Thermal Stress Analysis problem with Cosmosworks

I've reduced my thermal stress analysis problem to the most basic
scenario and the results are not reasonable.

I've taken a 1" x 1" x 1" cube of 1020 steel and applied 83 degrees f
to all sides, put an immovable restraint on one of the verticies.

The results give me 1,700 psi of stress. There's really no appricable
heat. Just 83 degress. How can it figure on this much stress?

My real world problem of a class 300 flange at 750 degress f., and
one side restrained, give me material failure results. About 200,000
psi of thermal stress.

Is Cosmosworks reliable for thermal stress, or is there something
basic I'm missing?

Pat

 

You don't say clearly how you applied the temperature boundary
condition. Likewise you don't say how you have constrained the cube.

I have to ask what problem you are proposing CW answer? Is this setup
as a steady state or a transient thermal problem? Since you are
modeling a solid with solid elements what is the meaning of
restraining just one node? You need at lease three non co-linear nodes
restrained just to prevent free body motion. If you wish that
restraint to be stress free you must do so in such a way as to allow
expansion. Then there is the problem of restraining at a corner which
can immediately induce a singularity and give high ficticious
stresses.

If you simply want to apply a uniform temperature to the cube I think
that is done during setup in properties somewhere.

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