[CIG-SHORT] problem getting fault rupture (slip weakening)

[Lucas Abraham Willemsen]

Hi Brad,

I will try to look at the length scales and see if I can find some appropriate nondimensionalizing values that will work with cell dimension of 10 meter and slip weakening distance of 5e-3 m . Although the preliminary investigations I did were not very hopeful when I restricted my nondimensionalization changes to the length_scale variable.

When I use 1 meter as slip weakening distance the linear solves go fast so I guess the conditioner number of the linear system is good and that the nondimensionalization scheme gives values with similar orders of magnitude. But even though linear convergence is great, the nonlinear iterations do not converge. Do you know of ways to improve nonlinear convergence as well?

thanks,
Lucas
________________________________________
From: cig-short-bounces at geodynamics.org [cig-short-bounces at geodynamics.org] on behalf of Brad Aagaard [baagaard at usgs.gov]
Sent: Thursday, April 25, 2013 14:49
To: cig-short at geodynamics.org
Subject: Re: [CIG-SHORT] problem getting fault rupture (slip weakening)

Lucas,

I re-read your email and now I see that you did try a larger
slip-weakening slip distance. I am not familiar with the problem you are
solving and don't have time to look into it.

I suspect you still have some scaling issues. I would start by writing
down the order of magnitudes of the stresses, tractions, BC,
displacements, and slip and rates you expect to see. These are the
driving scales in your problem. Select your nondimensionalization
parameters so that the nondimensional quantities of these fields are
within at least few orders of magnitude of each other. The further apart
the nondimensionalized fields are, the more ill conditioned the problem
is going to be.

Regards,
Brad
_______________________________________________
CIG-SHORT mailing list
CIG-SHORT at geodynamics.org
http://geodynamics.org/cgi-bin/mailman/listinfo/cig-short