Nodal outputs from BeamDyn

Wind & Water Structural Analysis
1

Hi all,

I am using BeamDyn with the NREL 5MW onshore turbine model in my analysis. I want to get some nodal outputs, like forces and bending moments at different nodes on the blade. I have been trying many things by changing the outputs section of the BeamDyn input file, but I have been unsuccessful in getting nodal outputs. I would very much appreciate some help in this matter.

For reference, here is my BeamDyn input file, where I have mentioned NNodeOuts = 9 and have specified the nodes at which I need the output under OutNd. The output channels “Mxr”, “Myr”, “Fzr”, “TDxr” and “TDyr” are what I need nodal values for and I used the BeamDyn_Nodes sheet in the OutListParameters excel file for reference.

--------- BEAMDYN with OpenFAST INPUT FILE -------------------------------------------
NREL 5MW - blade
---------------------- SIMULATION CONTROL --------------------------------------
False Echo - Echo input data to “.ech”? (flag)
True QuasiStaticInit - Use quasi-static pre-conditioning with centripetal accelerations in initialization? (flag) [dynamic solve only]
0 rhoinf - Numerical damping parameter for generalized-alpha integrator
2 quadrature - Quadrature method: 1=Gaussian; 2=Trapezoidal (switch)
“DEFAULT” refine - Refinement factor for trapezoidal quadrature (-) [DEFAULT = 1; used only when quadrature=2]
“DEFAULT” n_fact - Factorization frequency for the Jacobian in N-R iteration(-) [DEFAULT = 5]
“DEFAULT” DTBeam - Time step size (s)
“DEFAULT” load_retries - Number of factored load retries before quitting the simulation [DEFAULT = 20]
“DEFAULT” NRMax - Max number of iterations in Newton-Raphson algorithm (-) [DEFAULT = 10]
“DEFAULT” stop_tol - Tolerance for stopping criterion (-) [DEFAULT = 1E-5]
“DEFAULT” tngt_stf_fd - Use finite differenced tangent stiffness matrix? (flag)
“DEFAULT” tngt_stf_comp - Compare analytical finite differenced tangent stiffness matrix? (flag)
“DEFAULT” tngt_stf_pert - Perturbation size for finite differencing (-) [DEFAULT = 1E-6]
“DEFAULT” tngt_stf_difftol - Maximum allowable relative difference between analytical and fd tangent stiffness (-); [DEFAULT = 0.1]
True RotStates - Orient states in the rotating frame during linearization? (flag) [used only when linearizing]
---------------------- GEOMETRY PARAMETER --------------------------------------
1 member_total - Total number of members (-)
49 kp_total - Total number of key points (-) [must be at least 3]
1 49 - - Member number; Number of key points in this member
kp_xr kp_yr kp_zr initial_twist
(m) (m) (m) (deg)
0 0 0 1.33080000e+01
0 0 1.99875000e-01 1.33080000e+01
0 0 1.19986500e+00 1.33080000e+01
0 0 2.19985500e+00 1.33080000e+01
0 0 3.19984500e+00 1.33080000e+01
0 0 4.19983500e+00 1.33080000e+01
0 0 5.19982500e+00 1.33080000e+01
0 0 6.19981500e+00 1.33080000e+01
0 0 7.19980500e+00 1.33080000e+01
0 0 8.20102500e+00 1.33080000e+01
0 0 9.19978500e+00 1.33080000e+01
0 0 1.01997750e+01 1.33080000e+01
0 0 1.11997650e+01 1.31810000e+01
0 0 1.21997550e+01 1.28480000e+01
0 0 1.32009750e+01 1.21920000e+01
0 0 1.41997350e+01 1.15610000e+01
0 0 1.51997250e+01 1.10720000e+01
0 0 1.61997150e+01 1.07920000e+01
0 0 1.82009250e+01 1.02320000e+01
0 0 2.02002900e+01 9.67200000e+00
0 0 2.22002700e+01 9.11000000e+00
0 0 2.42002500e+01 8.53400000e+00
0 0 2.62002300e+01 7.93200000e+00
0 0 2.82008250e+01 7.32100000e+00
0 0 3.02001900e+01 6.71100000e+00
0 0 3.22001700e+01 6.12200000e+00
0 0 3.42001500e+01 5.54600000e+00
0 0 3.62001300e+01 4.97100000e+00
0 0 3.82007250e+01 4.40100000e+00
0 0 4.02000900e+01 3.83400000e+00
0 0 4.22000700e+01 3.33200000e+00
0 0 4.42000500e+01 2.89000000e+00
0 0 4.62000300e+01 2.50300000e+00
0 0 4.82012400e+01 2.11600000e+00
0 0 5.01999900e+01 1.73000000e+00
0 0 5.21999700e+01 1.34200000e+00
0 0 5.41999500e+01 9.54000000e-01
0 0 5.51999400e+01 7.60000000e-01
0 0 5.61999300e+01 5.74000000e-01
0 0 5.71999200e+01 4.04000000e-01
0 0 5.76999150e+01 3.19000000e-01
0 0 5.82011400e+01 2.53000000e-01
0 0 5.86999050e+01 2.16000000e-01
0 0 5.91999000e+01 1.78000000e-01
0 0 5.96998950e+01 1.40000000e-01
0 0 6.01998900e+01 1.01000000e-01
0 0 6.06998850e+01 6.20000000e-02
0 0 6.11998800e+01 2.30000000e-02
0 0 6.15000000e+01 0
---------------------- MESH PARAMETER ------------------------------------------
5 order_elem - Order of interpolation (basis) function (-)
---------------------- MATERIAL PARAMETER --------------------------------------
“../../../TurbineData/Baseline_Blade.dat” BldFile - Name of file containing properties for blade (quoted string)
---------------------- PITCH ACTUATOR PARAMETERS -------------------------------
False UsePitchAct - Whether a pitch actuator should be used (flag)
200 PitchJ - Pitch actuator inertia (kg-m^2) [used only when UsePitchAct is true]
20000000 PitchK - Pitch actuator stiffness (kg-m^2/s^2) [used only when UsePitchAct is true]
500000 PitchC - Pitch actuator damping (kg-m^2/s) [used only when UsePitchAct is true]
---------------------- OUTPUTS -------------------------------------------------
True SumPrint - Print summary data to “.sum” (flag)
“ES10.3E2” OutFmt - Format used for text tabular output, excluding the time channel.
9 NNodeOuts - Number of nodes to output to file [0 - 9] (-)
1, 6, 11, 16, 21, 26, 31, 37, 43 OutNd - Nodes whose values will be output (-)
OutList The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
“RootFxr”
“RootFyr”
“RootFzr”
“RootMxr”
“RootMyr”
“RootMzr”
“TipTDxr”
“TipTDyr”
“TipTDzr”
“TipRDxr”
“TipRDyr”
“TipRDzr”
“Mxr”
“Myr”
“Fzr”
“TDxr”
“TDyr”
END of input file (the word “END” must appear in the first 3 columns of this last OutList line)

The error I get is -

Nodal outputs section of BeamDyn input file not found or improperly formatted.

FAST_InitializeAll:BD_Init:SetParameters:SetOutParam:Mxr is not an available output channel.
SetOutParam:Myr is not an available output channel.
SetOutParam:Fzr is not an available output channel.
SetOutParam:TDxr is not an available output channel.
SetOutParam:TDyr is not an available output channel.

OpenFAST encountered an error during module initialization.
Simulation error level: FATAL ERROR

Aborting OpenFAST.

2

Dear @Vishal.Sairam,

BeamDyn’s nodal outputs are distinct from those of the OutList.

If you want to use nodal outputs Mxr, etc., these will be output for all BeamDyn analysis nodes (not just the NNodeOuts number of output gages), but the outputs must be listed in their own section of the BeamDyn input file. That is, after the line starting with END at the end of OutList, a new output section should be listed:

...
OutList The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)
“RootFxr”
“RootFyr”
“RootFzr”
“RootMxr”
“RootMyr”
“RootMzr”
“TipTDxr”
“TipTDyr”
“TipTDzr”
“TipRDxr”
“TipRDyr”
“TipRDzr”
END of OutList section (the word "END" must appear in the first 3 columns of the last OutList line)
====== Outputs for all blade stations (same ending as above for B1N1.... =========================== (optional section)
"All"         BldNd_BlOutNd       - Future feature will allow selecting a portion of the nodes to output.  Not implemented yet. (-)
                  OutList             - The next line(s) contains a list of output parameters.  See OutListParameters.xlsx for a listing of available output channels, (-)
“Mxr”
“Myr”
“Fzr”
“TDxr”
“TDyr”
END (the word "END" must appear in the first 3 columns of this last OutList line in the optional nodal output section)

Alternatively, if you want to just output NNodeOuts number of output gages, you should add gage outputs to the first OutList. That is, instead of, listing Mxr, etc., you should list N1Mxl, N2Mxl, …, N9Mxl, etc. in the first OutList. Note that these moments are in the “l” frame instead of the “r” frame; there are fewer gage outputs available than nodal outputs.

See the Outputs section of the online BeamDyn documentation on readthedocs for more information: 4.6.3. Input Files — OpenFAST v4.1.1 documentation.

Best regards,