3 Replies Latest reply on Aug 4, 2010 6:39 AM by Devi Prasad Samal

    Simulation of pressure vessel with variable wall thickness

      Have ran a simulation of a thin walled pressure vessel using shell elements.

      The model had uniform wall thickness and was OK

      I have now drawn a thin walled pressure vessel with a varying wall thickness.

      It is actually a model of a coke can the bottom is 0.3mm sidewall 0.1mm and

      where it tapers in at the top 0.16mm.

      With my previous study I created a surface offset mid plane then applied shell elements.

      Is this possible with a variable wall thickness?

        • Re: Simulation of pressure vessel with variable wall thickness
          Devi Prasad Samal

          Hi clive,

           

          i am not a simulation expert. but i can say that u can use shell mesh using mid-surface for multi thickness also.

           

          first create mid surface by going to insert-surface-midsurface and create different surface which have different thk u want to assign. then the surfaces are avaialable in simulation tree. edit them add the proper thickness.

          and run the required simulation.

           

          regards

          devi samal

            • Re: Simulation of pressure vessel with variable wall thickness

              Thanks for your help I was able to use mid surface and now have my 3 different thickness pressure vessel

               

              I had a problem with my original drawing I had sketched the profile of the can then sketched the pressure

              vessels varying wall thickness using offsets etc, then rotated about the centre line.

              when trying to use the mid surface command there was a problem that it could not find matched pairs (faces)

               

              The way I have got round it was to rotate the sketch of the outside of the vessel to produce a solid then used

              the variable shell command to shell out the solid giving me the required 3 thickness

              I was able then to use mid surface as you advised.

               

              I have split the vessel in two along the longitudinal axis and am looking into symmetry restraints

              any advise on setting up the simulation study would be appreciated as I am just starting out with

              using the package.

               

              thanks again Clive

                • Re: Simulation of pressure vessel with variable wall thickness
                  Devi Prasad Samal

                  hi clive,

                   

                  it's a pleasure that my instructions help somebody. but i am little bit confused what u have written and what u are going to do.

                   

                  so just forwarding some of my thoughts.

                   

                  1. you did not have to create different thickness in your modelling to imply the model in to analysis. create a simple pressure vessel with same thickness. just use the split line command to split surfaces of the model where u want to apply different thickness. go to insert and create mid surface by selecting the surfaces of pressure vessel. now you have 3 surfaces of pressure vessel.

                  2. now take them to the analysis. when u create a static study. you can find all the surfaces and solid body under simulation feature manager tree under part name feature. just expand the part name feature and all surface and solid body will appear. right click on the body whom u want to exclude from the analysis.and select exclude from analysis. right click on surface under part name feature and  click on edit defination and add the desired thickness required.

                  3. after thickness add material by right click on it.

                  4. most important is applying contacts. try to connect the edges of pressure vessel by bonded contact with edge selection.

                  5. give restraint and use symmetry condition if ur model is symmetric .

                   

                   

                  if you need any help regarding this please put a picture so that i will know where u find a problem....

                   

                  Regards

                  Devi Samal