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A free program to generate interface elements in an existing FE mesh

Hello all,

Last year when I started implementing interface elements to model material failure, I realized that the formulation is easy except how to generate a mesh with interface elements. I did a googling to search for such a free program. Amazingly, I did not find any although there are many researchers working on the fracture mechanics field.

So, I wrote a small object-oriented C++ program which reads a FE mesh, duplicates nodes and insert interface elements where asked. The program is able to

(1) insert 1D/2D interface elements everywhere in a FE mesh

(2) insert i1D/2D nterface elements along material interfaces, useful for delamination analysis or interface debonding

(3) insert 1D/2D interface elements along grain boundaries for a pollycrytalline solid, useful for inter-granular crack modelling in pollycrystals.

(4) support Discontinuous Galerkin methods.

The program is written in such a way that any FE mesh format is supported. Currently only Gmsh format is however implemented. The output can be written to Abaqus compatible *.inp files if needed. Some examples are given below and the algorithm is described in the attached paper which is the preprint of the article

 VP Nguyen, An open source program to generate zero-thickness cohesive interface elements, Advances in Engineering Software, 2014(74): 27--39.

 The code  is available at



Lianhua Ma's picture

Hi Nguyen, the code you mention may be convenient to generate interface meshes in open source FE software.  I think it is also easy to generate such meshes in ANSYS or ABAQUS.

I have one question for the simulation of material interfacial failure.

Is it possible to model the failure of the interface between the solid and shell model by zero thickness interface element?





Hi Lianhua,

Could you be more specific please? I din't get your point, sorry.


Lianhua Ma's picture

Hi Phu, I am sorry I did not give more details about my question.  I’m trying
to make it clear in this post.

In the commercial FE software(ANSYS or ABAQUS), as we know, most composite models (matrix
and inclusion) are generally constructed using
(2D or 3D) solid elements for all parts. In such cases, we need to generate interface elements as you mentioned when modeling material failure behavior. I think this can be easily implemented in ABAQUS.  

Now let’s consider a special kind of composite, carbon nanotube(CNT)-reinforced
composite, to simplify we can treat CNT as a shell model(which has already developed
in some literatures). In this case, the matrix and CNT can be modeled respectively
by solid and shell elements in ABAQUS. I am currently interested in the interfacial
failure issue of this model. Using your program, could you generate corresponding
interface elements for this model? Could you give more information about the
special cohesive interface failure simulation?



Hi Lianhua,

My interface element model is able to deal with solid-solid interfacial failure. My interface elements generator howver just reads a FE mesh and insert interface elements where necesarry. It does not know about solid or shell elements.

I leave your question on failure model for solid/shell interface to experts on this field. Sorry for not being so helpful.


Hi Phu,

 Abaqus provide a kind of element name cohesive, which can simulate interface between solid and solid. Can you describe your program how to solve the crack progression. I am also interest in the differences between your program and abaqus cohesive element.


Hi Hu,

My code implements the standard interface elements within the framework of cohesive zone models. I do not know the Abaqus implementation so I cannot describe the difference.

Happy new year,


Jianxu Shi's picture


I have a related question to Abaqus: can you code work on Abaqus input file: aka, input=abaqus inp file without interface elements, output=new abaqus input file with interface elements block inserted in a specified solid region.

 PS: I am interested in obtaining a copy of your program. we can talk about future collaboration. For more info about myself, see (quite dated but you can email me for updated info).



Hi Shi,

Although my code currently does not support Abaqus input, it has been implemented in such a way that new input format can be incorporated easily. 

Ok, I am sending you that piece of code. 


Hi Shi,

Could you send me your email? I couldn;t find it in the website you told me.


can your program is useful in ansys for generating interface elements.Since i am facing problem while modelling cohesive zone.

Hi Shi,

I am interesting in computational mechanics. Can you send me your code?I want to saw that how this build and how implement this code in another software.

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