GL Garrad Hassan at EWEA Offshore 2011: New Bladed link to offshore code checking tools
This link represents a new approach for the integrated structural analysis of OWT jackets and other space-frame support structures. The Bladed code accurately 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. This ensures that the effects of simultaneous wind and wave loading of the turbine and support structure are properly represented. 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.
The Bladed Offshore Code Checking feature creates a user-friendly link between the Bladed output and the ASAS/ SACS code-checking routines. An input file containing the jacket geometry and load time histories in the required format is generated by Bladed. This can be used directly in the ASAS and SACS code checking routines to analyse each joint in the jacket structure and assess the fatigue life and ultimate strength. The Bladed data conversion has been extensively tested and validated. By linking Bladed directly with these general-purpose offshore analysis codes, design iterations of the support structure can be assessed more easily and more accurately, enabling the creation of better optimised design solutions for offshore wind turbine support structures.
Germanischer Lloyd SE
GL Garrad Hassan is one of the world's largest dedicated renewable energy consultancies and a recognised technical authority on the subject. It offers independent technical and engineering services, products, and training courses to the onshore and offshore wind, wave, tidal and solar sectors. Although the GL Garrad Hassan name is new, the company has a rich heritage. It is borne of the integration of specialist companies that, united, form the renewable energy consulting division of the GL Group. GL Garrad Hassan is a consulting company; it has no equity stake in any device or project. This rule of operation is central to its philosophy, something which sets it apart from many of its competitors. For further information, please visit www.gl-garradhassan.com