The virtual tap test – a training system for wind turbine rotor blade inspectors


Wind turbine rotor blades are some of the tallest objects among modern civil structures. In order to ensure a lifetime of fifteen to twenty years, regular testing of their structural integrity is required. Advanced methods such as ultrasonic testing or thermography can be used, however, they are difficult to apply in the field, therefore more feasible yet robust and advanced methods are sought. The so called (coin-) tap test makes use of the human auditory system and its remarkable power for analysing the acoustic environment. This method is applied in everyday field inspection of rotor blades. Experienced engineers tap on the blade shell and listen to the emitted impact sounds which carry materialas well as geometry-related information. The change and disparity of certain perceived features between two adjacent tap locations indicate the transition towards a material defect. Although advantages like simple execution and the need for minimal equipment make it a feasible method for on-site tests, it is not an objective test method. Moreover, current practice offers no training for the inspectors of wind turbine rotor blades besides “learning by doing”. In this regard, experience plays a major role in robustly identifying defects in rotor blades. In order to overcome the lack of experience, this work presents a training system that aims at advancing the inspectors’ ability to robustly identify defects solely on acoustic information. The tap test training system (TTTS) mimics the execution of the tap test and features various types of defects, such as delaminations or deficient bonding at the trailing edge of the rotor blade. A test phase of the new system was carried out with inspectors of varying levels of professional experience. Preliminary results show that little experience can result in overlooked defects and false detections. Based on inspectors’ feedback, the training system offers a realistic virtual environment for the tap test. Moreover, inspectors’ feedback indicates that the idea of a training system is well perceived and the concept for this virtual system could lay the groundwork for further training in this

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@inproceedings{AndreisekTheVT, title={The virtual tap test – a training system for wind turbine rotor blade inspectors}, author={G. Andreisek and Dominik KORTHALS and Christian U. Grosse and Bernhard U. Seeber} }