Dynamic Load and Response Prediction of HAWT Blades for Health Monitoring Application

Wind turbine blades of a Horizontal Axis Wind Turbine (HAWT) are prone to damage; some insurance agencies report that as much as 40% of all claims are from blade damage. While most claims are not very expensive in comparison to other HAWT component repairs, for example, repairing of the gel coat, others, like replacing the entire blade can be one of the most expensive tasks. As the world moves toward larger and longer blades to capture more wind energy this problem will continue to grow. Inspecting wind turbine blades presents a challenge with most techniques requiring a technician to repel down the blade for inspection using nondestructive evaluation techniques such as ultrasound or X-ray. While some US companies like General Electric propose to use robots to perform blade inspections, there is an alternate solution to this problem which requires continuous monitoring of the blades. There is an ongoing study at Iowa State University to explore a real-time monitoring and analysis of blade response using a new type of skin-mounted strain-gauge sensor onto the inside surface of the blade. This technique would allow for damage to be detected sooner in order to reduce the overall operations and maintenance cost of wind turbines