We are happy to announce an updated alpha-version release of MLife (v1.00.00f-gjh), a MatLab-based tool that can efficiently process statistical and fatigue-related output needed for wind turbine certification. MLife's calculations follow the method required by the IEC in their 61400-1 Edition 3, Annex G, design standard, and the recommendations of Germanischer Lloyd (GL) in their Guideline for Certification of Wind Turbines, 2010 edition.
New functionality of this release includes:
- Use of Design Load Cases (DLCs)
- Use of Partial Safety Factors (PSFs)
- Fatigue calculations with and without using the Goodman correction
- Short-term aggregate calculations
- Short-term damage-rate calculations
- Support for binary FAST output files
- Faster rainflow counting using a MEX-file (requires installation of Visual Studio 2010 SP1 run-time libraries, which are included in the distribution archive)
- New wind speed binning scheme
- Use of turbine availability factor
- Many bug fixes
- Updated settings file format to accommodate the new features (this version is NOT backwards compatible with previous MLife releases)
- updated user and theory manuals
The input data for MLife are typically obtained from a large series of aero-elastic simulations (FAST, for example). The software functionality of version 1.0 -- including calculations of general statistics, lifetime damage, and damage-equivalent loads -- has been implemented and the project is now focused on verification and validation of the tool.
Engineers at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory had created a program called MCrunch that included these features and many more, but MCrunch must store the entire dataset concurrently in memory. For such a large number of simulations, the memory requirements would exceed the amount available in an engineer's typical computer. Staff at the NWTC recently addressed this problem by creating MExtremes for the extreme-event tables and MLife for fatigue-life predictions. These specialized tools process files sequentially, so only one data file is stored in memory at a time.
Feel free to download the software and associated documentation from the MLife webpage:http://wind.nrel.gov/designcodes/postprocessors/MLife
Feedback during alpha testing will be used to identify any problems which prevent analysis and results generation in accordance to the IEC and GL recommendations mentioned previously.
You can post your comments in the Computer-Aided Engineering Software Tools forum or email them to Greg Hayman, email@example.com