Selecting nodes in a triangular area 1

[vidiii]

Hi,

I have made a parametric model of ANSYS Batch (in APDL). The parameters are defined in the beginning, and every paramater can be changed with MATLAB and the results of ANSYS will be saved (in txt) and read in MATLAB. After that MATLAB can rechange a parameter and let ANSYS run again, etc. So the influence of a parameter can be investigated.

However when I let the "length" parameter change, at a certain moment the area numbers change, because the geometry changes. These volume numbers / area numbers are used in the batch program for the boundary conditions.

Is there a way to resolve this problem?

example:
ASEL is difficult for selecting the contact area of a rectangular plate with a triangular plate. I need to select the nodes in that area, so I could also use NSEL, however the problem is that the area is triangular and I dont know how to use NSEL,U in a decent way to unselect the nodes outside the triangular area (the nodes of the rectangular plate).

Any suggestions are very welcome. Hope to hear from you.

 

[cbrn]

Hi,
Unfortunately the basic answer is NO, you can't renumber the entities AFTER an operation.
There is a workaround: if your solid model is entirely built from APDL commands, then you can use a very strict "bottom-up" modeling procedure, where you can control the creation of every sigle piece of geometry, be it a keypoint, a line, a surface (area) or a solid (volume).
Create keypoints by APDL, in the correct order, numbering them explicitly -> Create lines bounding the areas, in the correct order -> Create the areas bounding the volume(s), in the correct order -> create the volume(s).
Trouble is when you need to use a Boolean operation. In this case, you need to *GET the entities numbers BEFORE the operation, and then the numbers AFTER the operation. You can then keep trace of what's happening with the entities numbers, and then make your selections work parametrically as well.

Hope this helps (or someone finds a better solution).

Regards

 

[bagarbilla]

Read this

http://en.wikipedia.org/wiki/Half-space

u can use the idea of half spaces for selecting nodes in triangular area. Three half spaces make a triangle (but if area is planar and not curved). But i think this can solve the problem u were facing as i understand it.
Hope it helps