General Mechanical

General Mechanical

Error when attaching a mass point and a longitudinal spring to a surface at different locations!!

    • Rana Nasser
      Subscriber



      Hi,


      To apply the above water modeling approach in ansys WB (mechanical) I have used remote attached point masses to model (M0) and a 1 m^3 solid box ( I had added it to the model in design modeler) connected to the structure with 2 longitudinal springs as shown in the images below.


      Note: I have divided M0 into to point masses and attached one point mass to the left wall and the other to the right wall. 


      when I tried to solve the model this warning "Two or more remote boundary conditions are sharing a common face, edge, or vertex.   This behavior can cause solver overconstraint and is not recommended, please check results carefully.  You may select the offending object and/or geometry via RMB on this warning in the Messages window."was appear then the solution stopped with this error "At least one contact pair or remote load has no elements in it. This may be due to mesh based defeaturing of the geometry.  You may select the offending object via RMB on this warning in the Messages window."


      To handle the error I turned the mesh defeaturing option to "no" and tried to solve again, but I get the same warning and the same error. I also edited the pinball region of the mass point from all the face to 0.05 meters and the pinball region of the longitudinal spring to .2 meters instead of all the face which means that each face have a pinball region of the mass point ans a pinball region of the spring and there is no contact between the 2 region.  


         Could anyone give a hand please?!!



       

    • peteroznewman
      Subscriber

      Hi Rana,


      Did you split each wall into two face at a height half-way between H0 and H1?  Then the bottom springs and the top springs are attached to different faces.


      Regards,
      Peter

    • Sandeep Medikonda
      Ansys Employee

      Please see this article by one of our channel partners that explains such warning messages very well.


      Regards,
      Sandeep

    • Rana Nasser
      Subscriber

      Hi,


      I have used Peter's suggested procedure, but I have got the same error!


      I have also used remote points as suggested in the article that Sandeep mentioned in the part "two remote objects operating on the same surface" (I have used remote points using the "promote to remote point" option for each point mass and each end of the longitudinal springs because there are 2 different locations on each face one for the mass point and the other for the spring end point), but the same error have stopped my solution again.


       


       


       

    • peteroznewman
      Subscriber

      Hello Rana,


      I had the error "At least one contact pair or remote load has no elements in it" once before.


      Use the Mechanical Menu, Tools > Variable Manager


      In the window that pops up, right click and select 'Add'.  Then set the variable name to be contactAllowEmpty, and its value to be 1.


      Then hit Solve.  Now at least solver will run and the Solution Information will have a complete listing of contacts and you can check which one is empty.


      Regards,
      Peter

    • Rana Nasser
      Subscriber
      Thanks peter. I'll do this and shear my findings
    • Rana Nasser
      Subscriber

      The contactAllowEmpty didn't work! I set the variable value to 1 and I got the same error, then I have changed the value from 1 to 10, but the same error appears.


      I have attached an archive if you can take a look it will be appreciated.


       


       

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