Conservation of a slender historical Mamluk-style minaret by passive control techniques

2005 ◽  
Vol 12 (2) ◽  
pp. 157-177 ◽  
Author(s):  
A. G. El-Attar ◽  
A. M. Saleh ◽  
A. H. Zaghw
Keyword(s):  
Passive Control ◽  
Control Techniques

A Comparative Study of Mass Based Vibration Dampers

2017 ◽  
Author(s):  
Mohamed Gharib ◽  
Mansour Karkoub
Keyword(s):  
Comparative Study ◽  
Passive Control ◽  
Initial Conditions ◽  
Free Vibrations ◽  
Decay Rates ◽  
Coupled Systems ◽  
Primary System ◽  
Operating Personnel ◽  
Control Techniques ◽  
Dynamic Structures

Undesired vibrations in structures, buildings, and machines lead to reduction in the life of the system and greatly affects the safety of the occupying or operating personnel. In addition, economic and time losses could result from needed repairs or reconstruction. Many control techniques, active and passive, have been devised over the years to reduce/eliminate the vibrations in the aforementioned systems. Passive vibration control techniques are favorable over the active ones due to their simplicity, ease of implementation, cost, and power consumption. In dynamic structures, such as large buildings, passive control techniques are favored over their active counterparts. The most common types of passive control devices are tuned mass and impact dampers. The advocates of each of these devices boasts advantages of the others; however, there have been no systematic studies to compare and quantify the effectiveness of each of these types of devices as well as their suitability for specific applications. In this paper, a comparative study between the tuned mass dampers and impact dampers is conducted. A one-story structure is used to show the effectiveness of each of these devices in absorbing the vibrations of the structure. The coupled systems are modeled and simulated under free vibrations. The time responses are acquired using the same geometric parameters, excitation, and initial conditions. The comparisons are based on the settling time and amplitude decay rates of the primary system using each damper type. The numerical results show that both dampers can produce similar dampening effects if the parameters are optimized; however, correlating the dampers parameters is a challenging problem in the field of vibration and control.

Passive Control Techniques for Seismic Protection of Chemical Plants

2020 ◽  
Author(s):  
Keisuke Minagawa ◽  
Fabrizio Paolacci
Keyword(s):  
Passive Control ◽  
Base Isolation ◽  
Seismic Damage ◽  
Pressure Vessels ◽  
Chemical Plant ◽  
Seismic Protection ◽  
Economic Losses ◽  
Chemical Plants ◽  
Northridge Earthquake ◽  
Control Techniques

Abstract Seismic damage of chemical plant facilities (pressure vessels, piping, storage tanks, etc..) can causes human and economic losses as well as heavy environmental damages. Therefore, it is of paramount importance to reduce such a consequences. The passive control techniques (PCT) as dampers or base isolation can represent an effective technique to mitigate the major damage caused by earthquakes. Viscous dampers, tuned mass dampers and base isolators are well-known passive control devices successfully applied to civil structures, as demonstrated during the last big events as Northridge earthquake in 1994, the Kobe earthquake in 1995, the Great East Japan earthquake in 2011. The scarce application to major hazard industrial facilities as chemical plants poses some questions, including the selection of suitable devices, their real applicability and effectiveness, because of the strict requirements of chemical plant equipment in terms of safety and business continuity. Therefore, this study aim at analyzing the possible applications of the most renew passive control techniques for seismic protection for chemical plant components. In this respect, a complete review of typical seismic damage of industrial (chemical) facilities and the investigation of the applicability of PCT as mitigation strategy is offered for all possible structural typologies of units presents in a plant.

scholarly journals Advances in Structural Control in Civil Engineering in China

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Hongnan Li ◽  
Linsheng Huo
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Passive Control ◽  
Civil Engineering ◽  
State Of The Art ◽  
Semiactive Control ◽  
Engineering Structures ◽  
Future Directions ◽  
Control Techniques ◽  
Practical Engineering

In the recent years, much attention has been paid to the research and development of structural control techniques with particular emphasis on alleviation of wind and seismic responses of buildings and bridges in China. Structural control in civil engineering has been developed from the concept into a workable technology and applied into practical engineering structures. The aim of this paper is to review a state of the art of researches and applications of structural control in civil engineering in China. It includes the passive control, active control, hybrid controland semiactive control. Finally, the possible future directions of structural control in civil engineering in China are presented.

scholarly journals A Critical Review of Stall Control Techniques in Industrial Fans

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Stefano Bianchi ◽  
Alessandro Corsini ◽  
Anthony G. Sheard ◽  
Cecilia Tortora
Keyword(s):  
Control Systems ◽  
Passive Control ◽  
Control Strategies ◽  
Warning System ◽  
Detection Methods ◽  
Stall Inception ◽  
Stall Margin ◽  
Control Techniques ◽  
Control Technologies ◽  
And Control

This paper reviews modelling and interpretation advances of industrial fan stall phenomena, related stall detection methods, and control technologies. Competing theories have helped engineers refine fan stability and control technology. With the development of these theories, three major issues have emerged. In this paper, we first consider the interplay between aerodynamic perturbations and instability inception. An understanding of the key physical phenomena that occurs with stall inception is critical to alleviate stall by design or through active or passive control methods. We then review the use of passive and active control strategies to improve fan stability. Whilst historically compressor design engineers have used passive control techniques, recent technologies have prompted them to install high-response stall detection and control systems that provide industrial fan designers with new insight into how they may detect and control stall. Finally, the paper reviews the methods and prospects for early stall detection to complement control systems with a warning capability. Engineers may use an effective real-time stall warning system to extend a fan’s operating range by allowing it to operate safely at a reduced stall margin. This may also enable the fan to operate in service at a more efficient point on its characteristic.

The Optimal Control Method of Impulse Response in Prosthetic Leg

2014 ◽  
Vol 915-916 ◽  
pp. 1181-1185
Author(s):  
Xin Yi Xiao ◽  
Han Bin Xiao
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Impulse Response ◽  
Passive Control ◽  
Control Method ◽  
Control Variable ◽  
The Body ◽  
Control Techniques ◽  
Suspension Systems ◽  
Optimal Control Method

Passive control and semi-active control of vibration in mechanical systems have recently successfully been used in automobiles and airplanes suspension systems. These control techniques are able to guarantee the performances of all vibration structures. Unfortunately, the knowledge and data has not been readily applied to human prosthetics. The information collected can be directly applied to accelerate research into dampening for prosthetics. A focus of this paper is on modeling and controlling vibrations by a given impulse onto prosthetic legs. Simulations of using passive control and idealized skyhook dampening are using Matlab to complete. Through model analysis, control variable, simulation procedures and comparison of two modeling, the models have been refined and with idealized skyhook dampening suspension provide significant improvement of the body characteristics compared with passive suspensions.

Integrating Structure and Controller Design to Mechanical Systems via Decentralized Control Techniques

2015 ◽  
Author(s):  
Yilun Liu ◽  
Lei Zuo
Keyword(s):  
Mechanical System ◽  
Decentralized Control ◽  
Output Feedback ◽  
Optimization Problem ◽  
Passive Control ◽  
Design Method ◽  
Lagrange Function ◽  
Integrated Design ◽  
Feedback Controller ◽  
Control Techniques

The overall performance of the mechanical system can be significantly improved by concurrently optimizing the plant and the controller. This paper proposes a new integrated design method via decentralized control techniques to concurrently optimize the structure and the controller, which aims at minimizing the system H2 norm from the disturbance to the system cost. The integrated design problems have been formulated in the cases of a full state feedback controller and a full order output feedback controller respectively. Inspired by noticing that the control techniques are capable of optimizing both the parameters of passive springs and dampers and the controller for the mechanical system, we extend the current LTI control system to a more general framework suitable for the integrated design needs, where the structure design is treated as the passive control optimization tackled by decentralized control techniques with static output feedback, while the active controller is optimized by solving the modified Riccati equations. With the extended system framework, we transfer the original non-convex integrated optimization problem to an unconstrained optimization problem by introducing Lagrange multipliers and a Lagrange function. The gradient-based optimization method is employed to effectively find the optimality solution of the integrated design. Two design examples including an active-passive vehicle suspension system and an active-passive Tuned Mass Damper (TMD) system are designed by the proposed integrated design method. The improvement of the overall system performance due to the integrated design is also presented in comparison with the conventional design methods.

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