General Mechanical

General Mechanical

Revolute joint not working

    • Naveed
      Subscriber

       Hi everyone!


      I have a quarter car model which is given a joint displacement. Parts are moving as single rigid body as seen in animation https://drive.google.com/open?id=1hFJO5mHGwoOPJ3li8-OS8xv-M7gByHiQ


      Revolute joint should work as seen by configuration (picture attached) 

      Any expert here, please?


      Thanku

    • Naveed
      Subscriber

      I can give archive file, too.

    • peteroznewman
      Subscriber

      Naveed,  please provide the archive, I will take a look.

    • Naveed
      Subscriber

      Thanks brother. 
      I cannot attach here. Should I provide the link?

    • Naveed
      Subscriber

      Here you go
      https://drive.google.com/open?id=1kNCRZG1ExjFbcs6JrPptluVeodzpGuvk

    • Naveed
      Subscriber
    • Naveed
      Subscriber

      The response should die out due to the damper.

    • Rob
      Ansys Employee

      I've just approved one of the linked posts: apologies if anything is out of posting order. 

    • peteroznewman
      Subscriber

       Naveed, I have your model. What version of ANSYS are you working with?

    • peteroznewman
      Subscriber

      You have too many parts. Several bodies are moving together, and you are using Fixed Joints to hold them together.  It is cleaner to go into DesignModeler and select all the bodies that move together as one part and Form New Part. Then you have a simpler set of joints in Mechanical.



      Automotive suspensions I know usually have two A-arms to make a parallelogram between the body and the hub. You only have one, so I will use a General joint to support zero rotations of the hub.



       


      An ANSYS 19.2 archive is attached.


      Regards,
      Peter

    • Naveed
      Subscriber

      Dear Peter, thanks for your quick response. 


      This is MacPherson suspension which has only lower arm. Thanks for the detailed description. I am currently using Ansys 15.0 in my university so I cannot open it. Let me try to get v19.2 and see your file. Thanks again. (Y)

    • peteroznewman
      Subscriber

      Dear Naveed,


      Thanks for the clarification.
      A MacPherson strut needs a spherical joint at the top of the strut as well as the bottom,
      and a translational joint between the cylinder and piston of the strut.



      I think I have ANSYS 15.0 on a spare computer at work.


      You can download an install ANSYS Student 19.2, from the link on this website.


      Regards,
      Peter

    • peteroznewman
      Subscriber

      So you can't have two spherical joints unless you add something to steer the tire. I made the joint on top a universal to prevent the tire from steering.


      Attached is an ANSYS 15.0 archive.


      If this answers your question, mark the post as Is Solution, or ask a followup question.


      Regards,
      Peter

    • Naveed
      Subscriber

      Thanks a lot Peter. I must say u are a life saver and a true ANSYS expert. Yes I got the solution. (Y)

    • Naveed
      Subscriber

      After investigating both of your files, as I am beginner, I find the first one more simpler. My problem was that I was translating wheel up and down. When the arm rotates, it makes wheel closer to the body, therefore, that axis must be free of translation by using general joint. And I learnt other features by you. Thanks )

    • peteroznewman
      Subscriber

      The first file imposed zero rotation constraint on the hub, but in a MacPherson strut design, the hub does tilt a little as the A-arm sweeps through its arc. The second 15.0 model implements more faithfully a MacPherson strut.


      Regards,
      Peter

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