Dear Nicolas,

You can simply use a DG0 Function for each Lame coefficient, and interpolate a spatially varying expression into it. For a case like this where you want a step function in the coefficient, you probably want to use a ufl.conditional (effectively an “if” expression) in the expression you interpolate.

Regards,

David

From: <firedrake-bounces@imperial.ac.uk> on behalf of Karin&NiKo <niko.karin@gmail.com>
Date: Wednesday, 27 May 2020 at 07:31
To: firedrake <firedrake@imperial.ac.uk>
Subject: [firedrake] Bi-material example

Dear Firedrakers,

I would like to model a bi-material medium. One can think of an elasticity problem where the domain is composed of 2 parts, one being made of steel and the other one of rubber. Then I would like to assign different Lamé coefficients to these parts.

I do not find such an example in Firedrake tests. 

Could you please give me some piece of advice?

Best regards,

Nicolas