8 Replies Latest reply on Nov 1, 2018 4:26 PM by Sam Zhang

    Pipe supported continuously on ground

    Nikhil Phatak

      Dear Friends,

       

      We are trying to simulate two cases where a pipe (323.9mm DIA and 23.8mm Wall thick), 200 meters long which is

       

      Case 1) continuously supported (i.e. resting) on the ground.

      Case 2) continuously supported on ground, with 50mm settled (i.e. embedded) inside the ground.

       

      We are using Solid Works Premium(Static solver).We intend to model pipe with SHELL element and with elastic support to simulate ground.

      However, we have observed that in SOLIDWORKS 2015 there is no option for elastic support for SHELL element.

       

      To run study with SOLID elements for pipe having 200m length seems not feasible in SOLIDWORKS.

       

      Kindly provide your suggestions. Sketch and Solid Works file showing problem is attached.

       

      Jared Conway as discussed I have created a separate string for this.

       

      Regards,

      Nikhil Phatak

       

      Thanks in advance.

        • Re: Pipe supported continuously on ground
          Jared Conway

          why do you need the elastic support?

           

          can you also link to the previous discussion? i don't remember it

           

          where are you stuck right now with respect to setting up and running the analysis or what challenges are you running into?

           

          what is your goal? do you want to know how it displaces? what is the effect of the embedding that you are trying to account for?

          • Re: Pipe supported continuously on ground
            Nikhil Phatak

            Q 1 Why do you need the elastic support?

             

            Ground or soil is normally simulated as beam on Winkler/elastic foundation considering the stiffness of the soil in three directions, Vertical, lateral and longitudinal (i.e. axial) direction along with the
            friction between pipe and soil. Please see attached figure. Please suggest us if not elastic support any other option is available in SOLIDWORKS.

             

            Soil Model.JPG

            Q 2 Where are you stuck right now with respect to setting up
            and running the analysis or what challenges are you running into?

             

            We are stuck while running the study and we get strange
            results. Strange results meaning loss of contacts without a reason or in 2015
            it automatically excludes the component when I run it.

            We are using shell elements for the pipe due to its long
            length. We cannot use beam because pipe is having internal pressure.

             

            Q 3 What is your goal ?Do you want to know how it displaces
            ? what is the effect of embedding you are trying to account for?

             

            Yes our goal is to find stresses and displacements of the pipe. Pipe may sink/embed in ground over the years due to its own weight and as such we have to analyse it In that condition.

             

            Thanks in advance.

              • Re: Pipe supported continuously on ground
                Seckin Uslu

                You can use other fix boundry conditionals.

                 

                There is also Soft spring to stabilize model.

                 

                2014 SOLIDWORKS Help - Use Soft Spring to Stabilize Model

                 

                Examine this link 

                  • Re: Pipe supported continuously on ground
                    Jared Conway

                    he's using nonlinear which is why he doesn't have the soft spring option. however i'm not sure if nonlinear analysis is needed in this case.

                     

                    Nikhil, i'd guess that your results aren't making sense because you have rigid body motions. And this could be solved with soft springs in a linear analysis.

                     

                    That being said, looking at your diagram, why not just use springs to setup your analysis? Model a "ground" and then connect your pipe to that ground with springs. It looks like what you have is a standard FE type analysis, just translate it into SWX Simulation.

                      • Re: Pipe supported continuously on ground
                        Nikhil Phatak

                        pipeline is very long.When i define two springs, pipeline will try to bend.so i need to define spring every one meter.and creating cross splitlines just to get a single point will be very lengthy process.I can not create these many split lines.thats why we are looking for some other options.I cant use elastic support on shell thts wht my VAR said.neither can i use virtual wall with shell as we observed that contacts behave randomly.If you see the model i hv attached i used soft spring option in one of its studies.In that L shapped model i dont think there will be rigid body motions.I hv fixed it on d top.defined virtual wall at d bottom.even we have tried it by making both ends fixed.when i run that model with solid elements then it runs fine.d time i use shell with virtual wall it simply explodes d contacts.it seems like using solid element is d only option left.my study gonna take forever to run.but i will find out how much time it may take.

                         

                        Thanks for the help.

                  • Re: Pipe supported continuously on ground
                    Sam Zhang

                    Hi Nikhil,

                     

                    Have you solved this question?

                    Could you please share the solution to me as I've got almost same question with yours.

                     

                    Thank you!

                     

                    Sam