Hi, I am currently using cohesive elements to model a bio polymer material. my material is undergoing negative displacements hence i want to superimpose my cohesive elements with another compression cohesive law so that when the displacements reach a negative value the second cohesive law will prevent that.
But now how to superimpose the compression cohesive law when the negative displacement criteria is reached?. Thanks in advance
Hi Arunachalam Muthukaruppan
I didnt get you well. Could you explain more. Maybe I can help.
Best Lucks
Hi khaled,
1. I have a bio polymer material and i'm using cohesive elements to model my material and to describe the behavior of my material i'm using a bi-linear cohesive law.
2. Then i'm conducting a uniform tension test on my specimen and I'm able to run my simulations successfully
3. But I found that many cohesive elements in my material are undergoing negative displacements (i.e they are bending) which is not permissible for my analysis .
Hence, in order to avoid negative displacement in my cohesive elements i have to impose a another cohesive law( which is compressive in nature),so that when my cohesive elements undergoes negative displacement the second cohesive law will prevent that from happening.
I want to know how to implement this in Abaqus
Cohesive elements can take mode I compression loads. But no failure happens under mode I compressive load.
There are two ways to implement in Abaqus
Hi Umesh thanks for your answer.
My problem exactly is that the cohesive elements are getting crushed so does cohesive interaction instead of elements solve this issue?
I also see that cohesive Interactions are used only for Debonding problems Is it true?? or we can use them for other applications too.
Hi Arunachalam Muthukaruppan ,
Using a cohesive UEL can help you. If you don't want to develop by yourself, I can recommend the PPR potential model by K. Park and G.H. Paulino. The script is available in web. In the script, at the beginning of 'k_Cohesive_PPR' subroutine, you can arbitrarily define the traction for negative (or a limit) displacement. If you put some time to read the following article and watch following simple instruction videos on implementation, it should be straightforward. This model has good convergence and is very good to capture mixed mode failure.
Article Computational implementation of the PPR potential-based cohe...
Video instruction:
https://www.youtube.com/watch?v=AEydxT3nGpM&t=788s
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