EXPERIMENTAL INVESTIGATION OF THE DYNAMIC CHARACTERISTICS OF THE DAMPED BLADE

The test facility and measurement system for the investigation of the dynamic characteristics of a damped blade are described. The test resu lts are analyzed, and some important conclusions are drawn. It is foun d that dry friction between the dampers (or between damper and blade) is a very effective means of reducing the vibration of a blade. The re sonance frequency, the response amplitude and the relative damping rat io can all be influenced by dry friction. High harmonic waves on the r esponse of the blade which are caused by dry friction are observed in the test. However, the wave response of the damped blade is still basi cally harmonic. The normal force acting on the rub surfaces of the dam ped blade will influence the dynamic characteristics of the blade. Sin ce the damped blade system is non-linear due to dry friction, the exte rnal exciting force can also influence the dynamic characteristics of the blade. (C) 1998 Academic Press Limited.