popLA Manual (PDF) - Materials Science and Engineering

Copying the following files to the standard-name input files, for example, would provide a consistent set of
input data for simulating a compression test on an initially isotropic material:
Purpose SXIN PROPIN TEXIN BCIN
predict texture in Cu SXCUB PROPCU TEXISO0.WTS BCCOM
evaluate fcc slip systems SXFCC PROPFCC TEXISO0.WTS BCCOM
A variety of additional input data are determined interactively during the run. Many of them are recorded in
a "TTY interaction file" called POTTY. When a POTTY file exists, you will be asked whether to skip a whole
raft of questions, in which case the existing POTTY will be used. You may also edit POTTY before the run:
sometimes, this is faster (and safer) than to have to answer, e.g., all but one question again in the same way. For
this purpose, POTTY lists, in the first line, the internal parameters:
ksys kpath ksol krc kond kavw kpri ngr0 nanal khar klh
0 1 3 1 1 0 0 100 9 1 0
The second line contains the current settings. Note that the number of grains that will be read from TEXIN is the
smaller of ngr0 and the number in TEXIN.
Output Files
Three main output files are generated: TEXOUT, HIST, and ANAL. All three files start with a number of lines
that begin with c and record the conditions used during the run. (They must be eliminated for certain re-uses of
these files; for example, TEXOUT may be used as TEXIN for a subsequent run, after the comment lines have
been deleted.)
TEXOUT is made only when KPATH=1; it records the orientations at the end of the run (or after every
NWRITE steps). It has the same format as TEXIN (once the comment lines are deleted), plus perhaps some new
state parameters; then it is also ready for plotting by DIOR.
HIST records information from every step (average over grains). When KPATH=1 the von Mises strain and
stress, Taylor factor, etc., plus information on computational progress; when KPATH=2 or 3 the strain and stress
vectors, Taylor factor; and when KPATH=4 the angle from X1, R-values, etc.
ANAL (if KPATH=1) contains details on the first NANAL grains: the stress and strain vectors, the yield vertex
ID, the number of constraints, the number and name of active slip systems and planes. In routine runs, set
NANAL =0.
LAPP.DAT contains some of the data from HIST in 5-column format, with no information preceding, for
input to plotting routines.
For strain paths with many steps in one strain direction (using BCIN), this file contains columns of von
Mises strain, von Mises stress, Taylor factor, average number of significantly active slip planes, and LHR: the
latent hardening ratio maximum.
For yield surface probes, this file contains the coordinates of the yield surface. The first two or three
columns are the computed values in 2- or 3-dimensional yield subspace; they permit complete plotting of the
surface. In the first two colums, X comes first, Y second ("Y versus X").
For R value computations: this file contains first the angle from X1, then the R value, then the 31-shear, and
finally the average Taylor factor in both versions. Note that "X1" is whatever was used as the sample Xdirection
in the definition of the Euler angles. (Thus, if you are plotting the RD up, but measure the sample
azimuth from the TD, X1 is the TD, not the RD.)
POTTY gets re-written with the current TTY input data.
Interactive Set-up
From within the directory to which you have unpacked the LApp files, and in which you have generated the
input files, follow these steps. (Steps preceded by [ are steps that occur only under some circumstances.)
1. Enter LAPP
The programs displays the first line of the TEXIN file.
2. Enter a title, up to 8 characters. This gets written into the first 8 characters of most output files (and is
then used in plotting routines)
[The next two steps may or may not show depending on SXIN and PROPIN:
LApp 48