Detect critical damage in wind turbine blades

The Smart Embedded Sensor System (SESS) is a market-oriented research project funded through the EUROSTARS Programme, which aims to develop a structural health monitoring (SHM) solution for wind turbine blades. The target SESS capability can be summarized as: Early detection of critical damage.

Detecting changes in energy level

The need for SHM on wind turbines is particularly crucial as more and more turbines are installed off-shore and inspection or maintenance costs are rising. With an adapted monitoring system, wind farm operators can gain an accurate overview of the status and reduce or better plan maintenance activities.

The principle is to measure vibration energy transferred between piezoelectric elements, compare this energy level with a reference point and detect changes in it. Piezoelements are distributed on both sides of the examined area, e.g. a bond line.

The research shows that even small a defect in such a connection or structure delamination causes a significant and measurable decrease in the energy level.

Implementing this solution for blades would cut down the time needed for inspections, avoid unnecessary replacement of components, forestall blade failure and improve overall reliability.

SESS prototypes

The original concept of the SESS is to combine active and passive measurement methods in the same hardware. In the active method, a piezoelectric transducer generates a mechanical wave (Lamb wave) in the structure. This wave is sensed by other transducers some distance away and any change in the energy transmission can be related to a change in the structure.

Project outcome

The project ended with a series of prototypes including piezo elements from Noliac driven by electronics from EC Electronics. One prototype was tested by Risø DTU National Laboratory for Sustainable Energy and showed good results in identifying de-bonds in a composite structure.
All partners are very enthusiastic about the product and are currently discussing a possible on-site demonstration of the system.

Partners and further information:

• Noliac A/S
• Riso National Laboratory for Sustainable Energy Technical University of Denmark
• Innowacja Polska z o.o. 
• Competence Centre in Electronics-, Info- and Communication Technologies (ELIKO), Estonia
• EC Electronics Sp. z o.o.

SESS in brief 

SESS leaflet (pdf)