[CIG-SHORT] Stress concentration near the fault tip

[Charles Williams]

Dear Josimar,

The primary purpose of using the fault edge is for faults that terminate within the domain.  This allows PyLith to properly form the cohesive cells.  Since your fault edge is on an external boundary you don’t need this.  It appears that you are not applying any normal force to the fault, so it is not clamped at all.  Have you verified that both your linear and nonlinear solutions are converging?

Also, what is the purpose of the tractions applied on the left side of the model?

Cheers,
Charles


> On 7/11/2016, at 1:31 PM, Josimar Alves da Silva <jsilva.mit at gmail.com> wrote:
> 
> Dear Charles,
> 
> Thank you so much for the reply. I am attaching a figure with the correct boundary conditions. 
> 
> My questions is:
> 
> 1) What causes the high normal and shear stresses near the fault tip ? 
> 
> Would it be possible that there is something wrong on the way I am parameterizing the fault edge ? I have tried turning on the "edges" command on the set up but I still observe the high stresses.
> 
> My simulation only runs for 15 years. At the end of the simulation there is no fault displacement. However, only the high stress values indicated above. I wonder if this behavior is normal because the failure criteria was not met ?
> 
> Best,
> Josimar
> 
> 
> 
>  
> 
> 
> 
> On Sun, Nov 6, 2016 at 1:25 PM, Charles Williams <willic3 at gmail.com <mailto:willic3 at gmail.com>> wrote:
> Dear Josimar,
> 
> I am somewhat confused about your boundary conditions.  Are any conditions being placed on the top and bottom boundaries?  Also, it appears that you are applying Neumann BC on the left boundary, rather than the fixed displacement BC shown in your figure.  Is this correct, or is something mislabelled?
> 
> Cheers,
> Charles
> 
> 
>> On 5/11/2016, at 11:24 AM, Josimar Alves da Silva <jsilva.mit at gmail.com <mailto:jsilva.mit at gmail.com>> wrote:
>> 
>> Dear All, 
>> 
>> I am running PyLith with a 2D fault friction model, including gravitational effects.
>> 
>> I am finding stress concentration near the tip of the fault and I would like to understand why this occurs. See attached figure.
>> 
>> On the link below Brad seems to address this issue, however it is still not clear to me why this happens.
>> 
>> http://lists.geodynamics.org/pipermail/cig-short/2014-November/001924.html <http://lists.geodynamics.org/pipermail/cig-short/2014-November/001924.html>
>> 
>> Details about my simulation are attached (log files, boundary conditions...)
>> 
>> Thank you in advance for your time.
>> Best,
>> Josimar
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> Charles A. Williams
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> GNS Science
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Charles A. Williams
Scientist
GNS Science
1 Fairway Drive, Avalon
PO Box 30368
Lower Hutt  5040
New Zealand
ph (office): 0064-4570-4566
fax (office): 0064-4570-4600
C.Williams at gns.cri.nz <mailto:C.Williams at gns.cri.nz>
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