Actuator Bonding Optimization and System Control of a Rotor Blade Ultrasonic Deicing System

摘要

The use of ultrasonic excitation has shown the ability to promote ice shedding of impact ice (<2 mm thick) during prior wind tunnel testing efforts. The ultrasonic deicing technology is implemented to structures representative of rotorcraft blade leading edges and tested under impact icing and centrifugal environments (390 gs). Finite Element Models (FEM) are experimentally validated and used to predict the ultrasonic ice shedding transverse shear stresses responsible for ice shedding. The FEM tools are then utilized to guide the design of an optimized bondline between the PZT actuators and the host structure forming the ultrasonic deicing system. The novel bondline approach is implemented to a rotor blade leading edge erosion cap representative structure (0.813 mm thick stainless steel leading edge). The system is tested under centrifugal loads and icing conditions generic to helicopter operational envelopes. Details on the optimized system fabrication and integration are provided. The optimized bondline configuration does not degrade during operation and increases the ice interface transverse shear stresses by 15% with respect to prior bonding approaches. To promote ice shedding of impact ice, a system control to identify and excite optimum deicing modes during rotor ice testing is also implemented and described in this paper. The power consumption of the deicing system is quantified to average 0.63 W/cm2. The deicing system is able to promote shedding of ice layers ranging from 1.4 to 7.1 mm in thickness for varying icing conditions within FAR Part 25/29 Appendix: C Icing Envelope.