Non-Destructive Techniques for the Condition and Structural Health Monitoring of Wind Turbines: A Literature Review of the Last 20 Years

Abstract

A complete surveillance strategy for wind turbines requires both the condition monitoring (CM) of their mechanical components and the structural health monitoring (SHM) of their load-bearing structural elements (foundations, tower, and blades). Therefore, it spans both the civil and mechanical engineering fields. Several traditional and advanced non-destructive techniques (NDTs) have been proposed for both areas of application throughout the last years. These include visual inspection (VI), acoustic emissions (AEs), ultrasonic testing (UT), infrared thermography (IRT), radiographic testing (RT), electromagnetic testing (ET), oil monitoring, and many other methods. These NDTs can be performed by human personnel, robots, or unmanned aerial vehicles (UAVs); they can also be applied both for isolated wind turbines or systematically for whole onshore or offshore wind farms. These non-destructive approaches have been extensively reviewed here; more than 300 scientific articles, technical reports, and other documents are included in this review, encompassing all the main aspects of these survey strategies. Particular attention was dedicated to the latest developments in the last two decades (2000–2021). Highly influential research works, which received major attention from the scientific community, are highlighted and commented upon. Furthermore, for each strategy, a selection of relevant applications is reported by way of example, including newer and less developed strategies as well.

Tensile and shear behavior of plain weave fabric carbon fiber reinforced polymer at elevated temperatures

“…In‐plane shear strength of the CFRP specimens predicted for different testing temperatures using different prediction models [ 5,26,27 ] …”

“…However, the experimental inplane shear strength fits well with the Hawileh model. It can be concluded that for the properties which relies mostly on the fiber orientation and fiber properties, F I G U R E 8 Tensile strength of the CFRP specimens predicted for different testing temperatures using different prediction models [5,26,27] F I G U R E 9 In-plane shear strength of the CFRP specimens predicted for different testing temperatures using different prediction models [5,26,27] modified Gibson and Nadjai model can be used. And Hawileh model can be used for predicting the properties that rely on the fiber-matrix interaction.…”

“…This is due to their high strength-to-weight ratio, resistance to various chemical attacks, good electrical insulation, and ease of application. [1][2][3][4][5] In fact, it has been estimated that the utilization of FRP panels in commercial aircrafts has reduced their downtime significantly. Similarly, in the large building structures, the utilization of FRPs have reduced the repairing time and cost significantly.…”

Health Monitoring of Serial Structures Applying Piezoelectric Film Sensors and Modal Passport

“…To provide safety and efficiency, the technical operation of these structures is ensured through regular periodic inspections (surveys). To survey structures, non-destructive techniques (NDTs) are mainly used, like ultrasound, eddy current, X-ray and others [ 1 , 2 ]. To be applied on structures like wind turbines or aircrafts, these techniques require stop of operation.…”

Damage Detection for Rotating Blades Using Digital Image Correlation with an AC-SURF Matching Algorithm

“…Currently, several sensing technologies have been applied to the online monitoring of operating wind turbines [ 6 , 7 ]. Chen et al [ 8 ] collected monitoring signals of acoustic emission systems from commercial wind fields, which were used for health condition assessment of the wind turbine blade (WTB).…”