Elements near Cohesive elements deform asymmetrically in a three point bend 2D model

[hermatician]

Dear All,

I am modelling a 3 point bend specimen with Cohesive elements tied to the upper and lower halves of the specimen in 2d.

The problem is that the CZ elements perform properly only for a combination of element sizes, i.e. a combination of element size of structure and CZ elements, for instance in my case the structure/specimen element size is 0.2mm and CZ is 0.001 or 0.002. For any other combination the adjacent elements bend as shown in the attached image.

I will be glad if someone could explain this behaviour and the solution.

I also attach the input file.

I use full integration Plane Stress elements for the continuum part.

I tried changing
Elastic Modulus, Tie constraint position tolerance, viscous regularization, reduced integration etc.

The problem is, the cohesive strength and fracture energy calibrated for 0.2mm element size causes bending of elements when i decrease the element size. 
In the attached input file I have a softer interlayer, but this problem exists even for homogeneous material model.

With regards,

Abhishek

 

[IDS]

The only attachment is a pdf of the input file (2493 pages).

You can embed images in the message, or attach a zip file with multiple files, or just post a new message with the image attached.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[hermatician]

here is the image