5 Replies Latest reply on Aug 11, 2011 5:59 AM by Cnu Vasu

    Basic simulation help - table

    Marshal Fitch

      Alright, I'm essentially completely new to simulation (haven't used it since freshman year of college), so go easy

       

      I'm trying to design and build new tables for our production floor, and want to know if the design I have is going to hold up to whatever weight they might put on it.  Now, since I've never done simulation at all, I'm not sure what I'm doing wrong.  I've got an assembly made (attached), but when I do what little I know about simulation and try to follow the tutorials, the mesh never works and I get a whole bunch of errors.  It should be constrained on the bottom of course, where it'd be sitting on the floor (I believe this used to be called "restraints"?)

       

      Can anyone help me out?  I'm not too worried about any lateral forces (yet), just would like to learn the basics of setting up simulation.

       

      Thanks for any help, and I'll check back tomorrow.

        • Re: Basic simulation help - table
          Marshal Fitch

          nothing?  no help at all? 

            • Re: Basic simulation help - table
              Michael Feeney

              I think the file you uploaded is corrupt. I'd be happy to help you.

                • Re: Basic simulation help - table
                  Marshal Fitch

                  well, let me see if I can try again:

                    • Re: Basic simulation help - table
                      Michael Feeney

                      Well that file works and can be downloaded, on the other hand, I used 2010SP5. At least other people will be able to see your work and give you advice. I can see some of the parts you made by looking at the icons. You have many components and several details. Perhaps consider the following approach:

                      1. Figure out what kind of forces (magnitude, directions, etc) the table will experience. Think of common, everyday forces the table will see, and also worst case scenarios.
                      2. Figue out how you can simplify the analysis, I'm not suggesting that you change your parts, however, I do think you can exclude some of the components. For instance, do you need to analyze the table surface? Will that component really fail before the frame?
                      3. Like I said I can't open up the assembly in SW, but from the icon it looks like you have the frame constructed (without the feet?). I think that starting with that assembly, excluding the feet (for the time being), is a good idea. You can use beam elements and apply your loading to the top members. You could also apply a horizontal load to simulate someone sliding the table across a surface.
                      4. Your analysis will be static so that simplifies things quite a bit. As for boundary conditions (or as you say "restraints" or constraints....it's all the same) you need to consider how the table will be anchored to the floor (if at all). My guess is that the table is not bolted to the floor so your boundary conditions cannot be fixed for the two bottom members that make contact with the floor (or the leveling feet). Instead of fixed constraints you should probably use two BC configurations:
                        1. For a vertical loading case, apply your boundary conditions as pins which resist loading the in the vertical and horizontal directions. If you model your table without the leveling feet, then your table would sit on those two members below the bottom frame of the table. One one of those members you would apply a pin condition (restricting vertical and horizontal degrees of freedom) to the entire member and on the other side of the table you would apply a pin condition that on resists vertical motion. This way, you aren't apply unrealistic moments on the table legs.
                        2. For a horizontal loading case apply you would use the same conditions. This would simulate the table being pushed across the floor, and the legs on one side of the table getting snagged on something.
                      5. Once you've done your beam element initial simulation, you could then consider including the feet and running a solid element model.

                       

                      In summary and for starters, take your table frame assembly and open a "new study." You'll be able to select all of the components and right click (treat as beam). Apply your fixtures (boundary conditions), external loads, and your connections. I would just use the "no penetration" and apply connections between your adjacent members. Connections are applied to each part of your assembly. Mesh and run.