2D Cohesive Elements

[stressengineer1]

Hi All,

I am new to cohesive elements and Abaqus. I need help regarding meshing related to cohesive elements. A rectangular block is meshed with 2D shell elements. I would like to add 2D cohesive elements between the shell element edges through out the model. In other words, I want zero thickness cohesive elements in 2D, and these cohesive elements needs to appear between the continuum element edges. Even I have gone through the Abaqus tutorial and could not get exact information for 2D cohesive elements. Any help will be highly appreciated.

Thanks,
Stress Engineer

 

[Regretful]

Perhaps a figure of some kind could help? I do not understand the need for cohesive elements if you want zero thickness.

 

[stressengineer1]

Hi Regretful,

Please find schematic picture of a rectangular block that is meshed. Figure 1 shows the shell elements in blue square, while the red colored areas at the edges of shell elements are cohesive elements.
Figure2 shows how the cohesive element is shared between the edges of shell element. Node 1 is shared for shell element and cohesive element. Nodes 2,3 and 4 are also shared in the similar manner. If nodes 1,4 and 2,3 are coincident nodes, that gives zero thickness cohesive element.
I am working on a fracture problem and I dont know the crack path. Hence I insert cohesive elements along the edges of the shell elements, so that the crack can propagate. Please let me know your suggestions.

Thanks,
Stress Engineer

 

[aamirmub]

You can use cohesive surfaces available in contact definition. It would be easier to setup the model using contact based cohesive surfaces than inserting zero thickness cohesive elements yourself.

 

[Mustaine3]

I'm not sure if cohesive contact works properly on shell edges...


@stressengineer1
The next best way to model your problem is this:
- Think about an initial width for the coh-elements and add that to you geometry. So your part is now bigger than it should be.
- Partition the regions to have the regular regions and the coh-regions
- Mesh that part
- Use the mesh only (create mesh part of that mesh in Mesh-Module)
- Move nodes (= edit mesh in Mesh-Module) to bring the coh-elements to zero width