Dear @Juan.LopezMuro ,
Your process sounds reasonable to me, but I’m not sure where the issue may lie.
The following forum topics are likely of use to you:
Dear jonkman,
I have a Bladed model and I want to transform this model to Fast. So I hope to use the BModes to calculate tower frequence and compare the two software(Bladed and BModes) results. In Bladed Model about the Turbine Information column only have Mass of Nacelle and Rotor,Yaw Moment of Inertia parameters. My question is how to find or calculate the 'cm_loc', 'ixx_tip','ixx_tip','ixx_tip','izx_tip' parameters in the 'tower.bmi' file? Does it must be using the ADAMS to calculate thes…
Hello everyone,
Tower fore-aft and side-side modes shapes are needed in FAST Tower input file. I used ModesV2.22 to calculate the modes shapes. The frequencies of the five shapes are increasing. Are the first two fore-aft modes and the second two side-side modes? In Blade calculation it was clearly expained.
If the tower has also point mass at different height position, like flange, how could we consider the point mass for Distributed Tower Properties Section in the Modes or BModes input file? …
Dear Daniel,
We obtained the data presented in Table 1 using the aggregate mass tool of MSC.ADAMS – see my post dated Jun 07, 2013 in the following forum topic for more information: Using Aggregate Mass in ADAMS to Check NREL CS_Monopile.bmi - #4 by Lingling.Yin .
You could also obtain these properties using the FAST v7 linearization if you set up your model to eliminate the platform and tower and locate the platform reference point at the yaw bearing.
Best regards,
Dear Jason,
I first used Aggregate Mass in ADAMS to calculate SNL 13.2MW mass moment of inertia and I used the outputs into .bmi file. The results of N.F are quite off from what I got from ADAMS (with only Twr DoFs on).
I then downloaded wind.nrel.gov/public/jjonkman/BModes/
and wind.nrel.gov/public/jjonkman/NR … Bsline5MW/
offshore part to run the Aggregate Mass in ADAMS.
I specified a rigid NRELOffshrBsline5MW_Monopile_RF with all DoFs turning off since I only want to see the mass moment …
The last in this list explains how to derive the 6x6 mass matrix of the RNA through an OpenFAST linearization analysis. I would suggest following this process to check your hand calculation.
Best regards,