Vibration suppression of cables using tuned inerter dampers

I.F Lazar,S.A Neild,D.J Wagg

doi:10.1016/j.engstruct.2016.04.017

I.F Lazar, S.A Neild + Show 1 more

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https://doi.org/10.1016/j.engstruct.2016.04.017

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Abstract

This paper considers the use of a tuned inerter damper (TID) system for suppressing unwanted cable vibrations. The TID consists of an inerter, a device that exerts a force proportional to relative acceleration, coupled with a parallel spring and damper. It may be thought of as similar to a tuned-mass-damper, but requiring two terminals. As a two terminal device, the performance of the TID is compared to the classical use of viscous dampers (VD) located close to one of the cable supports. We show that the limitation that exists with VDs, where the modal damping of the cable cannot exceed a maximum level for a given damper location, can be overcome through the use of the TID at the same location. A practical design methodology, based on the minimisation of the displacement amplitude at the mid-span of the cable subjected to support excitation, is proposed. An example where a cable is subjected to the El-Centro earthquake demonstrates that the system’s response is improved when a TID is used instead of a VD.

Highlights

Cables are widely used structural elements capable of bearing tensile forces
This paper proposed the use of tuned inerter dampers for cable vibration suppression, with the TIDs located in the vicinity of the cable support, as an alternative to the use of dampers
TIDs offer a promising alternative to tuned mass dampers (TMD) due to the fact that inerters, which generate a force proportional to the relative acceleration, are geared and can generate a far larger apparent mass than the actual device mass; ratios of 200:1 have been reported

Summary

Introduction

Cables are widely used structural elements capable of bearing tensile forces. Cables experience vibration problems due to their very low damping. The problems associated with cable vibration are especially important for bridge design and retrofitting. Bridge cables are subject to vibrations induced by wind, wind-rain, traffic and earthquakes. These unwanted vibrations need to be reduced to acceptable levels. Irvine gives an overview of cable dynamics in [1]. Rega published a review on the nonlinear vibrations of suspended cables in [2,3]

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