I am about to start my master thesis.
I would like to use PrePoMax for this thesis, but before i pitch this to my Professor, i would like to check if my idea/topic is possible in PrePoMax.
My experience is mostly limited to static linear topics, i have worked mostly with creo simulate but also a little with hyperworks and ansys.
I want to avoid these commercial offerings as much as possible.
To my topic, i want to simulate the bending and thread forming process of a therminal clamp, who are used in switchgear products like MCBs. therminal clamp
The bending would not be the problem, but the thread looks very challenging to me. I tried my best to get into the workflow of PrePoMax, but i am still not sure how to tackle this, or if its even possible. So i hope the experienced users here can give me hints, tips or even a go to workflow solution for my topic.
As far as i know i need you tackle this with nonlinear approche.
But i question myself if it would be better to tackle this with an explict solver, i dont have any experience for explicit workflows.
I wouldn’t count on it. Explicit dynamics procedure in CalculiX barely works even for simple models, it’s far from e.g. Abaqus/Explicit.
Try with static for now. Build the complexity gradually. Contact will be the biggest issue. It should be doable with some tweaks if it’s just screw tightening (contact between 2 threads) but thread forming with such significant deformation can be a bigger challenge. Make sure you apply prescribed displacement/rotation instead of force/torque.
Sometimes threads are treated as axisymmetric for simplification. Here you could maybe even try with just one thread to see if it can deform the other part properly.
Back to explicit, if you want to try it, there’s another powerful open-source solver specializing in this area - OpenRadioss. It should be much better for highly nonlinear dynamic and quasi-static problems. But preprocessing will be more tricky.
Thx @FEAnalyst for the fast reply, i try to inhale all you tutorials, great work of yours, would love to find even more videos of yours
I tried Radioss once, at times it was not open source yet, it was a pain in the a** for me so i am not sure if i would use that freely. If i need i would use LS-Dyna inside Ansys on student licence, but only because i might get local support for that. So i would like to dodge explicit solvers as far as i can, i dont have that much time to play around endlessly.
I have already tried some things.
As you mentioned i also thought about the 2D axisymetry but how do you model the pitch/ rotation of the thread in 2D? i can only think of a negative tolling setup that forms all flanks at once not per revolution.
the concept of convergence for nonlinear setups is clear to me, i try to use only displacements for BCs
Is there any casestudy with calculix which is similar to my case, i think Sealings like o rings or squising a tube must be a similar topic.
With the axisymmetric assumption you indeed won’t be able to model rotation. It’s only meant to simulate interference and tension: ABAQUS Example Problems Manual (v6.6)
There’s also cyclic symmetry where you can model twisting but geometry and loads have to exhibit this type of symmetry (circular patterns around an axis). Abaqus offers special cylindrical elements as well but they are not available in CalculiX.
I would start with a very simple model. Just to see if you can get one thread to from another thread on the other side.
@FEAnalyst ok thx i will try that as you said.
do you have any suggestion on the solver to use?
i have AMD hardware so Pardiso might not be the way to go.
PaStiX or Pardiso, those are the fastest solvers. Pardiso is usually the best option - fastest and can handle even large models where other matrix solvers in CalculiX fail.
@FEAnalyst i also experienced some lagging and poor response from PrePoMax while Pre or Postprocessing, is this usual behavior or just might be a topic for large Models/high node counts
