Free slip boundary condition in elasticity

[dokken]

@marcomusy

class BoundarySource(UserExpression):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

    def eval(self, values, x):
        values[0] = 0
        # values[1] = 0 # free slip?

    def value_shape(self):
        return (2,)


def solve_problem(mesh, force=()):
    V = VectorFunctionSpace(mesh, "CG", 1)
    u = TrialFunction(V)
    v = TestFunction(V)
    displacement = Function(V)

    subd = CompiledSubDomain("on_boundary && x[0] < -49")
    bnd_src = BoundarySource(degree=1)
    dbc = DirichletBC(V, bnd_src, subd)

This is not how to set a sub condition, see: Help a starter! - #9 by dokken