Numerical and Experimental Investigation of the Design of a Piezoelectric De-Icing System for Small Rotorcraft Part 3/3: Numerical Model and Experimental Validation of Vibration-Based De-Icing of a Flat Plate Structure

Abstract

The objective of this research project is divided in four parts: (1) to design a piezoelectric actuator-based de-icing system integrated to a flat plate experimental setup and develop a numerical model of the system with experimental validation, (2) use the experimental setup to investigate actuator activation with frequency sweeps and transient vibration analysis, (3) add an ice layer to the numerical model and predict numerically stresses at ice breaking with experimental validation, and (4) bring the concept to a blade structure for wind tunnel testing. This paper presents the third part of the investigation in which an ice layer is added to the numerical model. Five accelerometers are installed on the flat plate to measure acceleration. Validation of the vibration amplitude predicted by the model is performed experimentally and the stresses calculated by the numerical model at cracking and delamination of the ice layer are determined. A stress limit criteria is then defined from those values for both normal stress at cracking and shear stress at delamination. As a proof of concept, the numerical model is then used to find resonant modes susceptible to generating cracking or delamination of the ice layer within the voltage limit of the piezoelectric actuators. The model also predicts a voltage range within which the ice breaking occurs. The experimental setup is used to validate positively the prediction of the numerical model.

Experimental Study of a Piezoelectric De-Icing System Implemented to Rotorcraft Blades

“…Table 7 shows the shear stress calculated using the numerical model. The numerical model prediction for delamination was between 0.20 and 0.35 MPa, which was in the 0.20 to 0.90 MPa range obtained previously [19], meaning that the numerical model stress predictions are in accordance with what was obtained using the flat plate setup. No cracking, only delamination, of the ice layer was predicted by the numerical model and no cracking, only delamination was obtained experimentally.…”

“…However, they are excited, at the same voltage, and in counter phase with the actuators on the other side of the backslash. The ice delamination is predicted to be achieved when the calculated numerical shearing stress values at the ice substrate interface are within the yield limit range defined during experiments with the flat plate and validated in the literature, as detailed in [19]. The voltage range corresponds to the voltage required to achieve the stress range defined previously.…”

“…A similar ABAQUS FEA-based numerical model, as developed and validated in the previous investigations by [17,19], was developed to replicate the structure and boundary conditions of the blade-based testing setup. The blade geometry was designed to replicate as accurately as possible the experimental setup.…”

“…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.…”

Numerical and Experimental Investigation of the Design of a Piezoelectric De-Icing System for Small Rotorcraft Part 1/3: Development of a Flat Plate Numerical Model with Experimental Validation

“…The experimental setup designed is used in the next phase of the project to study transient vibration and frequency sweeps [22]. The numerical model is used in the third phase of the project by adding ice layers for numerical and experimental investigation of vibration-based de-icing [23], with the final objective of developing and integrating a piezoelectric actuator de-icing system to a rotorcraft blade structure.…”