6 Replies Latest reply on Aug 25, 2010 6:11 PM by Jeff Mirisola

    Study set up

    Jeff Mirisola

      Morning all,
      While I've done some Simulation studies in the past,  they've always been straight forward studies. This time I need some help  with the set up.
      I have an 8" diameter rod threaded into a 1/2 tube  with a 3" wall thickness. They are Acme threads at 1/2" pitch. Once threaded together, the rod will be welded to the tube as well. The  question is whether the threads, and weld, will withstand 24,000 lbf.  (FOS of 4). I did create the threads on the two pieces as I'm guessing  that I'll need to create contacts between them, but I'm hoping that  someone can tell me the best way to go about this.

       

      Thanks!

      Jeff

        • Re: Study set up
          Michael Feeney

          For clarification is this kind of what you mean? If so, that's an odd design : ]

           

          Rod.png

            • Re: Study set up
              Jeff Mirisola

              For clarification. This is only a small portion of the design and, no, I can't tell you what it is. Just know that, in the end, the rod will be supporting ~7,000 pounds and I need a FOS of 4.

               

              Simulation.jpg

                • Re: Study set up
                  Michael Feeney

                  Got it. Well you can do edge weld...but I don't know what edges you would choose. Normally you need to choose two faces and an intersecting edge to define the weld joint. Obviously this will be a single fillet weld (you access this feature in contacts). The only difficulty will be figuring out what faces and edge to choose to position the weld on the outer surface of the half tube and the corresponding thread edge of the 8" cylinder. You are right about the contacts though. You need to define contact between your half tube threading and the 8" diameter rod threading. I think you can just select the parts and automatically define the contact...if not the manually select each face and define the contact logically.

                   

                  Oh I thought of something. Make your rod with the threads ...but when you get to the edge of your half tube stop the threads so that it creates a flush edge. Drawing is better than words. Perhaps you've already done this. Hope it helps a little.

                  Rod2.png

                  • Re: Study set up
                    Michael Feeney

                    7000 lbs cantilevered? or axial?

                • Re: Study set up
                  Ryan Werner

                  Hi Jeff,

                   

                  You can use the edge weld feature only if you make the half tube a sheet metal part or surface body.  It does not work with two solid bodies.  So you can verify your weld using that method but unfortunately you cannot check the weld and the threads using that method because in making the half tube a surface body it will then have no thickness and your threads will be lost.

                   

                  Your best bet is to probably leave both bodies as solids and then create your No Penetration Contact Sets for the threads and then model a weld.  I created a weldment and then used the weld bead feature and it worked well.

                   

                  Ryan W.