Input Parameters of Tower for Bmodes and Elastodyn (IEA 15 MW)

Wind & Water Structural Analysis
7

Dear @Mohamed.Fekry,

Regarding your BModes inputs for the tower:

  • radius should be equal the tower height of 144.386 m.

  • hub_conn should be 2 to account for the full 6x6 mass and stiffness matrices from SubDyn

  • The-top mass properties should be the full rotor + nacelle, not just the nacelle

  • tow_support should be 1 if you are using BModes_JJ as recommended for towers

  • Your distributed mass and stiffness don’t fully agree with what is in the ElastoDyn tower file. And we generally recommend to set the distributed inertias to near zero to match the assumptions in ElastoDyn.

Regarding your BModes inputs for the blade:

  • radius should be equal the blade radius of 120.97 m

  • hub_conn should be 1 for a cantilevered connection

  • I would expect the blade-tip masses and inertias to be zero

  • Your distributed mass and stiffness don’t fully agree with what is in the ElastoDyn blade file (which has 50 input stations). And we generally recommend to set the distributed twist and inertias to near zero to match the assumptions in ElastoDyn.

FYI: The following forum topic provides further guidance: Consistency between Bmodes and MBC.

Best regards,