# Nonlinear coupling analysis

**URL:** <https://prepomax.discourse.group/t/nonlinear-coupling-analysis/1952>\
**Category:** General Questions\
**Created:** [August 17, 2024, 3:20pm UTC](https://prepomax.discourse.group/t/nonlinear-coupling-analysis/1952 "2024-08-17T15:20:28Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [August 17, 2024, 3:29pm UTC](https://prepomax.discourse.group/t/nonlinear-coupling-analysis/1952/2 "2024-08-17T15:29:43Z")

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> [@Udzi](#):
>
> If this can be done another way without making the shaft diameter 41 micrometers smaller that would be awesome.

You could try this option (has to be added via the keywords editor): [\*Clearance tò simulate an interference - CalculiX (official versions are on www.calculix.de, the official GitHub repository is at https://github.com/Dhondtguido/CalculiX).](https://calculix.discourse.group/t/clearance-to-simulate-an-interference/2225)

> [@Udzi](#):
>
> If I shrink the bolts using temperature dilatation, how would i implement the second step? The second step would make all parts have around 60 degrees Celsius. This would mean it would go from e.g. -1000 to 60 degrees, which will basically “reset” the bolts.

Can’t you use the bolt pretension load instead of thermal shrinkage for bolts ?

[![](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/1/1b3b8c3f510212014f67a3175b9145057332313c.jpeg "PrePoMax & CalculiX - Pre-tension - Bolt") ](https://www.youtube.com/watch?v=7ucoBTqCcWE)

> [@Udzi](#):
>
> - What would be a proper way of modelling the shaft → hub connection?
> - How much should I refine the mesh between the shaft → hub (element size) ?

See the first part of my reply for a potential workaround (which is commonly used in Abaqus in such cases).

> [@Udzi](#):
>
> Recent updates have added cylindrical coordinate system. Is there a way to display displacement relative picked coordinate system?

Check this thread: [GLOBAL NO and Transform](https://prepomax.discourse.group/t/global-no-and-transform/1949)

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