems is presented in this article. A new method of parameter optimization of the multiple-tuned mass damper system was proposed in order to obtain the best control effect, where the minimum of the dynamic magnification factor is used as the optimal objective. The numerical examples of parameter optimization indicate that optimal parameters can be obtained for the multiple-degree-of-freedom system to get satisfactory control effects. The application of the theory is used for the vibration control simulation of an offshore platform. The results indicate that reasonable control effects can be obtained by controlling the first mode and the control effects increase about 10% in average when the first two modes are controlled simultaneously.

Design of Suspension Vibration Control System Based on ON-OFF Algorithm

2012 ◽  
Vol 482-484 ◽  
pp. 1213-1217
Author(s):  
Jie Yue ◽  
Jin Qiu Zhang ◽  
Yong Qiang Gao ◽  
Zhi Zhao Peng ◽  
Zhi Tao Shi
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Suspension System ◽  
Signal Design ◽  
Single Chip ◽  
Control Effect ◽  
Damping Force ◽  
System A ◽  
Vehicle Suspension System ◽  
Control Accuracy

Aimed to satisfy damping force change requirement of vehicle MRF suspension vibration control system, a controller of MRF suspension system based on On-Off control algorithm is designed, and a control system is carried out. The system takes single chip AT90CAN128 which obey the CAN bus protocols as micro-controller, and it accomplish AD conversion of sensor signal, design of On-Off algorithm and output of PWM voltage power control signal. The system also is used in vibration control experiment of tracklayer vehicle suspension system. The experiment shows that the controller can improve control accuracy, and the control effect is obviously.

scholarly journals A Hybrid Tuned Mass Damper for Response Mitigation of Offshore Platforms

2022 ◽  
Author(s):  
Quoc Huong Cao
Keyword(s):  
Vibration Control ◽  
Tuned Mass Damper ◽  
Offshore Platforms ◽  
Structural Stiffness ◽  
Mass Ratio ◽  
Structural Vibrations ◽  
Numerical Computations ◽  
Tuned Liquid Column Damper ◽  
Parametric Investigation ◽  
Mass Damper

Abstract A new hybrid type of the Tuned Mass Damper (HTMD), which consists of a Tuned Liquid Column Damper (TLCD) fixed on the top of a traditional Tuned Mass Damper (TMD), is developed for vibration control of an offshore platform. The results obtained from the parametric investigation show that the mass ratio between TLCD and TMD significantly affects the HTMD's performance. To assess the effectiveness and robustness of HTMD, extensive comparisons are made between an optimized HTMD and an optimum TMD with the same weight as the HTMD. The numerical computations indicate that the proposed HTMD offers a higher level of effectiveness in suppressing structural vibrations compared with a traditional TMD. However, the optimum HTMD is not robust in resisting the variation of the structural stiffness.

Tuned mass damper asymmetric coupling system for vibration control of adjacent twin buildings

2019 ◽  
Vol 23 (5) ◽  
pp. 954-968
Author(s):  
Seung-Yong Ok
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Tuned Mass Damper ◽  
Independent Control ◽  
Control Approach ◽  
Coupling System ◽  
Mass Damper ◽  
Asymmetric Coupling ◽  
Coupling Approach ◽  
Twin Buildings

It is widely known that, in the vibration control problem of two adjacent structures, an inter-building coupling approach with the connecting damper is more efficient than an independent control approach with the bracing damper. However, the inter-building coupling approach is only valid for two different structures. When the two structures are twin, the existing inter-building coupling approach does not work properly due to the response symmetry of the twin structures. To overcome such limitations, this study proposes a new control approach based on the asymmetric coupling system where the twin buildings are coupled with the connecting damper and the additional damper is installed asymmetrically to perturb the symmetry of the twin structures. Under this intentional asymmetric condition, the proposed system can fully maintain the control efficiency of the conventional inter-building coupling approach. The tuned mass damper–based asymmetric coupling system is considered as a numerical example, and the independent control system with tuned mass damper is further taken into account for comparison purpose. For the optimal design of the proposed system, a multi-objective optimization technique was introduced, and the efficiency of the proposed approach has been investigated through the numerical simulations of the 10-story twin structures. By comparing the control performances of the optimal solutions between the proposed asymmetric coupling systems and the independent control system, it was verified that the proposed asymmetric coupling system can be a new efficient system for the vibration control of adjacent twin structures.

Research on active vibration control of flexible wing based on MFC actuator

2020 ◽  
Vol 64 (1-4) ◽  
pp. 565-571
Author(s):  
Yajun Luo ◽  
Fengfan Yang ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
...  
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Torsional Vibration ◽  
Fiber Composite ◽  
Active Vibration Control ◽  
Current Control ◽  
Control Effect ◽  
Flexible Wing ◽  
Control Scheme ◽  
Active Vibration

An active vibration control scheme was proposed based on Macro Fiber Composite (MFC) actuators for the bending and torsional vibration control of large flexible lightweight wing structures. Firstly, a finite element modeling and modal analysis of a flexible wing are carried out. Further, the number, type, and location distribution of the MFC actuators bonded on the supported beam of the wing are designed. Then, the actuated characteristics of the two kinds of MFC actuators required for bending and torsional vibration controls was theoretically analyzed. The simulation model of the overall vibration control system was also finally obtained. Finally, through ANSYS simulation analysis, the vibration control effect of the current control system on the first two-order low-frequency modal response of the wing structure is given. The simulation results show that the proposed active vibration control scheme has specific feasibility and effectiveness.

scholarly journals Exact Solutions for a Novel H2 Optimal Design of Electromagnetic Tuned Mass Damper

2021 ◽  
Author(s):  
Ge Li ◽  
Qibo Mao ◽  
Yifan Luo ◽  
Yong Wang ◽  
Lei Liu
Keyword(s):  
Vibration Control ◽  
Optimization Design ◽  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Parameters Optimization ◽  
Structural Vibration ◽  
Control Effect ◽  
Mass Damper ◽  
Two Parameters ◽  
H2 Optimization

To realize structural vibration control,a two parameters H2 optimization design was proposed to optimize the tuning ratio and damping ratio for electromagnetic tuned mass damper (EMTMD). The control effect of this two parameters optimization design is better than that of classical tuned mass damper (TMD).For this two parameters optimization,the most important thing is that the inductance of the coil can be set very small and the external load resistance can be positive ,which can avoid the use of complex negative impedance circuit. If Ref.[6] were designed according to the H2 optimization of two parameters, the EMTMD can be used for multi-modal vibration control of structures without connecting negative inductance and negative resistance spontaneously.

Vibration Control Effect Analysis on Tuned Mass Damper System Used in Urban Transportation

2012 ◽  
Vol 468-471 ◽  
pp. 1294-1299 ◽  
Author(s):  
Li Li ◽  
Chuan Zhi Geng ◽  
Ye Tian ◽  
Qing Yu
Keyword(s):  
Vibration Control ◽  
Impact Load ◽  
Effective Means ◽  
Urban Transportation ◽  
Tuned Mass Damper ◽  
Control Effect ◽  
Effect Analysis ◽  
Mass Damper ◽  
Reduction Effect ◽  
And Performance

With the development of urban transportation, vibration and noise control has attracted increasing attention. Vibration and noise level has become one of the important hallmarks of evaluating the influence of urban transportation to environment. As Tuned Mass Damper (TMD) is an effective means of vibration control, there is more and more emphasis on its research and application. Reasonably designed TMD can reduce vibration and noise caused by wheel/rail impact. So how to take into account the complex factors to improve the design of the TMD is still the important issue. TMD system is an effective structure. In order to study its vibration reduction effect, modal calculation and wheel-set drop simulation have been analyzed in this paper. Through varying the mass of TMD, the performance of vibration attenuation have been verified. The stability and performance of damping property under impact load have been confirmed by wheel-set drop simulation. Comparing the track which uses TMD and the normal one, the effect of TMD system can be testified effectively.

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