assemble slip systems for HCP crystal structure

[Karthik Palaniappan]

I need to assemble the slip systems for HCP crystal structure to plot the Schmid factor map.

% rotate slip systems into specimen coordinates

sSLocal_basal = grains.meanOrientation * sSBasal;

sSLocal_Prismatic = grains.meanOrientation * sSPrismatic;

sSLocal_Pryramidal = grains.meanOrientation * sSPyramidal;

% compute Schmid factor

sigma = stressTensor.uniaxial(vector3d.Z);

SF = sSLocal.SchmidFactor(sigma);

How to assemble slip systems to calculate SF (Schmid Factor)

[ruediger Kilian]

Try sS = [ sSBasal; sSPrismatic; sSPyramidal]

Cheers,
Rüdiger

[Karthik Palaniappan]

Thank you. 

[Karthik Palaniappan]

When I tried to add twinning system  and assemble them 

sS =  [sSBasal; sSPrismatic; sSPyramidal_a; sSPyramidal_ca; sSLocal_sSExtTwin];

I see the following error

No appropriate method, property, or field 'CS' for class 'vector3d'.

Error in vector3d/subsref (line 23)

    [varargout{1:nargout}] = builtin('subsref',v,s);

Error in Miller/cat (line 16)

    if ms.CS ~= m.CS

Error in slipSystem/cat (line 18)

sS.b = cat(dim,sSb{:});

Error in slipSystem/vertcat (line 4)

v = cat(1,varargin{:});

How to fix this?

With regards, 

Karthik 

[ruediger Kilian]

What is sSLocal_sSExtTwin, what's it output and what is the output of your other slipSystems?
Cheers,
Rüdiger

[Karthik Palaniappan]

sSLocal_sSExtTwin = grains.meanOrientation * sSExtTwin;

Output of sSLocal_sSExtTwin

sSLocal_sSExtTwin = slipSystem (show methods, plot)

 CRSS: 9

 size: 15391 x 6

If I exclude the twinning system then   sS =  [ sSBasal; sSPrismatic; sSPyramidal_a; sSPyramidal_ca]  

Output:

 

sS = slipSystem (show methods, plot)

 mineral: 1 (622, X||a, Y||b*, Z||c*)

 CRSS: 1 3 7

 size: 24 x 1

   U   V   T   W | H   K   I   L

   1   1  -2   0   0   0   0   1

   1  -2   1   0   0   0   0   1

  -2   1   1   0   0   0   0   1

   0   1  -1   0   2  -1  -1   0

  -1   1   0   0   1   1  -2   0

  -1   0   1   0   1  -2   1   0

   2  -1  -1   0   0   1  -1   1

   1   1  -2   0  -1   1   0   1

   1  -2   1   0  -1   0   1  -1

   1  -2   1   0  -1   0   1   1

   1   1  -2   0  -1   1   0  -1

   2  -1  -1   0   0  -1   1   1

   2  -1  -1   3  -1   1   0   1

  -1   2  -1  -3  -1   1   0   1

   2  -1  -1  -3  -1   0   1  -1

  -1  -1   2   3  -1   0   1  -1

   2  -1  -1   3  -1   0   1   1

   1   1  -2   3  -1   0   1   1

   2  -1  -1  -3  -1   1   0  -1

   1  -2   1  -3  -1   1   0  -1

   1   1  -2   3   0  -1   1   1

   1  -2   1  -3   0  -1   1   1

  -1  -1   2   3   0   1  -1   1

  -1   2  -1  -3   0   1  -1   1

With regards, 

Karthik 

[ruediger Kilian]

Yes, you should not mix those. Collect all slip systems in crystal coordinates and, if desired, rotate them later on into specimen directions. Or, as you seem to do, leave them as is and rotate the strain tensor into crystal directions.

Cheers,
Rüdiger

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[Karthik Palaniappan]

I could understand that slip systems and twinning systems should not be mixed. How can I incorporate the twinning system. while calculating SF. 

This is the latter part of my code

sS =  [sSBasal; sSPrismatic; sSPyramidal_a; sSPyramidal_ca];  

sSLocal = grains.meanOrientation * sS;

sigma = stressTensor.uniaxial(vector3d.X);

SF = sSLocal.SchmidFactor(sigma);

Could you please explain. I am confused.

With regards,

Karthik 

[ruediger Kilian]

Technically, there's no issue with mixing the twin systems and the slip systems. e.g.

sS = slipSystem.basal(cs)
tS = slipSystem.twinC1(cs)
ss=[sS.symmetrise; tS.symmetrise]
sSLocal = o * ss;

sigma = stressTensor.uniaxial(vector3d.X);
SF = sSLocal.SchmidFactor(sigma);

However, if you look at what you did earlier, it's just that you were rotating the twin system on into specimen/grains directions
and combing those then with slipSystems in crystal coordinates, followed by then using these with a stress tensor rotated into crystal coordinates. You can use one or the other solution - either rotate the slip/twin system or rotate the stress tensor - but don't mix the two.
Have a look here and try to understand what is happening: http://mtex-toolbox.github.io/files/doc/PlasticDeformation.html#20


Cheers,
Rüdiger

[Karthik Palaniappan]

Thank you, I got it.

With regards,

Karthik