Possible Joint connections issue “Constraint conditions are not satisfied”

- June 1, 2023 at 11:31 pm
  
  cheng089413
  Subscriber
  
  Hello,
  I am using planar joint connection (axial movement is restricted) to connect the bolt head bottom to the beam in order to simulate the effect of the washer. as shown in first figure.
  Since the washer is too thin compared to others, meshing would be difficult. I am not sure whether this method works because i kept seeing a message in the solution output, saying "Constraint conditions are not satisfied for 4 joint elements with lag mult option", plz see the second figure
  Will it affect the results however the solution was still finished anyway?
  Thank you!
- June 2, 2023 at 9:33 am
  
  Aniket
  Ansys Employee
  
  Solution does not seem to be converged right now, one good way of checking model constraints at the initial time step would be doing a modal analysis that would show if the model is constrained at the first time step or not.
  -Aniket
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  - June 2, 2023 at 9:51 am
    
    cheng089413
    Subscriber
    
    Hello Aniket,
    Thank you for your reply.
    I just took that screenshot for an example and had no idea wht that message meant. plz see the following screenshot that the message occured again while solving the model
    Could you plz give more info about that message? I believe the model is constrained but i am not sure whether i can apply the planar joint connection to simulate the washer under the bolt head.
    Thank you!
    - June 2, 2023 at 9:55 am
      
      Aniket
      Ansys Employee
      
      which message are you referring to?
      -Aniket
      How to access Ansys help links
      Guidelines for Posting on Ansys Learning Forum
    - June 2, 2023 at 1:26 pm
      
      cheng089413
      Subscriber
      
      Hello Aniket,
      I was referring to the message in the solution output " "Constraint conditions are not satisfied for 4 joint elements with lag mult option"
      i dont know wht it means
    - June 5, 2023 at 8:53 am
      
      Aniket
      Ansys Employee
      
      If the solution finishes successfully then such messages during the solution can be ignored.
      They are just part of the solution process. If a solution was not able to satisfy the constraint conditions for a joint after all the convergence iterations were completed then there would
      be the concern that a joint didn't do what it was supposed to do.
      For example, a cylindrical joint might not have kept the reference and mobile surfaces concentric.
      -Aniket
      How to access Ansys help links
      Guidelines for Posting on Ansys Learning Forum
    - June 5, 2023 at 9:16 am
      
      cheng089413
      Subscriber
      
      Thank you Aniket!

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