Interface elements versus continuum elements

Dear Gouse

As per my understanding, you can use continuum elements, but the only worried is about the material properties which normally varyies across the interface (if you see some of the experimental results). Hence, proper defining material properties is an important issue for modelling interface problem, otherwise you may not get the exact behavior of your system, which may be you are looking for.

I dont knw exactly about the interface elements of Abaqus, may be related to gradation of properties at interface region??

regards

Vijay

Dear Gouse,

as far as I know, the decision on whether using interface elements or not primarily relies on the thickness of the interface. If the thickness of the interface is pretty small as compared to the size of the body (as usually occurs), then the use of interface elements is necessary. A normal finite element mesh with intermediate elastic properties could also be used, but usually the computational effort is too much. 

Using interface elements, you are implicitly assuming that a strong strain localization would take place along the interface. Hence, the material behaviour in that zone is no longer defined in terms of stress vs. strain, as in classical continuum mechanics, but in terms of stress vs. relative (opening and sliding) displacements. The stress vs. displacement relationships are the so-called cohesive zone models and have different shapes. However, their most important parameters are the peak stress and the interface fracture energy (the area below the cohesive law).

If you are interested in deeper such a topic, you could refer to my publications:

M. Paggi, A. Carpinteri, G. Zavarise: "A unified interface constitutive law for the study of fracture and contact problems in heterogeneous materials", In: P. Wriggers, U. Nackenhorst (Eds.), Analysis and Simulation of Contact Problems, Lecture Notes in Applied and Computational Mechanics, Vol. 27, 297-304, 2006. Springer-Verlag  doi:10.1007/3-540-31761-9_33

A. Carpinteri, M. Paggi, G. Zavarise: "The effect of contact on the decohesion of laminated beams with multiple microcracks", International Journal of Solids and Structures, Vol. 45 (1), 129-143, 2008. doi:10.1016/j.ijsolstr.2007.07.012
 

If you have no access to such papers, do not hesitate to contact me by e-mail ( marco.paggi@polito.it ). I will send you the PDF files.

Hoping it could be useful, I remain with kind regards, Marco

__________________________________________________________________________ 

Dr. Ing. Marco Paggi, Ph.D.
Assistant Professor of Structural Mechanics, Politecnico di Torino

Alexander von Humboldt Research Fellow 2010-2011
Member of the Executive Board of the Italian Group of Fracture 2009-2011
e-mail: marco.paggi@polito.it
home page: http://staff.polito.it/marco.paggi/

Hi,

I see that interfaces are usually modelled with cohesive zone models. If I do want to try modelling it with continuum elements, for example with ductile damage, is there any specific way to "convert" the cohesive properties to the continuum ones?

Thank you in advance.

Regards