Hanging-chain impact dampers - A simple method for damping tall flexible structures

Abstract

This paper investigates a simple concept of achieving damping i n order t o suppress wind-induced oscillations of a class of erected structures such as antennas, stacks, and towers.It i s shown that a chain, covered with a rubber sleeve and suspended with freedom t o impact against a v e r t i c a l channel, i s capable of absorbing significant energy associated with transverse oscillations of the channel.t e r i s t i c s of such a damper are determined experimentally i n terms of mechanical impedance measurements.agreement with a simplified theory which i s derived on the basis of a singleparticle impact damper.launch vehicle increased t h e damping of t h e structure by a factor of up t o 3 . Results of t h i s generalized research study indicate that t h e performance ofhanging-chain impact dampers can be predicted with accuracy suitable f o r design purposes . The effects of various parameters on t h e performance charac-The experimental data are found t o be i n reasonable Chain dampers installed on a 70-foot-tall erected