6 Replies Latest reply on Oct 13, 2011 5:25 AM by Bill McEachern

    Composite Analysis Transverse Loading

    Irving Hu

      Hellow All,

       

      I have been using simulation reguarly to model isotropic carbon composite sheets and it works spelndidly but in doing so I am always appling loads to the face of the shell.  Now I am trying to model a condition where I have a carbon composite sheet and I have a bolt going through it.  I am concerned about tear out and trying to specify wall thickeness. As a results the loads are now plane with the face and applied to the hole edge, bearing loads.  The results I am getting are far off the mark.  I have also tried builing an aseembly and apply loads to solid bolts with a no pentration condition between the shell and the bolts but that does not seem to work either.  Any suggestions?

        • Re: Composite Analysis Transverse Loading
          Bill McEachern

          Shell edge contact is not support as I recall. Does a bearing load work on a shell edge? You might want to give that a go and at least get the right distribution. How off was the analysis that did work with the edge load?

            • Re: Composite Analysis Transverse Loading
              Irving Hu

              Yeah I am getting the sense that this is not supported.  I am getting results where a 3 kN load on a 4mm by 4mm hole with a 3mm wall is causing no deformation.  Any ideas on a work around?

                • Re: Composite Analysis Transverse Loading
                  Ryan Werner

                  Hi Irving,

                   

                  You could maybe use a split line and create a small ring around your bolt hole in which you can apply your force.  That way you are still choosing a surface to apply the load but it will be localized enough to the hole edge itself to possibly still give realistic results.  Just a thought.

                   

                  Ryan W.

                  • Re: Composite Analysis Transverse Loading
                    Bill McEachern

                    I did not buy the Premium version as I did not feel it was worth the money - NL contact is so lame as to be unusable in my  humble opinion so I can not test the composite shell element. I did do a test with a non laminated shell and it produced results that looked about right  - stress max at 38 ksi. Average for your calc was 250 MPa or so  - in the ball park. I used a sinusoidal dist on a bearing load on the shell edge. Shell was fixed at one end. I can't see why it wouldn't work in laminated shell element....but you never know with SWX sim......some stuff just doesn't work.

                      • Re: Composite Analysis Transverse Loading
                        Irving Hu

                        So I think I solved a little work around.  I made a model and then split it into multiple bodies using planes.  I then assigned material to each one and created coordinate systems to used for the reference geometry to change up the orientation of the orthotropic material.  Lastly I created a bonded contact between all the bodies.

                         

                        Thoughts?

                          • Re: Composite Analysis Transverse Loading
                            Bill McEachern

                            I think I know why you are in the ditch. It sounds like you are using the surfaces from solid bodies for a shell mesh. You need to know all about the secret decoder ring if you are going to use such an approach. Just make a SURFACE and apply the composite shell and loads. It should work fine. If you use solids, you need to ensure that the edge you pick is a surface - otherwise it won't fall on the extracted shell, hence no deformation. I would strongly advise you never use solid surfaces to extract shells. Just use the surfacing tools to make the surfaces and then delete the solid bodies. Your encounter frequency with grief will go way down.

                             

                            You don't need the work around. Just try the above. The work around may have issues with the bonded contacts. Try a bending case and see if looks just like the same case using one shell.

                             

                            Here are some images to prove the point that it works. The laminate is for some made up material 0.080" thick - 8 ply, 60 msi x 350 ksi, 0,90, +45,-45 symmetric.