Hello Everyone,

I'm working on an axi-symmetric formulation of elasticity in cylindrical
coordinates, and I'm a bit stuck when it comes to computing the gradients.
The problem is that I need to compute gradients of the shape functions that
contain values of shape functions as well.

For example, for a vector-valued shape function v^i, with components [v^i_r,
v^i_\phi, v^i_z], the first row of the gradient (written as a matrix) looks
like:

[\partial v^i_r / \partial r, -v^i_\phi / r, \partial v^i_r / \partial z]

My understanding is that the first and third term can be obtained from
FEValues shape_grad, but the term -v^i_\phi / r needs to be computed.  Am I
correct that this is not simply something like:

-fe_v.shape_value(i, qp)/quad_points[qp](0) ?

I think need to isolate the corresponding shape function to v^i and use its
value, but I'm not 100% sure on how, or if this is true.

This has been bugging for a while, so any help from someone with experience
in axi-symmetric problems and deal.ii would be greatly appreciated.  For
what its worth, I've been able to get scalar axi-symmetric problems to work
wonderfully.

Thanks,

Jon
_______________________________________________
dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii

Reply via email to