On Monday, June 24, 2019 at 11:36:32 PM UTC+2, Ramprasad R wrote: > > Hello Bangerth, > > The terms N_* are the resultant forces in the * direction and these forces > are calculated using the strains which in turn are calculated using the > displacements u. So the terms N_* are not constants, rather change with > each element. And these values directly depend on u. > > >> Hi Ramprasad,
I think that you want to do an eigenvalue calculation (step-36) I think that first you have to do an static calculation before your eigenvalue calculation in order to obtain the values for N_* (step-8) As discussed in your paper, the typical eigenvalue problem for the elastic equation takes this form, where omega^2 is your eigenvalue and Phi the eigenvector (K - omega^2 M)*Phi = 0 For the buckling case lambda is your eigenvalue. (K - lambda G)*Phi = 0 The calculation of K can be found in step-8, step-62 (or other tutorials). I think that in order to calculate G you need the resulting strain of an static calculation. You can do the static calculation, store the strain in a temporary buffer and use that data to calculate G. step-18 shows you how to do this. Once you have K and G, you can do an eigenvalue calculation. step-36 shows you how to do an eigenvalue calculation. Note that in step36 the stiffness matrix is called A. The equation in step36 is (D-epsilon M)*Phi=0 which is very similar to the buckling equation. Best, Daniel -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/d026c101-ffdd-4325-a1bb-f40c8283bbc9%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
