Mode shapes for the first and second bending modes of the tower of the 5 MW in both fore-aft and side-side directions without RNA

Wind & Water Computer-Aided Engineering Software Tools
1

Hello,

Does anyone have computed the mode shapes for the first and second bending modes of the tower of the 5 MW in both fore-aft and side-side directions without RNA mass ?

If yes, could you provide the corresponding polynomials ?

Thanks in advance.

Best Regards,

Riad

2

Dear @Riad.Elhamoud,

I don’t have these myself, but you can always compute them yourself with BModes or similar software.

Best regards,

1 Like
3

Dear @Jason.Jonkman,

Thank you for your response.

I have tried to use Bmodes. I use the executable named “BModes_JJ.exe” and the input file has the extension “.bmi”. Bmodes runs the same way as openfast (in the command prompt). The input file was configured based on the data i have found in the technical report of the 5 MW.
In the following, a screen capture of the results:

Capture
Capture957Ă—278 9.23 KB

What do you thnk about the frequencies ? Are they acceptable ?

Could you tell me please how to find the mode shape (Excel sheet or matlab script) ? In addition, in my understanding the mode shape is the best fit of the deflections obtained in the “.out” file. Do you confirm ? meaning that if i copy the deflections from the “.out” file and i fit them, i will obtain the mode shape right ?

Thank you in advance.

Best regards,

Riad

4

Dear @Riad.Elhamoud,

Again, I haven’t computed these myself, but the values seem about what I expect them to be.

The spreadsheet ModeShapePolyFitting.xls is available on my Google drive: ModeShapePolyFitting.xls - Google Sheets. Yes, your understanding is correct.

Best regards