Characterization of fan blade vibration with a non-contact method

The aim of this work is to characterize the vibration parameters of plastic blades installed in a wind tunnel fan by means of a non-contact method, namely BTT (Blade Tip Timing). Chapter 2 is dedicated to the description of basic theory on the vibration of blades and disks. In Chapter 3 are presented the features of BTT system, including the working principle, a few analysis techniques, the instruments usually employed and some of the main sources of uncertainty. Chapter 4 is a complete description of the work done by the author in ITWL and AERMEC labs, focusing on the particular system analysed and on the techniques used. It is possible to distinguish two main activities: • FEM modeling of the system • BTT measurements and analysis of data The BTT method is applied in two different configurations and the results of both are presented.