Research on Semi-Active Control of Large-Scale Aqueduct

2011 ◽  
Vol 194-196 ◽  
pp. 1997-2000
Author(s):  
Liang Huang ◽  
Bo Wang ◽  
Jian Guo Xu
Keyword(s):  
Active Control ◽  
Seismic Design ◽  
Theoretical Basis ◽  
Large Scale ◽  
Passive Control ◽  
Control Strategies ◽  
Active Method ◽  
Reference Base ◽  
Active Devices ◽  
Magneto Rheological

The magneto rheological damper (MRD) is employed to control the seismic response of large-scale aqueduct. The active control, semi-active control and passive control strategies are systematically compared, The results indicated that the magneto rheological dampers are effective in reducing the aqueduct response, the mitigation rate of semi-active control approaches with the active method The results from the present study may serve as a reference base for seismic design of large-scale aqueducts, and provide theoretical basis of aqueduct using semi-active devices.

Semi-Active Control for Large-Scale Aqueduct by MR Damper

2011 ◽  
Vol 204-210 ◽  
pp. 645-648
Author(s):  
Liang Huang ◽  
Bo Wang ◽  
Jian Guo Xu
Keyword(s):  
Active Control ◽  
Seismic Design ◽  
Mechanical Model ◽  
Large Scale ◽  
Mr Damper ◽  
Earthquake Excitation ◽  
Active Method ◽  
Reference Base ◽  
Active Devices ◽  
Magneto Rheological

The mechanical model of magneto rheological damper(MRD) is established, and the numerical simulation of seismic responses of aqueduct under earthquake excitation is performed with magneto rheological dampers. The results indicated that the magneto rheological dampers are effective in reducing the aqueduct response, the mitigation rate of semi-active control approaches with the active method The results from the present study may serve as a reference base for seismic design of large-scale aqueducts, and provide theoretical basis of aqueduct using semi-active devices.

Comparative research on semi-active control strategies for magneto-rheological suspension

2009 ◽  
Vol 59 (3) ◽  
pp. 433-453 ◽  
Author(s):  
Xiao-min Dong ◽  
Miao Yu ◽  
Chang-rong Liao ◽  
Wei-min Chen
Keyword(s):  
Active Control ◽  
Comparative Research ◽  
Control Strategies ◽  
Magneto Rheological

Validation and Implementation of Control Strategies for Liquid Composite Molding Processes

Materials ◽  
2003 ◽  
Author(s):  
Mathieu Devillard ◽  
Kuang-Ting Hsiao ◽  
Suresh G. Advani
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Control Strategies ◽  
Process Models ◽  
Injection System ◽  
Composite Part ◽  
Rtm Process ◽  
Flow Disturbances ◽  
Filling Time ◽  
Optimization Search

The manufacturing of polymeric composites ranges from using a rudimentary hand lay-up to the use of automated processes such as Liquid Composite Modeling (LCM) developed over the past decades in order to increase the yield of manufactured composite parts. In these processes, fiber preforms are placed in a closed mold and resin is infused into the mold to saturate the preform. After the resin cures, the mold is opened and the net shape composite part is demolded. However, by introducing more complexity into the part, one also introduces higher probability of flow disturbances, such as race tracking along preform edges, into the molding system. This can lead to incomplete saturation of fiber performs resulting in flaws such as dry spots in the composite part. The strength and existence of race-tracking is a function of the fabric type, perform manufacturing method, and its placement in the mold. It can vary from one part to the next in the same production run, and therefore it is not repeatable. In this work, after illustrating experimentally the unpredictability of variation of race-tracking and its influence on the flow, two approaches have been investigated and validated to address this issue associated with the variation of inherent disturbances in LCM processes. An active control strategy method using process models and simulations along with sensing and control to address flow disturbances during the impregnation stage of the process was shown to be reliable and effective for Resin Transfer Molding (RTM) process. In an attempt to improve the automation of RTM process, a modular RTM workstation including all hardware and software necessary to implement active control strategies for various part geometries and a novel injection system was designed and tested. In addition, a passive control method for Vaccum Assisted RTM (VARTM) aimed at optimizing the placement of distribution media for a given set-up in order to reduce dry spot formation and filling time was developed and validated experimentally. The optimization method employs numerical flow simulations and global optimization search techniques (Genetic algorithm) to generate the design for strategic flow control system.

scholarly journals Observation and assessment of crossing situations between pleasure craft and a small passenger ferry

2020 ◽  
Vol 19 (3) ◽  
pp. 337-355
Author(s):  
Kjell Ivar Øvergård ◽  
Marius Stian Tannum ◽  
Per Haavardtun
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Control Strategies ◽  
High Density ◽  
The Other ◽  
Right Of Way ◽  
The Right ◽  
Passenger Ferry

Abstract A study of navigational situations involving a small passenger ferry ‘Ole III’ was conducted based on participatory observations in the Husøysund strait in Tønsberg municipality, Norway. The aims were to document the extent to which crossing situations are solved according to navigational rules and practice, and to investigate the number of incidents which could pose a risk for Ole III and its passengers. Because of the high density of private pleasure craft, we expected a rather large number of non-compliance with navigational rules. Observations supported this assumption, and based on the total of 3152 crossings with Ole III where other vessels where present, a total of 279 (8.9%) incidents were considered to involve non-compliance with navigational rules and practice. A total of 165 incidents were caused by the other vessels failing to give way even though it had Ole III on its starboard side. This indicates that, at least in Norway, we may routinely expect pleasure craft to deviate from navigational rules for crossing situations. A number of incidents could partly be explained by a mismatch in understandings of which vessel had the right-of-way. Also, incident risk was higher when Ole III used active control strategies to handle crossing situations (e.g. keeping course and speed) as compared with passive control strategies. A taxonomy of situations based upon intentions is presented together with suggestions for control strategies for small passenger vessels that operate in waters with many pleasure craft.

Semi-Active Control for Benchmark Building Using Innovative TMD with MRE Isolators

2020 ◽  
Vol 20 (06) ◽  
pp. 2040009
Author(s):  
Xinchun Guan ◽  
Jingcai Zhang ◽  
Hui Li ◽  
Jinping Ou
Keyword(s):  
Active Control ◽  
Control Strategies ◽  
Variable Stiffness ◽  
Control Device ◽  
Structural Vibration ◽  
Control Force ◽  
Linear Quadratic ◽  
Structure System ◽  
Magneto Rheological ◽  
Active Damper

Tuned Mass Damper (TMD) with magneto-rheological elastomer isolators (MRE-TMD) is a novel control device for suppressing structural vibration caused by earthquakes. It is a nonlinear hybrid vibration absorber and the stiffness & damping can be controlled by changing the current of isolators’ coil. Using MRE-TMD as an adaptive frequency TMD to mitigate vibration and treating it as only a passive damper is the focus of most nowadays researches. In this paper, semi-active control theory is introduced to the MRE-TMD-structure system which means that the control force can be obtained through variable stiffness & damping technology, and MRE-TMD is a semi-active damper instead of a passive one. A control system sketch, as well as principles and control strategies of a semi-active MRE-TMD-structure system for vibration control is designed. An improved limited sliding (ILSL) algorithm based on linear quadratic optimal theory is also introduced. Numeric simulations of a five-story benchmark building model equipped with semi-active MRE-TMD subjected to several benchmark earthquake records are conducted to investigate the control performance of the proposed semi-active MRE-TMD. Control force characteristics of the structural MRE-TMD systems are also evaluated. The results indicate that semi-active MRE-TMD can provide control force to the system and it shows superior ability to suppress the structural vibrations of comparing to the passive MRE-TMD.

CONTROL OF WIND-INDUCED RESPONSE OF TRANSMISSION TOWER-LINE SYSTEM BY USING MAGNETORHEOLOGICAL DAMPERS

2009 ◽  
Vol 09 (04) ◽  
pp. 661-685 ◽  
Author(s):  
BO CHEN ◽  
JIN ZHENG ◽  
WEILIAN QU
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Control Strategies ◽  
Wind Loading ◽  
Induced Response ◽  
Strong Wind ◽  
Transmission Tower ◽  
Line System ◽  
Control Approach ◽  
Mr Dampers

Transmission tower-line system is a high-rise structure with low damping and it is therefore prone to strong wind excitation. In this paper, the control of wind-induced response of transmission tower-line system is carried out by using magnetorheological (MR) dampers. The effects of brace stiffness of damper are introduced and a multi-degree-of-freedom (MDOF) model is developed for both in-plane/out-of-plane vibration of transmission tower-line system. Two semi-active control strategies are proposed for the vibration mitigation of tower-line system. The first one is based on fixed increment of controllable damper force whereas the second one is a clipped-optimal strategy based on fuzzy control principle. The optimal parameters of the MDOF model of transmission line are investigated. A real transmission tower-line system constructed in China is taken as an example to examine the feasibility and reliability of the proposed approach. A parametric study is conducted for the effects of brace stiffness of MR damper, wind loading intensity, and parameters of MR fluids on the control performance. The results demonstrate that the incorporation of MR dampers into the transmission tower-line system can substantially suppress the wind-induced responses of transmission tower if the damper parameters are optimally determined. The performance of the two kinds of semi-active control approaches is better than that of a passive control approach.

Parametric Study of Damping Characteristics of Magneto-Rheological Damper: Mathematical and Experimental Approach

2020 ◽  
Vol 15 (3) ◽  
pp. 37-48
Author(s):  
Zubair Rashid Wani ◽  
Manzoor Ahmad Tantray
Keyword(s):  
Structural Control ◽  
Research Work ◽  
Testing Machine ◽  
Input Voltage ◽  
Damping Coefficient ◽  
Control Technique ◽  
Damping Force ◽  
Active Devices ◽  
Active Structural Control ◽  
Magneto Rheological

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

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