Large number of bolted structures exist in wind turbine equipment

once the bolt hole is defective

it may lead to fracture of the entire matrix and cause major accident

but the current bolt hole defect detection method has the situation of missed detection and misjudgment. Aiming at solving this problem

through investigation

theoretical analysis and physical research

two methods which combine special tooling with probe for bolt hole defect detection are developed

namely the direct beam method and the sector scanning deflection method. Taking the bolt hole of pitch bearing in wind turbine as the research object

the CIVA software is used to simulate the two detection methods

and the rectangular simulated crack can be detected. Experiments were carried out on the defects of rectangular grooves in the actual pitch bearing bolt holes

which showed that the direct beam method could realize the defect detection of bolt hole cracks. The research provides a new method for monitoring the service status of bolt holes

which is beneficial to ensure the safe service of bolted structures.