Structural Health Monitoring using structure- and airborne sound

TNT members involved in this project:
Alexander Lange, M. Sc.
Prof. Dr.-Ing. Jörn Ostermann
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Multivariate Structural Health Monitoring for Rotor Blades

KI-unterstütztes Schallemissionsmonitoring zur automatischen Schadenserkennung in
Tragstrukturen von Windenergieanlagen

German Federal Ministry for Economic Affairs and Energy (BMWi).

When operating a wind turbine, damage of the rotor blade is a serious problem and has to be taken into account. The rotor blades are subjected to varying dynamic loads during the whole lifespan which is planned to be at least 20 years. The production processes of modern blades is lowly automated with higher fabrication tolerances. Even small damages of the blade can accumulate over time and lead to structural relevant damage. Further the economic interest of higher wind turbines led to hybrid tower constructions with its lower part made out of prestressed concrete. Due to their importance for structural integrity and structural safety, there is a significant interest in the continous monitoring of steel tendons, which may suffer from stress corrosion cracking.

Therefore regular sight inspections are mandatory in many countries. However these inspections cannot provide an instant damage detection. Besides the safety risk of an undetected damage, the economical burdens are increasing rapidly if the damage increases given the costs of repairing, replacing and downtime. A system detecting reliably defects and in early stages helps to react fast and to avoid greater damage. Such a method will enable the wind turbine operator to provide higher operational safety and to minimize the economical burdens.

The aim is to pave the way to a damage detection system which reliably detects damage in early stages. A further goal is to extract useful information about the damage like its location and an estimate of the damage relevance.

One promising approach for early damage detection in steel tendons and rotorblades is the acoustic emission event detection method. In this regard acoustic emission events are stress waves emitted by a damage process. These sudden energy release caused by a damage event results in structureborne as well as airborne sound, which can be detected using mid-to-high frequency structureborne sound sensors and microphones, respectively. The higher risks of lightning strike damage with wired electrical sensors can be avoided by using fiber optic sensors. Measurement campaigns included two full-scale rotorblade tests, operational recordings of structureborne and airborne sound in the tower and the rotorblade of real wind turbines, respectively. With sophisticated signal processing methods and the application of machine learning,  environmental noise and non-damage related events can be handled, making the approach robust for operating under real world conditions.

Show recent publications only
  • Conference Contributions
    • Alexander Lange, Reemt Hinrichs, Jörn Ostermann
      Localized Damage Detection in Wind Turbine Rotor Blades using Airborne Acoustic Emissions (accepted)
      9th Asia-Pacific Workshops on Structural Health Monitoring 2022 (APWSHM 2022), December 2022
    • Alexander Lange, Max Käding, Reemt Hinrichs, Jörn Ostermann, Steffen Marx
      Wire Break Detection in Bridge Tendons Using Low-Frequency Acoustic Emissions
      European Workshop on Structural Health Monitoring. EWSHM 2022., Springer, June 2022
    • Thomas Krause, Jörn Ostermann
      Acoustic Emission Localization Using Airborne Sound: Where Did the Wind Turbine Rotor Blade Crack?
      9th European Workshop on Structural Health Monitoring (EWSHM), July 2018
    • Stavroula Tsiapoki, Thomas Krause, Moritz W. Häckell, Raimund Rolfes, Jörn Ostermann
      Combining a Vibration-Based SHM-Scheme and an Airborne Sound Approach for Damage Detection on Wind Turbine Rotor Blades
      8th European Workshop on Structural Health Monitoring, July 2016
    • Thomas Krause, Stephan Preihs, Jörn Ostermann
      Acoustic Emission Damage Detection for Wind Turbine Rotor Blades Using Airborne Sound
      10th International Workshop on Structural Health Monitoring (IWSHM) , September 2015
    • Thomas Krause, Stephan Preihs, Jörn Ostermann
      Airborne Sound Based Damage Detection for Wind Turbine Rotor Blades Using Impulse Detection in Frequency Bands
      1st International Wind Engineering Conference (IWEC), September 2014
    • Thomas Krause, Stephan Preihs, Jörn Ostermann
      Detection of Impulse-Like Airborne Sound for Damage Identification in Rotor Blades of Wind Turbines
      7th European Workshop on Structural Health Monitoring (EWSHM), July 2014
  • Journals
    • Thomas Krause, Jörn Ostermann
      Damage Detection for Wind Turbine Rotor Blades Using Airborne Sound
      Structural Control and Health Monitoring, February 2020
  • Technical Report
    • Thomas Krause, Jörn Ostermann
      Schäden an Rotorblättern akustisch erkennen
      ti! Technologie-Informationen 3 2016 Unter Strom, September 2016