*>>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.*

I checked all the data, everything matches mks. I know about agreed units, thanks. Here is the material:

Loads are also set correctly. WB has a menu for switching measurement systems, but this only changes the visual representation, does not affect the calculation.

I think there are large stresses due to the destruction of concrete, and the speed is very high, everything happens in 0.0001 seconds.

*>>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.*

Sorry for the stupid question, but how do you check the matsum and added mass on each PART in LS-Dyna ACT WORKBENCH?

*>>Try with the default approximation theory for now (FORM=0 in *CONTROL_SPH in LS-DYNA format) as your model is too unstable.*

It did not help

*>>Also, for the contact try sfs=sfm=1e-9 and SOFT=1.*

because of this, the bodies began to penetrate each other without deformation:

I also tried to solve the problem with these settings:

particles are still scattered.

My problem is changing the time. When I solve the problem at time 0.0001 without turning on the mass scale, everything is in order. When I change to a solution time of 1 s, I turn on the mass scale so that the calculation time is acceptable. Then the particles fly apart.

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PS

Here is another example why I wanted to switch to a solution time of 1sec. I rotate the part of the rigid drill with a deformable bit. The calculation time is 0.0001 sec, the feed rate is 2 mm per sec, I make 1 revolution by 360 degrees. I had to increase the speed to 20000 in order for it to work with a calculation time of 0.0001 sec. The results show what strong stresses and deformations the nozzle experiences, because to make a revolution in 0.0001 seconds is a space load, but the calculation ended without errors

Maybe I misunderstand the speeds when solving 0.0001 sec. I need your help.