Dear all,
I have a question about the content shown on page 28  29 in NREL report  NREL/TP50038060:
Not including platform motion, the higher fidelity ADAMS model of the landbased version of the wind turbine incorporates 438 DOFs as follows:
• One hundred and two DOFs in each of the three blades, including flapwise and edgewise shear and bending, torsion, and extension DOFs
• One bladepitch actuator DOF in each of the three blades
• One variablegenerator speed DOF and one driveshaft torsional DOF
• One nacelleyaw actuator DOF
• One hundred and twentysix DOFs in the tower, including foreaft and sidetoside shear and bending, torsion, and extension DOFs.
The questions are:
 How can we count the number of degree of freedoms in ADAMS model?
 What are the flapwise and edgewise shear and bending? Do they still use the modal analysis based on the mode shapes?
Thanks,
Dear Lingling,
The number of DOFs in an ADAMS model is identified in the command window when you run the simulation with ADAMS/Solver.
By “flapwise shear and bending” I’m refering to translational and rotational DOFs in the flapwise and edgewise directions of the blade.
ADAMS does not use modalbased DOFs; instead, ADAMS is a general multibody dynamics program where each “body” has six DOFs. (A blade is modeled as a series of 6DOF rigid bodies.)
Best regards,
Dear Jason,
Thanks for your response.
So, I still want to make sure I am understanding the model right:

“One hundred and two DOFs in each of the three blades” may yeild 17 rigid bodies of each blade and is equal to BldNodes. The aerodynamic force can only be determined for the 17 nodes. FAST will interpolate the NBlInpSt = 49 to the 17 blade node location to do aeroelasticity calculation.

“One hundred and twentysix DOFs in the tower” may yeild 21 ridid bodies of tower. Since the TwrNodes = 20, did you include 6 DoFs of the platform in your model?
Thanks,
Best regard,
Dear Lingling,
I agree with your 1st comment. If the blade had a tip mass separate from the distributed mass, the tip mass would introduce another 6DOF rigid body.
For the 2nd comment, the extra rigid 6DOF rigid body comes from the yaw bearing, not the platform. If the platform DOFs are enabled, they would introduce another 6DOF rigid body.
You should be able to examine subroutine FAST2ADAMS.f90/MakeACF() to see how the FAST model DOFs are related to the DOFs enabled in the ADAMS model.
I hope that helps.
Best regards,