ELEMENT DELETION IN ABAQUS/EXPLICIT COUPLED TEMP-DISP. PROBLEM

[mechdrive1]

Hello All!

I am trying to drill through an Al 6061 alloy layer (1.5mm thick) with a rigid tool (steel alloy). I have used Johnson-Cook plasticity model for both aluminum layer and tool. Also, to remove the elements I have specified JC damage model for aluminum layer with displacement based damage evolution. The aluminum layer is constrained (ENCASTRE Boundary Condition) on the side surfaces while all the other surfaces are free. The feed rate of tool is 260 mm/sec (artificially increased) to reduce computational time and rotational speed is about 8000 rpm. The JC model constants are as follows:
for tool:
*Plastic, hardening=JOHNSON COOK
1.15e+09, 7.39e+08, 0.26, 1.03, 1723.15, 293.15
*Rate Dependent, type=JOHNSON COOK
0.014,1.

for aluminum layer:
*Damage Initiation, criterion=JOHNSON COOK
0.071, 1.248, -1.142, 0.147, 0., 855., 293.15, 1.
*Damage Evolution, type=DISPLACEMENT
0.67,
*Plastic, hardening=JOHNSON COOK
3.35e+08, 8.5e+07, 0.11, 1., 855., 293.2
*Rate Dependent, type=JOHNSON COOK
0.012,1.

The elements are not getting deleted as it should have been instead the layer is getting displaced in the direction of tool movement (like compression). There is element deletion but not too extensive and not beneath the tool where it should be. I have tried using different values for displacement in the damage evolution criteria but nothing has worked so far.

I am attaching the input file for your reference. Any kind of feedback/clarification is welcome. Can anyone help with the element deletion please?

 

[mechdrive1]

Attached is the image from above input file model result. The job was aborted due to error (distortion in element of aluminum layer)

 

[Mustaine3]

Request and check the STATUS field output variable.

 

[mechdrive1]

I submitted some other models with 'displacement' and 'fracture energy' based damage evolution. The models completed the specified time without any errors but the elements are not being deleted beneath the tool instead the entire area of elements underneath the tool is being detached from the workpiece. I have tried quite low values in the damage evolution but the results are almost the same. Only in the case of fracture energy based damage evolution did I see some elements being deleted. I am attaching the results with 'status' output variable. The problem is the value of status variable is remaining 1 even though elements are being deleted.

NOTE- image which does not have any damage evolution specification has displacement based damage evolution criteria.

 

[Mcakir]

Hello mechdrive;
Are you still on this problem? Have you solved it?
If you havent please inform me. At a first glance I have pointed material model data contains an appropriate data

 

[mechdrive1]

Hi Mcakir,

I have changed my model a bit. Instead of one layer of workpiece there are two layers as in the original model. I was able to delete some elements from the tool path but not completely. The tool is rigid and the leftover top layer elements are intersecting the tool but the unusual thing is it is not creating any errors! I am attaching some images from the results. I have been using fracture energy and displacement as damage evolution crtieria with values of 125 and 1e-05 respectively.

Regarding the material data, can you please point what's wrong in it?

Thanks,
Ankit

 

[Mcakir]

If you send me your CAE an INP files I may help you with a video tutorial.
We can contact through cakir.muhammed@hotmail.com

 

[mechdrive1]

Dear Mcakir,

I apologize for the extremely late reply as I was traveling. I am sending the input file to your mail address. If needed I can share the CAE file too.

 

[mechdrive1]

I was able to delete a few more elements underneath the tool

Currently I am using a rigid tool which I later want to convert to a deformable tool.