hello dear fellows, I would like to know about the possible capability of sim scale to model the shrink fit pressure cylinders. I would like to know that how much residual stress gets imparted in my cylinders in the steady state at the start of analysis. then further i will continue with the internal pressure. Its OK if i can apply both conditions simultaneously.

the example picture is from another FE software, i want to do it in simscale to increase the computational size of my geometry and add more complex loading.

# Shrink_fit_cylinders

**hur_rehman**#1

**roy_g**#2

Hi @hur_rehman

The thermomechanical solver will calculate heat transfer through a solid and the resulting stresses and displacements. It also enables you to do a transient study. You can define a new material with a negative coefficient of thermal expansion. If need be the coefficient can be defined as a function of temperature (as it might not be a fixed value) . As long as you know the value of this coefficient and a few other material properties such as its thermal conductivity and young’s modulus then you should be able to simulate it.

**hur_rehman**#3

Hello roy,

actually my question is not about heat transfer and stresses due to that…, rather I am asking how can I model the shrink fit phenomenon… ? in this you press a relatively larger diameter cylinder into a big cylinder whose internal bore diameter is slightly less than the pressing cylinder. This induces stresses in both cylinders…

**roy_g**#4

Well in this case the inner diameter of the outer cylinder is larger than the outer diameter of the inner cylinder but i’m almost certain that it is not ok to leave an empty gap between the two cylinders so I think you will have to model it as if there is no gap and make the cylinders touch. You could also try defining a 3rd cylinder in the middle to take the place of the gap and give this new cylinder a very very low young’s modulus but to be honest i’m not sure this will work as it will cause the middle cylinder to be compressed by a huge amount and if the gap is very thin it will also be problematic to mesh. The thermomechanical solver uses a static mesh so there is a limit to how much deformation can be accurately modeled. @jousefm can you find out for us how much strain is permissible?

**hur_rehman**#5

actually roy,

sorry but you again misunderstood it have a look at it

https://www.google.com/imgres?imgurl=https%3A%2F%2Fwww.ctemag.com%2Fsites%2Fwww.ctemag.com%2Ffiles%2Farticle_images%2F09%252c%2520Machine%2520Technology_opt.jpeg&imgrefurl=https%3A%2F%2Fwww.ctemag.com%2Fnews%2Farticles%2Fshrink-fit-toolholder-fundamentals&docid=oIVz5FTYN1Ox6M&tbnid=-rJuMeawwzCwAM%3A&vet=10ahUKEwjSydGtkNPjAhULBWMBHT6NCsMQMwhcKBMwEw..i&w=528&h=519&bih=674&biw=1536&q=shrink%20fit&ved=0ahUKEwjSydGtkNPjAhULBWMBHT6NCsMQMwhcKBMwEw&iact=mrc&uact=8

its standard in other FE softwares just wondering if simscale supports such contact, because apparently it did not worked out with me…

**jousefm**#7

Cool project idea @hur_rehman!

You can make use of the geometries rotational symmetry and use the cyclic symmetry boundary condition, an example can be found here (unfortunately with an outdated geometry but re-uploading will do the job): **Tool Holder - Shrink Fit Analysis**

Best,

Jousef