Published: 30 November 2011 30 November 2011
GL Garrad Hassan has developed a direct link between its own aero-elastic wind turbine design tool Bladed and two offshore analysis codes: ANSYS ASAS and Bentley SACS. This link represents a new approach for the integrated structural analysis of offshore wind turbines (OWT) jackets and other space-frame support structures.
The Bladed code models the dynamics of the entire offshore wind turbine system, including the turbine, support structure and non-linear pile-soil interaction, using a multi-body approach. Non-linear wind and wave loading on the turbine and support structure is calculated through integrated time-domain modelling of aerodynamic loads, hydrodynamic loads and control system actions. The Bladed output consists of time histories of internal forces and moments at all locations in the wind turbine and support structure. The ANSYS ASAS and Bentley SACS codes perform fatigue and ultimate strength analysis of tubular joints in offshore structures on the basis of global load time series. Both packages contain built-in code-checking routines which allow the strength of the structure to be checked in accordance with the main design codes, according to joint classification. Stress concentration factors (SCFs) around each weld may be calculated automatically or entered manually by the user.