11 Replies Latest reply on Feb 7, 2013 11:20 AM by M. Grundy

    Bonding Beams to surfaces

    M. Grundy

      Hi All,

       

      I am creating a simulation of a large bodied object that has internal struts using Solidworks Premium. I have changed the internal struts to beams and the walls of the object to a mid-plane surface (shell thickness 6mm) and am trying to bond the end of the beams to the shell wall. The struts/beams now sit offset from the surface by 3mm, the joint is a yellow ball rather than purple and therefore needs to be connected to something. Usually when connecting beams to beams this is not a problem (i.e. 'Treat a joint for clearence'), but im finding some trouble connecting beams to shells?

       

      Could it be that i need to use 'contact sets -> bonded'? I have tried this and encountered trouble connecting the end of the beam to the surface. Error message 'invalid entity on beam body was selected. 

       

      I am new to solidworks simulation and will appreciate any help that can be offered.

       

      Thanks in advance.

       

      (picture incl.)

        • Re: Bonding Beams to surfaces
          Irfan Zardadkhan

          Hi,

          Try recalculating the joints and the adding the bonded contacts.

            • Re: Bonding Beams to surfaces
              M. Grundy

              Hi,

              When i recalculate the joints they just appear disconnected (Yellow).

              When i try to bond the contacts i get the error message 'invalid entity on beam body selected'. This appears if i select the end face of the beam and the side wall it should bond to.

                • Re: Bonding Beams to surfaces
                  Scott McElroy

                  Hi M. Grundy,

                   

                  Would it throw off your simulation to extend the beams to be coincident with the shell. That should allow the bonded contacts to solve properly. Or you could merge results in the extend feature to create one body. You could only use the extend feature and merge results if this was a multi-body part file. For an assembly file, you could create references when editting the beam part in the assembly environment to extrude the beams to be coincident and it should solve the bonded contacts correctly.

                    • Re: Bonding Beams to surfaces
                      M. Grundy

                      Hi scott,

                       

                      While it wouldnt throw off my simulation by extending the beams, i have tried to lengthen the extrusion by 3mm in both directions and it still will not bond (even though the faces appear to touch). The model is all one part rather than an assembly, would this be easier to run (and bond) as an assembly?

                        • Re: Bonding Beams to surfaces
                          Scott McElroy

                          Since it is a part file, try to merge the feature creating the beams to the walls (unless you need them to be different materials). You can try to set it up as an assembly. I know that simulation can be more finicky with assemblies but I also haven't gotten to try a simulation on a multibody part, and I still need to call and get a correct SN to install simulation with 2013.

                  • Re: Bonding Beams to surfaces
                    John Sutherland

                    I suspect that Bonding works only with coincident (or nearly) faces.

                    • Re: Bonding Beams to surfaces
                      Bill McEachern

                      I do lots of this type of work. You have options:

                       

                      Option 1

                      1. I would have ensured that the beam ends
                      2. lie flat and coincident to the flat face of the inside of the outer box.
                      3. I would have used a zero offset surface of
                      4. the inner face of the wall to make the shell. Then delete the solid body.
                      5. Assuming you are using a recent version of swx this would allow the beam ends
                      6. to be automatically bonded the shell face.
                      7. If you thought
                      8. it important you could use the offset capability to offset the shell neutral axis to the middel the wall thickness.

                       

                      Option 2

                      1. - as an aside it appears the forum doesn't like 2 lists in the same post.....
                      2. you can use what you have an bond the end nodes of the beam to the shell face using bonded connections. Make sure you selectt he end node option and not the beam option. This will work fine as long as the distance is not large relative the shell thickness. Other things to be careful of here is the element size of the near the connection - it will affect the joint stiffness. In the method above in the later releases of solidworks the beam x section will get imprented onto the face and the nodes inthe imprint will be bonded to the beam end yielding approximately correct stiffness.
                      • Re: Bonding Beams to surfaces
                        Bill McEachern

                        I do lots of this type of work. You have options:

                         

                        Option 1

                        -I would have ensured that the beam ends  lie flat and coincident to the flat face of the inside of the outer box.
                        -I would have used a zero offset surface of the inner face of the wall to make the shell. Then delete the solid body.
                        -Assuming you are using a recent version of swx this would allow the beam ends  to be automatically bonded the shell face.
                        -If you thought it important you could use the offset capability to offset the shell neutral axis to the middel the wall thickness.


                        Option 2

                        - as an aside it appears the forum doesn't like 2 numbered  lists in the same post.....it required a complete delete and rewrite and removal of hte numbered lists
                        -you can use what you have and bond the end nodes of the beam to the shell face using bonded connections. Make sure you select the end node option and not the beam option. This will work fine as long as the distance is not large relative the shell thickness - well at least you won't get a warning.

                        -Other things to be careful of here is the element size near the connection - it will affect the joint stiffness. In the method above option 1- in the later releases of solidworks the beam x section will get imprented onto the face and the nodes in the imprint will be bonded (rigidly connected) to the beam end yielding approximately the correct stiffness.

                        • Re: Bonding Beams to surfaces
                          Bill McEachern

                          I do lots of this type of work. You have options:

                           

                          Option 1

                          -I would have ensured that the beam ends  lie flat and coincident to the flat face of the inside of the outer box.
                          -I would have used a zero offset surface of the inner face of the wall to make the shell. Then delete the solid body.
                          -Assuming you are using a recent version of swx this would allow the beam ends  to be automatically bonded the shell face.
                          -If you thought it important you could use the offset capability to offset the shell neutral axis to the middel the wall thickness.


                          Option 2

                          - as an aside it appears the forum doesn't like 2 numbered  lists in the same post.....it required a complete delete and rewrite and removal of hte numbered lists
                          -you can use what you have and bond the end nodes of the beam to the shell face using bonded connections. Make sure you select the end node option and not the beam option. This will work fine as long as the distance is not large relative the shell thickness - well at least you won't get a warning.

                          -Other things to be careful of here is the element size near the connection - it will affect the joint stiffness. In the method above option 1- in the later releases of solidworks the beam x section will get imprented onto the face and the nodes in the imprint will be bonded (rigidly connected) to the beam end yielding approximately the correct stiffness.

                            • Re: Bonding Beams to surfaces
                              M. Grundy

                              Hi Bill,

                               

                              Thanks for your help, Sorry it took so long to reply. Simulation is working somewhere near to what i expected now. I used your option 2 method, bonding the end nodes to the shell. Turns out i was trying to use the beam option rather than the end node option.

                               

                              Thanks again.

                               

                              Mike

                            • Re: Bonding Beams to surfaces
                              Bill McEachern

                              Sorry about the repeats but I was getting an error that the post failed....