Shunted Piezoelectric Control of Airfoil Vibrations

The application of shunted piezoelectric elements to provide passive structural damping is investigated by means of experiments performed in the Purdue High Speed Axial Compressor Research Facility. Piezoelectric elements are bonded to three airfoils in the stator row. This airfoil is excited by the wakes generated by an upstream rotor. As the wakes drive the airfoil vibrations, the piezoelectrics experience a strain and in response produce an electric field. Tuned electrical circuits connected to the piezoelectrics as shunts dissipate this electrical energy, with multiple shunting techniques utilized. This electrical energy dissipation and the corresponding reduction in the airfoil mechanical energy result in a reduction in the magnitude of the resonant vibrations. Thus, these passive vibration control experiments demonstrate that shunted piezoelectrics have significant damping capability and could be practical for the elimination or minimization of gas turbine blading flow induced vibrations.