PrePoMax (CalculiX FEA) - Tutorial 34 - Bolted joint with preload

PrePoMax is an open-source pre- and postprocessor for (also open-source) finite element analysis solver CalculiX. It's extremely user friendly and doesn't even require installation. PrePoMax can be used only on Windows.
In this tutorial I would like to show you how to create a simplified FEA model of a bolted joint with pre-tension.
Geometry in step format: drive.google.c...
PrePoMax homepage: prepomax.fs.um...

[@N8trone]

Thank you for this tutorial and other excellent tutorials. I request more examples like this: analysis of assemblies, examples of contact types, and using parts of different materials.

[@FEAnalyst]

Sure, they will follow naturally in the future.

[@mathumphreys]

Just wanted to say thanks for this excellent tutorial.

[@xzarrandiko]

Great job!

[@jakubsobka2621]

W tym roku Oscar trafia do montazystysty-grafika....

[@wgmg7746]

Dziękuję

[@tiborkemeny8644]

Nice tutorial.
Next step is then stress linearization? :)

[@FEAnalyst]

Thanks. Unfortunately, stress linearization is not available in PrePoMax and even in ParaView. However, the FEM module in FreeCAD has it implemented.

[@tiborkemeny8644]

@@FEAnalyst Freecad had it? I thought, only Mecway and Salome have this tool...

[@FEAnalyst]

@@tiborkemeny8644 Yes, it’s also available in FreeCAD: wiki.freecad.org/FEM_PostFilterLinearizedStresses/en

[@tiborkemeny8644]

@@FEAnalyst Thanks. I'll check it

[@raghavsundararaman7066]

Thank you for this tutorial... But when ran it in the end I am getting an error "*ERROR: too many cutbacks
best solution and residuals are in the frd file" how to rectify this error?

[@FEAnalyst]

It's a standard non-convergence message. Most likely there's some difference in the setup. Maybe a missing tie or an incorrectly applied pre-tension section. But double-check all the input values too.

[@raghavsundararaman7066]

@@FEAnalyst thanks a lot I'll check it out

[@DharmitThakore]

Thank you for this excellent tutorial.
I am still learning and your videos provide excellent way to use PrePoMax effectively.
I am confused as to why did you make displacement 0mm in Step 2 for the surface that joins bolt with shank. Will this not make force applied on the bolt head to go in the top part of the bolt only?
I have a question regarding Contact surface pressure on the faces of the members that the bolt is joining. Can you please show in your video how to show Contact Surface Pressure. My understanding is that when you apply PreLoad, contact Pressure should be a certain value, and then when you apply other loads on the members that the bolt is joining (e.g. two flanges or two plates) then this pressure will increase or decrease depending on the direction of force/pressure. Am I correct in making this assumption?

[@FEAnalyst]

Actually, I set it to "fixed" for the second step. The same procedure is used in Abaqus. Like I said in the video, this way the adjustment of the bolt length is maintained in the second step by fixing (freezing) the degrees of freedom at their current values at the beginning of the step. Then, with further length changes due to preload prevented, the bolt acts as standard deformable component and can respond to other loads properly. Otherwise, the force in the bolt wouldn’t change from the first step.
Contact pressure has to be requested in field outputs before running the analysis. I showed its usage in tutorials 17 and 29. The clamping force will be equal to the pre-tension force and then decrease in the second step due to the external tensile load.