Difference between revisions of "Contrib:KeesWouters/partition"
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* tick first partition posibility (thick red line in the centre square) | * tick first partition posibility (thick red line in the centre square) | ||
* enter valid name for result name of partition ('partit' in my case) | * enter valid name for result name of partition ('partit' in my case) | ||
| − | * in the ''partition'' part select: | + | * in the ''partition'' part select: <br/> |
| − | + | objects: the part (fuse) you would like to partition (Fassemble)<br/> | |
| − | + | tool object: left clcik OP12, control left click PCyl1 and PCyl2 to get 3_objects<br/> | |
| − | + | reconstruction limit: keep solid because we need solid (volumes) to be partitioned<br/> | |
* apply and close | * apply and close | ||
* add the four solids with ''create group'' on the Partit to be accessible in Code Aster | * add the four solids with ''create group'' on the Partit to be accessible in Code Aster | ||
Revision as of 14:51, 3 June 2009
Contents
Defining a construction with four bodies in Salome
The construction consists of a shoe box, a plate on top of it and two cylinders inside the top plate. In total four different bodies are created by partitioning the main body. Each body can have different materials applied to it in the C-Aster command file.
* 
General definition of the construction with Salome
First a solid block is defined by the geompy.MakeBoxDXDYDZ(3,5,2). The internal block to cut away a apart of this block is defined by the four outside nodes. Four lines are linked between these nodes and a face is defined by the four lines. Extruding the face up to 1.8 mm high then defines a solid block. After the extrusion a shoe box remains with wallthickness of 0.2 mm.
On top of this shoe box a top plate is defined. It outer dimensions are 0.2 mm less than the shoe box and height is 0.8 mm.
Inside the top plate two cylinders are defined, radii 0.7 and 0.5 and height 1.0 mm. These two cylinders consist of one solid only within Salome because they are defined at once using the two axial areas of the cylinders.
Fusing the various parts
Now all parts are defined and we can fuse the three parts together. This is necessary if we want a mesh that is 'glued' together between the various parts. So we fuse:
- Fshoecyl <-- shoebox and cylinders and use the result together with top plate
- Fassembl <-- Fshoecyl and Btop
Now one solid part exists. To be able to apply different material properties to the various parts, we need to partition them again.
Partitioning the various parts
In order to partition the parts we need to define the boundaries between the parts.
- We define a plane P12 that coincides with the top plane of the shoe box. It divides the shoebox on the one hand and the top plate and cylinders on the other hand. We generate a centre point, a vector in z direction and define a size for this plane: P12 = geompy.MakePlane(centre point, direction vector, plane size). Make sure that the size Psize is large enough to cover the whole top plane of the shoe box. If this is not the case, Salome fails to partition the bottom and top parts.
- Between the cylinders and the top plate the areas of cylinders can be used as a boundary between these parts. Again, make sure that the height of the area is enough to cover the cylinders, otherwise Salome fails to generate the partition.
The partition can be calculated by MakePartition. The first argument is the fused body (Fassembl), the second argument are the dividing planes determined above. It is possible here to define multiple dividing planes, so the partition can be made in one go: Partit=geompy.MakePartition([Fassembl],[P12,PCyl1,PCyl2],[],[],geompy.ShapeType["SOLID"],0,[],0)
Most of the work has been done. We still need to create the groups under the entity Partit by CreateGroup(), UnionIDs() and GetMainShape(). See the attached Python script at the end for more details .
In Salome GUI, assuming that the fuse has been made and the three dividing planes P12, PCyl1 and PCyl2 are defined,we proceed as follows to make the partitioning:
- Geometry module has been selected
- Select Operations --> Partition from the main menu and right click
- tick first partition posibility (thick red line in the centre square)
- enter valid name for result name of partition ('partit' in my case)
- in the partition part select:
objects: the part (fuse) you would like to partition (Fassemble)
tool object: left clcik OP12, control left click PCyl1 and PCyl2 to get 3_objects
reconstruction limit: keep solid because we need solid (volumes) to be partitioned
- apply and close
- add the four solids with create group on the Partit to be accessible in Code Aster
Result of the partitioning
In the object browser the following tree is now visible:
Under the Partition Partit the fuse Fassembl is given, together with the three dividing surfaces: P12, Pcyl1 and Pcyl2. The partitions BPshoe, BPtop, BPcyl1 and BPcyl2 are defined and available to be transfered to the mesh and to Code Aster. Different material properties can be given to them.
Note the now four partions are available, because the two cylinders are now separated by the partition operation.
Of course there are many ways to create the fuses and the partition. This is one way that works for me. Hope that this is useful for you as well. And, pls do not hesitate to add improvements here ;-)
Carry out FEA on the construction
In the Python script the geometry described above is given, together with a meshing part. Also adding the previously defined blocks are added as groups in the mesh. A CA command file for calculating the resonance frequencies of the free floating construction is given. All that needs to be done is export the mesh file, update to ASTK file and run C-Aster. Hope this is usefull. Some of material properties are 'made up'.
To end the story - first resonance mode
And the first resonance frequency at 37 kHz:
