Abaqus/Matlab Parameterized Design

[ebdoep22]

I will describe this problem using some simple geometry though the actual model is more complicated. The problem is limited to 2D planar. Ultimately this will be a shape optimization problem, but right now I just want to do a parameter study.

--Setup
I have a square plate with a circular region defined within it. The outer square and inner circle have different material properties. Ultimately there will be optimization that takes place, so I have a Matlab script which defines the square plate, and the circle. The square plate will remain constant,but the circle size and placement will vary.

--Question
How can I take these regions defined in Matlab and mesh them for an Abaqus .inp file? I do know how to write .inp files from Matlab to Abaqus .inp, I just don't know how to redo the element connectivity matrix without opening CAE and meshing the regions, which is not feasible since there will be 100+ runs.

If I knew how to send seed node locations to Abaqus then it send back the node and element matrix I think I would be set.

--Things I have tried
I found a Matlab auto mesh routine, but it would mesh one region at a time and add additional nodes on the border between the plate and circular region. If nodes aren't shared by the two different materials they will not move together.

I can draw this in the CAE and then alter the node locations in .inp file, but if the nodes move large distance the mesh becomes distorted and really a new mesh connectivity matrix should be defined.

Any help would be appreciated.

 

[burningDiesel]

Have you considered using the abaqus python interface?
See 20.1.1 Scripting parametric studies in abaqus manual.

If you want to use matlab, if it is an easy and/or parametric structure, why not create the mesh directly in a structured way? If this is too difficult because of the geometry involved, have you tried delaunayTriangulation? This works on a stack of points, so if your regions are sharing points, it should also do so after meshing.

As far as I know, there is no way to add seed locations using the abaqus meshing.

 

[ebdoep22]

Thanks, the leading me towards delaunayTriangles was the key. It took a while but I got it. The way I did it was in Matlab layout all my nodes, making sure to place them along the borders of the materials. Run the Matlab delaunayTriangulation routine making sure to specify borders so that it would not mesh an element across a border. Then went back and found the center of each triangle, if it fell within a certain area that triangle was meshed with that areas element. Work great, now to get it into an .inp.

I had hoped to use Abaqus to mesh since I am sure it would do a better job than the Matlab basic routine, but this work for now.

NOTE-Matlab is completely changing the way they do the delaunayTri routine. If you have or are changing to 2013 it will mess with you.

 

[ebdoep22]

After working some with the Delaunay Triangulation in Matlab I have discovered that it can cause all sorts of problems with poorly formed elements; meaning triangles with high aspect ratios.

I guess with more work I can sort some of this out in Matlab, but I have Abaqus which has been designed to mesh structures why not use it. Does anyone know how to pass Abaqus nodes and have it return a mesh connectivity matrix in an automated process? I have tried to import an .inp with just nodes defined into the CAE with no luck so far.

Again the one issues making this extra difficult is that I have different areas/materials of the structure which share nodes. So I can't simply add or move nodes which lay on the border of two areas.

As always thanks.

 

[MechIrl]

Unfortunately I don't see how you will automatically get an element connectivity array with just a set of nodal data in Abaqus. Have you considered using python to directly control the CAE geometry kernel. If you set up your geometry carefully (use some clever partitions etc.) you might be able to get abaqus to redraw and mesh it automatically for each iteration while keeping fairly consistent mesh characteristics.

 

[IceBreakerSours]

Getpartinfo and getnodetoelemconn (not sure if I got this right) utility subroutines might be of some interest to you.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083