[dune-pdelab] Enquiry: testelasticity.cc

[Nagesh Eranki]

Hello

Thank you for the response. To give you a better idea of what I am doing,
allow me to describe the problem:

A cantilever plate measuring 4cm x 4cm with thickness 0.1cm in fixed into
the wall along its left edge. We want to analyze the plane stress situation
(i.e, in the 4cmx4cm plane). The plate is made of steel and is loaded at
the top right corner by a force say P Newton.

Hence, we are interested in Txx, Tyy, Txy stresses and corresponding
strains and displacements.

I have looked at the function 'g' that you have mentioned; it seems that
this function assigns to the local variable 'y', no matter the coordinates.
However, I am interested in imposing Neumann conditions only at the end of
the plate. (Apart from the "Tip loading")

(The fig. is from "Finite Element Procedures By K.J Bathe)

Thanks

Nageswararao E.
​

On Sun, Jun 3, 2018 at 2:52 AM, Christian Engwer <
christian.engwer at uni-muenster.de> wrote:

> Dear Nagesh,
>
> the current implementation does not include inhomogeneous Neumann
> boundary conditions. They should be fairly easy to implement, but
> nobody needed them up to now and thus nobody implemented them.
>
> Please have a look at linearelasticity.hh:310. This is where you might
> query a function for the surface force. The you have to compute the
> resulting residual contribution into `y`. The function `g` is supposed
> to return the surface force. The first question you have to answer
> your self is, which type of surface forces do you want to model here,
> i.e. which diemensionality do they have?
>
> Best
> Christian Engwer
>
> On Sat, Jun 02, 2018 at 07:59:48PM +0530, Nagesh Eranki wrote:
> > Hello
> >
> > I am a mechanical engineering undergraduate trying to learn the ropes of
> > Finite Element Analysis. To facilitate and practice the theory, I am
> > currently going through some test cases in:
> >
> > /dune-2.6.0/dune-pdelab/dune/pdelab/test
> >
> > In particular, I am interested in the file "testelasticity.cc". This file
> > contains "#include <dune/pdelab/localoperator/linearelasticity.hh>"
> which I
> > have tracked down and studied. That in turn requires "#include
> > "linearelasticityparameter.hh", also which   I have studied.
> >
> > I have noticed that there is a function "isDirichlet" that returns the
> type
> > bool.
> >
> > I am interested to impose non-homogenous Neumann conditions, in addition
> to
> > adding a concentrated "tip force" at the end of the cantilever.
> >
> > Please advise on how to implement this.
> >
> > Thanks
> >
> > Nageswararao E.
>
> > _______________________________________________
> > dune-pdelab mailing list
> > dune-pdelab at lists.dune-project.org
> > https://lists.dune-project.org/mailman/listinfo/dune-pdelab
>
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