2 Replies Latest reply on Jan 18, 2008 4:12 PM by Alex Herzog

    Pressure Gauge Analysis: static deformation + mechanism simulation?

    Alex Herzog
      I'm currently working on a project to model a pressure gauge and I'm stuck on the simulation. For those who don't know how a pressure gauge works, you pressurize a curved, elliptical cross-sectioned Bourdon tube resulting in the tube trying to straighten itself. The straightening tip of the tube is attached to linkages which moves gears and what not in the mechanism to cause the gauge pointer to rotate as the pressure increases/decreases.

      I've gotten successful models of the pressure deflecting the Bourdon tube tip but it doesn't seem like CosmosWorks alone can succeed in what I'm looking for. Is there any way of using CosmosWorks or perhaps CosmosMotion as well to get the simulation I need?

      Thanks in advance!

        • Pressure Gauge Analysis: static deformation + mechanism simulation?
          Vince Adams
          Hi Alex, it sounds like a great problem but you'll need to do it iteratively. You'll need to determine your required tube tip deflection in Motion then use Works to evaluate whether the tube behaves as you need it to. Alternatively, you could determine tip deflection in Works and then input this XY data into Motion to synthesize your linkage. Either way, it will be a 2 step process as the elastic physics of Works is not coupled with the Rigid Body Dynamics in Motion.

          I'd highly recommend that you use the Nonlinear study in CW Advanced Pro for the tube analysis for 2 reasons. First, the large displacements you are going to have may not solve (or solve with sufficient robustness) in a Static study, even with Large Displacement turned on. Second, the response as the pressure increases is probably not linear, in path or magnitude of deflection vs. pressure. You'll need N/L to track the actual tip deflection vs. pressure.

          Good luck!!!! When you nail this one, please consider presenting it as a case study at a local SolidWorks or COSMOS User Group!!!

            • Pressure Gauge Analysis: static deformation + mechanism simulation?
              Alex Herzog
              Vince- Thanks for the advice! Sounds like its going to be a real strain on my computer at work. This thing takes long enough to handle a simple Cosmos analysis. (tryin to get IT to get me something better!)

              You're right about the nonlinear study. I had done a static study on the tubes and the purely linear path the tip kept deflecting along wasn't accurate enough (it's fine at like 25% but 75% and 100% need a more curved path to be truly accurate).

              I'll definitely keep the case study in mind as I'm doing this too.