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Hi all.

I'm simulating rock drilling using SPG particles.

I use the increased density to speed up the solution to the problem.

The task is similar to LSTC

https://www.lstc-cmmg.org/drilling

Only I use the rock and my feed and drilling speeds.

I use an average speed of 25 m/s feed speed and 27 rad/s drilling speed.

While solving the problem, I encountered several problems.

1.I get a negative volume error. And when the particles fly apart, they pull the solid ring behind them and it is greatly distorted:

At low feed speeds there are no such problems.

2.I reduced the density a little, the solution became better and I got good stress. I also replaced the EROSION contact with AUTOMATIC:

But now I get warnings:

Why? how to deal with this?

[Ram Gopisetti]

Hi, 

Try setting the ERODE option to 1and try to use 1.6 in dilation parameter and set SMSTEP to 5, check the stretch value and try to use an updated solver. 

Cheers, Ram 

[javat33489]

Thanks for the answer. I tried your advice, I still get the warning

 

I used the settings in the CONTROL_TIMSTEP ERODE=1 map and in the SPG map:

 

Nothing has changed visually, but the stress has increased by 100 MPa:

[javat33489]

I found the reason why the particles fly apart. It's all about the JHC material model. When this model is used, the particles fly apart. When I used MOHR-COULOMB the warnings went away