Revision Date Description 1.00 09-Jul-2002 First publication. Supports FAST v4.0. 1.10 04-Sep-2002 Inserted an additional output channel (TipSpdRat or TSR) and additional prefixes ("-", "_", "m", or "M") for reversing the sign of the selected output channels. Still supports FAST v4.0. 1.20 28-Feb-2003 Clarified the descriptions of several input variables. 1.21 31-Mar-2003 Replaced drivetrain references from "rotational" to "torsional." 1.22 03-Apr-2003 Fixed the labels on the drawings of the coordinate systems. 1.30 08-Sep-2003 Added description of the FAST-to-ADAMS preprocessor and associated inputs. Added placeholders for the inputs of the currently undocumented FAST linearization and noise prediction routines. Clarified the descriptions of several input variables. Renamed input switch TeetDMod to TeetMod and altered its functionality so that routine UserTeet() can implement user-defined teeter spring and damper models. Added supplementary output names for the blade root in-plane, out-of-plane, flap, and edge bending moments. 1.31 03-Oct-2003 Added description of the FAST linearization analysis capability. Clarified the descriptions of several input variables. 1.32 07-Oct-2003 Updated the example summary, AeroDyn, and linearization output files. Had the Linearization chapter type edited by NREL communications. 1.40 28-Oct-2003 Changed the extension of the input file names from .fad or .inp to ".fst" Added Alpha, PrecrvRef, and PreswpRef to the FAST-to-ADAMS preprocessor. Supports FAST v4.4. 1.41 07-Nov-2003 Inserted additional output channels for the blade and tower torsional deflections. Moved the origin of the nacelle/yaw coordinate system to the tower-top. 1.42 11-Dec-2003 Documented that the dummy supplied UserGen() routine now calls the sample UserVSCont() routine. 2.00 05-Mar-2004 Added description of new FAST furling capability and associated I/O. Added additional output channels for blade tip-to-tower clearances. Clarified the descriptions of several input variables. Supports FAST v5.0. 2.10 01-Oct-2004 Added a chapter on how to compile FAST. Documented upgrades relating to turbine control, including yaw and high-speed shaft brake control. Added a description on the interface between FAST and Simulink and on the interface between FAST and Bladed-style DLL master controllers. Clarified the descriptions of several input variables. Added supplementary output names for the angular speed and acceleration of the high-speed shaft and generator. Supports FAST v5.1. 3.00 09-Jun-2005 Added description of new platform motion and loading functionality. Documented upgrades relating to turbine control and output capabilities. Added additional output channels and names for the angular (rotational) deflections of the tower-top and blade tips. Clarified the descriptions of several input and output parameters. Supports FAST v6.0. 3.01 12-Aug-2005 Incorporated editorial changes from NREL communications. Added reference to the certification report from Germanischer Lloyd WindEnergie. Added a Sample Input Files section in t...

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The vast deepwater wind resource represents a potential to use floating offshore wind turbines to power much of the world with renewable energy. Comprehensive simulation tools that account for the coupled excitation and response of the complete system, including the influences of wind-inflow, aerodynamics, structural dynamics, controls, and, for offshore systems, waves, currents, and hydrodynamics, are used to design and analyze wind turbines. Continuing our work presented previously, we outline the development of such an analysis tool for floating offshore wind turbines, including a recently added, quasi-static mooring system module. The fully coupled simulator was developed with enough sophistication to address the limitations of previous frequency and time domain studies and to have the features required to perform an integrated loads analysis. It is also universal enough to analyze a variety of wind turbine, support platform, and mooring system configurations. The simulation capability was tested by model-to-model comparisons to ensure its correctness. The results of all of the verification exercises are favorable and give us confidence to pursue more thorough investigations into the behavior of floating offshore wind turbines. Some of the potential challenges to their design are highlighted through sample response simulations.

NOTICEThis report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. ABSTRACT This paper addresses the statistical uncertainty of loads prediction using structural dynamics simulation codes and the requirements for the number and duration of simulations for obtaining robust load estimates. Substantial statistical variation is observed in loads data and a statistical model that enables extrapolation and determination of quantiles is presented. Further reduction in the numerical work necessary to determine extreme loads with an acceptable uncertainty is possible using a stochastic process model for the dynamic responses. A procedure allowing for a slightly nonGaussian response is proposed and satisfactory accuracy is found. Finally, the extreme loads from the revised IEC 61400-1 wind turbine standard on safety requirements are calculated for the turbine, and loads from the gust models and the properly extrapolated simulation extremes are compared.