Detektion und Beseitigung lokaler Vereisungen an einem Flugzeugtragflächendemonstrator

Icing detection and de-icing strategies are important to assure a safe operation of airplanes in harsh environments. The authors aim on the use of innovative sheet-metal compounds, consisting of a piezomodule embedded in a layer of adhesive between two aluminum sheets. The sensor and actuator functionality of the piezomodule enables these compounds for icing detection and de-icing. An innovative production and forming technology was presented in earlier studies, where the piezomodule is integrated in a local sandwich built-up. Forming takes place in a viscous condition of adhesive. This allows for forming of brittle piezoceramic fibers, preventing the piezomodule from forming induced strains. Within the study two demonstrators of sheet-metal compounds with piezoceramic modules are fabricated with this technology and used for ice-detection and de-icing. At first a bending beam with a local sandwich built-up and an integrated piezomodule was manufactured. Furthermore a demonstrative airfoil structure was designed and built. The airfoil structure includes several piezomodules. Pieomodule locations were identified by FEA. Ice-detection is performed by measuring of impedance and loss angle. In case of icing the additional ice mass leads to a change of resonance frequencies, which is monitored by the impedance and loss angle signals. Icing was performed inside a cold chamber at 40 C. Vibrations assisted de-icing is performed by a stimulation of resonance frequencies using the integrated piezomodules as actuators. The stimulation of appropriate resonance frequencies leads to a mechanical removal of the ice layer. The obtained results show, that the integration of piezomodules in sheet-metal-compounds with a local sandwich built-up successfully enables additional functionalities as ice detection and de-icing.