On 16 Apr 2014, at 12:08, David Ham <[email protected]> wrote:
> Hi Jack, > > The student who was working on isoparametric mappings last summer didn't get > very far, however we were very fortunate to host Martin Alnæs for six weeks > this spring. We designed, and he implemented, the UFL layer changes needed to > get isoparametric in. We still have some legwork to do in our FFC branch to > get those changes into Firedrake and I believe the equivalent work for Dolfin > is still underway, but there is progress and we hope to have isoparametric > by the summer. > > On the shell subject, Firedrake now supports simulation on extruded shells > formed of triangular prism elements. I'm not sure if that helps you but > you're welcome to give it a try. > Jack is referring to a different type of shell - he’s referring to shells in the structural mechanics sense rather than a spherical shell. Garth > Regards, > > David > > > > On 16 April 2014 10:39, Jack HALE <[email protected]> wrote: > Hi Corrado! > > Sorry for the slow reply on here, I know we have discussed this > privately, but of course this is the best place for discussion. > > 1. First half of the presentation; My understanding of the current > 'PDE on Manifold' functionality in FEniCS is that the weak form cannot > include terms relating to the geometry of the manifold. i.e. it would > be natural to have terms such as the fundamental form expressed > through UFL which you could then define the shell model. > > I have seen someone discuss this idea before here: > http://www.mail-archive.com/[email protected]/msg08932.html > > albeit in the context of isoparametric mappings. I think though, that > isoparametric mapping is just relating R^3->E^3 and the shell concept > is relating R^2->E^3, the efforts towards shell models should work > within bringing isoparametric mappings to FEniCS. > > @David Ham: I remember David Ham discussed with me that he had a > student working isoparametric mappings, did anything come of it? > > 2. Second half of the presentation; local projections. As you can see > I have done some simple local projections at the linear algebra level > (ie. post assembly), but I do not think this is a suitable path for > implementing the MITC operators which are significantly more > complicated. One initial option would be to do the full mixed problem, > at the expense of engendering extra unknowns. Also you suggested in > our private email that we could do these local projections using a > custom C++ kernel/assembly routine. > > I can see there are still some problems with the RT elements on > manifolds, it would be important for this functionality to work first: > > http://fenicsproject.org/pipermail/fenics/2014-March/001340.html > > And only two threads up from this one, this discussion seems pertinent: > > http://fenicsproject.org/pipermail/fenics/2014-March/001371.html > > Another option is that we avoid this second piece of functionality and > go with trying to get DG-Koiter shell models working first which work > which are rotation-free and use standard element constructions. > > @Garth Wells: I know this is something Garth Wells is an expert on so > perhaps it is the best path forward for now? > > 3. Generality. So I know a lot about shells, but not about other PDEs > on manifolds. I remember Douglas Arnold mentioned that any approach > implemented in FEniCS > should be as general as possible. Any comments on this? > > Kind regards, > ----- > Dr. Jack S. Hale > > Research Associate > > University of Luxembourg > Campus Kirchberg G005 > Phone +352 44 66 44 5236 > [email protected] > > Latest publications and conferences: http://goo.gl/rNiISG > ORCID: http://orcid.org/0000-0001-7216-861X > Google Scholar: http://scholar.google.com/citations?user=Fx9lQ7MAAAAJ&hl=de > _______________________________________________ > fenics mailing list > [email protected] > http://fenicsproject.org/mailman/listinfo/fenics > > > > -- > Dr David Ham > Departments of Mathematics and Computing > Imperial College London > > http://www.imperial.ac.uk/people/david.ham > _______________________________________________ > fenics mailing list > [email protected] > http://fenicsproject.org/mailman/listinfo/fenics -- Garth N. Wells Department of Engineering, University of Cambridge http://www.eng.cam.ac.uk/~gnw20 _______________________________________________ fenics mailing list [email protected] http://fenicsproject.org/mailman/listinfo/fenics
