The authors have recently developed a soft elastomeric capacitor (SEC) for monitoring surface strain over wind turbine blades. The SEC combines the advantages of cost-effectiveness, high scalability, mechanical robustness, customizability in shapes and sizes, and low power requirement. Arranged in a network configuration, the sensing solution can monitor local strain over a global region analogous to biological skin. The sensing principle is based on changes in the sensor geometry produced by local strain, which can be indirectly measured via changes in the capacitance value. Given that strain in any particular direction will provoke a change in the sensor geometry, the sensor measures the combined strain along both principal axes at a first level of approximation. Here, this bidirectional measurement mode is analyzed, and practical advantages and limitations discussed for both dynamic and static monitoring. In a dynamic measurement setup, tests show that the SEC is capable of measuring fundamental modes in all axes, and can detect dynamic input. In a static measurement setup, we show that the signal can be decomposed by identifying a strain map and enforcing boundary conditions along the free and fixed edges. We conclude that the bidirectional sensing capability of the SEC can be taken as an advantageous feature in monitoring surface strain over large areas.

Study of the Bidirectional Sensing Characteristic of a Thin Film Strain Gauge for Monitoring of Wind Turbine Blades

UBERTINI, Filippo
2014

Abstract

The authors have recently developed a soft elastomeric capacitor (SEC) for monitoring surface strain over wind turbine blades. The SEC combines the advantages of cost-effectiveness, high scalability, mechanical robustness, customizability in shapes and sizes, and low power requirement. Arranged in a network configuration, the sensing solution can monitor local strain over a global region analogous to biological skin. The sensing principle is based on changes in the sensor geometry produced by local strain, which can be indirectly measured via changes in the capacitance value. Given that strain in any particular direction will provoke a change in the sensor geometry, the sensor measures the combined strain along both principal axes at a first level of approximation. Here, this bidirectional measurement mode is analyzed, and practical advantages and limitations discussed for both dynamic and static monitoring. In a dynamic measurement setup, tests show that the SEC is capable of measuring fundamental modes in all axes, and can detect dynamic input. In a static measurement setup, we show that the signal can be decomposed by identifying a strain map and enforcing boundary conditions along the free and fixed edges. We conclude that the bidirectional sensing capability of the SEC can be taken as an advantageous feature in monitoring surface strain over large areas.
2014
9788494284458
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1296097
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