On Wed, Nov 14, 2018 at 11:45 AM Benjamin W. Spencer via Libmesh-users < libmesh-users@lists.sourceforge.net> wrote:
> It's pretty standard for shell elements to have multiple integration > points through the thickness at every in-plane integration point. > Integrating the response through the thickness allows you to represent the > variation in the nonlinear constitutive response of the material through > the cross-section, and come up with resultant quantities at the locations > of the in-plane integration points, which are then integrated using > standard procedures. > > I haven't really gotten too far into this yet, but I don't think > accommodating those extra integration points would involve changing how the > integration rules or data structures would work in libMesh. I think you > would just evaluate vectors of properties at the standard integration > points, with each entry in the vector representing a different point > through the thickness. We are just getting started on the path of > developing shell elements in MOOSE, so our group will be looking into how > to handle this. > Yes, I agree with this description. We do this for modeling composites for example, since they have different properties in each layer of the composite which you can model via quadrature through the thickness. However, I think the libMesh example that is being discussed here is just meant to be as simple as possible and hence it doesn't do this. Also, I believe you can use analytical formulas for the integration through the thickness in the case that the material is uniform, so I guess that is what is done in the example. Best, David > On 11/14/18, 8:19 AM, "John Peterson" <jwpeter...@gmail.com> wrote: > > On Tue, Nov 13, 2018 at 11:22 PM Yuxiang Wang <yw...@virginia.edu> > wrote: > > > Dear all, > > > > As one usually reads from literature (or commercial software > > documentation), usually, a shell element would need >= 2 Gaussian > > quadrature points through the thickness to capture its bending > behavior. > > For example, in the LS-DYNA documentation > > < > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.dynasupport.com_tutorial_ls-2Ddyna-2Dusers-2Dguide_elements&d=DwICAg&c=54IZrppPQZKX9mLzcGdPfFD1hxrcB__aEkJFOKJFd00&r=hn5akMybrkn-1oiQB8nm_y7trT_BOQm9jBgbzQWwxXA&m=d16wjsgwuY6Xejdr47KKgE8srFi-kHjT92yv6KeNbt0&s=XxuqMBzy7V7pzqu5KNGEyqWuMwh-JQEAJerwVZsdQFU&e=> > or > > mentioned in this paper > > < > > > https://urldefense.proofpoint.com/v2/url?u=http-3A__web.mit.edu_kjb_www_Principal-5FPublications_Performance-5Fof-5Fthe-5FMITC3-2B-5Fand-5FMITC4-2B-5Fshell-5Felements-5Fin-5Fwidely-5Fused-5Fbenchmark-5Fproblems.pdf&d=DwICAg&c=54IZrppPQZKX9mLzcGdPfFD1hxrcB__aEkJFOKJFd00&r=hn5akMybrkn-1oiQB8nm_y7trT_BOQm9jBgbzQWwxXA&m=d16wjsgwuY6Xejdr47KKgE8srFi-kHjT92yv6KeNbt0&s=tSn1-9z_P8T0uME2jwoYDUO7AQEElPc8f3IjxytF-EA&e= > > > > > . > > > > I guess I'm confused about what you mean by "thickness". Our SHELL > elements are logically two-dimensional (have zero thickness) so IMO it > doesn't make sense ask about integration in the transverse direction... > > -- > John > > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@lists.sourceforge.net > > https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.sourceforge.net_lists_listinfo_libmesh-2Dusers&d=DwICAg&c=54IZrppPQZKX9mLzcGdPfFD1hxrcB__aEkJFOKJFd00&r=hn5akMybrkn-1oiQB8nm_y7trT_BOQm9jBgbzQWwxXA&m=d16wjsgwuY6Xejdr47KKgE8srFi-kHjT92yv6KeNbt0&s=CrRFwn9nab2x8xz4ZBh1T-gH5-hRr1_hZ-mFsYImu-E&e= > > > > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/libmesh-users > _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
