On Wed, May 22, 2019 at 3:30 AM marco <ing....@gmail.com> wrote: > Mass lumping is defined by using trapezoidal quadrature rule. > In this way, the weights of a trapezoidal rule should be the integral over > the element of each basis function. > > I noticed that this is not always true for hexahedral elements. Am I > missing something or could there be a bug? >
We form the trapezoidal rule for tri-linear hexahedral elements by taking the tensor product of the 1D trapezoidal rule, which simply has all weights = 1. This results in all weights equal to 1 for the HEX8. Are you talking about the (tri-quadratic) HEX27? For those elements I think you should use a QSimpson rule which are also formed from tensor products, but I don't know if that results in your statement, > the weights of a trapezoidal rule should be the integral over the element of each basis function. being satisfied. I have not heard of this condition before, but it seems plausible... I would have to look into it further. -- John _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
