Do you know how the FAST and ADAMS (Using A2AD) compute tower base loads?
In ADAMS it is computed outside of the adm file and results are found in plt file. I used following statements to get the results myself(inside of adm file), but the results are different from that one computed outside the adm file.
! adams_view_name=‘TwrBsMy_V’
VARIABLE/310, FUNCTION=TY(1301,1400)
! adams_view_name=‘TwrBsMx_V’
VARIABLE/311, FUNCTION=TZ(1301,1400)
! adams_view_name=‘TwrBsFx_V’
VARIABLE/312, FUNCTION=FY(1301,1400)
! adams_view_name=‘TwrBsFy_V’
VARIABLE/313, FUNCTION=FZ(1301,1400)
Are my statements true?
Any comment
Dear Mehdi,
The ADAMS-to-AeroDyn (A2AD) interface computes the tower-base fore-aft bending moment (TwrBsMyt) using the equivalent of FUNCTION=TY(1400,1101,1100); likewise for the other tower-base loads. (I say "equivalent’ because it is actually computed in the A2AD source file using a call to SYSARY(‘FORCE’,…).)
FAST uses the load summation method to compute the tower-base loads. That is, the tower-base bending moment is calculated in FAST by integrating along the tower the ( radial vector ) x ( applied aerodynamic forces + gravitation forces - inertia forces ). All of these forces, moments, and distances are vectors and are oriented with the tower as the tower deflects.
Best regards,
Dear Jonkman
I am using another hydrodynamic diffraction software for my multi-body platform analysis. so for aerodynamic effects, can I use FAST’s tower-base loads instead of aerodynamic loads? TwrBsFxt is sumation of just airodynamic loads on blades an tower. am i right??? what about other loads???
Dear Mehdi,
As I mentioned above, the tower-base loads output from FAST include the effects not only of aerodynamic loads, but also load contributions from gravity and inertia.
Best regards,