ABS-BOX.pmx (748.8 KB)
I am honored to be using PrepoMax for impact analysis, and I am a newcomer in this field. I created a simplified model to verify all the settings. The model is an ABS box with a virtual screw fixation, and it impacts an aluminum alloy floor.
Now, I am facing some issues:
When I constrain the left and right plastic parts to contact at the edges, the solver fails. I’m not sure why. For now, I’ve deactivated it.
Additionally, when I enable Nlgeom, the solver also fails. Is this an issue with my settings?
If I use a Hyperelastic material, the calculation cannot proceed. Is this a limitation of Calculix, or is it an issue with my setup?
Generally speaking, the explicit dynamics procedure is suitable for impact / drop test simulations, but in the case of CalculiX, it’s very underdeveloped and has many bugs and limitations. You can find some tips here (be particularly careful regarding automatic mass scaling): https://www.youtube.com/watch?v=-X0Shj7UXE0
It might be better to merge the two halves (you can create a compound out of them). This will simplify the model.
Nlgeom should be enabled in such cases. If it doesn’t work, try further simplifying the model gradually until it starts working. Same with hyperelasticity. You could try implicit dynamics too but it might be problematic to converge.
Thank your for your recommendation .
I creat a reference point and make the floor rigid body, it saves about 30% calculation time. Great.
I creat 3D version of this bar impact before I build this ABS box,result almost same it is very usful.
2 halves, i hope to keep them separated, and only connectored at center. So is there any special requrement for this contact ?
Ok, I see. Then you could add a contact pair between them (of course, apart from the tied region in the middle). This is in case they interact when deforming.