[Sanam]

Dear all,

For my thesis, I have a serious problem for which I have tried and read different sources, but since I am so new to FEA, I couldn't solve it and I would really appreciate your help.
I need to simulate thermal stresses and cracks in a ceramic coated steel pipe with Calculix. I should write scripts by Python and execute by Calculix.
The simulation has already been done by a previous student who has written scripts by Matlab and executed it by Abaqus. I have his codes and I need to convert the code in Python to be executable by Calculix. But I am stuck in one part.
Between ceramic coating and metallic substrate, I am supposed to introduce am interface layer with a specific shear modulus.
In scripting for Abaqus, such a layer is specified by the following codes:

*ELEMENT,TYPE=COH2D4,ELSET=Cohesive

% Printing Sections

*Cohesive SECTION,ELSET=Cohesive,MATERIAL=Cohesive,RESPONSE= TRACTION SEPARATION,THICKNESS=GEOMETRY,CONTROLS=CONT\n0.01, \n*SECTION CONTROLS,NAME=CONT,ELEMENT DELETION=YES\n'

% Breakable Cohesive layer
*MATERIAL,NAME=Cohesive\n*ELASTIC,TYPE=TRACTION\n4 .1e+11,179e+9,3e+14\n*DENSITY\n3210.,\n*DAMAGE INITIATION,CRITERION=MAXS\n100e+10,100e+10\n*DAMAG E EVOLUTION,TYPE=DISPLACEMENT,SOFTENING=LINEAR\n0.00 001\n'

% Cohesive unbreaking
*MATERIAL,NAME=CohesiveUNB\n*ELASTIC,TYPE=TRACTION \n3e+11,179e+9,3e+14\n*DENSITY\n3210.,\n'

However, there is no cohesive element type of "COH2D4" in Calculix and it is not possible to define "Cohesive Section" with "Traction Separation" response. Especially, I am confused about material type for which again there is no "TRACTION" type defined in Calculix.
Can anybody who is familiar with this problem or at least has an idea how these definitions can be replaced by similar ones to satisfy the requirements of an interface layer please help me with that?

Thanks in advance,

Sanam