[Getfem-users] problem with the von Mises stress: different materials

[Florian Kolbl]

Dear users of getfem,

I am trying to learn getfem for different applications, making 
individual steps to explore the possibility of the package with python. 
I am currently simulating linear elasticity, more precisely a simple 2D 
cantilever with Dirichlet conditions on the sides and an external force 
on the top (see the attached step2.pdf for illustration), however my 
geometry (see the attached .geo file) contains 2 materials. I described 
my problem specifying the region label when adding the linearized 
elasticity brick:

# adding the physical equations of the linear elasticity to the model
model.add_fem_variable('u', displacement)
# for the Steel
model.add_initialized_data('lambda_S', clambda_S)
model.add_initialized_data('mu_S', cmu_S)
model.add_filtered_fem_variable('lambdastar_S', clambdastar_S)
model.add_isotropic_linearized_elasticity_brick(mim,'u','lambda_S','mu_S',STEEL_CANT)
# for the Aluminium
model.add_initialized_data('lambda_Al', clambda_Al)
model.add_initialized_data('mu_Al', cmu_Al)
model.add_initialized_data('lambdastar_Al', clambdastar_Al)
model.add_isotropic_linearized_elasticity_brick(mim,'u','lambda_Al','mu_Al',ALUMINIUM_CANT)

I have a result for the displacement, however I am blocked to compute 
the von Mises stress as I can't specify a region to the 
compute_isotropic_linearized_Von_Mises_or_Tresca method... Is there any 
solution to overcome this issue. (by the way, I am using gmsh to create 
the mesh, the input and output files are attached as well as my python 
script for getfem).

I thank you in advance,

best regards,

--
Dr. Florian Kolbl
Senior Research Officer

University of Essex
School of Computer Science and Electronic Engineering
Brain-Computer Interface Lab
Room 3A.532D
Telephone 01206 874384

Winvenhoe Park
Colchester - Essex CO4 3SQ
United Kingdom

Step2.pdf
Description: Adobe PDF document

problem_step2.geo
Description: Text document

problem_step2.msh
Description: Mesh model

solver1_step2.py
Description: Text Data