2 Replies Latest reply on Apr 26, 2011 4:16 PM by Jeremy Feist

    SolidWorks Simulation for Assembly Jack Stand

    Aaron Ferguson

      I have been using SolidWorks now for almost 6 months and recently started focusing more on the Simulation aspect. My background is in Mechanical Engineering/FEA Analysis and most of my training so far has been with Alignex and online courses, tutorials, and reading books. Recently I got a project from a client, mostly as a training tool for my company, where I have to do a test on a jack stand. This jack stand will be used to support a mining vehicle of some sort. I have attached a picture of my assembly model.

       

      Basically, it consists of a rectangular base plate, a larger rectangle attached on top of the base plate with an X pattern inside for support, two structural tubes ASTM A500 Grade B about halfway up for support and a fork lift to move the jack stand, and a cradle top curved with a 63" radius where an 85 ton load will be applied.

       

      This will all be welded together with ASTM A36 Steel, which is to be determined on weld size. It will be resting on concrete or a gravel floor, which might not always be even like the 85 ton load. What we want to determine is if the structure will be able to support the 85 ton loaded on the cradle top both as a distributed load and if say the vehicle was putting all that weight on one edge of the jack stand. Also, what happens if the floor is uneven?

       

      I guess my main concern, is just how to run a test correctly and where to even begin? Other things I have questions on is:

       

      Since this an assembly, will there be concerns with meshing?

      How do the welds affect the test? Should they be used such as an edge weld connector?

      With this being symmetric, could I just model ¼ of assembly and make it one part to simplify the test. Would that be an accurate enough?

      If I do it a ¼ model using two different types of materials (structural steel and the tubing), can that be modeled in just one part?

      I don’t see ASTM A500 Grade B in the material database. I know you can create custom materials. How do I got about that or is there a way to download more materials from the internet, such as using 3D Content Central?

      Is there a way to determine what weld sizes need to be used during or after the test?

       

      The more I use SolidWorks, the more I love it. Not only for what it has done for me, but for what it can do for my company in the future. But, it can be overwhelming. I know where I want to end up when the test is over, but just don’t know how to get there and being the most accurate possible to real world conditions. I have been in contact with Alignex and figure these forums, being fairly new to them myself, are a great resource to help with this and further my knowledge. I appreciate any advice given.

       

      Note: I am using SolidWorks Professional 2011 SP2 with the full Simulation Package

        • Re: SolidWorks Simulation for Assembly Jack Stand
          Jerry Steiger

          Aaron,

           

          I don't know much about SolidWorks Simulation, so my response will be pretty general. I'm also not at all familiar with welded steel structures. Forgive me if this sounds harsh, but it seems from your questions that you are pretty naive about FEA, even more than I am. 

           

          Looking at your part, the wall thickness is pretty small compared to the other dimensions, so it is going to be difficult to analyze using solid elements. You'll either end up with a huge number of elements or very badly shaped elements, or both. I would be inclined to try and model it with shell elements, but I don't know how well that will work with the loads, boundary conditions, welds and possible failure modes. Buckling might be a particularly tricky problem.

           

          You should be able to use symmetry in the case where the load and floor are nice and symmetrical. You might be able to use half symmetry in the case where you are applying the load or the restraint on one edge, depending on which edges you are loading/restraining.

           

          I think that SW Simulation supports multiple materials for mult-body parts, but I'm not sure about that. If not, you will need to model it as an assembly. MatWeb is a good place to find material properties.There are a number of others that I don't remember now, but searching in the forums will probably turn up more than you can easily check out. As I recall, adding a new material is most easily done by copying an existing, similar material and then saving it with the new values under a new name. I think you may have to save it in a new location that you have the system look in.

           

          I think that weld sizing is a rather specialized area of expertise. You need to talk to people who are knowledgeable in this area. I suspect that a number of the people who post here fit that description. They are quite likely expecting to be paid for their expertise. Perhaps they have gotten in touch with you through email and that is why there aren't any responses from those who know much more than I do. On the other hand, it seems like the experts here are more inclined to ignore questions they deem to be beneath their notice than in the other forums. That just seems to be the way that FEA people are.

           

          Jerry Steiger