According to the future energy policy of the EU, wind energy is expected to account for more than 50% of the EU's total power generation by the year 2050 [2]. The offshore wind energy production poses great
challenges but adds significant percentage of green energy to the overall energy mix. A recent report from The Offshore Renewable Energy Catapult shows a need for advancements in the analysis of condition monitoring systems (CMS) and structural health monitoring (SHM) data [1]. Bolted joints are widely used in the construction industry in Wind Turbines (WT) are playing a crucial role as they connect the WT tower with the foundation and thus successfully transmit the loads to the ground [2]. Bolt loosening may lead to a wide variety of issues ranging from overstressing to reduced fatigue life of the structure, thereby requiring
frequent and systematic maintenance and checks over the lifespan of the structure [3]. This procedure is very inefficient and expensive with unsafe procedures that involve one-by-one examination of each bolt link at periodic time intervals. Developing a physics based twin of such structures with a combination of a remote and robust condition monitoring system is therefore of great interest to the industry as it could reduce costs which would help secure the future of clean energy. Vibration based Structural Health Monitoring (VSHM) methods have shown to be a reliable and attractive method for loose bolt identification. Such methods assume the structure to emit vibration responses due to the existence of abnormalities and variations in dynamic characteristics. The extracted modal parameters with respect to time allow the detection of fluctuations of dynamic parameters dues to the flaws existing in bolts [4, 5]. Recently, Laser ablation, a vibration testing and health monitoring system based on an impulse response excitation, has been used to identify changes in the dynamic characteristics in the high frequency region caused by a slight abnormality in the structural system. This can essentially distinguish between the effect of loose bolts from other sources of vibration [4].