I am trying to simulate buckling phenomenon of ion source grids under thermal load in vacuum.Two grids namely screen grid and acceleration grid made of SS304 are mounted on a SS flange.The grids are electrically isolated from each other and SS flange by ceramic bushes.The inter grid spacing is maintained by brass spacers.I want to fix the grids at the bolting location so that it does not have any deflection there.A heat load of 300W is applied on the face of screen grid which faces the flange.There are no apertures in the model as it is just a preliminary study.The thickness of each grid is 1mm.
Following are my questions.
- What kind of contact(bonded,rough,frictional etc) should i define between brass spacer and grid and brass spacer and ceramic bushes to get proper deflection results?
- On what faces of the assembly should I define radiative boundary conditions? (Just 2 grids or even bolts,nuts, flange etc)
- Which area of the assembly should contained the fine mesh size? Since I am using a regular 8GB desktop I am not able to make meshes
Dear Bharat Singh Rawat.
Check the following article out. It might help you:
http://www.cae-wiki.info/wikiplus/images/1/13/UM2014-2.01.07.pdf
Thank you Mehran Shahpari but the document you mentioned shows buckling under external force whereas in my case the buckling is due to the thermal load.
Hi Bharat,
Setting the boundary conditions will only be part of the solution. In the case that the grids are dished, when heated they will expand in the direction they are dished. When they are flat, they could buckle away from the heat, towards the heat, or just become wavy or a saddle shape, depending on which bolt lets the grid slip first.
You should try adding a very shallow dish to your grid model, and make sure that it buckles in the same direction as that dish when heated. (i.e. the radius of curvature of the spherical surface goes down)
-Charles
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