I’m having a strange issue where my analysis is reported as finished in monitor, but it did not reach the final analysis time. to be more specific I’m running a explicit dynamic analysis (PPM v 1.4.0) with ccx v2.21 same as in my other posts with some modifications to the model. In the step definition I specified the Time period to 0,1 s. I run the analysis and it finishes without errors in about 10 minutes.
When I check the results i see the final analysis time is 0,012 s, so only 12% of the total analysis was completed. This is also evident from the displacements, since I’m have the displacements prescribed and they don’t reach the final position.
Any ideas? I know I have a lot of questions but the problems with this analysis just don’t stop coming. I’m attaching the .pmx file so you can have a look. Roller_die-analysis5.pmx (5.5 MB)
I would first solve the quasi-static problem pressing the plate up to its final thickness to estimate the contact pressure and maximum VM stress before going to dynamics.
You are most probably completely out of the Stress Strain curve.
Those values are just placeholders, for a more complex material model and the values are so unusual since the material is uncured rubber. I experimented with Johnson-Cook, but couldn’t get it to converge. You can read about it here:
I tried getting the Johnson-Cook parameters using manual curve fitting to the data from this paper using excel, but this is probably not ideal. Then because I couldn’t get it to converge I went back to bi-linear plasticity.
From my point of view your model has other issues apart from the material .
First you should solve a rectangular plate, quasistatic , elastic material with no friction to understand the problem.
Elastic rubber band passing below the cylinder.
Friction, Plasticity and Dynamic Explicit are hard enough by themselves to arrive to them without the model perfectly solved and clean.
Provide a gentle entrance into your machine by sloping slightly the front end.
CD20R to start and reduce your node numbers as much as possible until you manage to make it work.
If one part do not enter into contact, remove it.
Read about master and Slave requirements in the manual.
Always look at the deformations and animation. If the analysis has failed, all the more reason. Most of the time it tells you where the problem is.
Should be, normally explicit dynamics analyses don’t fail to converge for other reasons. The incrementation settings are really crucial in those analyses in CalculiX.
