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 results are analyzed, and some important conclusions are drawn. It is found that dry friction between the dampers (or between damper and blade) is a very effective means of reducing the vibration of a blade.The resonance frequency, the response amplitude and the relative damping ratio can all be influenced by dry friction. High harmonic waves on the response of the blade which are caused by dry friction are observed in the test. However, the wave response of the damped blade is still basically harmonic. The normal force acting on the rub surfaces of the damped blade will influence the dynamic characteristics of the blade. Since the damped blade system is non-linear due to dry friction, the external exciting force can also influence the dynamic characteristics of the blade.