Inspection of wind turbine bolted connections using the ultrasonic phased array system

Area of Science:

• Engineering
• Materials Science
• Non-Destructive Testing

Background:

• Wind turbine bolted connections are critical for structural integrity.
• Ensuring bolt integrity under operational stress is vital for safety and longevity.
• Current inspection methods may have limitations in detecting subtle stress changes or early deformation.

Purpose of the Study:

• To evaluate Phased Array Ultrasonic Testing (PAUT) for inspecting bolted connections in wind turbines.
• To assess PAUT's capability in monitoring bolt stress and detecting deformation under operative loads.
• To verify PAUT results using Finite Element Analysis (FEA).

Main Methods:

• Acoustoelastic Constant calibration for stress measurement.
• High tension testing and blind tests on bolts of varying sizes.
• Finite Element Analysis (FEA) for validation.
• Utilizing PAUT's multi-modal imaging for stress and defect detection.

Main Results:

• PAUT accurately determined bolt stress under operative loads.
• The method clearly indicated when bolts exceeded operational loads and began to deform.
• FEA verification confirmed the accuracy of PAUT stress measurements.
• PAUT demonstrated simultaneous stress monitoring and defect detection capabilities.

Conclusions:

• Phased Array Ultrasonic Testing (PAUT) is a promising tool for wind turbine bolt inspection.
• PAUT enhances wind turbine safety and longevity through reliable stress monitoring.
• The study supports PAUT for future in-situ inspection applications in wind energy.