3 Replies Latest reply on Jan 23, 2014 11:32 AM by Jared Conway

    'improper contact surfaces for a contact area'

    Robin Moore

      I am running a Nonlinear study and I have three parts moving and making contact with each other.  During the sliding of one component over another I get an error, 'improper contact surfaces for a contact area'.  Does anyone know what it means and how to solve it.  I have tried different mesh densities, contact types (surface to surface, node to surface), and changing from fixed to automatic time steps, etc.  No difference.  My materials are set at Plasticity - von-mises.  I have also tried playing with increasing the Tangent Modulus, but to no effect.

       

      Any help greatly appreciated.

       

      Thanks

       

       

      Rob

        • Re: 'improper contact surfaces for a contact area'
          Jared Conway

          what does the geometry look like?

           

          what does the error look like? does the solver just stop at that point?

            • Re: 'improper contact surfaces for a contact area'
              Robin Moore

              This is what I get in the OUT file, if it helps. The simulation comprises of a thin metal disk that is being formed using a circular punch.  The solver stops and gives the error 'improper contact surfaces for a contact area'.  It then suggests I look in the OUT file.  I have had other models with the same geometry and restraints work before.  I have no idea how to change the 'soft spring' mentioned in the OUT file.

               

               

               

              G A P  D A T A

                    Total Number of Gap Elements . . . . . . . . . . . . . = 3624

                    Number of Gap Blocks (flexibility matrix) . . . . . . .=    1

              GAP        g        fric        1./k       f0          G          c         p

              No.

                     Soft spring for contact for step   144

                     x-dir          y-dir         z-dir

                    2.806          2.908          40.06   

                     0.2000E-06

                 

                   Penalty value is raised to  0.20479E+14

               

                   Check connectivities and direction for surfaces:

                    20316 19802 19960 19881

                 

                   Other Possiblities:

               

                    a) Coincident Gap sub-surfaces exist in the same Gap group.

                       [Repeated (identical) sub-surfaces must be deleated]

                    b) The structure may not be constrained properly

                       (Stiffness matrix is close to singular)

                    c) The soft springs used for stability may be too soft

                    d) Load increment may be too large (reduce the time inc.)

                    e) The structure may be close to a state of buckling

               

               

              T O T A L   R U N   T I M E   (Sec) . . . . . . . . . . =     20

                • Re: 'improper contact surfaces for a contact area'
                  Jared Conway

                  have you reviewed all of these?

                   

                        a) Coincident Gap sub-surfaces exist in the same Gap group.

                           [Repeated (identical) sub-surfaces must be deleated]

                        b) The structure may not be constrained properly

                           (Stiffness matrix is close to singular)

                        c) The soft springs used for stability may be too soft

                        d) Load increment may be too large (reduce the time inc.)

                        e) The structure may be close to a state of buckling