12 Replies Latest reply on Jan 19, 2015 2:09 AM by Jared Conway

    Bolt connector Problem,

    Rajan P

      Picture-1.jpg

      I have three plates and connected using simplified bolt and nut connection using Solid geometry. The reason of avoiding bolt connector is, I am not interested in

      using Bolt preload and friction coefficient.

      Can any one help me, using simplified solid geometry, how to view the results of tensile and shear force of the bolt model using simplified bolt connection.

       

      Is there is any other method to find the tensile and shear force of the bolt (excluding the effect of torque and friction coefficient values).

       

      simulation file is attached with boundary conditions, you have to just run the analysis. From the above model please assist me how to extract tensile and shear force

      of each bolt model.

       

      Regards

      Rajan.P

        • Re: Bolt connector Problem,
          James Riddell

          I haven't downloaded your model but from the image that is a fairly simple hand calculation.  If you set up your FBD the forces will become self-evident.

           

          On the other hand, if you are asking merely how to show the effects on the components you could use ISO plot or sections for viewing.  Make sure your through bolt doesn't have bonding surface contact with the blocks and personally I'd artificially 'shorten' the blind screws to the length of about 3 threads since the theory of fastening R.O.T. is that only the top three threads hold any load.

            • Re: Bolt connector Problem,
              Rajan P

              You can have look over the model and contact conditions, to get conservative values bonded contact is given between bolt shank and block hole.

              Can you please further explain how to show the tensile and shear force of the each bolt. Since I can view only stress results on the bolt.

                • Re: Bolt connector Problem,
                  James Riddell

                  RMB click on the 'Results' tab and define a new stress plot that will show you the shear stress, principle stress, etc.

                   

                  Bonding the bolt to the hole will not give you 'conservative' values, it gives unrealistic values.  No bolt, in reality, can transfer load along it's side to the adjoining material.  I'd suggest removing the 'bonded' condition between the two and replace it with 'no penetration'.

                    • Re: Bolt connector Problem,
                      Rajan P

                      We can get only stress values on the bolt member, I am right?, then using cross section of the bolt. I should calculate the bolt force , tensile (Fz) force and shear force (Fx,Fy) manually but if we use bolt connector option , we can get directly the Shear force(Fx,Fy) and tensile force Fz directly from connector force option. Please advice

                       

                      Case-2.

                      Using bolt connector option , whether it is possible to exclude the effect of pre-load and can able to run the analysis. Please suggest.

                • Re: Bolt connector Problem,
                  Seckin Uslu

                  Here is a simple file with bolt. Right click result file and you can see bolt results.

                   

                  Don't forget  mesh refinement.

                    • Re: Bolt connector Problem,
                      Rajan P

                      I am not interested in bolt pre load and friction co efficient value, can you tell how to run the same study by excluding the friction coefficient (0.2) from bolt connector property manager.

                        • Re: Bolt connector Problem,
                          Jared Conway

                          i think what is confusing is that the purpose of the bolt connector is to simplify the export of the values that you're interested in but you don't want to use it

                           

                          as such, you're stuck with using the outputs from a solid mesh (displacement, stress and strain) to calculate the value that you want.

                           

                          just for reference, if you don't include any preload and friction, it will warn you but the analysis will go through and then you can just export the values that you want

                            • Re: Bolt connector Problem,
                              Rajan P

                              Yes, Jared to get these shear and tensile forces, best way is to use bolt connector by avoiding pre-load and friction values.

                              It is possible to remove the preload and run the analysis, but if I make friction value 0 in the bolt connector property manager. I am getting warning message (minimum value from 0 to 1 to be entered in friction value). Can you explain how to avoid(exclude) friction value and run the analysis.

                                • Re: Bolt connector Problem,
                                  Mikael Martinsson

                                  The friction value is only used to convert a torque to an axial force in the bolt connector. Since the torque value is 0 you don't get any preloads or friction.

                                  If you toggle to "axial" instead of " torque" you will see that the friction input disappear.

                                    • Re: Bolt connector Problem,
                                      Rajan P

                                      Yes Mikael, I accept with you and if we change to axial and have default value 0 , it will run the bolt analysis without having the effect of pre-load on the bolt.

                                       

                                      It will be interesting how to get the same values of shear and tensile forces without using bolt connectors and by using simplified bolt 3D models. This will be used to compare the results between adding bolt connector and using simplified 3D model of the bolt. Can you explain how to get result of tensile and shear force Fx,Fy on simplified 3D model of the bolt.

                                • Re: Bolt connector Problem,
                                  Seckin Uslu

                                  I think we have talked the same things. İf you run the study , you will see the result force.

                                   

                                  Otherwise you can apply pin with no rotation. That pins behaves like bolt.You will see again result forces.