I am dealing with a design subject where I have to size a small chemical reactor. In order to size it, I want to know the Von Mises constraints as well as the displacements caused by the internal pressure and temperature (from 3 to 5 bars and 200°C). To do this, I started with a classic Solidworks static study by adding a temperature. However, after reading the discussion below on the forum, I adapted my study by first carrying out a thermal study before coupling it in my static study: Question on the same topic on the forum
However despite this method, I have the same problem as the one described by the person in the question: without the temperature, the resulting stresses are coherent and relatively small, but with the coupling of the thermal study, the resulting stresses "explode" and no longer seem coherent... I then ask for your help: Does the problem come from my thermal study which would be poorly done? Is it a good method to couple the two studies so that my temperature is taken into account in the resulting constraints? Has this ever happened to you?
Having made an analysis that takes into account the expansions of the material, it quickly becomes apparent that an ultra-rigorous model is needed at the limits of the model.
As soon as you have a little expansion, you quickly find yourself with crazy stresses (if you block the displacements on a bore for example (fix the inner surface of the bore), the expansion of the material in the axial direction will generate high stresses because all the points of the cylinder concerned will be considered fixed while the material around it will expand > crazy stresses).
It is therefore necessary to be able to fix your model while having enough degrees of freedom so as not to block the free expansion of the parts. An isostatic type of modeling plus the use of elastic support with high stiffness (for the blocking of surfaces for example) should make it possible to solve this kind of problem.
Thank you very much for your answer, indeed my "delusional" constraints are probably due to the simulated dilation. I tested the use of elastic supports on a part of my assembly and indeed it relieves the constraints on the supports.
However, in my assembly I have tubes that pass through a perforated plate and at this level the stresses are also aberrant (normally the tube and the bore are supposed to expand in the same way and therefore the stresses remain standard...). I'm still looking for the solution for this problem