Title

A novel tuned visco-elastic damper for floor vibration abatement

Date of Award

2009

Degree Name

Ph.D. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Advisor: Reza Kashani

Abstract

The main goal is to study the viability of tuned dampers with VE polymers as their damping or combined damping and resilient element(s) for dampening large civil engineering structures with emphasis on floors. Two design configurations are pursued in this study using both numerical (FEA) and experimental techniques. The first configuration relies on the VE polymer mainly as the damper and uses a leaf spring as the elastic element (design A, also dubbed sandwich beam design) and the other relies on VE polymer as both spring and damper (design B). In exploring design A, based on sandwiching VE material between two layers of steel beams commonly used in realizing small tuned VE dampers, a large number of iterations varying the thickness and width of VE material were analyzed using FEA. All the analyses indicating insufficient damping commensurate with high stiffness requirement of large TMDs; the numerical predications were verified experientially. Considering the fact that VE material is mainly responsible for providing damping in this design, not stiffness, a relatively small volume of this material was needed to realize a realistic TMD, resulting in inadequate damping. Design B, a novel design using VE rubber rings as the resilient and damping element constrained by thin aluminum rings between layers, turned out to be a quite promising TMD for dampening civil engineering structures. The aluminum layers are to enhance the shear deformation mechanism in the VE ring; in addition, with proper thickness they would help removing the heat from the VE material preventing an undesirable rise in their temperature. The effectiveness of this design in terms of their load carrying capacity and damping is numerically analyzed using the ABAQUS finite element software package. The analytical results are validated experimentally in the laboratory; the frequency response function plots show a good agreement between the numerical and experimental results with various number of the rubber ring layers. Damping ratios in excess of 30% are achieved using six VE rubber ring layers.

Keywords

Commercial buildings Vibration, Damping (Mechanics), Structural control (Engineering), Rubber Testing, Polymers Testing, Viscoelasticity

Rights Statement

Copyright 2009, author

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