11 Replies Latest reply on Oct 15, 2018 4:03 PM by Sam Zhang

    Pipe deformation with water in it on ground

    Sam Zhang

      Hi,

       

      I am new to Solidworks, and I have been struggling a whole week, to perform a simulation about pipe deformation of cross-section when it is filled with water, put on ground.

       

      I have got some idea from this video and this video, but they are both different with my case.

       

      My questions are:

       

      1. How can I define "ground" or a surface to put my pipe on it? Do I have to make the other individual part (like rectangular solid) , then put pipe on it?
      2. Should I  use "Solidworks flow simulation" instead of  "Solidworks simulation"?

       

      Thank you very much for any idea / help!

        • Re: Pipe deformation with water in it on ground
          Sam Zhang

          The pressure is very weird as shown on attached picture

            • Re: Pipe deformation with water in it on ground
              Bill McEachern
              1. sim is the program
              2. linearly varying pressure load
              3. virtual wall contact
                • Re: Pipe deformation with water in it on ground
                  Sam Zhang

                  Many thanks Bill,

                   

                  1. I will go with "Solidworks simulation" as your suggestion

                  2. For "linearly varying pressure load", I am a bit confused about it. I have done as said below, which is same as those 2 videos I mentioned in my question. Is this what you mean?

                   

                  "Recommended procedure to define an hydrostatic pressure:

                  1. When defining hydrostatic pressure, the pressure direction should be Normal to selected faces.
                  2. The location and orientation of the Coordinate system used to define the  variable pressure is important. The best practice it to have the XZ plane lying on the surface of the fluid and  to have the Y axis pointing downward  (same direction as the gravity).
                  3. Select SI as the unit system, and make  sure the pressure unit is N/m² and not MPa.
                  4. If the above conditions are met, In the Pressure value  field, enter 0*X + 9810*Y + 0*Z

                  "

                  3. for virtual wall contact, thanks for your suggestion, I made one for my simulation.

                   

                  new question:

                  if 2 is correct, I've got a question about the pressure show in attached picture, as @James Riddell found, the water is pulling down on the top.

                   

                  Snipaste_2018-10-08_11-18-39.png

                    • Re: Pipe deformation with water in it on ground
                      Bill McEachern

                      The rules for best practice above are not something I would agree with.

                      I would suggest u need two pressure loads: one for the horizontal component and another for the vertical. The relation is rho x g x h (density of fluid x acceleration due to gravity x height or depth at the case maybe) in a consistent set of units. For whatever orgin you pick (coordinate system) your equation has to satisfy what u know. Pressure is zero at the top of the water and the pressure is rho x g x h at the depth. The pressure is a directed pressure for each component not normal to the face. That is how I would do it in this case at any rate.

                        • Re: Pipe deformation with water in it on ground
                          Sam Zhang

                          Thanks again Bill!

                           

                          I have tried to apply Vertical Pressure load but failed, seems something wrong with my reference coordinate .

                          I set up a reference coordinate as shown on previors picture, by which I 'd like to simulate half full situation. That is to say, no pressure upon the original point of my reference coordinate. but, there are 2 pressures when I apply vertical pressure, one is on up direction, another is on down direction. it seems they act as mirror  of each other...

                           

                          For horizontal pressure, I am still tring to figure out how to apply it.

                    • Re: Pipe deformation with water in it on ground
                      James Riddell

                      Sam Zhang wrote:

                       

                      The pressure is very weird as shown on attached picture

                      How can the water 'pull down' on the top? Seems this needs a pressure profile (varied by depth) as Bill McEachern suggests.

                    • Re: Pipe deformation with water in it on ground
                      Sam Zhang

                      Here come the newest result:

                      1. I applied virtual wall beneath  cylinder as the ground, but the result shows as if I put cylinder on a line(blue arrow) instead of a plane
                      2. maybe becuase of 1, there are 2 hollows appear beneath the cylinder.  The "varying pressure load" in side cylinder seems right, which simulates half filled pipe.
                      3. I have to add 2 fixtures on both side of cylinder as shown by green arrows, otherwise sw refuse to calculate.

                      Snipaste_2018-10-09_11-20-36.png

                      • Re: Pipe deformation with water in it on ground
                        Sam Zhang

                        Below is what I have done.

                         

                        1. I decided to make a rectangular solid below the Pipe part to simulate "ground". then I set "ground" to fix in my simulation study .  then I found I don't need to set fixtures/Connections any more.

                        Snipaste_2018-10-16_08-57-16.png

                        2. I chose "solidworks simulation" instead of "solidworks flow simulation" as Bill told me

                         

                        3. About water pressure, I set a reference coordinate (Set Y direction oppsite to normal Y direction)in the right place, then add a Pressure of Nonuniform Distribution and set my reference coordinate to it, and set Equation:   F(x,y,z) = 9810 * "y".      at "Faces for pressure ", simply select inside surface of pipe.

                            In my case , I have to split inside surface of pipe to several parts by  adding "split line" as I have to simulate situation cases of 50% full,   2/3 Full, 100% Full.

                        Snipaste_2018-10-16_08-58-12.png

                        Snipaste_2018-10-16_08-59-51.png