Surface-based cohesive behavior in abaqus 6.9-1

Hi As, I have used cohesive surfaces for debonding problem, I can say that the behavior of the cohesive surfaces is same as the cohesive elements, also you can model frictional behavior of debonded surfaces as in addition to cohesive forces. The application part is much simple if you are using abaqus 6.9., in that you can have cohesive surface interaction in contact of interaction module. In addition to this you have to define the damage parameters as you define for cohesive elements. For the further details you can refer the example of Alfano for debonding.  

Regards 

Dr. Yaqoob Yasin and Rajnish Sharma

Hi Rajnish,

for modeling of bond-slip in a RC member I have used interaction model with cohesive behavior/Explicit. Therefore I have assign it in to surface to surface, but I got the message that I can not use these type of contact. Could you please help in this matter and tell me why I cannot do it?

Regards

Hi

 I am working on cohesive zone model using abaqus inbuilt cohesive element. I am doing 3 element test for validating the traction separation law. cohesive element is sandwitched  between two 3d elements. Bottom element is fixed and displacement boundary condition is applied to the top element. I have some questions. Plz gime me youe valuable suggessitions

1. How to select the cohesive material parameters (stiffness, damage criterion, evolution law)

2. I am plotting Rf versus U graph but only linear part of t-delta curve is coming. I am not getting the softening part. why?

3. Is there any modeling issues or problem with cohesive material properties?

4. After simulation what should be the plot in abaqus to match global force deformation curve obtained from experiments?

5. If we unload the sample the traction separation curve should come to origin but how to do that?

Waiting for your positive reply 

 Hello chintan

 As per my best knowledge In abaqus element manual
"cohesive element" is described, there they have discussed the traction
separation and softening behavior. you can follow the same for element
test.

Regards

Dr. Yaqoob Yasin and Rajnish sharma

I am trying to use cohesive material to simulate cutting.

When I am applying the cutting tool in the speciman ,  Instead of cutting it is just going in without creating any damage to the speciman.

Can you help me out with that?

Hi chintan,

Ktt is a constant relating the traction to the separation of the top and bottom surface of the interface. The unit of Ktt is N/m^3. It is not as same as stress's unit. Turon et al. gave a detailed discussion on how to determine the stiffness, Ktt etc.

see Turon A, Davila CG, Camanho PP,
Costa J. An engieering solution for mesh size effects in the simulation of
delamination using cohesive zone models. Engineering fracture mechanics

2007;74:1665-1682 

hi

i wanto model composite slab, which is concrete and steel deck, the interface between the concrete and steel deck will be model using surface based cohesive, however when i try to run there is a problem in the interaction part, do anyone have simple CAE file the use surface based cohesive or any tutorial on how to model using surface based cohesive.

Please  help.

maxfeeler2@yahoo.com

Hi,
I'm newborn in ABAQUS. I want to make a static analysis of RC frame with the
bondslip effect after apply cyclic loading to the frame.

At the moment,I tied the reinforcement bars with the concrete. And manage to
plot hysteress curve of the frame. what I'm aspect was degradation of stiffness
and perhaps I can see pinching behaviour in the hsteresis curve which is not
happen to the current plot.
Detail of my model;
1.2D beam model (beam element for beams and column, truss element for
reinforcement bars)
2.Concrete damage plasticity-concrete model
3. Have inlude damage material properties to concrete and steel.

Hope to get help from you all.

Regards,Ayda

Hi there! I am really new to Abaqus and I need to model a composite laminated crash cone under impact to a flat solid wall (analytical surface is used). I modelled a cone with a layers of conventional shell elements with hashin failure criteria and surface-based cohesive behaviour as interaction between layers representing the interface of composite laminates. The model runs successfully but once I checked the energy balance, the damage dissipation energy from the cohesive, it turned out to be NEGATIVE (I think this is wrong).
I tried to model a simple geometry model with cohesive elements and the damage energy from cohesive element is POSITIVE (which seems to be correct).

As far as I know the energy balance: internal energy = strain energy + artificial energy + damage dissipation energy + penalty contact energy +contraint penalty energy + plastic energy

where Total energy = internal energy + viscous energy + kinetic energy + frictional energy + external work = constant
I set up another history field output request to capture the energy of hashin damage to compare with the all damage energy of model and the result is that damage from surface-based cohesive is NEGATIVE. This means the more damage to the cohesive, the less internal energy in the cone which means that less energy absorbed from the impact. <-- totally wrong...

Due to the complex geometry of the model, cohesive element does not seem to the one I can apply to my model.
Could anyone explain or give me a solution why the damage energy from surface-based cohesive is NEGATIVE? Is it wrong?

Here is the interaction property of the surface-based cohesive

** INTERACTION PROPERTIES
**
*Surface Interaction, name="interface prop"
*Cohesive Behavior, eligibility=ORIGINAL CONTACTS
20000.,15000.,15000.
*Damage Initiation, criterion=QUADS
60.,90.,90.
*Damage Evolution, type=ENERGY, softening=EXPONENTIAL, mixed mode behavior=POWER LAW, power=2.
 0.6,2.,2.
*Contact Damping, definition=CRITICAL DAMPING FRACTION
0.1,

hi every body
i try to do the simulation of impact on glare structure (glare :glass aluminium reinforced),and to study the growth of  delamination between the aluminium layer and the glass fiber, i have done a cohesive layer with 0.0001 mm thikness,my problem tat i can't find the properties of the cohesive zone(for damage initiation and damage evolution),if some one can help
thanks a lot
Ibrahim

Hi I want to model FRP debonding based on Lu bilinear model.

I read in an article that I can model it in ABAQUS by cohesive element, now I have some questions:

1- In definition of elastic parameter should I use Traction type or Coupled Traction?

2-To define debonding initiation should I use MAXS DAMAGE orQuads Damage?

3- How should I show to software that in the normal direction debonding not occur due to pressure?

4- To show completion of debonding in 3 directions (1 normal and to tangential direction) I want to define maximum energy in every direction, but by clicking on the Suboption key I see that there is only one energy that can be defined. how can I define energy in 3 directions?

5-What kind of element I should use for cohesive element? 3D stress or Cohesive?

6- What is the meaning of this error and how can I fix it ?

" ***ERROR: TOO MANY ATTEMPTS MADE FOR THIS INCREMENT "

(I try static,Riks step with Maximum number of increment, initial, minimum and maximum, 10000,0.01,1E-010 ,1E+036,respectively to fix it but after 40 min the error was repeated!)

Hi Everyone

 I am currently working on the project of  structural health monitoring of sandwich composite beam and I am not able to find how to model the disbond model of sandwich composite beam. I just know that cohesive element and cohesive behaviour is helpful to make the debonding of skin of sandwich beam from core but I dont know how to make model and how to insert cohesive elements for debonding. please help me if anyone have an idea about that

regards,

Harshad

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