General Mechanical

General Mechanical

how to define rotational velocity as initial condition?

    • Vanderbezi
      Subscriber

      Hello everybody!


      my aim is to model a 3-cylinder engine crankshaft with variable piston loads and with an initial rotational velocity of 5000 rpm.


      As i am new to Ansys, i am not sure which type of analysis to use. I thought the transient structural analysis to be right, but for some reason within the "initial conditions" the rotational velocity is grayed out and i cannot use it.


      should i change the analysis type? or am i doing something wrong with the rotational velocity?


      regards,


      Bezi

    • Sandeep Medikonda
      Ansys Employee

      Hi Bezi, 


      According to the manual, you should be able to define Initial conditions in a Transient Structural Analysis. Please see this:



      I checked this in 19.1, what version are you using?


      Regards,


      Sandeep

    • Vanderbezi
      Subscriber

      Hello,


      I am using the 19.1 version.


      My problem is, although the button for rotational velocity is there, it cannot be pressed, and only the normal velocity can be applied.

    • Sandeep Medikonda
      Ansys Employee

      Ahh, I see. I don't think this is possible from the GUI, but let me check if we can do this through a command object.


      Regards,


      Sandeep

    • Sandeep Medikonda
      Ansys Employee

      Hi Bezi,


        This can be done using the command snippet using the "icrotate" command snippet.


      !   Commands inserted into this file will be executed just prior to the ANSYS SOLVE command.
      ! These commands may supersede command settings set by Workbench.

      ! Active UNIT system in Workbench when this object was created: Metric (mm, t, N, s, mV, mA)
      ! NOTE: Any data that requires units (such as mass) is assumed to be in the consistent solver unit system.
      ! See Solving Units in the help system for more information.

      !arg1 - omega
      !ar2-4 - (x,y,z) of the initial point of the vector in csys,0
      !arg5-7 - (x,y,z) of the final point of the vector in csys,0

      icrotate,all,arg1,arg2,agrg3,arg4,arg5,arg6,arg7,0,0,0,0


      I tested this on a simple model and was able to successfully run this. I think this should be available from the GUI itself and will file an enhancement request on this. Thanks for bringing it to our attention.



      P.S: If a post answers your original question, please mark it as a solution (‘As Solution&rsquo so that it might help someone in the future. This will help reduce repetitive questions and help provide better support on this Forum.


      Regards,


      Sandeep

    • Vanderbezi
      Subscriber

      thank you for your quick answer.


      regards,


      Bezi

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