popLA Manual (PDF) - Materials Science and Engineering

Analyze using the WIMV Method
For this, you need the .FUL pole figures just obtained; WIMV will ignore the values above a tilt of 80° (but
needs the normalization obtained in the last step). You also need "pointer files". They have the extension .WIM,
.BWM, or .WM3, depending on which level of WIMV you use. Use the default files supplied for now. (Later
you can make your own on p.4#8.) There are three levels of the WIMV program in popLA, depending on the
complexity of your problem: look at p.4 numbers 2, 3, and 4. We have the easiest case, so we will use the fastest
program:
• Opt for p.4#2. Take the defaults on all options (especially the one on treating these as “incomplete” pole
figures (even though they go to 90°). The progress will be displayed. The error estimates are listed for you
to judge the rate of conversion. One may wish to stop when the change from one iteration to the next is only
a fraction of a percent. (For the DEMO. files, we have stopped after iteration 17. The number of iterations,
the final error estimate, and the Texture Strength will all be listed on the title line of the resulting .SOD and
.WPF files.
At the end you have an option as to which Euler angles you wish to have the files sequenced in. Your choice
will be recorded in the output file, on the second line, position 5: B or R or K (for Bunge, Roe/Matthies, or
Kocks). Pick 1 for now.
• Before you look at the files, opt for p.4#7: make a file of WIMV-calculated inverse pole figures, .WIP. Since
you have just made it, you may as well look at it first:
• Opt for p.6#2 (for which you need to go back to p.1 first), answer 0, then defaults until "...plots on page?" If
you answer 3, you get the whole file; but answer 2 to get the Z- and Y-axis pole figures. (You can print only
2 plots in higher resolution). Note that a whole quadrant is shown even though, for this case, just one of the
“stereographic triangles” would have been sufficient. (You can cut it out...)
Figure 3 – DEMO.WIP
• Now you are back on p.6, opt again for #2, etc., but this time look at .WPF: the WIMV-recalculated pole
figures; the first two suffice. Use scale 400/3 again. Do they look familiar? They should be similar to the
original .EPF, only rotated a bit and symmetrized, and completed in the rim. Since we assumed orthotropic
sample symmetry (as one of the default answers while WIMVing), the four quadrants of the pole figure
contain the same, averaged information. Plotting only one quadrant allows a better resolution of the figure in
the same area.
For a quantitative comparison of the recalculated and the input pole figures, we could either EXPAND the .WPF
(p.2#7) or, which we suggest, SYMMETRIZE (p.2#6) the input pole figure. The actual input to WIMV was the
.FUL pole figure, and we compare to it – firstly, because it has the rotation already built in, and second because
it is properly normalized. As a fringe benefit, we get a comparison of the rim predictions from WIMV and from
the harmonic method. Thus:
TUTORIAL 12