Abaqus - mesh seeds at partition edges, cell constraint? 1

DKEngineer · Apr 30, 2023

Hi,

I am currently working on creating a model for the contour integral calculation of an arbitrary internal crack using Abaqus scripting. However, I have encountered a problem with my mesh at the crack contours, where regions with unstructured elements (as seen in Figure 1) create noise in the contour integral calculations. I would like to achieve a mesh like that shown in Figure 3.

To address this issue, I have divided the model into 9 partitions (as shown in Figure 2), with each partition edge seeded with the same number of elements (e.g., 100). However, I am still struggling to achieve the desired mesh.

I believe that constraining the number of elements in the cells between partitions could potentially solve the problem. Therefore, I am wondering if there is a way to select a cell and define the number of elements for that cell.

However, as I am conducting a parametric study of many models, manually adjusting the meshing for each model is not feasible.

Any suggestions or guidance on how to address this problem would be greatly appreciated. Thank you in advance!

FEA way · Apr 30, 2023

You can apply local seeds to cells and faces too. Just change the selection mode (drop list next to the cursor arrow symbol on the top toolbar).

DKEngineer · Apr 30, 2023

Thanks, I actually did not try that. But it seems that it still applied seeds at the edges when selecting cells. This, again, results in the elements between the edges splitting up into more elements than desired. Even when I use the constraint "Do not allow the number of elements to change". So it doesn't constrain the number of elements in a given cell but applies seeds to the edges of the cell.

DKEngineer · Apr 30, 2023

As add on, here is a mesh where I seeded the cells:

FEA way · Apr 30, 2023

Maybe additional partitions perpendicular to those contours would help. Or seeds with size control instead of prescribed number of elements.

DKEngineer · May 1, 2023

Hi FEA way, thanks again for your help.

Additional partitions perpendicular is a great idea, but however very hard to script and hard make parametric for irregular spline geometries.
I dont think seeds with size control will work. Then the outer contours will have more seeds than the inner contours, which will not give me a structured mesh.

The best solution I can come up with is to make all jobs from one script, and use another script to submit the jobs with a acceptable mesh.

DKEngineer · May 1, 2023

I can use the tools-query-mesh to display number of elements in a region/cell. But it doesnt record in macro.
Is there a way to obtain element number at a certain cell-set using scripting?

Then I can just loop until I get the desired element number in the cells between the partitions for the crack contours.

DKEngineer · May 1, 2023

I found the element number in a set using:

set1 = mdb.models[model_name].rootAssembly.sets[set_name]
# get the elements in the set
elements_in_set1 = set1.elements
elem_number_set1 = np.size(elements_in_set1)

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Abaqus - mesh seeds at partition edges, cell constraint? 1

DKEngineer

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