michalhabera / dolfiny Goto Github PK

With PR #2 we now should extend the demo/bingham to some bingham_block_lm.py in which the tangential velocity at the inner ring is actually enforced by a Lagrange multiplier. The mesh functions for this are already in place.

Hello, I'm very excited that libraries like dolfiny make it easier to implement universal material constitutive under fenicsx. I was wondering if you could share a tutorial on viscoplastic constitutive variational theory? Because while I learned in the demo program, the dλ = ufl.max_value(f, 0) and the reinforcement criteria represented by bh, qh, bb and qb on solid_plasticity_monolithic.py are somewhat unclear.Thanks very much!

Hi @michalhabera

Many thanks for creating this wrapper. I wanted to check the feasibility of using dolfinx to simulate nonlinear viscoelasticity (a bit similar to plasticity but with some differences). I started by taking a look at the plasticity example and https://github.com/FEniCS/dolfinx/blob/c9f3c459a75f02abcf255a9dd05185350eb1edde/python/test/unit/fem/test_expression.py#L170-L253

but wanted to check if it is possible to interpolate into a quadrature function. I do see an open issue. Has there been any work on the same? In any case, the following should give an idea of what I want to do

from dolfinx.mesh import create_unit_cube
import dolfinx.fem as fem
from mpi4py import MPI
from ufl import TensorElement

metadata = {"quadrature_degree":5}
mesh = create_unit_cube(MPI.COMM_WORLD, 5, 5, 5)
Wq = TensorElement("Quadrature", mesh.ufl_cell(), degree=metadata["quadrature_degree"], symmetry=True, quad_scheme="default")
Vq = fem.FunctionSpace(mesh, Wq)
Cv = fem.Function(Vq, name="Cv")

# now something like?
Cv.interpolate(lambda x: np.eye(x))  # the initial state is identity

Please let me know if you see a way to implement it.
Thanks in advance!

I was just idly browsing and noticed this. I'm conflicted whether it's even worth creating an issue for this :D