[CIG-SHORT] static friction and cohesion on fault (2D)

[BOK10 at pitt.edu]

So the fault isn't straight, it has a bend in it. I expect a portion of it
to display fault opening based on its orientation relative to the
direction of block motion, but the rest of the fault is oriented in such a
way that there should be zero slip until the friction is overcome. I just
ran the problem with a friction of 1 to see if that part of the fault
locked, and it does, which is a good sign. I'm going to play around with
it a bit more at various cohesion values and see what happens.

In regards to your earlier email, I ran the simulation with a prescribed
slip of zero and the deformation does make sense, so I'm thinking the
setup is okay.

Bobby

> Bobby,
>
> If your shear tractions do not agree with your friction parameters, then
> it suggests your problem is not setup correctly. If your normal
> tractions are zero, then the fault is opening and the tractions will go
> to zero. You may want to try using a prescribed slip of zero
> (FaultCohesiveKin) to force zero slip and see if the deformation makes
> sense. This will also allow you to monitor the tractions on the fault
> with zero slip.
>
> The quadrature types FIATLagrange and FIATSimplex must match the cell
> type of the mesh. FIATSimplex is for triangular cells.
>
> Regards,
> Brad
>
>
> On 11/12/12 2:37 PM, BOK10 at pitt.edu wrote:
>> So, I plotted the traction time histories on the fault, and i'm getting
>> similar slip rates and tractions no matter what the friction
>> coefficient.
>> I'm looking at the length of time it takes to get to >1cm/yr slip on 75%
>> of the fault, and every result is the same. Is there something else that
>> could be causing this? I've toyed between FIATLagrange and FIATSimplex
>> and
>> settled on the latter one based on the fact I'm using a tri-mesh model
>> in
>> 2-D.
>>
>> Bobby
>>
>>
>>> Bobby,
>>>
>>> I suggest plotting the traction time histories on the fault. You should
>>> behavior consistent with the fault constitutive model and parameters
>>> you
>>> are choosing.
>>>
>>> Regards,
>>> Brad
>>>
>>>
>>> On 11/8/12 5:09 PM, BOK10 at pitt.edu wrote:
>>>> I have a 2D model with a fault that I have static friction and
>>>> cohesion
>>>> on, but no matter what friction (0-1) or cohesion (0-200 kpa)
>>>> estimates
>>>> I
>>>> pick, the slip rates along the fault are identical and occur in the
>>>> same
>>>> exact time-step. I am pushing the blocks past one another by applying
>>>> velocity boundary conditions. I didn't have this problem before until
>>>> I
>>>> changed the geometry of my faults slightly. Is there something else
>>>> that
>>>> could be causing this?
>>>>
>>>> Bobby
>>>>
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>>
>>
>>
>
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