Development of a Multiple Modes Simulator of Rotating Bladed Assemblies for Blade Tip-Timing Data Analysis

Blade Tip Timing (BTT) is a promising technique for the measurement of blade-tip vibrations in bladed
assemblies. After an engine test is performed, the vibration’s Engine Order (EO) and amplitude information
is recovered from the collected BTT data using suitable analysis methods. The validation of such analysis
methods can be carried out more conveniently on simulated BTT data. In this paper, a BTT data simulator is
developed to produce controlled BTT data for bladed assemblies in which multiple modes of vibration are
excited. The mathematical model used allows for multiple blade modes and multiple assembly modes to be
simulated. Additionally, single or multiple, integral and non-integral EO excitations can be selected and the
rotational speed of the assembly can be varied linearly. Results from several test cases are shown,
demonstrating that the simulator successfully emulates assembly and blade mode combinations. A number of
BTT analysis methods were able to recover with accuracy the correct EOs from the simulated BTT data.