4 Replies Latest reply on Jun 2, 2008 1:49 PM by Bill McEachern

    Cosmos works bolt connectors

    bobbi dassow
      I have been working with a model that is bolted with a clearance hole in cover and a threaded hole in base. There is pressure applied to the pockets in the base. If I use the major dia of a 1/2-13 bolt I get a large stress around the edge of the threaded bolt hole. I tried a chamfer on the bolt hole and induced more stress. I then tried to use the minor dia on the base with the same 1/2" bolt. The stress was less. Is this the proper way to model threaded holes using the minor dia? If not what is the proper way to model for threaded hole connectors?
      Bobbi Dassow
        • Cosmos works bolt connectors
          Bill McEachern
          What is the objective of your analysis?

          Are you using a simplified version of a solid fastener?
          A bolt connector?

          I would suggest you use a blot connectro and it will provide the loads in the fastener. Then just ensure you have the proper spacing to any edges from bolt hole center.

          You high stress sound like it might be a modeling error but it depends on what the objective is.
          • Cosmos works bolt connectors
            bobbi dassow
            I am modeling a flange and cover. I then appliy pressure to see if the flange can wthstand the applied pressure. I am using the bolt connector in Cosmos works. With varying answers I am nto sure which way is correct. The sample lessons from the class shows using holes fromhte hole wizard. This really increased the stress on the threaded hole edge.
            Bobbi
              • Cosmos works bolt connectors
                Bill McEachern
                What are you trying to figure out?

                You need to understand what a bolt connector is. It is a beam element run down hte center of hte bolt hole and connected to the adherents with rigid bar lements. If you are trying to resolve the stresses in the adherents in close proximity to the hole your modeling approach may not be valid. If hte faster load is with in the faterener allowables and the edge distances from hole center to edge are in the right range I would bet that the stresses are not real as all the load will get taken by the inital rigid elements if they are attached to the bore which it sounds like they are. In real life and depending on the thread type (fine or coarse) the load will be distributed in the first 3 or more threads.

                Good luck.
                • Cosmos works bolt connectors
                  Bill McEachern
                  If this was useful can you do me a favor and add some support for my post on engineering notation to implemented in COSMOSWorks.
                  Thanks,