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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

  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


    I downloaded the posted WM3 file and reopened.

    In friction I now find:


    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.


    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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