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Bearing AT contact

Josef K.
Hello,
 
I am trying to understand how Bearing AT works. In the manual, it says that the order of operations is:
 
1) Preprocessing mesh -> generates .bpf, .bof, .bif files (for ball bearings)
along with the .pch files from Nastran
 
2) Preprocessing contact -> consumes (unless otherwise stated) the .pch file to create a .bcf file and .bre files.
 
As I understand it, in the manual it says that the data for the bearings is precomputed and cotnained in the .bre files, but I managed to run a simulation whithout the .bre files in the working directory (or anywhere on the computer since I had deleted them by mistake).
 
How is this possible? Did I not understand something about how Bearing AT works? Are the .bre files not mandatory?
 
If possible, I would like a more thorough explanation of how the Bearing AT plugin works, regarding the files generation/deletion at least.
 
Thanks,
 
Josef
  • 0
    I fear the only one who can shed light on this is Johann Zeischka who devolped this method.
    Basically it's more or less a NASTRAN run, saving data in tables and the ADAMS usersub doing fast & simple table lookups.
     
    Haven't seen him for quite some years as he left MSC a while ago.
    But this is his LinkedIn profile: be.linkedin.com/.../johann-zeischka-b1008482
  • 0
    Hello Josef,
     
    sorry for late response...
    The *.bre files are not mandatory, but *.bpf, *.bif, *.bof are required for the solver. This is true for a Deep groove Ball Bearing, as well as for Cylindrical Roller Bearing and Needle Roller Bearing. However the Tapered Roller Bearing and Axial Cylindrical Roller bearings currently differ a bit but we are going to align it in future releases.
     
    There is some brief explanation in Introduction section of online help, see screenshot below:
    Bearing_AT_Online_Help_Intro
     
    Could you please pin-point me to the page where you found misleading info in Online Help or Reference Manual, so we can correct that?
     
    Thanks and regards,
    Jan
     
     
     
  • 0
    Hello Jan,
     
    It was a misunderstanding on my part, not misleadeing information. I had read somewhere (can't really remember where. It was either in the forum or in the documentation.) that the bearings work in a "tabulated contact data" manner and I assumed that the contact related forces would be contained inside the contact related file i.e., .xcf. Guess I was wrong, since in the intro you attached it is clearly stated that the forces are stored in the .xif, .xof files.
     
    Thanks for clarifying,
     
    Josef
     
     
  • 0
    Hello again,
     
    I have also noticed that when using the Bearing AT plugin, what Adams does is to use a gfosub kind of function for the forces (as I recall, I noticed a gfo821). Can I acces these subroutines? I would like to alter them in order to simulate faults on the bearings.
     
    Thanks
     
    Josef
     
     
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