[CIG-SHORT] Nonlinear solution did not converge

[Chunyu Liu (cliu5)]

Hi all,

I try to lock a fault shoulder and keep the central part of the fault free to displace by changing friction coefficients and cohesions.

Like the following database, keep lower cohesion in the central part but linear changing values in the shoulder of the fault.

But when the max cohesion is bigger than 1000MPa, It could not converge.

The mesh aspect ratio( from Trelis) :  most 1~3 , some of them are 4.5 ( ideally 1~3, but I think the mesh quality is ok).

How can I turn on inner solves to further diagnose things?
 Are there any thing I can do to make it converge or even converge faster ?

Thanks for your time

Solution parameters

# Preconditioner settings.
pc_type = asm
sub_pc_factor_shift_type = nonzero

# Convergence parameters.
ksp_rtol = 1.0e-10
ksp_atol = 1.0e-9
ksp_max_it = 5000
ksp_gmres_restart = 50

# Linear solver monitoring options.
ksp_monitor = true
ksp_view = true
ksp_converged_reason = true
ksp_error_if_not_converged = true

# nonlinear convergence parameter
snes_rtol = 1.0e-10
snes_atol = 1.0e-3 ( Just save time)
snes_max_it = 5000

# Nonlinear solver monitoring options.
snes_monitor = true
snes_linesearch_monitor = true
#snes_view = true
snes_converged_reason = true
snes_error_if_not_converged = true


Fault properties spatial database

#SPATIAL.ascii 1
SimpleDB {
  num-values = 2 // number of stress components

  // names of the fault coeffients
  value-names = friction-coefficient cohesion

  value-units = None MPa  // units

  num-locs = 33
  data-dim = 2
  space-dim = 3

  cs-data = cartesian {
    to-meters = 1.0
    space-dim = 3
  }
}
// Columns are
// (1) x coordinates(m)
// (2) y coordinates(m)
// (3) z coordinates(m)
// (4) friction_coefficient
// (5) cohension(MPa)
-163000 300000  0           0.6     1000
-163000 300000  -60000      0.6     1000
-163000 300000  -120000      0.6    1000
-111000 222000  0           0.6     978.8375
-111000 222000  -60000       0.6    978.8375
-111000 222000  -120000      0.6    978.8375
-74000  166500  0           0.6     555
-74000  166500  -60000      0.6     555
-74000  166500  -120000      0.6    555
-47000  126000  0           0.6     420
-47000  126000  -60000      0.6     420
-47000  126000  -120000     0.6     420
-37000  111000  0           0.6     0
-37000  111000  -60000      0.6     0
-37000  111000  -120000      0.6    0
37000        0  0           0.6     0
37000        0  -60000      0.6     0
37000        0  -120000      0.6    0
111000 -111000  0           0.6     0
111000 -111000  -60000      0.6     0
111000 -111000  -120000      0.6    0
121000 -126000  0           0.6     420
121000 -126000  -60000      0.6     420
121000 -126000  -120000     0.6     420
148000 -166500  0           0.6     555
148000 -166500  -60000      0.6     555
148000 -166500  -120000      0.6    555
185000 -222000  0           0.6     978.8375
185000 -222000  -60000       0.6    978.8375
185000 -222000  -120000      0.6    978.8375
237000 -300000  0           0.6     1000
237000 -300000  -60000      0.6     1000
237000 -300000  -120000      0.6    1000
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.geodynamics.org/pipermail/cig-short/attachments/20150727/dedb69db/attachment.html>