3 Replies Latest reply on May 26, 2014 9:45 PM by Jared Conway

    "Model may not have adequate fixtures."

    Conrad Lawson

      I'm attempting to run FEA on two hinges with a specific weight on them, and I'm having trouble getting the fixtures/connections correct.

       

      The basic setup is two hinges mounted to a door.  I have the geometry and density of the door set so I have the weight correct for an odd shaped door we have designed.  I'd like to set the wall side of the hinges (or the bolt holes) as fixed, and have the gravity.

       

      I've tried several types of connections between all of the parts. I ended up taking the hinge pins out, and added pins under connectors in it's place.  I have pins set to all connecting bolt holes between the hinges and door to keep alignment.  Then I have tried both "no penatration" and "bonded" contact between the hinges and the door (seperately).  I have also done the same between the two sides of hinges (also did this when the hinge pins were unsupressed).

       

      I have attached two pics to show this.

       

      Please let me know if anyone has any ideas of what should be added/changed.

        • Re: "Model may not have adequate fixtures."
          Kumar Dandapani

          Hi Conrad,

           

          For better understanding kindly upload your model with all preprocessing.

           

          From your screen shot updated i can understand that your fixture or contact may be a problem. You can use from the study properties select "use soft spring to stabilize Model" option to stabilize your model. It will Create external stiffness virtualy to stabilize your model. Again if your getting "Large Displacement" warning then use "No" option to run simulation with small displacement. Then you will get some result. From that result select displacement plot and do animation and find which part or sub assembly not properly constrain, that will move abnormaly. Then constrain that part or sub assembly. Then just unselect "use soft spring to stabilize Model" option and run the simulation. Thanks

           

          A.D.Kumar

          EGS Computers India Pvt Ltd

          http://www.egsindia.com

          http://www.egs.co.in

          • Re: "Model may not have adequate fixtures."
            Stefan Wozniak

            Perhaps your pins or hinges allow axial movement.

            I just gessing without files with setup

            • Re: "Model may not have adequate fixtures."
              Jared Conway

              A couple of things.

               

              It looks like you haven't modeled the pins in the hinges, you need to replace them with multiple pins to hold the hinges together.

               

              The second is that once you are there you have a semi static problem. There may still be rotating in your pins so at least one of them needs to be rotation fixed.