Re: [Libmesh-users] A mistake in the miscellaneous example 12?

[David K. <dav...@ak...>]

On Sun, Oct 21, 2018 at 3:48 AM Yuxiang Wang <yw...@vi...> wrote:

> Dear all,
>
> I seem to find a mistake in the implementation of the MITC4 shell
> element, in the miscellaneous example 12.
>
> In the reference used, "Modelisation des structures par elements finis,
> Vol. 3: Coques.", on page 372 equation 6.3.90 it only added a small
> drilling stiffness. This was done by a coefficient alpha that is
> sufficiently small (1e-4 to 1e-7). However, in line 779
> <
> https://github.com/libMesh/libmesh/blob/master/examples/miscellaneous/miscellaneous_ex12/miscellaneous_ex12.C#L779
> >of
> the code (corresponding to this equation), this coefficient is dropped.
>
> Could anyone please help discuss this issue?
>

Hello,

My colleague Sylvain implemented that example, and I passed your question
onto him. His reply was "The drilling dof coefficient value is very
empirical, and I think in that specific example I just got good results
with a value of 1." So there is no bug here, it's just that he had to set
the value in a way that worked well for this example.

Best,
David