rate-state dependent friction in ANSYS

Dear collegues

a quick question:- I am playing with continuum models of Contact (Hertz, Westergaard and so on) and friction laws. However, I prefer for my students to use ANSYS FEM code. In Ansys there is standard Coulomb, rate-dependence but not rate-state (unless one codes some user subroutines). See

https://www.sharcnet.ca/Software/Fluent14/help/ans_ctec/Hlp_ctec_realkey...

Dieterich (1979) and Ruina (1983), see also Dieterich (2007), suggested a rate- and state-dependent friction law to explain a large amount of laboratory data on rock friction. Other regularized friction laws exist, in particular a simplified version of a Prakash and Clifton (1993) friction law obtained experimentally was used by Cochard and Rice (2000) which confirmed in the unstable range numerical solutions do not converge through grid size reduction. Finally, Ben-Zion and Huang (2002) found that the self-sharpening and divergent behaviour exists also with a regularized law, for large enough propagation distance and that "the parameters of regularized friction have to be fine tuned to produce apparent stability for a given propagation distance".

Do you know who can have implemented these user subroutines for the classical rate-state laws?

Best regards and thanks in advance for your help.

Mike

References

Dieterich, J.H., (1979). Modeling of rock friction 1. Experimental results and constitutive equations. J. Geophys. Res. 84, 2161-2168
Dieterich J.H. (2007) Applications of Rate- and State-Dependent Friction to Models of Fault Slip and Earthquake Occurrence, Treatise on Geophysics, 2007, Chapter 4.04, Pages 107-129
Prakash V., Clifton R.J., (1993) "Time-Resolved Dynamic Friction Measurements in Pressure- Shear, Experimental Techniques in the Dynamics of Deformable Solids", Applied Mechanics Div., vol. 165, 33-48.
Cochard A., Rice J.R., (2000) "Fault rupture between dissimilar materials: Ill-posedess, regularization and slip-pulse response", Journal of Geophysical Research, 105, 25 891.