Learning Forum

[eliasedwarde]

I am modeling a rigid/inclined PDC cutter cutting into a rock block in LS-DYNA using an RHT-type rock material, MAT_ADD_EROSION, and CONTACT_ERODING_SURFACE_TO_SURFACE. The cutter motion is prescribed only in the positive x-direction, while the rock is constrained at the base and, in some trials, subjected to lateral confining pressure of 40 MPa. The model initializes without fatal errors in many runs, but it stalls very early or shortly after contact/erosion starts; CPU usage drops significantly, the time step becomes very small, and failed rock elements are either not visibly deleted or only a few elements erode before the simulation stops progressing.

I have tried changing erosion/contact parameters such as CON1/CON2, ISYM, EROSOP, IADJ, commenting out the confining pressure, and running in double precision, but the same stalling behavior persists. I suspect the issue may be related to the eroding contact definition, contact update after element deletion, conflicting contact/control keywords, or inappropriate RHT/erosion parameters. I would appreciate advice on the required/typical keyword setup for rock cutting with CONTACT_ERODING_SURFACE_TO_SURFACE, especially regarding contact cards, CONTROL_CONTACT, erosion deletion/update settings, and stable parameter ranges.

[ErKo]

 

 

Hi

Perhaps use SPH or SPG as that does not need erosion and has shown to be perhaps/possibly more accurate than Lagrange methods using erosion.

Search for papers:

RHT and SPG and SPH and LS-Dyna

All the best

Erko