Hi all,

 I'm trying to model a 2D cohesive layer with a zero-thickness in Abaqus (6.11.2)
The shape of the layer is a quarter circle.

When modelling this i first create a cohesive layer with a certain thickness.
I then convert the part of this cohesive layer to a orphan mesh, then edit the mesh, such that a zero thickness layer is created.

However when i want to submit the job i get the following error message:

 Error in job XX: THE NODE NUMBERING MIGHT NOT BE CORRECT FOR ELEMENT YY INSTANCE ZZ

For my
graduation project I’m working on a model to describe cracking behavior. For
this model I want to model a fibre-epoxy interface, see the attached figure 1
(due to symmetry only a quarter is modeled). The fibre part is modeled with
lineair elastic material. The epoxy part is modeled with CPS4 elements, with
elastic behavior and MAXPS damage (damaged evolution included). The connection
between the fibre and epoxy interface can be modeled with both a cohesive
surface and cohesive elements.  However
cohesive surface will give inaccurate results due to peak stresses (see
attached image 2).

Hello, 

I'm coding a user materils for cohesive elemnt in dyna, But I met some problems, hope anyone could give some guidance or help . 

I'm trying to code my own user material subroutine for cohesive element in ls-dyna.  The cohesive element formulation is already predefined and exists  in *SECTION card ( elform=19). 

By default, four integration points are used for one cohesive element , so my first question is that (1)how do we change number of integration points for one cohesive element ?  Because this is not what we can decide in the subroutine part. And I couldn't find any option in any card which would do.

Hello,

I am simulating crack propagation with cohesive elements. In order to verify that my model is working correctly I wanted to compare it to some real world data or benchmark examples. One such example is in the Abaqus Benchmarks manual - a flat plate with a crack in the center.

Dear Abaqus Users,

    When modeling Composite structures,I got a difficulty in giving the properties of Traction, can some one expalin me

E/knn, 1/kss, G2/ktt

How can we determine the values of Knn,ktt,Kss

Thanks

Rajesh

Fachhochschule Jena

Hi,
I am working on effects of Blast Loading in sandwich composites using Abaqus. I want to incorporate Cohesive behaviour at the interface of the two materials in the sandwich composite structure i am analysing.

 When I specify the interaction proporty as a cohesive bahaviour(if i dont intend to use thedefault parameters given by Abaqus), I am supposed to input whether its coupled interaction or uncoupled interaction and inpur the relevant values of Knn, Ktt, Kss etc. As of now, I am not able to find any standard literature values available for these contants on the internet. So I've been using the defaults given by Abaqus.

Can anyone please suggest material for Cohesive Failure Model. I need to know the basic concepts that deals with cohesive failure model. I would also like to know how deltanc, deltatc etc are formulated in this model. Please sugggest.