7 Replies Latest reply on Jul 5, 2012 11:45 AM by Bert-Jan Knol

    Bolt Connector - Reaction Force

    Harshal Shah
    Harshal Shah Jul 2, 2012 3:35 PM

      I am trying to find a reaction force on a parts surface which is bolted to another part.

      I am using the bolt connector tool in solidworks. The axial load i am defining in the bolt connector is 120 lbf.

       

      So the expected results for the resulatant force should be close to that no.

       

      The conditions i have set up is a no penetration conatct between the two bolted components.

       

      Please look at the attached snap shot . What i am looking to calculate is the reaction force at the bottom surface of the red part when it is bolted to the otehrt part using a #0-80 bolt .

        • Re: Bolt Connector - Reaction Force
          Bert-Jan Knol
          Bert-Jan Knol Jul 3, 2012 8:43 AM (in response to Harshal Shah)

          Harshal,

           

          After running the study use right mouse button on the "Results" folder in the tree (see attached image) then click "Result Force...". A new menu will open, in this menu select "Contact/Friction force" (see attached image) then select the surface of interest and click "Update". This should show you the result forces of the no penetration contact set.

           

          Hope this helps.

          Result force 1.pngResult force 2.png

            • Re: Bolt Connector - Reaction Force
              Harshal Shah
              Harshal Shah Jul 3, 2012 10:07 AM (in response to Bert-Jan Knol)

              Thank you Bert,

               

              The problem i am facing here is that the values are not coming out to be correct . I would expect the reaction force to be some where close to the axial load no. that i use while defining the bolt connector . In this case i am defining to be 120 lbf .

               

              Also when i look into the stress results the stress is only 550 psi. Which is a very low no.

               

              Another query was I tried looking at the pin/bolt/bearing force no’s but it gave me an error as follows.

               

              ” Pin/bearing/bolt forces are not available due to non-existing connectors or changes in connector forces”.

               

              I have set up a no penetration contact between the two bodies.

               

              Am i missing any specific settings for bolt connectores OR is there any specific method to do it correct.

               

              I am attching a couple of snap shots of my results hope this helps.

                • Re: Bolt Connector - Reaction Force
                  Bert-Jan Knol
                  Bert-Jan Knol Jul 3, 2012 10:32 AM (in response to Harshal Shah)

                  The load you are missing off the 120 lbf  is probably in the fixture you used. Both blocks are now fixed in space by the faces on the sides. Try a roller/slider fixture or reference geometry on the small block instead of completely fixating it.

                   

                  A more realistic setup would be to use another no penetration set on the vertically touching side and let the bolt and pretension handle the shear forces. This will make things slower to calculate though.

                    • Re: Bolt Connector - Reaction Force
                      Harshal Shah
                      Harshal Shah Jul 3, 2012 12:10 PM (in response to Bert-Jan Knol)

                      Thanks Bert. I made the changes you recommended but its ending up to be the same. I set up the no penetration mate for the vertical wall . And also added the roller/slider fixture to the side walls. But it comes with the same results.

                       

                      What strikes me is that when i click show pin/bolt/bearing force it gives me an error which says no bolt connector which is very weird because i already have it.

                       

                      Have you faced such a problem before. Any other alternative approach.

                        • Re: Bolt Connector - Reaction Force
                          Bert-Jan Knol
                          Bert-Jan Knol Jul 4, 2012 4:10 AM (in response to Harshal Shah)

                          Sounds odd.

                           

                          Could you attach the files so I can look at your setup? If it's an assembly be sure to attach all the parts.

                           

                          Edit:

                           

                          I just noticed when I make a bolt connector and enter a value for pretension it jumps back to 0. Could you check your bolt connector setup?

                            • Re: Bolt Connector - Reaction Force
                              Harshal Shah
                              Harshal Shah Jul 5, 2012 11:21 AM (in response to Bert-Jan Knol)

                              Hey Bert,

                               

                              I had also conacted my solidworks Supplier . And he sent it to solidworks and they came back with a answer.

                               

                              The reaction forces were in correct just beacuase i did not have the tight fit option Which is incorrect but due to a bug you have to use it .

                              The the no bolt connector error is a bug in Solidworks 2011 SP5 but it has been resolved in Solidworks 2012.

                               

                              Below is the reply from Solidowrks.

                               

                              ****************************************************************************

                              Thank you for contacting SolidWorks Technical Support.

                              The issue here is caused by SPR 652405 “*generic* ‘Pin/bolt/bearing forces are not available’ error when listing bolt force of screw type bolt with thread faces from same body as head edges.” This occurs when a thread face is selected from the same body as the head/nut edge. I have attached it to this SR, and you will be notified when it is resolved.

                              The closest workaround that I am aware of in 2011 SP5 is to use the tight fit option. Instead of selecting the same-body face as a thread face, you can select it in the tight fit option instead.

                              The only other option until the bug is resolved would be to use the bolt series option in the same manner. Unfortunately, this workaround is not functional in 2011 due to SPR 599531 “Missing bolts in the bolt result force list.” This bug prevents bolt results from being listed if bolt series faces are from the same body as the bold head/nut. It was fixed in 2012 SP2.

                               

                              ****************************************************************************.

                               

                              I hope this helps.

                               

                              Thank you for your help.