Publications

Abstract not provided.

A basic structural concept of the blade design that is associated with the frequently utilized %E2%80%9CNREL offshore 5-MW baseline wind turbine%E2%80%9D is needed for studies involving blade structural design and blade structural design tools. The blade structural design documented in this report represents a concept that meets basic design criteria set forth by IEC standards for the onshore turbine. The design documented in this report is not a fully vetted blade design which is ready for manufacture. The intent of the structural concept described by this report is to provide a good starting point for more detailed and targeted investigations such as blade design optimization, blade design tool verification, blade materials and structures investigations, and blade design standards evaluation. This report documents the information used to create the current model as well as the analyses used to verify that the blade structural performance meets reasonable blade design criteria.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Operations and maintenance costs for offshore wind plants are expected to be significantly higher than the current costs for onshore plants. One way in which these costs may be able to be reduced is through the use of a structural health and prognostic management system as part of a condition based maintenance paradigm with smart load management. To facilitate the creation of such a system a multiscale modeling approach has been developed to identify how the underlying physics of the system are affected by the presence of damage and how these changes manifest themselves in the operational response of a full turbine. The developed methodology was used to investigate the effects of a candidate blade damage feature, a trailing edge disbond, on a 5-MW offshore wind turbine and the measurements that demonstrated the highest sensitivity to the damage were the local pitching moments around the disbond. The multiscale method demonstrated that these changes were caused by a local decrease in the blades torsional stiffness due to the disbond, which also resulted in changes in the blades local strain field. Full turbine simulations were also used to demonstrate that derating the turbine power by as little as 5% could extend the fatigue life of a blade by as much as a factor of 3. The integration of the health monitoring information, conceptual repair cost versus damage size information, and this load management methodology provides an initial roadmap for reducing operations and maintenance costs for offshore wind farms while increasing turbine availability and overall profit.

Sixty-three years of aero-hydro-elastic loads simulations are demonstrated for a 5 MW offshore wind turbine deployed in shallow water. This large amount of simulation was made possible through the use of a high-performance computing cluster. The resulting one-hour extreme load distributions are examined; the extensive number of one-hour realizations allows for direct estimation of fifty-year return loads, without resorting to extrapolation. This type of simulation study opens up new possibilities for developing wind turbine design standards and discovering physical mechanisms that lead to extreme loads on wind turbine components.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

This paper discusses the development of a consistent methodology for mapping one-dimensional distributed beam loads to a three-dimensional shell structure. The resultant force distribution is a linear approximation to the actual aerodynamic pressure distribution but is sufficient to obtain accurate strain and displacement results. The purpose of the mapping technique is to apply more realistic wind loads to the shell model of a wind turbine blade without the need to set up and run expensive computational fluid dynamics or fluid structure interaction problems. Subsequent buckling and stress analysis reveal how this approach compares to other simplified methods of defining the loads. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc.

Abstract not provided.

Abstract not provided.

Abstract not provided.