Free BC with body force problem
Free BC with body force problem
(OP)
Hey guys (and girls :),
i d like to simulate thermal stresses in a hybrid material consisting of several different materials. Static Analysis is all fine and yields nice results.
Now for a thermal analysis i d like do some research on the thermal expansion and on the resulting stresses.
To check out whether everything would work i set up a generic example. A cube with a body force of 100K in each direction.
CTE is isotropic and 14*10-6. The problem is that with any kind of boundary condition, the Temperature results in unreasonable high stresses (where there should be none).
Normally a 3,2,1 - 3,2 - 3 bearing should do the job.
Please help me on this. I don t have a clue of what could be wrong. Nevertheless it has to be some silly fault.
Best regards,
Maddog
i d like to simulate thermal stresses in a hybrid material consisting of several different materials. Static Analysis is all fine and yields nice results.
Now for a thermal analysis i d like do some research on the thermal expansion and on the resulting stresses.
To check out whether everything would work i set up a generic example. A cube with a body force of 100K in each direction.
CTE is isotropic and 14*10-6. The problem is that with any kind of boundary condition, the Temperature results in unreasonable high stresses (where there should be none).
Normally a 3,2,1 - 3,2 - 3 bearing should do the job.
Please help me on this. I don t have a clue of what could be wrong. Nevertheless it has to be some silly fault.
Best regards,
Maddog






RE: Free BC with body force problem
BA
RE: Free BC with body force problem
I m using ABAQUS 6.8-4.
RE: Free BC with body force problem
Nagi Elabbasi
Veryst Engineering
RE: Free BC with body force problem
RE: Free BC with body force problem
BA
RE: Free BC with body force problem
Does/do the restraint(s) on a face prevent perpendicular movement?
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Free BC with body force problem
are chosen (in my opinion) in a way that free expansion without stresses should be possible (given a homogeneous material).
RE: Free BC with body force problem
RE: Free BC with body force problem
when you say you've done the statics and they work out well, was that with a model or hand calc ? (i'm uessing it the model). temperature loadings are a funny thing ... the temp only creates strains and it's only when the strains are prevented that loads build up. i think too that they're quite code dependent ... try running an abaqus example or call their helpdesk.
RE: Free BC with body force problem
I need to get my hands on some examples.
I thought that a simple generic example would do it.
And 100 Kelvin are not a force, that s right. I don t know why ABAQUS calls it "body force".
Thanks for your help.
Yet maybe someone already did a similar simulation and would like to supply a Python-file, or an Input-file.
Best regards,
Maddog
RE: Free BC with body force problem
BA
RE: Free BC with body force problem
I am sure you'll find some input files in the Abaqus documentation that can serve as good starting points for you.
One more thing. You described the boundary conditions as "Normally a 3,2,1 - 3,2 - 3 bearing should do the job.". I did not understand that description, so please elaborate on your boundary conditions maybe there is something there that's causing those high stresses.
Nagi Elabbasi
Veryst Engineering
RE: Free BC with body force problem
A chinese gave me the advice with the body force.
It turned out to be totally wrong. I now use "predefined field" as load and it works all fine.
Thanks for your help,
this thread can get closed.
Best regards,
Maddog