Hello everybody, I want to solve a 2-D linear elasticity problem in the area [0,1]X[0,1], which has Dirichlet boundary condition: u_x(0,0) = u_y(0,0) =0, u_y(x,0) = 0, u_y(x,1) = -0.001 where u_x(x,y), u_y(x,y) represent the displacement in x, y direction of point (x,y). So, how should I define …

See for instance: Bitbucket on how to set Dirichlet conditions on sub spaces. If you use dolfinx, consider: Component-wise Dirichlet BC — FEniCSx tutorial

Thanks very much! But I am not clever and still have problems. I think I do not use dolfinx. And I still do not know how to set ux instead of u as boundary condition after reading the first instance. I try to write it by myself: from fenics import * L = 1 nu = 0.499 mu = 1 lambda_ = mu 2 nu/(1…

The code you have posted is a mix between dolfinx and dolfin. You need to follow either the first link I sent (Taylor hood, using dolfin) or the second one if you are going to use dolfinx. Secondly, for further code snippets, please use 3x` encapsulation to ensure proper formatting.

Thank you for pointing out the error. I decide to use dolfinx. I try to install dolfinx in ubuntu 20.04 by sudo add-apt-repository ppa:fenics-packages/fenics sudo apt-get update sudo apt-get install fenicsx but I failed. When I run from dolfinx.fem import Constant, DirichletBC, Function, Functio…

I use ubuntu 20.04 as mentioned. It seems there is no problem with sudo apt-get install fenicsx

Could you list the output of apt-get install fenicsx and do also call pip3 list?

[image] This image consists all the packages which name has ‘fenics’. Is it ok?

So the package is there, could you try calling python3 -c “import dolfinx;print(dolfinx.__version__)”

Define DirichletBC for a Vector Function

mesh

dokken December 9, 2021, 7:33am 7

What system are you running on? Ubuntu 18.04 for instance is not supported: Error when building Basix from source - #4 by dparsons

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Define DirichletBC for a Vector Function

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