2 Replies Latest reply on Jul 6, 2017 11:17 AM by Marc Rigollet

    Pipe fitting pressure simulation

    Marc Rigollet

      Hi all,

       

      I'm working on a project where I need to simulate a pipe fitting under pressure (see below) and would like some advice on how to set up the most realistic simulation scenario.

      2017-06-27 10_37_47-SOLIDWORKS Premium 2017 x64 Edition - [14878-DWG-170626 .125 MALE BSP TO .375 MA.jpg

      We can assume it's fastened at both ends in the corresponding female threaded connections and is subjected to 620 bar (62MPa).

      To reduce the processing load I've sectioned it @ 60 deg and simplified the threads (see below).

      2017-06-27 10_50_40-SOLIDWORKS Premium 2017 x64 Edition - [14878-DWG-170626 .125 MALE BSP TO .375 MA.jpg

      I've applied 4 slider/roller fixtures to the part. On each and and on each cut face. I then applied the 62 MPa normal to the bore.

      I'm feeling this is too simplistic as the fitting will likely stretch ever so slightly in the real world.

      Any comments are welcome and appreciated.

       

      Thanks in advance,

      Marc

        • Re: Pipe fitting pressure simulation
          Ryan Dark

          Hi Marc,

          The simplification looks good as you don't want to deal with meshing your threads for a setup like this.  As a general thought you may want to cut the threads off rather than fill them in so it does not make the model artificially stiffer than it would actually be and err on the side of it being thinner/weaker.

           

          For the fixtures, On Flat Face works fine for your cut faces.  You would not, however, want to place On Flat Face on both ends of the model as it may change length as a result of the pressure load and you want to allow the model to be free on one end to allow for that length change.  Having one side fixed just sets the zero location for that length change and itself is fine.

            • Re: Pipe fitting pressure simulation
              Marc Rigollet

              Hi Ryan,

               

              I've been off on a short vacation and am just getting back into things here.

              First of all - thanks for your comments. Two stand out -  not over-constraining the fitting and allowing it to stretch and erring on the conservative side by removing the threads and not filling them in. Both make sense.

              The fixturing is tricky and is often the part of the simulation I spend most of my time trying to visualize and set up.

              In the end (suggestions from another source) I artificially 'capped' the thicker end of the fitting in to supply a face that I could apply a force to. I used a reference geometry fixture fixuring some (not all) threads with no freedom along the axis (blue arrows), a cylindrical fixture constraining any rotation (pink arrows) and a cyclic symmetry fixture to simulate the whole part (threads were modified in order to use this option) (green arrows). The loading was applied as a pressure of 63 MPa on the end and the cylindrical surfaces (red arrows).2017-07-06 08_16_17-SOLIDWORKS Premium 2017 x64 Edition - [14878-DWG-170626 .125 MALE BSP TO .375 MA.jpg

              In fact, I did it a few ways to compare results and all were relatively consistent.

              All the best.

              Marc