Human exposure to motion during maintenance on floating offshore wind turbines

Working on floating offshore wind turbines is a complex operation. An important factor is the influence that the structural motion has on humans located on the asset in a harsh environment during maintenance activities and its implications towards personal safety, human comfort and the ability to work. For the research presented in this paper, extensive simulation studies were conducted to assess if and to what extend working on floating offshore wind turbines may be compromised due to extensive structural motion. Results show that weather windows for maintenance activities are reduced by up to 5% when adhering to guidelines suggesting limiting threshold values for acceleration exposure. The corresponding potential financial losses materializing due to longer turbine unavailability after a fault are significant. All the presented and discussed results underline the importance of considering motion criteria in the design phase of a new project - a factor which is not included in design procedures today

Whole body vibration on offshore structures: an evaluation of existing guidelines for assessing low-frequency motions

An extensive literature research has been conducted to create an insight into the existing norms and standards regulating the assessment of human exposure to motions in offshore environments. A summary of current threshold values and their specific fields of application is included. The presented literature is analysed with respect to their applicability for assessing low frequency oscillatory motions of floating offshore wind turbines to which technicians are exposed during maintenance tasks. The review identifies the need for a consistent assessment method in combination with threshold values for floating structures