# Experimental Study of a Piezoelectric De-Icing System Implemented to Rotorcraft Blades
###### Abstract  
A four-year project investigating the use of piezoelectric actuators as a vibration-based low power de-icing system has been initiated at the Anti-Icing Materials Laboratory. The work done preceding this investigation consisted of studying, numerically and experimentally, the system integration to a flat plate structure, the optimal excitation of the system, the resonant structural modes and the shear stress amplitudes to achieve de-icing for that structure. In this new investigation, the concepts and conclusions obtained on the flat plate structure were used to design and integrate the system into a rotating blade structure. An experimental setup was built for de-icing tests in rotation within an icing wind tunnel, and a finite-element numerical model adapted to the new geometry of the blade was developed based on the expertise accumulated using previous flat plate structure analysis. Complete de-icing of the structure was obtained in the wind tunnel using the developed de-icing system, and its power consumption was estimated. The power consumption was observed to be lower than the currently used electrothermal systems. The finite-elements numerical model was therefore used to study the case of a full-scale tail rotor blade and showed that the power reduction of the system could be significantly higher for a longer blade, confirming, therefore, the relevance of further de-icing investigations on a full-scale tail rotor.  
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study, cracking was obtained due to tensile stress, which also leads to the delamination zone following the crack propagation. An ANSYS model was developed by [PERSON] et al. [14], which also demonstrated that delamination is caused by shear stress at the ice/substrate interface and that it is initiated at the edges of the ice layer. Finally, [PERSON] [15] and [PERSON] [16] confirmed the validity of this concept by successfully achieving total de-icing of a static actual tail rotor blade structure.  
The present study represents an incremental improvement and complexification of previously presented experimental and Finite-Elements Analysis (FEA)-based numerical investigations where the principle of the proposed design method was demonstrated using a simple flat plate structure. The results of these experiments were published in [17; 18; 19], where a comprehensive literature study was presented, and the optimal integration and excitation of the actuators, the steady-state and transient vibration response and the stresses involved in icebreaking were extensively studied experimentally and numerically. In this new study, the developed and demonstrated concept was applied to a more complex structure, e.g., a rotating small-scale 22.9 cm (9 inches) long blade setup.  
A new experimental setup was designed for testing the piezoelectric de-icing system integrated into a blade in rotation in an icing wind tunnel. An FEA-based numerical model was adapted to the new geometry of the blade, and the new experimental setup was developed based on the expertise accumulated previously. The model was used to determine the frequencies and shape of the structural resonant modes susceptible to generating de-icing of the blade. The FEA-based numerical model was used at several stages of this study, allowing the design of the optimal positioning and excitation of the actuators to investigate shear stresses and obtain useful conclusions. Complete de-icing of the blade was successfully achieved experimentally, and the power consumption of the system showed a reduction compared to electrothermal systems. The numerical model was, therefore, further modified to simulate a full-scale, 0.60 m long, tail rotor blade leading edge, using the information obtained from the small-scale model, and demonstrated that the power reduction could be significantly greater on the full-scale blade, demonstrating the relevance of further developments on a full-scale blade.