Scaling Anisotropic Stiffness Matrix

Wind & Water Structural Analysis
1

Hello all,

I am trying to scale down the IEA 22 MW RWT by using the data from IEA-22-280-RWT/OpenFAST/IEA-22-280-RWT at main · IEAWindTask37/IEA-22-280-RWT · GitHub . However as to my understanding, BeamDyn_Blade data includes anisotropic stiffness matrix for each blade element as given in here, https://openfast.readthedocs.io/en/main/_downloads/fd7a8bc10f2371a50828391f75170032/beamdyn_inputs_sectional_props.pdf and I don’t think it is possible to linear scaling the blades as I did for classical beam matrices. My questions are:

  1. What kind of scaling method I can implement for this data type?
  2. Is it possible to convert anisotropic blade data to isotropic one?

Thank you,

Best Regards.

2

Dear @Berat.Ercin,

Regarding (1), I have not done this myself before, but if you assume that the materials themselves don’t change, only the geometry changes (length ratio), then the elements of the stiffness matrix would scale by (length ratio^2, length ratio^3, length ratio^4) for the (upper-left quadrant, upper-right and lower-left quadrants, lower-right quadrant), respectively.

Regarding (2), the simplest approach is to neglect the anisotropy, which is essentially what we do when model a blade with anisotropy as an isotropic blade in ElastoDyn.

Best regards.

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