Cohesive bond

[Vocs]

Hello,

I'm trying to simulate a cohesive bond in Abaqus. It is supposed to connect two 3D elastic blocks which are in contact on one side. Since the interface thickness is negligible in my problem, I tried to use a cohesive surface interaction and I set the cohesive behavior and damage properties. The aim of my simulation is to analyze the progressive debonding which occurs for big displacements between the blocks. However when I fix one block and I impose a displacement for the other one (Bounday Conditions), I can't complete my analysis with Abaqus, which fails exactly when the most solicited part of the bonding gets damaged. What should I do? Am I using a correct procedure for my problem or should I try something else like a user subroutine?


Thank you very much.

 

[amubashar]

Cohesive elements or surfaces are good for modelling debonding but from my experience they are sensitive to the cohesive law parameters. How did you obtain your cohesive law parameters and which governing law are you using?

 

[Vocs]

I'm trying to simulate a mode II delamination with a linear damage evolution. The parameters that I used are taken from an article about this subject. The initial stiffnesses are high (10^7 and 10^8) and the main focus is on the damage evolution. I tried to add the viscosity stabilization in order to overcome my issue but it isn't very effective. If I use a big viscosity coefficient, significant slips between the blocks are prevented while if I use low coefficients the analysis is extremely slow and I can't complete it.

 

[Composites_FEA_Guru]

Hi Vocs,

The convergence difficulties using cohesive elements in Abaqus is a well known and shared frustration among FEA users...so rest assured that you are not doing anything incorrectly.

There is a new product coming out in March/April from Firehole Composites that provides an add-on to Abaqus that significantly aids in the convergence of using cohesive elements to model damage evolution.

Contact me at milligand@firehole.com if you are interested in staying informed of the progress.

Regards,
-Dan


Dan Milligan
Firehole Composites (

http://www.firehole.com)

FHC provides software and consulting for analysis of composite structures.