Kontinuierliches Monitoring zur Schädigungsverfolgung an Tragstrukturen von Windenergieanlagen

Dr.-Ing. Stefan Lachmann, Oer-Erkenschwick,received his doctorate in the first quarter of the year. In his dissertation "Continuous Monitoring for Damage Tracking on Supporting Structures of Wind Turbines", he deals with lifetime estimation or prognosis of the remaining lifetime of the supporting structure of wind turbines.
Especially in the focus of the ongoing expansion ("revamping") of wind turbines in the next years, but also for the continued operation of older turbines that have already reached their useful life or will reach it in the next years, this research project has a high importance. Up to now, the mechanical lifetime of wind turbines has been calculated relatively roughly on the basis of estimated impacts. In order to improve the informative value and reliability of the estimates, directed prognosis methods are developed in the work, which are directly aimed at the operational strength problem. In doing so, the operational loads for decisive structural components must be recorded as realistically as possible. For this purpose, the doctoral student developed a continuously operating measurement system with modern sensors for recording the mechanical structural response ("Structural Health Monitoring"). The monitoring system was mounted on an existing wind turbine in Dortmund (see Figure 1 below), and an extensive amount of data has since been continuously stored on a faculty server via fast data lines. Statistical, multivariate data analysis is used to create a database as a basis for the lifetime estimation of the tower structure. Limited to certain decisive construction details identified in the course of a weak point analysis, representative fatigue strength tests are carried out in the work and thus degrees of damage to the tower structure on the one hand, but also service life reserves are demonstrated.