Millimeter Wave Inspection Tool for Wind Turbine Components

Improving wind energy harvesting system reliability is a challenge that requires advanced technologies and innovation to support growth and development of domestic wind energy. Toimprove quality assurance inspection of wind turbine parts and, in particular, to improvetechnologies to perform quality assurance inspection on very large, thick wind turbine parts, new technology is critically needed to uncover hidden defects before and after field installation. To address this urgent need, a new millimeter wave inspection tool for nondestructive testing of wind turbine components is being proposed. The tool is based on an array of scanningmillimeter wave probes that use penetrating, yet harmless, low-energy electromagnetic waves to image defects throughout the full thickness of wind turbine composite parts. Within theproposed system architecture, the sensors are arranged in a modular array that conforms to the blade contours and expedites the inspection process. In Phase I, the proposed systems feasibility was successfully demonstrated through computer simulations, designing, developing, and demonstrating a working prototype based on a series ofproof-of-concept experiments and tests. It was demonstrated that the Phase I prototype can detect small-scale (delaminations and porosity 0.2 mm) and larger scale (cracks and voids 10 mm to 100 mm) defects on an engineered sample. Phase I also demonstrated the systemspenetration depths 380 mm. The results of the testing were in good agreement with the simulation and modeling results. The overall goal of Phase II is to develop a full-scale prototype of the proposed system for pilottesting with wind turbine manufacturers and for evaluation by a national lab. During Phase II, theprototype system will be developed to include several enhancements based on the Phase I results and first-hand end-user feedback. The depth resolution to provide defect classificationcapabilities will be improved, signal processing to provide enhanced image resolution will be optimized, mechanical mounting and automation to achieve higher inspection speeds will beimplemented. Commercial Applications and Other Benefits: The inspection tool being developed will provide a fast and reliable diagnostic device that canbe directly applied both in the wind plant after manufacturing and in the field prior to installationand uptower after installation. This will benefit the nation by improving the reliability of windturbine components, thereby reducing maintenance costs and extending wind turbine lifetimes.Improving the reliability and operability of wind turbines will help to establish domestic wind energy manufacturing capabilities and create a large number of green and clean energy jobs for Americans in the coming decades. Other commercial applications for the inspection tool includenondestructive inspection of large-scale composite materials such as parts for bridges, aircraft,and structures and spin-off applications in remote sensing and surveillance.