Chapter 12: Creating Geometric Results
Displays
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12.1 Using the GUI to Display Geometric Results
In a geometric results display, you can review your solution results in a
postprocessing display of your model's elements. The choice of geometric results
displays includes displaced shapes, results contours (including line-element
"contours," such as moment diagrams), and vector (arrow) results (such as
thermal flux vector displays). These displays are available only within the general
postprocessor, POST1. Figure 12-1 illustrates a typical geometric results display.
Figure 12-1 Contour results plot
The most convenient way to create and control geometric results displays is by
using the functions available under Utility Menu>Plot and Utility
Menu>PlotCtrls. Alternatively, you can use graphics action and control
commands, as described in the following subsections.
12.2 Creating Geometric Results Displays
The following commands create geometric results displays in POST1:
Table 12-1 Commands for creating geometric results displays
| Command
|
GUI Menu Path
|
Purpose
|
| PLDISP
|
Main Menu>General Postproc>Plot
Results>Deformed Shape
Utility Menu>Plot>Results>Deformed Shape
|
Display displaced shapes
|
| PLESOL
|
Main Menu>General Postproc>Plot
Results>Element Solu
Utility Menu>Plot>Results>Contour Plot>Elem
Solution
|
Display contours of results,
discontinuous across element
boundaries
|
| PLETAB
|
Main Menu>General Postproc>Element
Table>Plot Elem Table
Main Menu>General Postproc>Plot
Results>Elem Table
Utility Menu>Plot>Results>Contour Plot>Elem
Table Data
|
Display contours of element
table data
|
| PLLS
|
Main Menu>General Postproc>Plot
Results>Line Elem Res
|
Display element table items
along line elements and 2-D
axisymmetric shell elements
|
| PLNSOL
|
Main Menu>General Postproc>Plot
Results>Nodal Solu
Utility Menu>Plot>Results>Contour
Plot>Nodal Solution
|
Display continuous results
contours
|
| PLTRAC
|
Main Menu>General Postproc>Plot
Results>Plot Flow Tra
Utility Menu>Plot>Results>Flow Trace
Main Menu>General Postproc>Plot
Results>Particle Trace
Utility Menu>PlotCtrls>Animate>Particle Flow
|
Display particle flow or
charged particle trace
|
| PLVECT
|
Main Menu>General Postproc>Plot
Results>Predefined
Main Menu>General Postproc>Plot
Results>User-defined
Utility Menu>Plot>Results>Vector Plot
|
Display solution results as
vectors
|
| /REPLOT
|
Utility Menu>Plot>Replot
|
Re-executes the last display
action that executed
|
In Figure 12-2, a typical geometric results display (in this example, created with a
PLNSOL command) illustrates the kinds
of information included in such displays.
Figure 12-2 A typical ANSYS results plot
12.3 Changing the Specifications for POST1
Results Displays
Besides reading about the features listed below, also see Chapter 8 for
general graphics specifications that you can apply to any kind of display, including
geometric results displays.
12.3.1 Controlling Displaced Shape Displays
You can control displaced shape displays in two ways:
- By superimposing undisplaced and displaced shapes. A display of a
structure's displaced shape will often be more meaningful if you can
compare the displaced configuration against the original configuration. You
can do this by using the KUND argument on the PLDISP command.
- By multiplying displacements for distortion displays. In most
small-deformation structural analyses, the displaced shape is hard to
distinguish from the undisplaced shape. The program automatically
multiplies the displacements in your results display, so that their effect will
be more readily apparent. You can adjust this multiplication factor, using
the /DSCALE command (Utility
Menu>PlotCtrls>Style>Displacement Scaling). The program interprets
exactly zero values of this multiplier (DMULT = 0) as the default setting,
which causes the displacements to be scaled automatically to a readily
discernible value. Thus, to obtain "zero" displacements (that is, an
undistorted display) you must set DMULT = OFF.
12.3.2 Controlling Vector Symbols in Your Results Display
You have two options for controlling vector symbols:
- Displaying nodal or reaction force symbols. You can add arrow symbols
representing nodal and reaction forces (and moments) to your results
display with the /PBC command
(Utility Menu>PlotCtrls>Symbols).
- Vector length scaling. You can control the lengths of vector symbols (such
as are displayed by PLVECT or /PBC) with either of the following:
Command(s):
GUI:
Utility Menu>Plotctrls>Style>Vector Arrow Scaling
12.3.3 Controlling Contour Displays
When light-source shading is on, the colors shown in the contour legend will not
exactly match the contour colors used in the shaded model display. You can
manipulate contour displays in the following ways:
- Labeling contours. In both vector and raster mode, your contours will
always be automatically color-coded. In vector mode, you can add
alphabetic contour labels (and a contour legend), using the /CLABEL command (Utility
Menu>PlotCtrls>Style>Contours>Contour Labeling). In raster mode,
/CLABEL will add (or remove) the
contour legend.
- Controlling the contour legend. Sometimes, lengthy text in the legend
column can cause part of the contour legend to be truncated. You can
make more room available for the contour legend by issuing /PLOPTS,LEG1,0 (Utility
Menu>PlotCtrls>Window Controls>Window Options). To remove the
contour legend from the legend column, issue /PLOPTS,LEG3,0.
- Changing the number of contour labels. In vector mode, if you apply
contour labels, they will, by default, appear in every element crossed by a
contour line. You can use /CLABEL to control the number of
alphabetic contour labels per element.
- Changing contour colors. To change the contour colors used in your
display, use the stand-alone CMAP program to create a new color-map
file. (See Chapter 17 for more information.) Then, in the ANSYS
program, use one of the following to read the new color-map file:
Command(s):
GUI:
Utility Menu>PlotCtrls>Style>Colors>Load Color Map
To restore color to contours that are grayed out, issue the command /NUMBER,0.
- Changing isosurface colors. Using the ISURF label in the /COLOR command (Utility
Menu>PlotCtrls>Style>Colors>color type) enables you to change
isosurface colors.
- "Inverting" (or reversing) the contour colors. By default, the ANSYS
program displays the algebraically greatest results values with a bright red
contour color, and the algebraically lowest values, with a blue contour color.
In some cases, you may want to invert this order. The CMAP program has
a "reverse" feature that enables you to create a reversed color-map file
easily. In the ANSYS program, you can then read that reversed color map
file into the database with the /CMAP command.
- Changing the contour interval. To change the contour interval on your
results display, either issue the /CVAL
command or the /CONTOUR
command or use one of these GUI paths:
GUI:
Utility Menu>PlotCtrls>Style>Contours>Non-uniform Contours
Utility Menu>PlotCtrls>Style>Contours>Uniform Contours
These commands change the range of values displayed in contour
displays. /CONTOUR produces
uniform contour intervals, while /CVAL produces specified contour
values (which need not be uniform). If you issue both commands, the
program uses the last one specified. For related information, see Section
12.3.4.
- Topographic contour displays. You can transform "flat" contour results
displays into "three-dimensional" topographic displays with the /SSCALE command (Utility
Menu>PlotCtrls>Style>Contours>Contour Style).
- Displaying numerical results values. To display results values at each node
in a contour display, issue /PNUM,SVAL,1 (choose Utility Menu>
PlotCtrls>Numbering).
- Turning "MN" and "MX" symbols on and off. The MN and MX symbols
identify the locations of the minimum and maximum contour values. The
MINM label on the /PLOPTS
command enables you to turn these symbols on and off.
- Producing 3-D isosurface, particle gradient, or gradient triad displays.
Isosurfaces, particle clouds, and gradient triads are tools that can help you
visualize the state of response within a 3-D solid body. By issuing the /CTYPE command (Utility
Menu>PlotCtrls>Style>Contours>Contour Style), you can change your
contour displays to one of these three styles of display.
12.3.4 Changing the Number of Contours
By default, the ANSYS program displays nine contours. To decrease (but not
increase) the number of contours, you can either issue the /CVAL command (Utility
Menu>PlotCtrls>Style>Contours>Non-uniform Contours). To change
(increase or decrease) the number of contours, you can issue the /CONTOUR command (Utility
Menu>PlotCtrls>Style>Contours>Uniform Contours). However, one or more
of the following factors can prevent ANSYS from displaying more than nine
contours:
- The device name.
- Whether the display is directed to the screen or to a file.
- The display mode (vector or raster).
- The number of color planes.
Any of these factors can override the number of contours you specify via /CONTOUR. You control these factors
using either the /SHOW command (Utility
Menu>PlotCtrls>Device Options).
The paragraphs below explain how device name, display mode, etc. limit the
number of contours available to you:
| Driver
|
Contour Display
|
The X11 driver
(screen display)
and raster mode
|
You can display a maximum of nine contours, no matter how many
contours the /CONTOUR command
specifies.
|
The X11 driver
(screen display)
and vector mode
|
You can display more than nine contours, but the number of contours
displayed will be rounded down to the next lowest multiple of nine. For
example, if you specify 20 contours, the program displays only 18
contours. In addition, if you specify more than nine contours, contour
colors will not be unique (that is, you might have two or more adjacent
contour lines with the same color).
|
The X11C driver
(screen display) in
either vector or raster
mode
|
If eight graphic planes are available, you can specify any number of
contours, up to 128. If your display device does not support eight graphic
planes, you are limited to displaying nine contours.
If another process has used some of the colors, making fewer than eight
graphic planes available, you cannot display more than nine contours. (To
verify how many graphic planes are available, issue the /PSTATUS command after a
plot command.) To make more graphic planes available, you must exit
from the ANSYS program, re-enter, and then issue the /SHOW,X11C-FORC to force
selection of the full set of eight graphic planes.
|
| Plotting to an ANSYS
neutral graphics file
|
Nine contours are the maximum, unless you specify the contour range
(using VMIN and VMAX in the /CONTOUR command), or
unless you explicitly set NCPL to 8 on the /SHOW command).
|
Note-If the current ANSYS graphics are not displayed as Multi-Plots (Utility
Menu>Plot>Multi-Plots), then the following is true:
If the current device is a 3-D device [/SHOW,3D], the model contours in all
active windows will be the same, even if separate /CONTOUR commands are issued
for each active window.
For efficiency, ANSYS 3-D graphics logic maintains a single data structure
(segment), which contains precisely one set of contours. The program
displays the same segment in all windows. The view settings of each
window constitute the only differences in the contour plots in the active
windows.
12.4 Q-Slice Techniques
Q-slicing is a technique you can use to query the interior or your model via slice
planes. To implement Q-slicing, change the hidden surface type to Q-slice using
either of these methods:
Command(s):
GUI:
Utility Menu>PlotCtrls>Style>Hidden-Line Options
By default, the slice plane is perpendicular to the view and is positioned at the
focus point. You can set the slice plane via the GUI path shown above or by using
the /CPLANE,1 command.
To position the working plane, you can use either of these methods:
- Choose Utility Menu>WorkPlane>Align WP with>Keypoints.
- Click on the dynamic mode button in the Offset WP menu. To access this
menu, choose Utility Menu>WorkPlane>Offset WP by Increments.
You can animate Q-slices. To do so, choose either of these GUI paths:
GUI:
Utility Menu>PlotCtrls>Animate>Q-Slice Contours
Utility Menu>PlotCtrls>Animate>Q-Slice Vectors
12.5 Isosurface Techniques
Isosurface displays are surfaces of constant values (for example, stress). To
obtain an isosurface display of Von Mises stress, perform these steps:
1. Issue the command /CTYPE,1
(Utility Menu>PlotCtrls>Style> Contours>Contour Style).
2. Issue the command PLNS,S,EQV (Main Menu>General Postproc>Plot
Results>Nodal Solu).
You can animate isosurfaces. To do so, either invoke the ANISOS macro (Utility
Menu>PlotCtrls>Animate>Isosurfaces).
12.6 Controlling Particle Flow or Charged
Particle Trace Displays
You can produce graphic displays of how a particle travels in a flowing fluid or how
a charged particle travels in an electric or magnetic field. See Chapter 5
for more information on graphic displays and see Chapter 15 for
information on particle trace animation. See Chapter 15 of the ANSYS Theory
Reference for simplifying assumptions on electromagnetic particle tracing.
To produce particle flow or charged particle trace displays, use either of the
following:
Command(s):
GUI:
Main Menu>General Postproc>Plot Results>Plot Flow Tra
Utility Menu>Plot>Results>Flow Trace
Main Menu>General Postproc>Plot Results>Particle Trace
Utility Menu>PlotCtrls>Animate>Particle Flow
Such displays require you to select the trace points by number or by picking. To
select points, use either method shown below:
Command(s):
GUI:
Main Menu>General Postproc>Plot Results>Defi Trace Pt
You can list or delete these points using the commands shown below:
Command(s):
GUI:
Main Menu>General Postproc>Plot Results>List Trace Pt
Command(s):
GUI:
Main Menu>General Postproc>Plot Results>Dele Trace Pt
Use either of the following to animate the particle flow or charged particle trace to
a specified elapsed time.
Command(s):
GUI:
Main Menu>General Postproc>Plot Results>Time Interval
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