Displacements don't make sense for cantilever beam

1

Hi All,

I have run the elasticity tutorial problem as given in the official website:

My problem is the beam’s deformation does not make sense. I expect a symmetric deformation for XZ-plane, but that’s not what I got. Can someone please explain what is the problem? I have included the deformed beam for your review.

clamped_beam
clamped_beam.png1083×978 15.8 KB

2

While the exact solution would be symmetric, the mesh is not symmetric, so you don’t expect to get an exactly-symmetric discrete solution. As you add more elements, the discrete solution will converge to a symmetric one.

Alternatively, if you use a more recent version of FEniCS, you can get a symmetric hexahedral mesh via

mesh = BoxMesh.create(MPI.comm_world,
                      [Point(0, 0, 0), Point(L, W, W)],
                      [10, 3, 3],
                      CellType.Type.hexahedron)

which preserves the symmetry of the exact solution.

1 Like
3

You are right. Cool. That explains it. Thanks so much :slight_smile: