Loic Ivaldi
Ansys Employee
Hello,
 
as @Sidram already said, double check your system of units to see if it's consistent and if workbench doesn't perform a conversion on your model that could lead to some problems.
 
I say that because on your screenshot, I saw that you are in mks = meter / kilo / second and if we look the screenshot where the tools cuts the concrete your scale of stress is from 0 to 8756. In meter/kilo/second, the unit of Stress is Pa and if you have 8756 Pa at max it's really low. On the other side if it's 8756 MPa it's pretty high.
 
Here a link for consistent units : https://www.dynasupport.com/howtos/general/consistent-units
 
You said this :
 
2.I used calculation time 1 sec, mass scale - off, MLS - off. The resolution in this case takes 937 hours. I followed your advice and made TSSCF=5 (and more). Now negative volume errors appeared and the calculation did not lead to anything.
 
I didn't say to take a TSSFAC>0.9. You should never use TSSFAC larger than 0.9. I said TSSFAC=0.8. If you really used TSSFAC=5 it's normal to have issues.
 
Another strange thing is the "ENDMASS" normally the default value in LS-DYNA is 1e+8 and it's a "Percent change in the total mass" meaning if you increase the mass of by 100 million percent, the simulation will end.
You should check the matsum and the added mass on each PARTs. As a rule of thumb, we tolerate 5% of mass increase for each PARTs.
 
Try with the default approximation theory for now (FORM=0 in *CONTROL_SPH in LS-DYNA format) as your model is too unstable.
 
Also, for the contact try sfs=sfm=1e-9 and SOFT=1.
 
Best,
Loïc