Cohesive Surfaces in v6.9

[mbqueens]

I'm looking for additional information on cohesive surfaces (for use in Abaqus/Standard). I've read the documentation but it doesn't really give you any advice on choosing parameters.

I'm particularly interested in the stiffness coefficients Knn, Kss, and Ktt. I know that the default enforcement method is based on the underlying element stiffness but I found a paper (based on cohesive elements not surfaces) that shows a big difference between the default parameters and chosen values. I've also read that choosing higher stiffness coefficients will cause the time increments to be very small. I'm having a convergence issue right now and I believe it has something to do with these stiffness parameters and the fact that my maximum nomimal stresses at failure are relatively small (weak bond) compared the the stresses in the parts.

Can anybody point me to a journal paper or something that might help with this issue?

Thanks in advance,
-MB

 

[Woongbi]

Hi MB,

There is a webinar March 22/24 that discusses new cohesive element modeling solutions for composite materials. I don't know if you are modeling composites but the webinar would be informational regardless.

http://www.firehole.com/webinar/mct4.aspx

Regards

 

[mbqueens]

Thanks for the link Woongbi.

I'm trying to model the bond between a liner and its host pipe. I'm applying a moment to a section of the host pipe that has cracked circumferentially. The liner remains intact. I need to determine how much of the liner debonds from the host (from the location of the circumferential crack) as the moment is applied.