The fundamental frequency of jacket offshore wind turbines (JOWTs) lies within the range of the forcing frequencies induced by the environmental loads and operational loads from the turbine itself. Minor changes in the dynamic characteristics of JOWTs during their operation lifespan, such as shifts in natural frequency or damping properties, can increase the risk of resonance, potentially leading to an accelerated exacerbation of structural fatigue. To investigate the long-term behavior of JOWTs, we comprehensively consider the similitude in structural dynamics, load characteristics, and supporting conditions and develop an experimental setup featuring a 1:100 scaled JOWT in sand. A series of laboratory tests were conducted under various cyclic loads to simulate real-world operational scenarios of JOWTs. The natural frequencies, damping ratios, accumulated tilting, and strain field variation of the scaled JOWT are monitored using the data collected from vibration accelerometers and strain gauges. The results provide valuable insights into the long-term dynamic behavior of JOWTs, offering a foundation for improved structural health monitoring strategies and the development of more resilient offshore wind turbine designs.
Zhou et al. (Wed,) studied this question.