11 Replies Latest reply on May 15, 2015 1:29 PM by Jared Conway

    Beam 1D, joint issues..

    Markku Sutinen

      Hi,

       

      Could someone pelase assist me with following case:

      I have a roof truss structure, which I tred to model as centerline sketch skeleton and weldemt profiles sweeped along sketch lines.

       

      In order to ensure flawless joint connections I tried to be smart and splitten my top an bottom main profile skeches, so that every diagonal member shares explicitely a common & one end point with main profile(s). The outcome was somewhat opposite,

      1. Joint points are drifting along screen, as seen in enclosed screen capture
      2. there are more visible joint points than I expected, but mybe this is because of merged points shown as one and orphans with different colour.
      3. one piece if I beam profile appears & meshes as solid part, but I'm pretty sure that such an extrusion does not exist in history tree. Normally I could RMB on feature tree and select "treat as beam" but in this case there does not exist such an option
      4. some diagonal (secondary) members have a blue "i", maybe this is because of orphan Joint points?

       

      In general alternative way would be use a shell model, but it is somewhat complex thing to do it, trim, split, define thickensses.. so I'd preferably stay with Weldment & Beam 1D, if possible.

       

      Any hints what to do? Please find following screen captures:

      2015-05-13 23_05_40-Custom Selection.png2015-05-14 00_13_39-SolidWorks Premium 2014 x64 Edition - [Part5-test12345 _].png

      TIA,

      Markku

        • Re: Beam 1D, joint issues..
          Gary Blenkhorn

          I am not 100% clear on what you are trying to do.  I work with weldment everyday so I am hoping I can help you.

           

          Are your sketch lines for the HSS braces all on the same plane and do the center lines of the sketch end at the same point on the lines for the I beam?  Also are your sketches fully defined?

           

          Where the HSS braces are to be trimmed to the I beam and then to each other it is best to create the I beam first an then create the braces.  Then it is simply having the trim done correctly to the way you want it.  Creating the braces prior to the beam could cause the beam to trim itself to the braces.

           

          When you create the trim function do not include the I beam as part of the trimmed list but do select it as the part to be trimmed to.

           

          The location of the point(s) that your center lines converge is important whether you want a gap joint or an overlap joint.

           

           

           

            • Re: Beam 1D, joint issues..
              Markku Sutinen

              Thanks for your reply Gary,

               

              This is a 2d sketch / structure. All end points, coincident lines etc have been constrained, but when I redrawed that short line and that solid I-beam section reappeared as a beam. Now model behaves as expected, no loose brace ends, no haunting solid stubs.

               

              Next I tried your method to draw a single line for each I beam and then trim HSS braces to that surface (body). As side bonus it gives an oppoturinity to dimension convergence point value "e", which is not so easily available in my current "splitted skecth". We'd like to go with gapped structure (welding..).

              The outcome was awesome, just what I expected:

              2015-05-14 16_37_05-SolidWorks Premium 2014 x64 Edition - [Part8-test12345 _].png

               

              For now my questions have been addressed / resolved by themselves.

              Even question  #4: apparently letter "i" warns about an non-trimmed stub of brace profile, which was hiding between I-beam flanges?

               

              Is it so that with Beam1D I can have only 6DOF or 3DOF constraints, no springs, no elastic supports?

              I'm using version 2014 (premium) for this customer.

               

              thanks,

              Markku

              • Re: Beam 1D, joint issues..
                Markku Sutinen

                One more thing: what would you recommend if I need to model this whole building and add some stabilizing braces between vertical columns, can I make an assembly and use those 2d frames there (pattern, spacing 5000mm), or should I stay in one *.sldprt and make all profiles there? My first intuition says that I should stay in one part, since it feels more robust and I'll most likely avoid a bunch of connetion issues when compared to an assembly?

                 

                2015-05-14 18_59_05-2015-05-14 18_58_04-SolidWorks Premium 2014 x64 Edition - [Part9-test12345 -in- .png

                  • Re: Beam 1D, joint issues..
                    Jared Conway

                    part is easier

                    but beams can work between assemblies

                      • Re: Beam 1D, joint issues..
                        Markku Sutinen

                        yep, apparently you're correct with this one: When I add at least one non-beam body to that model, Connetions menu activates and becomes selectable.

                        This leads to my next issue: My next concern is how to connect corrucated panels (mid ceiling) to horizontal I-beam, so that all frames are connected to each other. I tried to create a contact set between panel and I-beams, but none of Touching faces / Non-.. / Find Shell edge- .. options worked.

                        Any hints?

                        2015-05-14 22_46_55-2015-05-14 22_43_00-SolidWorks Premium 2014 x64 Edition - [Part11-test12345] - P.png

                          • Re: Beam 1D, joint issues..
                            Jared Conway

                            i'm not sure what the problem is

                             

                            the interface doesn't let you do it

                            or you're not sure what to select

                             

                            similar to your previous question, what fidelity are you looking for?

                             

                            you should be able to choose joint > surface of the shell or beam > surface of the shell. but if you're trying to choose edges of the shell, that may not make sense to the solver because it doesn't know that level of detail about your beam. the beam is just 2d.

                             

                            best to do some testing on some sample parts to see what the different connection behaviors look like and compare to solid > solid so you know which one is "best"

                              • Re: Beam 1D, joint issues..
                                Markku Sutinen

                                Thank you for all your help, Jared.

                                 

                                My VAR quoted SWX Database as follows: "

                                 

                                Question:

                                 

                                Is it possible to establish no penetration contact between a beam and a

                                shell or solid?

                                 

                                Answer:

                                 

                                No. Beams get meshed as one dimensional elements which only have the

                                dimension of length, so it is not possible to accurately model contact

                                with the actual cross sectional beam geometry using beam elements.

                                 

                                For cases like this, most users would model the beam using shells

                                (using the midsurface feature in SolidWorks is best since this will give

                                the results closest to the actual geometry). Then, it is possible to set

                                up contact sets between the shell or solid and the face of the beam

                                which has been meshed using shells."

                                 

                                So this is a show stopper, but we more or less likely will also need to take a closer look at some bolted joints.

                                These reasons combined will force me to start from a scratch with surface models.

                      • Re: Beam 1D, joint issues..
                        Jared Conway

                        is the joint the important part or the overall behavior of the structure?

                        if the former, i would go with solids/shells combo

                        if the latter, beams

                         

                        the reason being that with beams you have really the joints and connections at the joints and the beams, not the fidelity of the connections between the flanges...etc which i think you are trying to achieve

                          • Re: Beam 1D, joint issues..
                            Markku Sutinen

                            I'll consult my senior colleague, and we'll see if we manage to avoid going too deep to joint details.

                            If we must, I'll follow your proposal and go with shell model.

                            More likely there will be some bolted joints and we must model at least them in more detail.

                             

                            Thanks for this Jared,

                            Markku