Aliyu Abdullahi

Offshore wind turbines (OWT) have become hugely important to modern societies as they strive to meet their future targets of sustainable and environmentally friendly energy utilization. With the advantages OWT turbines offer with respect to the foregoing, comes the challenges of the ends of their initial design lives, fast approaching as well as an insufficient track record. This inadvertently will lead to unanticipated breakdowns in need of unplanned maintenance, which are carried out at huge costs as well as unnecessary downtime. Also, the nature of forces (i.e. cyclic and dynamic) that an OWT experiences as well as the environment (both sea and supporting soil) where it operates, make it difficult to accurately capture, ab-initio, the conditions it may be exposed to, while in operation.

These thus warrant a monitoring system capable of keeping track of the conditions of OWT systems at regular intervals or better still, in real time. Other researchers have developed monitoring methods targeting specific damage types and limited to the first two damage detection levels. In this sense, this research embarks on the development of calibrated FE models to be used for the assessment of the long term effect(s) of vibration on the structural integrity of OWT systems and sets the stage towards the automation of the monitoring procedures (i.e. Digital Twins) for this purpose.

This strategy involves building Finite Element Models of OWTs; Experimental modal testing of OWTs; Updating of the Finite Element Models and finally, linking the updated FE models with their physical counterparts. With the developed FE model, the structural states of the physical OWTs can be interrogated after long term load applications for the identification of damage in the OWT structure.