[CIG-SHORT] Questions about traction application

[Surendra Nadh Somala]

Attached is an image of shear tractions after running your problem (based
on your third email).  Pylith does seem to set them exactly as you have
asked them to in the spatialdb files.

You haven't showed us how you were expecting to set the initial tractions
with a figure and how different they are from those that Pylith is setting
up based on your input files.  Without this it is hard to understand what
is the anomaly you are trying to point out.

Clearly, the transition of shear tractions is happening in between 400-500m
(along both x- and y-axes) from 31MPa to 20MPa on fault1 and in between
-1900 to -1800m along y-axis on "fault".

NOTE: The attached figure is based on first timestep of your fault output
as you are not asking pylith to write any vertex_info_fields for your
faults.

-Surendra

___________
*Surendra Nadh Somala*
Assistant Professor
Department of Civil Engineering (Block-E, 208)
Indian Institute of Technology (IIT) Hyderabad
Kandi, Sangareddy
Telangana, India - 502285
Phone : +91 (0)40 2301-8457
http://www.iith.ac.in/~surendra/

On Sat, Apr 1, 2017 at 9:37 AM, Li, Teng <tengli2 at illinois.edu> wrote:

> Hi,
> I have a question about applying traction on different faults.
> Here is the model description:
> #-----------Geometry---------------------
> Block size:
> 5000m * 5000m
>
> Main fault:
> (0,-2500) to (0,0)
> length:2500m.
>
> Overstressing length: 600m
> Overstressing point: (-2500,0). Bottom of the main fault.
>
> Main fault and the secondary fault share a node which is (0,0).
>
> #----------------Initial traction-------------------
> And followings are the initial traction file for main fault and secondary
> fault:
>
> #----------------------------
> #------------------Main fault-----------
> #SPATIAL.ascii 1
> SimpleDB {
>   // number of physical properties
>   num-values = 2
>
>   // Names and units of physical properties
>   value-names =  traction-shear traction-normal
>   value-units =  MPa MPa
>
>   // Number of locations where physical properties are given
>   // 1 location -> data is uniform -> data dimension is 0
>   num-locs = 4
>   data-dim = 1
>
>   // Problem is in 2-D
>   space-dim = 2
>
>   // Coordinate system (2-D with coordinates in meters)
>   cs-data = cartesian {
>     to-meters = 1.0
>     space-dim = 2
>   }
> }
> // Columns are x, y, traction-shear traction-normal
> 0.0      -2500.0   31.0  -50.0
> 0.0      -1900.0   31.0  -50.0
> 0.0      -1800.0   20.0  -50.0
> 0.0          0.0   20.0  -50.0
>
>
>
>
>
> #----------Secondary fault----------------
>
> #SPATIAL.ascii 1
> SimpleDB {
>   // number of physical properties
>   num-values = 2
>
>   // Names and units of physical properties
>   value-names =  traction-shear traction-normal
>   value-units =  MPa MPa
>
>   // Number of locations where physical properties are given
>   // 1 location -> data is uniform -> data dimension is 0
>   num-locs = 4
>   data-dim = 1
>
>   // Problem is in 2-D
>   space-dim = 2
>
>   // Coordinate system (2-D with coordinates in meters)
>   cs-data = cartesian {
>     to-meters = 1.0
>     space-dim = 2
>   }
> }
> // Columns are x, y, traction-shear traction-normal
> 0      0   31  -50.0
> 0    400   31  -50.0
> 0    500   20  -50.0
> 0    2120  20  -50.0
>
> However, in the plot, I see 20Mpa stress first occur in position about
> 600m away from point(0,0). I think it should occur at 400-500m. Could you
> please tell me how to apply initial traction? Or should I use local
> coordinates system or global coordinates system for both fault?
>
> Thanks!
>
> Teng Li
>
> Master Candidate in Structures
>
> Department of Civil and Environmental Engineering
>
> University of Illinois at Urbana-Champaign
>
> 205 North Mathews Ave, Urbana, IL. 61801
>
> Phone:(217)8196210, Email: tengli2 at illinois.edu
>
>
>
>
> _______________________________________________
> CIG-SHORT mailing list
> CIG-SHORT at geodynamics.org
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>
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