Hi Lauren The elasticity model is step-18 is "curious" in that it is not finite deformation nonlinear elasticity or small strain linear elasticity. I would not use it as a template for small strain linear elasticity.
In linear elasticity the strain state anywhere in the domain is simply a function of the displacements (which you have at the nodes after a SolutionTransfer). The corresponding stress is simply determined from the action of the elasticity tensor on the strain. You don't need to previous stress state as you can determine the stress directly from the total displacement. There is a tut nearing completion on finite deformation elasticity for incompressible hyperelastic materials. There are various other options to transfer quadrature point data in problems where one classically has an evolution equation for an internal variable that is satisfied at the level of the quadrature point (e.g. return mapping algorithms in plasticity). I would be keen to help with these once you need them. Regards Andrew On 2 February 2011 20:55, Lauren Ferguson <[email protected]> wrote: > > Markus and Andrew, > > >my first try would be to compute the residual stresses on the quadrature > >points of the new grid with the interpolated solution you obtained from > >SolutionTransfer. > > I also thought this might be a possible solution. However, in computing > the stress update, the old stress values are required, which are stored on > the old quadrature points. > > > As Markus suggests, if you are only interested in transferring the > > stress state and the problem of interest is linear elasticity then the > > easiest is simply to reconstruct the stress from the nodal displacement > > and the resulting strain field at the quadrature points of the new mesh. > > By reconstructing the stress, do you mean interpolating the old stress on > the old quadrature points to the new quadrature points? > > > If you really had internal variables related to some inelastic process > > that had their own evolution rule (e.g plasticity, damage, > > visocelasticity, etc.) then you have to do something different. If this > > is the case, let me know as I have some routines for this but they need > > completing and checking. > > I'm currently only looking at linear elasticity, but may eventually want > to look at plasticity as well (this is a long way down the road though). > > Lauren > _______________________________________________ > dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii >
_______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
