13 Replies Latest reply on Sep 22, 2018 5:58 PM by Nick Cradock

    Roll Cage Sketch

    Uchenna Offor

      Hello all,

       

      I have a new problem (surprise, surpise )!

       

      I got a hand sketch of a roll cage ( check attachments) to make a roll cage, which is a simple enough task... if I fully understood how to combine each view to make the intended design. The below is what I currently have, which is NOT a good roll cage design, so I know the problem is either me or the drawing. What can any of you make from it?

       

       

        • Re: Roll Cage Sketch
          Tom Helsley

          Yep, it's a little confusing.  I'd say give it your best shot, then show the 3D sketch to the person who sketched the frame and roll cage on paper to see if you have done what he wants.

           

          Looks like a fun exercise!

          • Re: Roll Cage Sketch
            Dave Bear

            Hi Uchenna,

             

            Just to add to what Tom has mentioned, I reckon you got the good basics there to get started. i would just ignore the major 'cube' perimeter in it and instead perhaps throw in some angular tube instead. Of course, this is all subjective to the vehicle it's for and that vehicles other parts etc.

             

            Go for it!

             

            Dave.

            • Re: Roll Cage Sketch
              Neville Williams

              Uchenna Offor wrote:

              What can any of you make from it?

               

               

               

              Apart from lack of radii on change of direction of tubes (presume that is taken as given that they will be included)

              As Dave Bear  intimated, design needs some "refinement" for bracing etc but  apart from that GO FOR IT!

              Sit back and see what feedback is. If client sketched like that I presume that is the way they want it !!

              • Re: Roll Cage Sketch
                Sameer Qureshi

                Hi Uchenna,

                 

                I'd say the basic design on paper of the roll cage is acceptable for a first attempt but could use some tweaks - it's also not the easiest thing to interpret. As long as the major roll cage frame is connected and reinforced with the angled minor bracing, and all members are connected node to node (where possible), the structure will be rigid enough.

                 

                Suspension mounting points are key to consider as they transfer most of the load through the structure so brace from here to the rest of the roll cage.

                 

                I personally would brace slightly differently from the top of the front wheel arch to the trapezoidal outline that forms the 'passenger cockpit' (see orange line in attached image) and edit or remove some blue floor members but there may be constraints that stop you from changing this? Try to avoid beams meeting in the middle of other beams (weak point in structure design as beam bending can occur). (yellow boxes in image)

                 

                The X brace in the cockpit is probably shaped that way to allow driver ingress/egress and side impacts but this could be adjusted too to better meet the front bulkhead.

                 

                With regards to the SOLIDWORKS modelling, you're on the right track, keep adding in the members and it will start to take shape. I would assume as others have suggested that there will be some radii in the tubes so it's not such a boxy design?? As long as you use simple arcs and lines you should be able to use the weldment tools to build this without much issue. But it comes down to checking with the designer to see what their justification for the design is!Modify.png

                 

                All the best with it.

                 

                Sameer

                • Re: Roll Cage Sketch
                  Brian Brazeau

                  Hi Uchenna, Not trying to highjack your post here, I just was interested and had a few moments to spare so I mocked up a frame design quickly.(see attached.) Something I learned is if you include radii at intersections and check the "merge arc segment bodies" you will cut the numbers of individual bodies in the cut list down considerably as the software assumes they can be bent from a single piece instead of having to be all weldments. (see attached for reference) now for my highjacking question to the others in this thread. If you look at my file you'll see I had to use a delete face to get one of the intersections to trim (miter) up properly. Is there a way to avoid having to do this?(something I did wrong)

                  I have found another odd behavior with the pipe function. If you have a radius on a section of one of your groups where it intersects another group and should be trimmed, it doesn't see below. Any one know why?

                  • Re: Roll Cage Sketch
                    Craig Schultz

                    You could draw the frame as a solid piece with the cuts/chamfers/radii you need. Start a 3D sketch and convert the edges. Then use that 3D sketch as your guides for a weldment.

                    • Re: Roll Cage Sketch
                      Dan Pihlaja

                      Uchenna Offor

                      Look at this presentation:

                      SWW18 Presentation - All The Small Things  by Todd Blacksher

                       

                      If you get a chance to watch the video, fast forward to "3Dsketch ASAP".

                       

                      This might be a huge time saver for you.

                       

                      Edit: I just noticed that Craig Schultz just said the same thing. 

                      • Re: Roll Cage Sketch
                        Uchenna Offor

                        Oh wow. Thanks for all the assistance Dave Bear @Neville Williams @sameer @dan @todd Craig Schultz @brian

                         

                        I will look at all you've said and see what works and post an update for anyone who would like to see what was done.

                        • Re: Roll Cage Sketch
                          Uchenna Offor

                          For those who are interested:

                           

                          What I did was I cut each drawing as good as I could get it from the picture and assigned them to different planes in order to mimic the top, side, front and rear views.

                           

                           

                          Then I began sketching and dimensioning the lines, starting with the blue lines (foundation). When it came to the 3D sketches, I used the pictures on each view to see where a specific line orients with respect to those views in order to properly connect it to the right nodes and give it proper dimensions.

                           

                          Some of the proportions of the cuts I made to the pictures were considerably off and not everything matched up, like when you use blueprints of a car to begin modeling it, but it was good enough. Although the fillets weren't in the picture I just decided to add those.

                          • Re: Roll Cage Sketch
                            Nick Cradock

                            If this was me i would be finding out what hes building it for and finding rules for the chassis (eg CAMS in Aus) then very gently talking with the person to change the design.

                             

                            Cheers