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Where has all the friction gone? devOLVED

Discussion in 'Dynamics for Geomagic Design (Motion Analysis)' started by RCH_Projects, Apr 18, 2017.

  1. RCH_Projects

    RCH_Projects Alibre Super User

    Trying to finalize analysis of a model I am creating a "clean" simulation from scratch and applying all I've learned about Dynamics.

    But try as I might my friction has faded to oblivion. I especially use high friction (with a variable) to determine available torque - the end goal so to speak.
    I have used the original sim for a hundred variants this way.

    On this rebuild I have to push the values "orbital" to have effect.
    Maybe I have overlooked or forgotten a setting. Please take a look and advise.

    I created a new assembly with just a flywheel and axle, using an inserted torque (-10 ft. lbs.) to analyze and found no clue.


    Typically I have a coefficient of .8 and a 1.07 foot radius to slow things to a crawl.
    Coefficient 20 at 111,000 ft. to do the same seems a bit much.

    The part properties are set to coefficient of friction of .8 as well.





    I can't keep on this glitch indefinitely, care giving - so Thank you!
     

    Attached Files:

  2. RCH_Projects

    RCH_Projects Alibre Super User

    Re: Where has all the friction gone?

    Using a second flywheel with sim applied torque (-10 lbs.) and a belt constraint to flywheel-1, produces normal friction and torque results!

    Removing the torque from the second flywheel and placing it on flywheel-1 (the flywheel with friction and measured torque to shaft) only produces about 1/3 torque (and friction, based on rotation acceleration) now. That is better but far from acceptable and without explanation.

    Sim applied torque on a metered object has issues I suppose.

    The implication is that I should be able to get what I need with an extra flywheel in the target sim (although it is presently belted to a rotor????).
    The prior sims actually have such a relationship by luck, as the "second flywheel" was construed as a wheel.

    Success by luck/accident/trial and error/dogged determination? Awesome! :?: YMMV



    http://design-simulation.com/ Anything else I should know about? :shock:
     

    Attached Files:

  3. RCH_Projects

    RCH_Projects Alibre Super User

    Forget it - random success on slopware.
     
  4. listastudio

    listastudio Member

    I tried to download Your file to investigate it but it contains error and cannot be opened with actual build 9.85 of SimWise.
    Please try to post it again, ciao

    upload_2018-1-10_20-57-54.png
     
  5. RCH_Projects

    RCH_Projects Alibre Super User

    "file contains error" ... ... ... ... ... hmmmm

    Dynamics 8.7, build 1336 - money ran out for maintenance - and ... ... ... here I am.

    I doubt if you can get there from here.
    I work with what I have, which could get me to what I need, which is what I want, if I can push through what I have.

    Would love to see error details for insight.
     
  6. RCH_Projects

    RCH_Projects Alibre Super User

    OK????

    I downloaded the posted WM3 file and reopened.

    In friction I now find:

    WildFriction.jpg

    That is crazy of course. "I" didn't do that, but I can see why it gave anyone an error! OH - I see, I tried an extreme value for "any" effect.

    I'll inspect original and post findings.
     
    Last edited: Jan 11, 2018
  7. RCH_Projects

    RCH_Projects Alibre Super User

    I have to take focus away a lot for care giving, and a lot for sim efforts. So If I step back from sim efforts it is because there is no stepping back from care giving. At 87 mother is getting the respectful care that she always deserved and her 4 legged, other loving companion is near terminal as well. This has gone on for about 15 years and usually I work after it is her "lights out" and I am practically never at my sharpest. My posts here are as much to help me track what does or may or may not work. That said;

    The initial effort posted was a return to "simulation 101" level. Getting stumped there is like applying the emergency break at 100 MPH on slick roads. I complain.

    I started over with the original assembly (same as zipped above) and recreated the sim file from scratch. It is only an anchored pulley shaft with a flywheel. Inserting torque on the flywheel or a revolute constraint, with variations in sim settings return no friction.

    As noted in a later post, it appears the mere difference in constraint orientation can cause unpredictable failures. At 19 I was a programmer analyst at Rice University ("The Ivory Tower of Evil"). I could take pseudo code and a memory dump and ferret out issues like this. Without that I can only isolate "hard error" by trial and error. A very long process.

    With nothing else to go on, please try to open this sim. It is a clean export from the "GeoMagic" as-is from the "Export to Dynamics..." menu, with no modifications. Please let me know if it opens cleanly.

    Ciao

    New Assembly (1).2.zip
     

    Attached Files:

  8. RCH_Projects

    RCH_Projects Alibre Super User

    5 downloads, no replies, dog dead...

    Bad week!
     
  9. RCH_Projects

    RCH_Projects Alibre Super User

    I should note that I need to know if any other version of Dynamics / Simwise can open the New Assembly (1).2.zi.p file above.
     

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