4 Replies Latest reply on Feb 25, 2008 7:13 PM by Oronde Armstrong

    Bolt connectors - help needed

    James Canney
      I have a study of some bolted cast iron components that I need to analyse, hoping someone can give me some advice.

      In the attached picture the flanged bolt has clearance through the top hole (the flange locking it down), this then bolts into the second component which has a tapped hole in it.

      Firstly looking for some guidance on how to set this up with bolt connectors in COSMOSworks.

      The assembly has symetry, will cosmos analyse the bolt connectors correctly when they have been cut along the symetry line.

      Any help here would be much appreciated.
        • Bolt connectors - help needed
          Fernando Cuenca
          If you are using Cosmos 2008 the program wll analyze the connectors properly even if they are cut by the symmetry plane. If not you'll have to model the whole assembly.

          To use the bolt connectors you need to suppress the hardware first and then go through the different options depending on what you want. This is explained in the Cosmosworks help.
          • Bolt connectors - help needed
            Oronde Armstrong
            I'm a little confused, what exactly are you trying to analyze? The bolt, or the joint? The bolt being the thread interface or joint being the surrounding material? Cosmos' method of calculating bolt preload is very crude. I would recommend doing a classical hand calculation and applying that axial force to your joint. There are a lot of factors like pitch, co-efficient of friction and head contact area, that can greatly affect your answer. Once you are confident that the thread will not strip and you have a good value of bolt preload I think you can effectively analyze the joint. Unfortunately I'm not convinced of cosmos being effective in analyzing thread strength
              • Bolt connectors - help needed
                James Canney
                I am actualy trying to analyse the effect that the bolt is going to have on the dark blue component, in the image you can only see half of it.

                There will be a load in the centre (which would be off screen to the right) of the assembly, and I want to analyse the effects of having a bolt in this position, i have already analysed the effect with no bolt.

                I am confident that the bolt being used is beefy enough, and the thread will not strip. I am also confident in the material surrounding the bolt.
              • Bolt connectors - help needed
                Oronde Armstrong
                You should be all set, I would go ahead and use bolted connectors but try to get some sort of accurate axial load value. I have no clue what cosmos does with that friction factor or what ever they call it since it doesn't account for the differences in pitch for example a M8X1 v/s M8X1.5 would have the same axial load but in real life we know this isn't true. Maybe there is a look up table but I do that stuff the old school method.