Grain Orientation

aspects of evaluating simulation results and their graphic presentation using either DisplayMICRESS or other software tools. Features and possibilities of DisplayMICRESS
Bernd
Posts: 1504
Joined: Mon Jun 23, 2008 9:29 pm

Re: Grain Orientation

Post by Bernd » Thu Mar 07, 2013 10:50 pm

Hi Raghav,

the connecting points, temperature gradient etc. are for directly specifying temperature boundary conditions.

But in case of 1d_temp, when using the Homoenthalpic Approach, the 1d temperature field solution is the temperature boundary condition for MICRESS, so you do not have to specify connecting points etc. This happens automatically if you specify 1d_temp at the top of the driving file.
Then you will need to specify the number of cells and grid size for the 1d temperature field (the total length is given by the casting size, the resolution should be typically a factor of 20-50 coarser as compared to the normal MICRESS grid.
Use of latent heat is default, and you have to specify a thermal conductivity for each phase (best is temperature-dependent from file if you find corresponding data) and an interval for updating enthalpy data (can be quite small without hurting too much, e.g. all 100 time steps).
Furthermore it is necessary to specify the position of the 2D/3D-MICRESS domain inside the 1d-temperature field corresponding to your sampling position.
Finally, you specify the boundary conditions and the thermophysical properties (from the .dTLat output) like mentioned above.

Bernd

RAGHAV
Posts: 45
Joined: Thu Jul 10, 2008 6:21 pm

Re: Grain Orientation

Post by RAGHAV » Fri Mar 15, 2013 7:57 pm

Dear Bernd,

I don't have temp. - dependent data for the different parameters for different phases.
So i use constant values that i got hold from books or web.
In this scenario, what i want to understand with the data i have
for Al Cu 4.5 wt%,
102 K temp. drop
for temp. at the bottom 923 K
which results in appearance of FCC_A1 appears at 922K and ALCU_THETA at 821K.

Should my aim be to get a temperature gradient of 102K across the top and bottom from different parameter
settings? In that case, it would be nice to have a understanding of how temp. gradient gets calculated?

P.S. I did some simulation with the constant values that i got but it seems to hang without proceeding to the initial time steps.

Best Regards,
Raghav

Bernd
Posts: 1504
Joined: Mon Jun 23, 2008 9:29 pm

Re: Grain Orientation

Post by Bernd » Wed Mar 20, 2013 1:16 am

Hi Raghav,

I don't understand exactly what you mean - I guessed you want to perform simulation such that they are as close as possible to the experiments!
Consequently, it depends on the relation of the size of the castig and the cooling conditions whether there will be a temperature gradient over 102°C inside the sample (and then also inside the 1D-temperature field of MICRESS) or not.
You can check the shape of the temperature field with the *_1DTemp_temp output. As it is non-linear, you cannot easily define a temperature gradient. The value which is written into the .TabL file is calculated inside the micro domain (top minus bottom temperature divided by the domain height).

Bernd

Raina
Posts: 13
Joined: Thu May 21, 2015 2:03 am
anti_bot: 333

Re: Grain Orientation TabO

Post by Raina » Sat Jun 13, 2015 2:25 am

Hello,

I ran the code for anisotropic growth and output the table of orientation(.TabO).
When I open the file xxx.TabO, I found there are four columns titled "Quaternion_0", "Quaternion_1", "Quaternion_2" and "Quaternion_3". Could you tell me what's that mean?

Your early response will be appreciated.
Thank you!

Bernd
Posts: 1504
Joined: Mon Jun 23, 2008 9:29 pm

Re: Grain Orientation

Post by Bernd » Mon Jun 15, 2015 3:49 pm

Dear Raina,

In Micress you can chose between different formats to define orientations (i.e. rotations) of grains:

# How shall grain orientations be defined?
# Options: angle_2d euler_zxz angle_axis miller_indices quaternion


The .TabO output gives you the list of grain orientations for all existing grains. As the quaternion description is the most general one and can be transferred to all other formats without loss of information, we provide it in all cases in the .TabO even if you specified another format. The different rotation formalisms are described e.g. here: https://en.wikipedia.org/wiki/Rotation_ ... dimensions

Bernd

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