A genetic algorithm–based design approach for smart base isolation systems

2017 ◽  
Vol 29 (7) ◽  
pp. 1315-1332 ◽  
Author(s):  
Mohtasham Mohebbi ◽  
Hamed Dadkhah ◽  
Hamed Rasouli Dabbagh
Keyword(s):  
Genetic Algorithm ◽  
Optimization Problem ◽  
Base Isolation ◽  
Design Procedure ◽  
Design Parameters ◽  
Linear Quadratic ◽  
Isolation System ◽  
Isolation Systems ◽  
Magneto Rheological ◽  
Smart Base Isolation

This article presents a new approach for designing effective smart base isolation systems composed of a low-damping linear base isolation and a semi-active magneto-rheological damper. The method is based on transforming the design procedure of the hybrid base isolation system into a constrained optimization problem. The magneto-rheological damper command voltages have been determined using H2/linear quadratic Gaussian and clipped-optimal control algorithms. Through a sensitivity analysis to identify the effective design parameters, base isolation and control algorithm parameters have been taken as design variables and optimally determined using genetic algorithm. To restrict increases in floor accelerations, the objective function of the optimization problem has been defined as minimizing the maximum base drift while putting specific constraint on the acceleration response. For illustration, the proposed method has been applied to design a semi-active hybrid isolation system for a four-story shear building under earthquake excitation. The results of numerical simulations show the effectiveness, simplicity, and capability of the proposed method. Furthermore, it has been shown that using the proposed method, the acceleration of the isolated structure can also be incorporated into design process and practically controlled with a slight sacrifice of control effectiveness in reducing the base drift.

scholarly journals Optimal Response-Related Weighting Matrices to Control Semi-Active Base Isolation Systems

2017 ◽  
Vol 25 (2) ◽  
pp. 24-32
Author(s):  
Hamed Dadkhah ◽  
Mahsa Noruzvand
Keyword(s):  
Base Isolation ◽  
Linear Quadratic ◽  
Isolation System ◽  
Design Objective ◽  
Optimal Force ◽  
Base Isolation System ◽  
Isolation Systems ◽  
Magneto Rheological ◽  
Shear Frame ◽  
Active Base

Abstract In this paper, the performance of a semi-active base isolation system, including a magneto-rheological (MR) damper and base isolation system for different combinations of response-related weighting matrices, has been studied. To consider all possible sets of response-related matrices, seven H2/linear quadratic Gaussian (LQG) control designs have been considered. For a numerical simulation, a six-story shear frame has been subjected to different earthquakes, and the performance of the control system has been evaluated. The results show that the optimal force-related weighting parameter is identical for different sets of response-related weighting matrices and is also independent of earthquake records when minimizing the maximum base drift is considered as the design objective. Also, the results of different sets of response-related weighting matrices show that the optimal sets for the design objective of minimizing the maximum base drift are the velocity and displacement/velocity-related weighting matrices.

A feasibility study on smart base isolation systems using magneto-rheological elastomers

2009 ◽  
Vol 32 (6) ◽  
pp. 755-770 ◽  
Author(s):  
Jeong-Hoi Koo ◽  
Dong-Doo Jang ◽  
Muhammad Usman ◽  
Hyung-Jo Jung
Keyword(s):  
Feasibility Study ◽  
Base Isolation ◽  
Isolation Systems ◽  
Magneto Rheological ◽  
Smart Base Isolation

Dynamic Analysis of a Smart Base-Isolation System Based on MR Elastomers

2010 ◽  
Author(s):  
Hyung-Jo Jung ◽  
Jeong-Su Park ◽  
Jeong-Hoi Koo
Keyword(s):  
Smart Materials ◽  
Base Isolation ◽  
Dynamic Performance ◽  
Building Structure ◽  
Seismic Excitations ◽  
Isolation System ◽  
Base Isolation System ◽  
Magneto Rheological ◽  
Shear Building ◽  
Smart Base Isolation

This paper presents a numerical investigation of a smart base isolation system employing magneto-rheological (MR) elastomers or an MR elastomer-based base isolation system. MR elastomers are a new class of smart materials whose elastic modulus or stiffness can be adjusted depending on the magnitude of the applied magnetic field. Hence, they can be used as controllable stiffness elements in engineering systems. The primary goal of this study is to investigate the dynamic performance of the smart base-isolation in mitigating excessive vibrations of a building structure under earthquake loadings. To this end, a five-story shear building model coupled with a smart base-isolation is developed. Using this model, a series of numerical simulations is performed to evaluate the effectiveness of the MR elastomer-based base isolation system under several historic seismic excitations. The results show that the proposed base isolation system outperform the conventional passive-type base isolation system in reducing the responses of the building structure for all seismic excitations considered in this study.

Genetic Algorithm Based Optimum Semi-Active Control of Building Frames Using Limited Number of Magneto-Rheological Dampers and Sensors

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Vishisht Bhaiya ◽  
S. D. Bharti ◽  
M. K. Shrimali ◽  
T. K. Datta
Keyword(s):  
Genetic Algorithm ◽  
Active Control ◽  
Optimization Problem ◽  
Numerical Study ◽  
Accurate Estimation ◽  
Computationally Efficient ◽  
Linear Quadratic ◽  
Building Frames ◽  
Mr Dampers ◽  
Magneto Rheological

Optimum semi-active control with a limited number of magneto-rheological (MR) dampers and measurement sensors has certain requirements. Most important of them is the accurate estimation of control forces developed in the MR dampers from the observations made in the structure. Therefore, the observation strategy should form an integral part of the optimization problem. The existing literature on the subject does not address this issue properly. The paper presents a computationally efficient optimization scheme for semi-active control of partially observed building frames using a limited number of MR dampers and sensors for earthquakes. The control scheme duly incorporates the locations of measurement sensors as variables into the genetic algorithm (GA) based optimization problem. A ten-storied building frame is taken as an illustrative example. The optimum control strategy utilizes two well-known control laws, namely, the linear quadratic Gaussian (LQG) with clipped optimal control and the bang-bang control to find the time histories of voltage to be applied to the MR dampers. The results of the numerical study show that the proposed scheme of sensor placement provides the optimum reduction of response with more computational efficiency. Second, optimal locations of sensors vary with the response quantities to be controlled, the nature of earthquake, and the control algorithm. Third, optimal locations of MR dampers are invariant of the response quantities to be controlled and the nature of earthquake.

Hysteresis Loops of Base Isolation System - An Overview

2021 ◽  
Vol 879 ◽  
pp. 189-201
Author(s):  
M.A. Amir ◽  
N.H. Hamid
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Base Isolation ◽  
Numerical Models ◽  
Hysteresis Loops ◽  
Human Beings ◽  
Rc Buildings ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Systems

Recently, there are a lot of technological developments in the earthquake engineering field to reduce structural damage and one of them is a base isolation system. The base isolation system is one of the best technologies for the safety of human beings and properties under earthquake excitations. The aim of this paper is to review previous research works on simulation of base isolation systems for RC buildings and their efficiency in the safety of these buildings. Base isolation decouples superstructure from substructure to avoid transmission of seismic energy to the superstructure of RC buildings. The most effective way to assess the base isolation system for RC building under different earthquake excitations is by conducting experiment work that consumes more time and money. Many researchers had studied the behavior of base isolation system for structure through modeling the behavior of the base isolation in which base isolator is modeled through numerical models and validated through experimental works. Previous researches on the modeling of base isolation systems of structures had shown similar outcomes as the experimental work. These studies indicate that base isolation is an effective technology in immunization of structures against earthquakes.

Effects of Damper Force Ranges and Ground Motion Pulse Periods on the Performance of Semi-Active Isolation Systems

2003 ◽  
Author(s):  
Henri Gavin ◽  
Julie Thurston ◽  
Chicahiro Minowa ◽  
Hideo Fujitani
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Base Isolation ◽  
Near Field ◽  
Shaking Table ◽  
Isolation System ◽  
Active Isolation ◽  
Isolation Systems ◽  
Fail Safe ◽  
Strong Ground

A large-scale base-isolated steel structural frame was tested at the shaking table laboratory of the National Research Institute for Earth Sciences and Disaster Prevention. These collaborative experiments featured auto-adaptive media and devices to enhance the performance of passive base isolation systems. The planning of these experiments involved determining appropriate device control methods, the development of a controllable damping device with fail-safe characteristics, and the evaluation of the performance of the controlled isolation system subjected to strong ground motion with pronounced near-field effects. The results of the planning study and their large-scale experimental confirmation provide guidelines for the development and implementation of auto-adaptive damping devices for full scale structures.

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