Development of Electromagnetic Friction Dampers for Improving Seismic Performance of Civil Structures
type: CreativeWork
description: Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration can, for example, significantly affect the seismic response of a multi-story base-isolated building as it undermines the seismic isolation system by inserting high-frequency pulses into the floor acceleration. This may pump a considerable portion of the seismic input energy into higher modes, resulting in the increase of the floor inter-story drift. Therefore, a passive friction damper not only decreases the comfort of occupants but also increases the risk of damage to non-structural components during large earthquakes. The focus of this dissertation is on developing novel electromagnetic passive and semi-active friction dampers in which the undesirable effects of stick-slip motion are effectively reduced. The first part of this research focuses on the development of passive friction dampers for seismic hazard mitigation of civil structure. The first proposed passive friction damper, which is termed as passive electromagnetic eddy current friction damper (PEMECFD), utilizes a solid‐friction mechanism in parallel with an eddy current damping mechanism to maximize the dissipation of input seismic energy through a smooth sliding in the damper. In the proposed PEMECFD, friction force is produced through magnetic repulsive action between two permanent magnets (PMs) magnetized in the direction nor…
abstract: Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration can, for example, significantly affect the seismic response of a multi-story base-isolated building as it undermines the seismic isolation system by inserting high-frequency pulses into the floor acceleration. This may pump a considerable portion of the seismic input energy into higher modes, resulting in the increase of the floor inter-story drift. Therefore, a passive friction damper not only decreases the comfort of occupants but also increases the risk of damage to non-structural components during large earthquakes. The focus of this dissertation is on developing novel electromagnetic passive and semi-active friction dampers in which the undesirable effects of stick-slip motion are effectively reduced. The first part of this research focuses on the development of passive friction dampers for seismic hazard mitigation of civil structure. The first proposed passive friction damper, which is termed as passive electromagnetic eddy current friction damper (PEMECFD), utilizes a solid‐friction mechanism in parallel with an eddy current damping mechanism to maximize the dissipation of input seismic energy through a smooth sliding in the damper. In the proposed PEMECFD, friction force is produced through magnetic repulsive action between two permanent magnets (PMs) magnetized in the direction nor…
author: Amjadian, Mohsen
keywords: Eddy Current Damping, Electromagnetism, Friction, Passive control, Semi-active Control, Stick-slip motion, Acoustics, Dynamics, and Controls, Electro-Mechanical Systems, Structural Engineering
date published: 2019-01-01T08:00:00Z
date modified: 2026-07-24T01:57:21Z
provider: City University of New York - City College
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: City University of New York - City College