8 Replies Latest reply on Oct 18, 2012 1:54 PM by Charles Culp

    Surfacing artery

    Gwgw Kar

      Hi,

       

      I have an iges file with an artery model.

      The artery consists of many  surfaces (not solid).

      I do not want to have many small surfaces cause this artery is going to be imported in ansys for meshing.

      Imagine that my geometry is like a cylinder. I only want to have 3 surfaces and then from these surfaces generate a solid.

      I tried by knitting  (using also  the button make solid ) but the final model had also the small surfaces too.

      This causes me problem in ansys because it influences the mesh generation.

      I would be very greatful if someone could suggest me something

       

      Thx

      gwgw

        • Re: Surfacing artery
          Robert Stupplebeen

          1. On the FEA side many meshers can merge together these faces so that the mesh ignores the boundaries to allow a better mesh.

          2. On SolidWorks side you will have to recreate the geometry using the IGES as a guide for the creation of sweeps and boundary surfaces.

          3. Can you post a model or image?

          I hope this helps.

            • Re: Surfacing artery
              Gwgw Kar

              Hi Robert,

               

              could you please tell me what you mean by recreating the geometry?
              I am pretty new in solidworks ...

              I have attached a picture of the model.

               

              artery.png

              thx a lot

              Georgia

                • Re: Surfacing artery
                  Matt Lombard

                  Georgia,

                   

                  This is not a job for someone who is pretty new in SolidWorks.  If you want to learn about surfacing, take a class or read a book. On the other hand, there are softwares that can take a bunch of patches and make single surfaces out of them, but SolidWorks is not one of them.

                   

                  In general, the steps to do this would be to make a bunch of planes that intersect the model at a cross section, then use Intersection Curve to make splines at the intersections, and Fit Spline to join all the individual segments into a single closed loop spline. Then use Loft or Boundary with connectors to create the shape as a single outer surface. Then use Fill to close one end, with the Merge option, and then do it again for the other end, but also using the Create Solid option.

                   

                  Best of luck.

                  • Re: Surfacing artery
                    Jerry Steiger

                    Georgia, 

                     

                    If you really want a single surface and you also want to accurately capture all of those little lumpy features, you are in for a very painful process.I'm not sure that it is even possible.

                     

                    I would follow Robert's suggestions as to the meshing rather than try to generate a single surface with all of the lumps.

                     

                    Matt doesn't say it, but the book to buy if you want to learn SolidWorks surfacing is his Surfacing Bible. Highly recommended by many of the folks who frequent this forum. (That includes me, if that wasn't obvious.)

                     

                    Jerry S..

                    • Re: Surfacing artery
                      Charles Culp

                      Where did this data come from? A 3D scanner, a theoretical plot from another piece of software? Why did you pick SolidWorks as an intermediate step between whatever that is and Ansys?

                       

                      I ask this because there may be a better way then SolidWorks.

                  • Re: Surfacing artery
                    Gwgw Kar

                    Thank you all for your advice!!!

                    I think I must take a look in Matt's book...

                      • Re: Surfacing artery
                        Robert Stupplebeen

                        I am most familiar with Abaqus and in that this would be a simple task. Basically in Abaqus/CAE you would merge all tangent faces into 1 with 'virtual topology' I assume that Ansys/Workbench has something similar since it has been around for a while. The Ansys forum at www.eng-tips.com may be able to help you more.

                         

                        Are you getting bad aspect ratios with the mesh? The surface patches look to be relatively well behaved. Assuming you are getting good elements at appropriate mesh densities you may not need to do this extra work. It is very easy to get caught up in getting a pretty mesh instead of a good mesh.

                         

                        I hope this helps and Good luck.

                        Rob Stupplebeen

                         

                        PS: Get Matt's Book and go to his web page.

                        http://www.dezignstuff.com/blog/