Vibration-based Structural Health Monitoring of Wind Turbine Blades from Laboratory Testing to in-Operation Wind Turbine

Modern wind turbine blades (WTB) are designed to last 25 years of service under severe environmental conditions. Damage is likely to occur during this time span and therefore there is a need of reliable systems to ensure the structure integrity. Vibration-based structural health monitoring (VSHM) is becoming one of the most commonly used methods to monitor damage in wind turbine blades. These methods rely on vibration measurements, from the instrumented WTB, to either operational loads or artificial induced excitation that are used as an input to statistical algorithms for decision-making. One important aspect is that sensors do not directly measure damage, but they provide information on where to extract reliable sensitive features that might be used to monitor the damage. This presentation will outline a methodology that lies within a popular strategic for data-driven VSHM, which consists to compare new observations measured in the WTB against to a reference state that defines the original (pristine) status of the WTB. The methodology learns from the past and present towards successful damage diagnosis and hence to project the learning onto future decisions. To illustrate the methodology, two case of study are presented; first in a 34m WTB in a laboratory testing and secondly in 27m WTB in an operation wind turbine. Finally, an expansion to detecting instability of centrifugal compressors is also presented.