Stitch many ff-HEDM layers together & Calculate the Schmid factor/CRSS for certain slip system.

[minety]

Hi Joel,

Question 1: In ff-HEDM analysis, we normally have several-layer scans for a certain volume. How can I stitch them together with good alignment in terms of positions and orientations? I have some ideas in my mind, but I guess you may already have a solution (script) for that.

Question 2: When we do RAMS in situ loading experiments, we may want to calculate the Schmid factors for individual grains or the critical resolved shear stress for certain slip systems. I'm not familiar with the functions in hexrd regarding this issue (coordination systems/axes conventions), can you give me some suggestions? Or any scripts available for similar analysis?

Thanks a lot, Tian

@joelvbernier

[joelvbernier]

Ok, so we have approaches for both; item 2) is very straightforward, and I will follow up in this thread with an example for HCP (⍺-Ti). We have looked at several approaches for 1), and I can try and collect things that we've used in the past. Generally, a misorientation threshold augmented by a cutoff in COM position is sufficient to stitch. I'll try to follow up in a few days!

[minety]

Thanks a lot, I just found it too hard for me to write the functions myself. Another function (item) that would be very helpful is in MTEX (MATLAB). I will open a new issue for the convenience of searching for other users.

[minety]

For item 1, I found a script in your 2.7 version hexrd named stitch_grains.py. https://github.com/joelvbernier/hexrd/blob/master/scripts/stitch_grains.py But I found it was using the old material input file ".cpl". I haven't figured out a way to make it compatible with my materials.h5 file.

For item 2, I found another script in your folder to calculate crss (post_process_stress.py and gen_schmid_tensors.py) https://github.com/joelvbernier/hexrd/blob/master/scripts/post_process_stress.py https://github.com/joelvbernier/hexrd/blob/master/scripts/gen_schmid_tensors.py Still, it was hard for me to adjust my materials.h5 files into this script to make it work.

It would be very appreciated if you could give me some advice on this.

@joelvbernier

Thanks, Tian

[joelvbernier]

We are in the process of moving these utilities to the latest hexrd (with Darren Pagan’s help).

As for the old materials databases… the old ‘cpl’ files are cPickles, which are unfortunately not very portable; if you have a file you want converted h5, I can do that for you.

On Dec 11, 2021, at 4:59 PM, Ye Tian @.***> wrote:

For item 1, I found a script in your 2.7 version hexrd named stitch_grains.py. https://github.com/joelvbernier/hexrd/blob/master/scripts/stitch_grains.py <x-msg://2/url> But I found it was using the old material input file ".cpl". I haven't figured out a way to make it compatible with my materials.h5 file.

For item 2, I found another script in your folder to calculate crss (post_process_stress.py and gen_schmid_tensors.py) https://github.com/joelvbernier/hexrd/blob/master/scripts/post_process_stress.py <x-msg://2/url> https://github.com/joelvbernier/hexrd/blob/master/scripts/gen_schmid_tensors.py <x-msg://2/url> Still, it was hard for me to adjust my materials.h5 files into this script to make it work.

It would be very appreciated if you could give me some advice on this.

@joelvbernier https://github.com/joelvbernier Thanks, Tian

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[minety]

@joelvbernier Thanks, I will wait for the update. I have already moved to the latest hexrd, and I'm using .h5 files.

[joelvbernier]

Trying to bump up the priority on this task in the next few weeks...