DYNAMIC TESTING OF PROTOTYPE PRESSURE CONTROLLED AIR DAMPER UNDER CYCLIC LOADING PROTOCOL

Abstract

Passive damping devices can effectively control the seismic structural response of the building in which they are fitted. The paper aims to develop a prototype Pneumatic Controlled Air Damper (PCAD) and study its hysteresis behaviour under cyclic displacement input under varying frequencies. A piston based pneumatic cylinder was used to fill with air under external pressure of 1.0 bar and 1.5 bar. The prototype PCAD device, so developed, exhibits elliptical shaped stable hysteresis loop under each displacement input frequency ensuring energy dissipation capabilities. The damper force produced by the PCAD increases with each frequency of displacement input as well as with the increase in the external pressure applied. The PCAD shows energy dissipation characteristics, measured by an equivalent viscous damping coefficient, ζ, improves with input motion frequencies but found to decrease with an increase in the external pressure. The PCAD works efficiently for low frequencies of displacement input.