Model main-shaft bending stiffness reduction in OpenFAST

Wind & Water Structural Analysis
1

Hi all,

I am currently investigating structural stiffness degradation of the main shaft in a wind turbine using OpenFAST.

I understand that in ElastoDyn, the drivetrain flexibility represented by DrTrDOF, DTTorSpr, and DTTorDmp mainly describes the torsional flexibility of the drivetrain, rather than the lateral bending flexibility of the main shaft.

However, in my study I would like to investigate degradation of the main-shaft bending stiffness, for example due to shaft damage or cracking. Ideally, I would like to model reductions in the effective bending stiffness, and study their influence on shaft, nacelle, tower, and rotor dynamic responses.

My questions is:

Is there currently a recommended way in OpenFAST to explicitly model the bending flexibility of the main shaft / low-speed shaft?

Any suggestions would be greatly appreciated.

Thanks!

Hang

2

Dear @Hang.Zhang,

See a similar question recently asked and answered on our OpenFAST GitHub site: Drivetrain bending in OpenFAST for rotor OMA studies · OpenFAST/openfast · Discussion #3287 · GitHub.

Best regards,