2.6 THE
PLOT PROGRAM Z88P
The more modern Z88 plot program is the new OpenGL plot program Z88O, ref. Chp. 2.11. However, the approved plot program
Z88P stays part of the Z88 FEA system.
The plot program Z88P plots
undeflected, deformed, both undeflected and deflected structures as well as
super structures.
Z88P can plot on the screen
or into a file. The plot file contains so-called HP-GL commands which are used
by HP plotters. Of course, it is optional to process the HP-GL files also in
other programs, e.g. in CorelDraw, WinWord etc. If necessary change the ending
.TXT. E.g. Winword expects the ending . HGL or .PLT for HP-GL files.
In addition, von Mises
stresses can be plotted on the screen or send to a plotter. The screen colors
can be adjusted for Windows in the file Z88P.COL. The file Z88.FCD for the UNIX
operation system allows for much more possibilities in changing colors and
fonts as well as the sizes and locations of the pushbuttons, radioboxes etc. You
can completely modify the whole appearance of Z88P for UNIX as you wish.
Needed Files |
Super structures |
Undeflected FE struc. |
Deflected FE struct. |
Yes |
No |
No |
|
No |
Yes |
Yes |
|
Z88O2.TXT |
No |
No |
Yes |
Z88O5.TXT |
No |
Yes, for Mises stresses |
No |
For fastest operation Z88P
connects the nodal points with straight lines, although for Serendipity
elements 7, 8, 10, 11 and 12 the edges of the elements are square or cubic
curves.
Note: You can also use your CAD program
together with CAD converter Z88X to plot super structures and undeflected finite element structures, yet
deflected structures and von Mises stresses do need Z88P. Or convert Z88's plot
files (HP-GL language) into DXF files: CorelDraw does a very good job.
Z88P saves the last
structure file name, the several factors and label adjustments in a file
Z88P.STO. This file is loaded when starting Z88P, so that the last structure is
restored automatically. If you like to start with a new structure, the file
Z88P.STO should be deleted before launching Z88P. This can be done with Plot
> Delete Z88P.STO (Windows) or Plot with option rm z88p.sto
(UNIX) in the Z88-Commander Z88COM.
Special key strokes for
Windows:
Prior: increase zoom
Next: decrease zoom
Cursor left: panning X direction
Cursor right: panning X direction
Cursor up: panning Y direction
Cursor down: panning Y direction
..And in addition for
3-D structures for Windows:
Home: panning Z direction
End: panning Z direction
F2: rotate around X axis
F3: rotate around X axis
F4: rotate around Y axis
F5: rotate around Y axis
F6: rotate around Z axis
F7: rotate around Z axis
F8: reset all rotations to 0
Under UNIX use the usual
X and Motif key assignments: Tab key and arrow keys for choice and space bar
for activation.
Pen plotters draw the
undeflected structure with pen 1 and the deflected structure with pen 2.
Explanation of some menu items:
Name of
Structure File:
Windows: File >
Structure File
UNIX: Stru. text field directly on window
Choose the structure file
here. Enter name, if necessary with path, press return. The new stucture is
loaded and drawn immediately.
Name of
Plotter File:
Windows: File >
Plotfile
UNIX: Plot. text field directly on window
Choose a plotter file name
here. Default name is Z88O6.TXT. The plot file includes HP-GL commands in ASCII
code ready for reprocessing by other programs, e.g. CorelDraw.
Windows: Serial
plotters: A direct
output from Z88P to a plotter does not always work. If necessary, put Xon/Xoff
sequence in Z88O6.TXT with the Z88-Commander after producing Z88O6.TXT. Then
Z88O6.TXT can be send to a serial plotter by
copy /B Z88O6.TXT com1: (or com2:)
You also can use the
Hyperterminal of Windows. Try ASCII, CR-LF ending, local echo, line delay 10
msec, byte delay 1 msec. However, large files can cause timeouts. This is a
generally poor attribute of serial interfaces, cf. the notes below for UNIX.
Windows: HP LaserJet: Some laser
printers can be switched from PCL mode to HP-GL mode by hand, for others this
works unfortunately only by software. In this case put a LaserJet sequence in
Z88O6.TXT with the Z88-Commander Z88COM after producing Z88O6.TXT. Then do
normal printing.
UNIX: Serial plotters: Serial
interfaces are adjusted with the stty-command as root
stty sane ixon ispeed 9600 cs8 -cstopb -parenb
< /dev/ttyS1
Here /dev/ttyS1 is the
second serial interface. The first serial interface is /dev/ttyS0 . If your
plotter needs a software switchover on protocol Xon/Xoff, start the little
utility pxon88 after the production of Z88O6.TXT by Z88P . Then send
Z88O6.TXT as root to the interface:
cat z88o6.txt > /dev/ttyS1
You can also put the serial
plotter as a raw-device into /etc/printcap directly. Lets say it would be
called HP7475A-a3-raw there. As a normal user you can then plot via the UNIX
spooling system
lpr -PHP7475A-a3-raw z88o6.txt
Caution: Serial pen plotters are extremely
slow devices, i. e. they can plot a lot due to the very efficient HP-GL
language with extremely little information. For huge HP-GL files this can have the
effect that the serial interface - despite Xon/Xoff - delivers far too few
bytes to the plotter and therefore gets a timeout. See these general
difficulties for LINUX under /usr/doc/howto at printer-howto and serial-howto.
UNIX: LaserJet: Some laser printers can be switched
from PCL mode to HP-GL mode by hand, for others this works unfortunately only
by software. In this case put a LaserJet sequence in Z88O6.TXT by the little
utility laserj88 after producing Z88O6.TXT with Z88P. Take care that
laser printers have a raw entry in /etc/printcap as the UNIX spooling
system is supposed to pass the HP-GL files completely unfiltered. Plot using
lpr -Praw z88o6.txt
Notes Windows and UNIX: The HP-GL commands produced by Z88
work faultlessly on several HP and IBM plotters if the physical adjustments are
fixed correctly. Check out if your plotter is actually 100 % HP-compatible !
Another predefined file
name is Z88O7.TXT. You can store the undeflected structure in Z88O6.TXT and the
deflected structure in Z88O7.TXT if you do not want to do it by the Z88P
command Structure > Un- and Deflected. The file Z88O7.TXT can be
appended alternatively to Z88O6.TXT later allowing the plotting of the
undeflected and the deflected structure in one run. Mind the order: Store
Z88O6.TXT first, then Z88O7.TXT. But you can also plot completely different
structures.
Deformation
Modes of the Structure:
Windows: Structure
> Undeflected, Deflected, Un- and Deflected
UNIX: Radio box Undefle., Deflected, Un+Defle.
Plots the undeflected
structure, the deflected structure or both. Stresses can be plotted only on
undeflected structures. When using Un- and Deflected nodes and element
labels are plotted on the undeflected structure.
Caution Deflected and Un- and Deflected:
The user must have executed a calculation of displacements before using this
function. Do a FEA run with Z88F before using Z88P. Otherwise, some old files
Z88O2.TXT (displacements) from earlier Z88 runs are opened causing totally
wrong results !!
Output
in Plotter File:
Windows: Output >
CRT, Plotter
UNIX: Pushbutton Plot.
Default is plotting on the
screen (CRT). Selecting Plotter produces a HP-GL file whose name has
been selected with Interface at choice. This runs very fast. Z88P shifts
back again immediately to CRT after storing the HP-GL file and after quitting
the message box.
Choice
of View:
Windows: View >
XY, XZ, YZ, 3-Dim
UNIX: Radio box XY, XZ, YZ, 3D
Select view depending on
structure: At 2-dimensional structures XY, at 3-dimensional structures 3-Dim. Mind
3-D structures: The desired side views can be shown with XY, XZ and YZ,
however, the nodes and element labels are plottet ascendingly (starting with
node 1 or element 1 ascending to the last node or element), the stress points
in the order of the Gauss points, ascending from element to element. The
finished pictures can therefore show nodes and element numbers as well as
stresses which does not really lie in the level of the side view! Only 3-D view
gives reliable information. Note: If starting with a "fresh" 3D-
structure in Z88P you will see under Windows the menu hook improperly set on XY
or under UNIX the radio button XY set, because the menus are built up before
reading the Z88 files. Do not care.
Drawing
Node and Element Numbers:
Windows: Labels >
No Labels, Elements, Nodes, Label All
UNIX: Radio box No Labels, Elements, Nodes, Both
Plot the element numbers or
the node numbers or both or skip numbering. Labeling can get confusing because,
depending on view, different numbers of complicated space structures are
plotted several times at the same location. Carefully place structure parts by
corresponding rotations.
Coordinate
System:
Z88P uses a coordinate system which starts in the center of the CRT or the center of the sheet. It is fixed as follows:
Axis |
CRT min |
CRT max |
Plotter min |
Plotter max |
X |
-100 |
+100 |
-138 |
+138 |
Y |
-100 |
+100 |
-100 |
+100 |
Z |
-100 |
+100 |
-100 |
+100 |
For 3-D structures the
transformation of the 3-D coordinates to the 2-D CRT or plotter is carried out
via an isometric view ref. ISO 5. If the rotation angles ROTX, ROTY and ROTZ
are set to 0 respectively, then is valid: X : Y : Z = 1 : 1 : 1. Z points up
and X and Y are tilt by 30 degrees.
Windows: The rotation angles can be modified
by steps of 10 degrees with the buttons F2 to F7 or with Factors
> Rotations 3-D in optional values. F8 resets all rotation angles
to 0 degrees.
UNIX: The rotation angles can be modified
by steps of 10 degrees with the Pushbuttons RX+, RX-, RY+, RY-, RZ+ and RZ-.
Pushbutton Rot 0 resets all rotation angles to 0 degrees.
Plots fitting entirely on
the screen usually work with the same factors for the plotter. However, because
plotters have different X-Y ratios, factors need to be changed slightly for
plotter output sometimes.
Global
Magnifications:
Windows: Factors >
Global Magnifications
Do zooming either in steps
with the keys Prior and Next or delicately with factors FACX,
FACY, FACZ. The entry of factors is also useful if several structures should be
plotted using the same factors.
UNIX: Pushbuttons Zoom+
and Zoom-
Panning:
Windows: Factors >
Centre Factors
Do panning into X direction
with left and right cursor keys, into Y with cursor up and
cursor down and into Z (at three-dimensional structures) with Home
and End. Alternatively you can use Factors > Centre Factors :
CX, CY and CZ.
UNIX: Pushbuttons X+, X-,
Y+, Y-, Z+, Z-
Enlarging
Deflections:
Windows: Factors >
Deflections
UNIX: Text fields FUX, FUY and FUZ
Enlarge the computed
deflections with the factors FUX, FUY and FUZ. Default values are 100.
Attention UNIX: As usual for UNIX, the changes only apply at a respective Return.
However, you can type in all three fields without Return and then press
the Pushbutton Regen (for Regenerate).
Rotations:
Windows: Factors >
Rotations 3-D
The rotations around X, Y
and Z axises are defined with Factors > Rotations 3-D : ROTX, ROTY and ROTZ.
Default values are 0. With the F2 . . F7 keys the structure can be revolved in
steps of 10 degrees.
UNIX: Pushbuttons RX+, RX-, RY+,
RY-, RZ+, RZ-
Turn in steps of 10
degrees. Pushbutton Rot 0 resets the rotations to 0.
Height
Ratio:
Windows: Factors >
X-Correction FXCOR
UNIX: Text field FXCOR
With the function
X-Correction FXCOR the height ratio can be adjusted to the monitor
customization. The default values are 0.75 for NT and 0.85 for UNIX. Modify
FXCOR depending on monitor type if necessary. FXCOR is stored in Z88P.STO for
further use.
Von
Mises Stresses:
Windows: Mises
Stresses > No von Mises stresses, Show von Mises stresses
UNIX: Pushbutton Mises
If you have calculated von
Mises stresses by Z88D (only
useful and possible for continuum elements of the type 1, 3, 6, 7, 8, 10, 11,
12, 14, 15, 16, 17, 18, 19 and 20) then you can plot the von Mises stresses
either into the Gauss points (elements No.1, 7, 8, 10, 11 and 12) or into the
center of gravity of the elements (elements No.3 and 6). Possible for CRT and
Plotter.
Stresses will only show if
you have chosen Structure > Undeflected. Z88P otherwise recalls that
you wanted to plot von Mises stresses and shows them when switching from Show
von Mises stresses to Structure > Undeflected.
If you choose Show von
Mises stresses and then Output > Plotter the von Mises stresses
are converted into a letter scale from A to J to match even ancient pen
plotters with only 2 or 6 pens or monochrome laser printers.
On the screen the stresses
are plottet using a color scale. You can adjust this color range in Z88P.COL
(Windows) or Z88.FCD (UNIX) to match your personal wishes.
Consult the output file
Z88O3.TXT for exact stress results because Z88P shows stresses only in a
10-step range.
Caution: The operator is
responsible for first running a stress calculation by Z88D before using this function. Run Z88F or the Iteration solver for calculating the displacements
and then the stress processor Z88D before starting Z88P. Otherwise some old
stress files Z88O5.TXT from earlier calculations are read causing totally wrong
results !!
Keep in mind:
Automatic
Scaling:
Windows: Autoscale
> No Autoscale, Yes Autoscale
UNIX: Pushbutton AutoS
The Autoscale function
takes care that structures will completely fit on the screen.
Autoscale activates
automatically if no file Z88P.STO is available or if a new structure is loaded
by File > Structure File. Autoscale again is deactivated immediately
and the hook points to No Autoscale. If a file Z88P.STO is present the
factors are read from this file. You can then scale properly with Autoscale
> Yes Autoscale. However, Autoscale switches again immediately to No
Autoscale. Autoscale > Yes Autoscale is a kind of pushbutton. The
explanation above corresponds to UNIX as well.