Hi Wolfgang, Apologies but could you just clarify?
I get that the stress boundary can be put into the weak form, but only really when you have Neumann conditions. And why would I have to use a compute_nonzero_normal_flux for a zero one? I believe it my have been my fault not being clearer. On the 'side' boundaries, I have no normal flux. On the other boundaries, I have a prescribed nonzero inhomogeneous normal component of the normal stress (so this is only one of the components). On all boundaries, I have zero tangential stresses (which sorts out the other 2 components in 2D in additions to the normal component conditions from the above). I believe this is equivalent to the 4th condition mentioned in step-22. Pardon my potential ignorance, but I'm unsure how I can put these in the weak form when i have component-wise conditions (partial conditions). I had thought to use compute_no_normal_flux_constraints for the side boundaries and compute_nonzero_normal_flux_constraints for the other two as constraints, but this doesn't seem to work. On Friday, December 1, 2017 at 11:48:07 PM UTC, Wolfgang Bangerth wrote: > > > Jane, > > > The whole point of not imposing zero for all components in a Dirichlet > > sense is that I am testing for a case where I have inhomogeneous normal > > component of the normal stress, with the tangential stress being zero on > > some boundaries. > > This case is easy: the stress is only imposed weakly anyway, so you need > to put this into the bilinear form. > > > > On some boundaries, I have zero normal flux and zero > > tangential stress but I'm pretty sure this doesn't amount to the actual > > components being zero anyway. > > Correct. In this case, all you need to do is impose a nonzero normal > flux (for which I believe there is a function); the tangential stress > would have to be imposed in the bilinear form, but since it's zero there > is nothing to do (the term one would have to add to the bilinear form > just happens to be zero). > > Best > W. > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > <javascript:> > www: http://www.math.colostate.edu/~bangerth/ > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
