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.

scholarly journals A Critical Review of Supersonic Flow Control for High-Speed Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig
Keyword(s):  
Supersonic Flow ◽  
Flow Control ◽  
Active Control ◽  
Critical Review ◽  
High Speed ◽  
Passive Control ◽  
Control Method ◽  
Sudden Expansion ◽  
Control Approach ◽  
Cost Efficient

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.

A shuffled frog-leaping algorithm based mixed-sensitivity H∞ control of a seismically excited structural building using MR dampers

2017 ◽  
Vol 24 (13) ◽  
pp. 2832-2852 ◽  
Author(s):  
Xiufang Lin ◽  
Shumei Chen ◽  
Guorong Huang
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Structural Parameters ◽  
Mr Damper ◽  
Inverse Model ◽  
Shuffled Frog Leaping Algorithm ◽  
Weighting Functions ◽  
Inference System ◽  
Mr Dampers ◽  
Shuffled Frog Leaping

An intelligent robust controller, which combines a shuffled frog-leaping algorithm (SFLA) and an H∞ control strategy, is designed for a semi-active control system with magnetorheological (MR) dampers to reduce seismic responses of structures. Generally, the performance of mixed-sensitivity H∞ (MSH) control highly depends on expert experience in selecting the parameters of the weighting functions. In this study, as a recently-developed heuristic approach, a multi-objective SFLA with constraints is adopted to search for the optimal weighting functions. In the proposed semi-active control, firstly, based on the Bouc–Wen model, the forward dynamic characteristics of the MR damper are investigated through a series of tensile and compression experiments. Secondly, the MR damper inverse model is developed with an adaptive-network-based fuzzy inference system (ANFIS) technique. Finally, the SFLA-optimized MSH control approach integrated with the ANFIS inverse model is used to suppress the structural vibration. The simulation results for a three-story building model equipped with an MR damper verify that the proposed semi-active control method outperforms fuzzy control and two passive control methods. Besides, with the proposed strategy, the changes in structural parameters and earthquake excitations can be satisfactorily dealt with.

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.

Damage Inspection and Assessment on a Transmission Angle Tower in Coastal Areas

2013 ◽  
Vol 671-674 ◽  
pp. 650-654
Author(s):  
Peng Yun Li ◽  
Bo Chen ◽  
Yu Zhou Sun
Keyword(s):  
Structural Model ◽  
Wind Loading ◽  
Transmission Tower ◽  
Line System ◽  
Steel Material ◽  
Transmission Angle ◽  
Commercial Package ◽  
Loading Effects ◽  
Structural Responses ◽  
Element Approach

The field inspection and safety assessment of a transmission angle tower are actively carried out in this study. The field measurement and inspection are firstly introduced and then the structural model is constructed based on finite element approach with the aiding of commercial package ANSYS. The equation of motion of the transmission tower-line system is established for numerical analysis. The gravity, base settlement and dynamic wind loading are applied on the tower to examine the structural responses. The deformation and stresses distribution of the transmission angle tower are computed to explore the damage reasons. The made observations indicate that the peak stresses of some members are large than the permitted yielding stresses of steel material. The damage event is induced by coupling loading effects

Active Control of a Circular Membrane to Reduce Transient Noise Transmission

1995 ◽  
Vol 117 (3A) ◽  
pp. 252-258 ◽  
Author(s):  
J. L. van Niekerk ◽  
B. H. Tongue
Keyword(s):  
Feedback Control ◽  
Active Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Circular Membrane ◽  
Velocity Feedback ◽  
Circular Duct ◽  
Control Approach ◽  
Noise Transmission

An active control approach that reduces transient noise transmission through a membrane in a circular duct is presented. Discrete sections of piezo-electrical film, PVDF, are used as actuators to adjust the tension of the membrane. Different control strategies, such as optimal, sliding mode and velocity feedback control, are investigated analytically and then implemented experimentally. It is shown that velocity feedback control is the more effective, stable controller for this application.

scholarly journals Random Wind-induced Response Analysis of Transmission Tower-line System

2012 ◽  
Vol 16 ◽  
pp. 1813-1821 ◽  
Author(s):  
Qin Li ◽  
Yuan Junjian ◽  
Li Wei
Keyword(s):  
Induced Response ◽  
Response Analysis ◽  
Transmission Tower ◽  
Line System

Wind-Induced Progressive Collapsed Performance of Cup-Type Transmission Tower-Line System

2013 ◽  
Vol 353-356 ◽  
pp. 2392-2396
Author(s):  
Zhuo Qun Zhang ◽  
You Xin Lin ◽  
Hong Nan Li
Keyword(s):  
Progressive Collapse ◽  
Finite Element Models ◽  
Strong Wind ◽  
Transmission Tower ◽  
Line System ◽  
System Collapse ◽  
Simulation Results ◽  
Element Technique ◽  
Simulated Wind ◽  
Collapse Process

The Cup-type transmission tower-line system was a classic representative of high voltage electric power carrier, which was an important lifeline project. However, it frequently collapsed under different environmental loadings, especially strong wind. In this work, four tower five line finite element models simulated wind-induced progressive collapse process by birth-to-death element technique in ABAQUS/Explicit. The numerical simulation results demonstrated that this application could describe the structural collapse performance clearly and effectively and transmission tower-line system collapse path depended on the number, position and last deformation of damage elements.

scholarly journals Investigation and Development of a Three-Dimensional Transmission Tower-Line System Model Using Nonlinear Truss and Elastic Catenary Elements for Wind Loading Dynamic Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-29
Author(s):  
Xiao Zhu ◽  
Ge Ou
Keyword(s):  
Transmission Line ◽  
Open Source ◽  
Three Dimensional ◽  
Initial Strain ◽  
Wind Loading ◽  
Transmission Line Model ◽  
Transmission Tower ◽  
Line Model ◽  
Line System ◽  
Truss Element

The accuracy of transmission tower-line system simulation is highly impacted by the transmission line model and its coupling with the tower. Owing to the high geometry nonlinearity of the transmission line and the complexity of the wind loading, such analysis is often conducted in the commercial software. In most commercial software packages, nonlinear truss element is used for cable modeling, whereas the initial strain condition of the nonlinear truss under gravity loading is not directly available. Elastic catenary element establishes an analytical formulation for cable structure under distributed loading; however, the nonlinear iteration to reach convergence can be computational expensive. To derive an optimal transmission tower-line model solution with high fidelity and computational efficiency, an open-source three-dimensional model is developed. Nonlinear truss element and elastic catenary element are considered in the model development. The results of the study imply that both elements are suitable for the transmission line model; nevertheless, the initial strain in nonlinear truss element largely impacts the model accuracy and should be calibrated from the elastic catenary model. To cross-validate the developed models on the coupled transmission tower and line, a one-span eight-line system is modeled with different elements and compared with several state-of-the-art commercial packages. The results indicate that the displacement time-history root-mean-square error (RMSE) of the open-source transmission tower-line model is less than 1 % and with a 66 % computational time reduction compared with the ANSYS model. The application of the open-source package transmission tower-line model on extreme wind speed considering the aerodynamic damping is further implemented.

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.

Analytical Study on Wind-Induced Vibration and its Control of Transmission Towers in Mountainous Area

2011 ◽  
Vol 105-107 ◽  
pp. 635-639
Author(s):  
Zheng Yi Sheng ◽  
Chun Xia ◽  
Wei Ping Xu ◽  
Peng Yun Li
Keyword(s):  
Induced Response ◽  
Mountainous Area ◽  
Superposition Method ◽  
Transmission Tower ◽  
Control Effect ◽  
Line System ◽  
Viscoelastic Dampers ◽  
Transmission Towers ◽  
Out Of Plane ◽  
Wind Induced Vibration

A method for analyzing wind-induced vibration and its control of transmission tower-line system in mountainous area is described. The method is applied to a real transmission line containing two self-supporting steel angle towers, 3 spans of conductors and ground lines together with insulators. Analyses are conducted for the out-of-plane wind direction, and the fluctuating wind load on tower-line system is simulated by harmony superposition method and davenport spectrum. The numerical results indicate that the wind-induced response and its control effect are mainly related to the stiffness of the towers, rather than the mounting height or the spans of the power lines. At the same time, viscoelastic dampers fixed on the main members can suppress the wind-induced displacement of the towers effectively.

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