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in large assembly solving contact constraints take long time.
i got same problem in analysis of large assembly.
i used only seven different contact sets.
How large assembly that ever yo did uisng cosmos ?
10, 20, 30 ... meter ?
So, have you some tips work with large assembly in cosmos ?
BTW, where is the younger cosmos user.... ?
size is not a matter.you may use 30 m or 40m assembly.
but time is depends on no of nodes and no of contact constraints.
if you use global contact you may reduce analysis time.
Global Contact to set the default contact condition between touching faces of different parts in an assembly document or different bodies in a multibody document. It sets the contact condition at all areas that are common to two faces. It does not set any contact conditions for two faces that touch each other along a point or edge or if the area of contact is extremely small.
but i don't know how global contact is affect the results?
In my experience when using solid mesh....
I ALWAYS got a problem when meshing process.
How about you....?
Could you give me a sample ( at least picture ) of a HUGE assembly / part that ever you did, please....
Another thing, let`s wait the Cosmos Companion for HUGE ASSEMBLY. Hope Mr. Vince Adams look / hear this.
Thank`s for your tips Jeya....
SW 2007 sp3.1
CW Professional 2007
yes you are correct.
in huge assembly definately have more no of fillet areas.
fillet dimension is very small comparing other dimensions.
so we cannot maintain same mesh size in fillet areas.
so meshing get failed.
if you maintain small mesh size al areas , no of nodes will increase.
it will affect solving time.
here we can use mesh tool.
after mesh failed , we can easily find failed areas using failure diaganostics.
then we can apply small mesh size on failed areas using mesh tool.
now we can create mesh.
For big or small assemblies, containing high length/thickness ratios (good example is any beam, PFC etc) you should use mesh control before meshing. With this you can decrease mesh element size in small parts like fillets, weld beads, etc.
The assembly does not have to be too big to run into trouble with COSMOS if you want to maintain the basic rule which suggests using a maximum element size of half-third of the _smallest_ material thickness. It is here where shell meshing comes into play but it is time consuming.
I just ran an analyzis on a small assembly (130 parts after using symmetry constraint) which I wanted to analyze with a solid mesh. I should have used 2-2.5 mm element size (minimum wall thickness being around 6 mm) but COSMOS (32 bit, 2 MB RAM) did not allow to go below 12 mm. The consequence is that the results can only be used for a rough analysis. Below 12 mm C said the memory is not enough and performance would suffer - and the analysis will go forever, even if it not fails.