Dear researchers,
I'm working with line cohesive interface element. It is been implemented in Fortran Code. I have some doubts about it.
The first one is: this element will be coupled with shell element, but as the line interface element doesn't have degrees of freedom of rotation this could cause some problems. Someone knows a formulation to line interface element that incorporate rotation in formulation?
The second one is: My material is FGM (Functionally Graded Materials).The constitutive law to the cohesive element is based in relative translation displacement. I don't know any constitutive law that take into account the rotation displacement. If someone know, please contact me.
Sincerely,
Joabson
Forums
Cohesive Models for Shell Elements
Dear Joabson,
I once extended the traditional cohesive interface element to handle shell elements. In addition to the traction-displacement law, I implemented a very simple bending moment-rotation relation that resembles the one used for the displacements. This allowed me to model the initiation and propagation of cracks growing through the thickness of an elastic plate, caused by the out-of-plane bending moments, using traditional shell elements.
The extension of these cohesive laws to other materials remains to be studied. I can imagine that these simple models will soon find a limitation if one wants to study the complexity of the tree-dimensional stress field near the crack front (especially when large plastic deformations are involved). However, in some cases, a simple model (specially when one needs to use shell elements) can be a good alternative.
Check the following reference:
¨Modeling of Crack Propagation in Thin-Walled Structures Using a Cohesive Model for Shell Elements¨, Journal of Applied Mechanics, 73(6), pp. 948-958 , 2006.
The paper also include some references to similar works (for example, see the work by F. Cirak & M. Ortiz).
I hope this helps,
Regards,
Pablo