Turbomachinery blades damping thanks to optimized shunted piezoelectric circuits

Abstract

Dynamics of gas-turbine blades are particularly aero-elastic coupling sensitive. These aerodynamic limits can be pushed away by adding extra damping to the structure in order to reach even better compressor performance. However nowadays design and manufacturing techniques in aero-mechanics are achieving their maximum of state-of-the-art. As in many fields active control would solve easily this kind of instability. But the diffculty remains in the needed energy supply for actuators whereas these components are aimed to be bonded on rotating structures. The capacity of different auto-supplied devices using shunted piezoelectric circuits had been studied here to prevent turbomachine bladed from fluttering. Before realizing the study on complex turbomachine geometries, the presented technique uses a numerical development thanks to a 1D Euler-Bernoulli beam model combining both mechanical and electrical coupling parameters. A second development thanks to a 3D model had been made using a commercial tool, Comsol software. These approximate models are used to optimize electrically the shunted piezoelectric element and its localization. The results, verified experimentally, let suppose that vibrations can be reduced signiffcantly when shunted piezoelectric circuits are mounted on a real structure.