Vibration of a Loosely Held Tube

Abstract

The results of a series of over 700 measurements of the tube damping and natural frequency of heat exchanger tubes are presented. The damping and frequency measurements of the loosely held tube show considerable scatter. Damping increased slightly with increasing excitation force or decreasing preload applied to the tube. Increasing the proportion of the tube length held in the support strongly increased damping. Third mode vibrations were more lightly damped than first mode vibrations. The resonance frequency increased with static preload applied to the tube.