11 Replies Latest reply on Jun 3, 2013 3:28 PM by Jared Conway

    nonuniform pressure distribution

    Serhey Moroz

      Hello colleagues

      I am simulating a model of storage bin, assuming it's loaded with coal. Bin walls are nonuniformaly loaded due to pressure decrease in vertical direction. I use "nonuniform distribution" in "pressure" feature. It seems to be simulating all right. My walls are quite big, I can see that stress is changing a lot between top and bottom. Now, I would like to confirm that my quadratic function that I inserted is actually doing right job. I am trying to prob "free body force" by using "List Result force" feature in repots. Unfortunately I cannot measure my load close to certain node/area. It selects whole surface, and giving me force as function of area and pressure applied to it.

      Please, anyone who has bigger experience, advice me on that. Ideally it would be great to know the pressure in certain areas of surface. Or, maybe it's possible to measure the pressure acting on separate "mesh element". I cannot get it right.

      Thank you for any advice

        • Re: nonuniform pressure distribution
          Chatura Elkaduwa

          Hello Serhey,

           

          Create splitfaces (using split lines) on the respective faces where you need to measure localised forces, prior to running the simulation.

          Once the calculation is complete you may use the pre defined splitfaces as references to measure forces.

           

          force.png

            • Re: nonuniform pressure distribution
              Serhey Moroz

              Thank you Chatura

              I just did a bunch of experiments with that, that works. But, there is another problem now. My bin is difficult shape structure, every applied to it force/pressure tends to deform it, there is a lot of moments (rotations) in between components. So, now when I prob my separate elements, numbers do not make any sense. Even if I select only one direction, it still shows me a number which is under moment’s effect. I think this feature is not what I need, since it shows me an actual force/moment as a sum of all forces acting on mesh element. I am actually looking for a chance to measure amount of force/pressure which is acting on surface initially. That's what you load your model with only, it's independent of any reaction/deformation forces.

                   For instance, if you support your component not evenly, apply pressure load on whole surface. One end of component might move toward (opposite) to direction of applied load, because of the way it's supported. However, the pressure applied to this end is still acting in initial direction and has same rate, no matter where your reactions go. That's what I want to measure in my case. I know it might be unnecessary, I can always verify the load in feature settings, but in nonuniform load distribution case that would be a good help to track-down mistakes.

              Any thoughts?

            • Re: nonuniform pressure distribution
              Jared Conway

              "Now, I would like to confirm that my quadratic function that I inserted is actually doing right job."

               

              If this is all that you need to do, what about setting up a sample that is simpler to calculate the total force from your nonuniform pressure distribution vs area and then read off the reaction force at the fixed face. if they match, you know your method is working and you can probably assume that as long as you applied things properly, your full model is working especially if the displacements and general shapes are as you expect.

               

              or are you looking for something more simple?