Fatigue analysis

Good day everyone,

I am trying to simulate DLC1.2 (power production, NTM, fatigue analysis). GL documentation suggests that 300 changes from Vrated to Vcutin (and vice versa) as well as 50 changes from Vrated to Vcutout (and vice versa) for one year period should be considered. I am using FAST to compute loads and to my knowledge there is no way to incorporate these speed changes into FAST directly. I would like to hear any suggestions on how to account for these speed switches in fatigue analysis.

Thank you for your help

Alexandra Seber
Modular Wind Energy, CA

We run lots of separate simulations. We use Perl scripts to create the input files and run them. We are working on a script that will run all (or a subset) of the DLCs for you, but it’s not ready for release. I hope we will be able to release it before the end of the year. We used to use older scripts (RunIEC and RunNTM), which are available on our web site (visit http://wind.nrel.gov/designcodes/miscellaneous/), but they are decidedly inferior to the new script and work with an old version of FAST. You can modify them for your needs if you can’t wait for the new script. You can get a freeware version of ActiveState Perl, which is what we use. You may also consider writing a script in MatLab, if that is a language your are more comfortable with. You can look at our Perl scripts to get an idea of a way to do it.

In addition to running jobs sequentially, the new script (also called RunIEC) can also submit jobs to a Windows HPC cluster for parallel processing. Our 240-core cluster can run an entire loads analysis in less than an hour by running hundreds of jobs in parallel.

Dear Marshall,

I am running some DLCs from the IEC standard for a 1.5 MW turbine to study the fatigue and ultimate loads, and the wind speed range is from 4 to 26 m/s in steps of 1 m/s. From your reply on this thread, could you kindly send me the new script RunIEC on my email please? My email ID is vishalsairam1995@gmail.com

Currently I am running separate openFAST simulations for each windspeed and it is proving to be cumbersome and very time consuming. I would be very grateful if you can send me this script.

Best regards,
Vishal Sairam

Dear Vishal,

Marshall Buhl has since retired from NREL. RunIEC and RunNTM are no longer supported at NREL, but I just sent you an e-mail.

Best regards,

Dear Jason,

I am on the same cross-path as Vishal. Could you please share the script where I can run the DLC 1.2? or if it is publically available please direct me to the location.


with regards

Dear Satwik,

I just sent you an e-mail.

Best regards,