Bakgrunn og aktiviteter


Offshore Wind Turbine and installation : 
Numerical modelling of installation of offshore wind turbine components and system ( offshore wind blade installation with floating crane vessel), safety assessment of installation of offshore wind turbine components and systems (response based criteria), the effect of wave slamming forces and impact force coming on the foundation structures of an offshore wind turbine model.

Offshore wind blade:
Aerodynamic and structural analysis of blade, ultimate strength, and fatigue life prediction of blade, nonlinear time domain impact analysis on the blade during lifting operation with equipment on the vessel or with pre-assembled tower with the help of floating crane vessels.

Composite material and sandwich structures:
Numerical modelling of low-velocity impact on composite material and sandwich structure, development of damage models to explicitly capture different failure modes, Finite element methods applied to composite materials.

Marine Operations: 
Operational and safety criteria for marine operations related to offshore wind turbine transport, installation and access for maintenance and repair; numerical modeling and time-domain simulation of marine operations.

Weather Forecasting :
Effect of uncertainty involved in the weather forecasting regarding safety assessment and decision making and operability. 

Ph.D. Topic:  Development of explicit response-based criteria for operability assessment for installation of offshore wind turbines using floating vessels

In view of the movement of offshore wind industry into deeper waters and the limitation of jack-up vessels, floating crane vessels are now being developed and used for installation of bottom-fixed wind turbines and also floating wind turbines (for example spar wind turbines). However, the big challenge is the motions of floating crane vessels, which may lead to contact/impact between the objects and therefore damages in the critical components (blades, nacelle or pre-assembled rotor-nacelle-tower) in particular in the lift-off and mating operations. In order to obtain an accurate estimate of the operability to reduce the cost for such operations, it is crucial to develop response-based criteria by explicitly assessing the damages in the wind turbine components in case of contact/impact. The purpose of this study is to develop the numerical methods for response and damage assessment of critical wind turbine components during installation and to derive the operational limits in terms of sea state parameters (Hs and Tp) for operability assessment. Case studies for installation of individual blades and integrated rotor-nacelle assembly onto bottom-fixed foundations and floating foundations using floating installation vessels will be considered. Active winch control to reduce or avoid the contact/impact during lifting operations will also be considered.