Is Cosmos worth it?

I'm looking for some input.
We're going to be purchasing an FEA package within the next month or so
and I'm looking for insights into Cosmos and whether it's worth it or
not. We're also looking at NEi/Nastran and PlassoTech, so if you've
used either...
Any information would be greatly appreciated!

 

I have Cosmos/M and it works fine. I currently use NEiNastran with
FEMAP and am very happy with it. For quick and dirty I use DesignStar
(an SRAC product).

I am not a big fan of integrating FEA with CAD. There are many reasons
for this. If you want to know more just ask. Before you do please let
us know what you intend to do FEA on.

 

For the immediate future, we'll only be doing linear stress analysis.

 

Quote TOP: "I am not a big fan of integrating FEA with CAD."

Maybe we're both nuts, but at least I'm not alone in this anymore.

 

Sounds like you are just getting started. The best investment you can
make regardless of which FEA package you get is Vince Adams book. Look
it up on Amazon.

Of the ones I listed DesignStar would be the easiest to use and it can
do linear, some non-linear and contact. DesignStar has a CosmosWorks
type interface and you can choose to link to SW or not when making
changes. NEiWorks would also be a good candidate because although it's
CAD interface is integrated, it keeps a separate solver and a separate
record of what was done. Having a separate solver and a record of each
analysis is very important from the standpoint of keeping CAD busy and
documentation.

 

You never were alone, you just didn't know it. Integrating CAD and FEA isn't
such a bad idea if all of your analyses run in a few minutes. Most of ours
don't.

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

Run time is an important consideration. With 3D tet meshes of solids
easily exceeding 1 million dof memory can sometimes become a
consideration. As soon as anything non-linear is added, be it gaps,
inplane stress stiffening, or transient thermal analysis run time can
greatly increase. One of the advantages of the higher end systems is
that they allow hex meshing (using brick or rectangular elements) and
using simplified elements like shells, plates, and beams. More skill is
required in setup, but run time is greatly reduced and sometimes
accuracy can actually be improved.

I have on occasion run jobs that took over 60 hours to converge (or
not) on a fast PC. Run of the mill is an hour. Quicky jobs run in a few
minutes. So separating the CAD side from the solver side and resetting
task priority is a big time saver even on a single processor machine.

Take this model for example:

http://www.engtran.com/examples.htm

To do this in CosmosWorks might be possible, but in Cosmos/M it was
quite easy and it was certain it was going to work before the project
was started. What you are looking at is a four bar linkage with over
center spring and a lever which contacts the joint in the four bar. It
runs really fast and took an hour to build and get running. In the
model are:

beam elements
spring elements
generalize line type gap elements
plate elements

The model is driven by an enforced displacement.