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The IUP Journal of Structural Engineering

Development and Characterization of Air and Nitrile Rubber-Based Prototype Passive Damping Devices

Article Details

Pub. Date	: Jan, 2024
Product Name	: The IUP Journal of Structural Engineering
Product Type	: Article
Product Code	: IJSE030124
Author Name	: Utsav K Koshti and Sharadkumar P Purohit
Availability	: YES
Subject/Domain	: Science and Technology
Download Format	: PDF Format
No. of Pages	: 23

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Abstract

Passive damping devices are a workable technology for structural response control of a variety of structures to seismic excitations. The paper develops a low-cost passive damping device using air and/or nitrile rubber flecks (NRF), a waste material from industries available locally. A prototype damping device comprising cylinder made from PVC pipe housing a piston with a rod with covered ends is fabricated. Entrapped air-cum-friction damper (EAFD) device has air entrapped in the cylinder subjected to sustained triangular, and ATC-24 displacement loading protocol offers force due to air compression and dissipates energy due to air viscosity and side wall friction. EAFD damper is further modified to include NRF of irregular shape on each side of the piston (EAFD-NRF), which might improve the energy dissipation capabilities of the device due to the porous form of the nitrile rubber. Both damping devices (EAFD and EAFD-NRF) are characterized under cyclic loading of different loading rates. It has been found that both passive damping devices show hysteresis behavior under cyclic displacement loading test performed pseudostatically. While the EAFD device sees energy dissipation by friction mechanism dominant over air viscosity, the EAFD-NRF device observes inelastic deformation of NRF leading to relatively lower energy dissipation vis-a-vis EAFD device due to the absence of a redispersion mechanism of NRF in the device. EAFD damper yields an average equivalent viscous damping ratio of 0.43, which is on a par with other metal-based passive damping devices.

Introduction

Many buildings and structures across the world have suffered varying degrees of damage, including complete collapse, during earthquakes. Besides their direct structural impact, earthquakes lead to substantial economic costs, infrastructure rebuilding, disrupted services, loss of business and temporary relocations (Park et al., 1986). Therefore, it is important to safeguard buildings and structures by