Sensor platform for periodic integrity inspection of subsea structures with a permanently installed measuring system

• Published in: E-journal of Nondestructive Testing Vol. 29; no. 7
• Main Authors: Weihnacht, Bianca, Wollstadt, Johann, Gaul, Tobias, Schnabel, Andreas, Kruska, Carsten, Klesse, Thomas, Schubert, Lars
• Format: Journal Article
• Language: English
• Published: 01.07.2024
• DOI: 10.58286/29692
• ISSN: 1435-4934

Offshore structures are inspected with high costs and risks. In order to reduce both, the Fraunhofer IKTS has developed a sensor platform for automated periodic inspection by underwater vehicles like Remotely Operated Vehicles (ROV) or Autonomous Underwater Vehicles (AUV). The monitoring tasks are numerous. Temperature or pressure measurements are widely needed to ensure safe operation. Welded seams are a critical element of offshore infrastructure. If they fail due to high wave loads, extraordinary ice collision or due to fatigue behaviour, the entire structure becomes critical regarding the stability and safety. The Fraunhofer IKTS developed a technique for the permanent installation on subsea structures in order to enable a periodic inspection. The communication and energy supply are realized wireless by WiFi and inductive energy supply. The sensors used differ from application to application. For the welded seam inspection, shear wave laminable transducers ensure a flat design to prevent damage due to current or waves. Shear waves give a relative independency from fouling to make the interpretation of the data more comprehensive. The device has been tested in maritime environment for 2,5 years to ensure reliability. Furthermore, a modular setup with integrated transducers into the circuit board provide market relevant potential low prices on the long term. The connection unit has been designed in a way that also small ROV/AUV can operate the light-weight unit to ensure a broad applicability by almost any vehicle on the market.