Development of Advanced Shearography System for On-Site Inspection of Wind Turbine Blades
Wind energy has become one of the fastest growing sectors in the world’s energy markets, at a rate of 20% per annum. All this indicates that there will be more wind farms to be built in the coming decade. However, more wind turbines in operation means more accidents that may occur.
There is therefore a clear market need to develop various inspection techniques that can meet the requirements of inspecting wind turbine installations so that such kind of structural failure and catastrophic consequences can be avoided.
- Gain further knowledge about SPS-DS in terms of its principles and mechanics, in particular, the tolerance to rigid body shift and rotation.
- Develop a robust phase extraction technique able to detect phase of the speckle pattern of a blade on-site. New techniques that can extract phase from a single specklegram will be developed based on wavelet transformation, phase-only-filter and image processing.
- Develop automatic motion compensation technique to compensate the rigid body rotation and translation of a WTB. A combination of DIC, shearography and high-speed camera will be employed, and a new algorithm for rigid body motion compensation will be developed.
- Develop a robotic manipulation system that can carry and deploy the integrated digital shearography system along the wind tower. This robot will be able to manipulate, in principle (i.e. by design), various wind tower sizes and diameters, allowing the shearography system to inspect the WTBs. The robotic system will be designed to withstand the strong wind currents that typically exist in such fields. The robotic platform and the shearography system will be controlled by an operator on the ground, thus eliminating the danger of operating at height for the inspection engineers.
- Develop a software system with high-level functions comprising image signal processing, phase extraction, displacement field calculation and display, automatic rigid body motion compensation, defect reconstruction from shearographic fringes, data storage and user interface.
- Finally, to integrate the techniques into a system, validate its performance in field and then demonstrate the system on wind turbine installations.
This project addresses the increasing demands of SMEs in the wind energy sector for a novel noncontact NDT system that can be employed to inspect wind turbine blades (WTB) on-site, so that defects due to fatigue or natural incidents can be identified before a catastrophic structural failure occurs.
DashWin is a result of a research project funded by the European Commission Research Programme under grant no. 283533.