Dear Jason
It is received, thank you very much.
Kind regards,
Liang
Dear Jason,
I would also really like to use the Seismic module and can’t seem to download it online. If possible could you send me the Seismic v2.00.00 archive?
My email is emily.anderson@eng.ox.ac.uk
Thanks so much,
Emily
Dear Emily,
I just sent you the Seismic archive using WeTransfer.
Best regards,
Dear Jason,
Could you please also send me the Seismic v2.00.00 archive via WeTransfer?
Here is my email: tan.lei@riam.kyushu-u.ac.jp
Many thanks in advance,
Lei
Dear Lei,
I just sent you the Seismic archive using WeTransfer.
Best regards,
Dear Jason,
Thank you very much for sending me the Seismic archive. I am trying to use it to obtain ground motions and calculate seismic loads on a TLP by my own code. Could you please explain how to obtain vertical ground displacement due to earthquake? I have no problem in simulating acceleration.
Besides, I checked the results in “primary.out”, and found that the vertical acceleration of platform is smaller than the output acceleration in SynMotionZ. I do not understand the reason. Could you please give some explanations?
Dear Lei,
You can prescribe displacement instead of acceleration by setting PtfmMotionType = 3 instead of 1 in the seismic input file.
If the platform motion does not match the motion you are prescribing well, I would guess you are not setting PtfmMass in the ElastoDyn primary input file or the ActFreq and ActDamp in the seismic input file appropriately, based on the recommendations in the “Seismic Loading for FAST” documentation (NREL/SR-5000-53872).
I also see that you mention a TLP. It is probably obvious by the input file settings, but the seismic functionality of FAST v7 applies only to land-based or fixed-bottom offshore wind turbines with monopile substructures.
Best regards,
Dear Jason,
I am trying to simulate a turbine subjected in seismic motion. But I can’t download the SEISMIC module and example files from NREL Wind Research website. Could you also share me the Seismic v2.00.00 file, 6 simulation examples and related documents by my email : [15738390599@163.com or pengfeifeixu@mail.dlut.edu.cn) ?
Thanks,
Pengfei Xu
Dear Pengfei Xu,
I just sent you the Seismic archive using WeTransfer.
Best regards,
Dear Jason,
Thank you very much for your reply.
Best regards,
Lei
Jason Jonkman via NREL Forum <nrel@discoursemail.com> 于2022年3月3日周四 01:57写道：
Dear Jason,
Thanks for your sending Seismic v2.00.00 archive via WeTransfer. However, I met some troubles. I have read out the pdf titledSeismic Loading for Fast and tried running the example 1_NRELOffshrBsline5MW_Onshore_udm_wo_baseline_wo_target.
The command line window told me that the pitch.ipt and spd_trq.dat files were missing, so I copied them from other folders into the example file directory. Then the calculation starts running, prompting a warning: small Angle assumption violated.
Later in the out file, I also see that the result is invalid. What is the reason for this? How to solve it?
Great thanks,
Pengfei
Dear Jason,
I’m sorry that I forgot to tell you that at the beginning of the simulation, I adjusted the GBRatio as prompted as shown following.
Dear Pengfei,
Your use of a wind turbine controller that is incompatible with the wind turbine you are simulating is causing the problems you are facing. Did you recompile the Seismic version of the FAST executable yourself? It appears that you recompiled the executable but did not include the interface to the Bladed-style DISCON controller.
The sample seismic models do not need the Pitch.ipt or Spd_Trq.dat files and do not need GBRatio = 1. Instead, the seismic models use blade-pitch and generator-torque control logic from a Bladed-style DLL (DISCON.dll). This DLL will be called when the Seismic version of the FAST executable is compiled with the interface to the DISCON controller. (This is how the Windows executable provided in the Seismic archive was compiled.)
Best regards,
Dear Jason,
Thank you for your reply. I think I have figured out the reason. In fact, the executable I run is fast_iwin32. exe, not fast_iwin32_DLL.exe. I think the latter is the compiled executable program with the seismic module , now I have been able to run the example successfully, thank you!
Pengfei
Dear Jason,
I have some questions to consult you. You said the seismic functionality of FAST v7 also applies to fixed-bottom offshore wind turbines with monopile substructures, but I can’t find HydroFile in the input file settings. Could you please tell me how to apply the seismic functionality to fixed- bottom offshore wind turbine with monopile substructue? In addition, I can’t find FAST v7 anywhere, could you tell me how to find it?
Great thanks,
Dear @Xu.Pengfei,
In FAST v7, the HydroDyn module inputs are included with the platform-related inputs in the platform file. To include seismic functionality for an offshore wind turbine atop a monopile, the model should be set up similar to the coupled springs model–e.g., see the platform file named NRELOffshrBsline5MW_Platform_Monopile_CS.dat and the associated tower file named NRELOffshrBsline5MW_Tower_Monopile_CS.dat that I shared in my Nov '18 post in the following forum topic: Simulating OC3 phase II coupled springs in FAST v7 - #2 by Jason.Jonkman. In that post, setting PtfmLdMod = 1 referenced a SUBROUTINE UserPtfmLd() that included an implementation of a coupled springs foundation. When running the seismic version of FAST v7, SUBROUTINE UserPtfmLd() includes the seismic functionality instead, which requires the addition of the seismic input file.
The standard version of FAST v7 is available here: https://www.nrel.gov/wind/nwtc/assets/downloads/FAST/FASTv7.02/FAST_v7.02.00d-bjj.exe. The version of FAST v7 with the seismic functionality should be available here: Seismic | Wind Research | NREL, but I’ve had to send the associated archive via WeTransfer as stated above.
Best regards,
Dear Jason,
I guess it is not possible in the current version of FAST_Seismic to directly enable a coupled springs or distributed springs model solely through settings in the input file, right? Whether a slight customization (requiring recompile) of FAST is currently required? I need to replace the SUBROUTINE UserPtfmLd() in UserPtfmLd_CS.f90 file you uploaded with the SUBROUTINE UserPtfmLd() in UserPtfmLd_Seismic.f90 and recompile based on FAST_v7 all Source, is that right?
Great thanks!
Dear @Xu.Pengfei,
The Seismic functionality of FAST v7 is essentially based on a coupled springs foundation except that (1) the Seismic functionality is only implemented for the translation DOFs (surge, sway, heave), not the rotational DOFs (roll, pitch, yaw) and (2) the stiffness and damping are defined by via an actuator frequency (ActFreq) and damping ratio (ActDamp) rather than through direct stiffness and damping matrices. The Seismic functionality does not support a distributed springs foundation model.
I need to replace the SUBROUTINE UserPtfmLd() in UserPtfmLd_CS.f90 file you uploaded with the SUBROUTINE UserPtfmLd() in UserPtfmLd_Seismic.f90 and recompile based on FAST_v7 all Source, is that right?
Regarding this statement, would say that to compile the Seismic version of FAST v7, you should recompile FAST v7 with the UserPtfmLd_Seismic.f90 source file in place of the UserPtfmLd_CS.f90 source file.
Best regards,
Dear Jason,
I’m sorry, I don’t fully understand you.
I have learned that the seismic feature does not support distributed spring foundation model due to the rotational DOFs. But what about the seismic functionality appling to coupled springs foundation model? Your suggestion is to be directly recompile FAST v7 with the UserPtfmLd_Seismic.f90 source file in place of the UserPtfmLd_CS.f90 source file. But I think this can only achieve the basic function of coupled spring and lose the seismic function, I don’t know if I understand correctly.
Thank you for your patience, which is very helpful to me
Dear @Xu.Pengfei,
I agree with your statements concerning the Seismic functionality of FAST v7. The term “coupled springs” foundation typically refers to a stiffness matrix (and damping) applied at the base of the tower. This is what the Seismic functionality is using, except only in the translation DOFs (surge, sway, and heave directions).
Best regards,