Dear @Disla, @JuanP74, @Calc_em, @SergioP
thanks for your hints and for pointing how to get forward with this case!
I adopted your mesh creation tip and extruded the tools surfaces and applied BCs at the back sides. Indeed this worked a lot better. I managed to run the case also with the explicit solver (I guess “Pardiso” means that you ran with an implicit solver?).
But I still had issues at the contact surfaces (several nodes seemed to be “pushed away” too far and in the vicinity high plastic strain was present).
I could not set it up the way like @Disla (only tool volumes and sheet shell) because of some shortcomings in my mesh toolchain (I used unical1 mesh converter to convert from salome-exported UNV to INP and the free-standing sheet faces get removed in the conversion process; only the volumes remain). I thus had to run it with all volumes.
I was looking for an all-shell model because my actual model will be much bigger and I have some fear that with volumes it will be all too big in the end. Because of this and because I ran out of time and the contact issues, I decided to give OpenRadioss a try (thanks for pointing me there, @JuanP74! I was not aware that this tool had been released to the open source world).
With OpenRadioss, it worked very nicely in the first attempt: all shell model, rigid material for the tool surfaces, friction, plastic material and a quite manageable run time with the explicit solver (of course only with a considerable mass scaling).
This is still with a too coarse mesh:
So thanks for your help and tips, guys!
Regards, Hannes