Output & Post-Processing
NISA II/Composites offers a number of output and post-processing
options to meet individual needs. All output is interactive and can be
printed, very conveniently, from stress and displacement output
files. The user may, at his discretion, select only a few of the options
and select additional output through a restart after the
displacement solution.
Output
The following output can be selectively controlled using the print
control options of NISA II
- Nodal displacements
- Reaction forces at nodes where displacements are specified
- Element strain energy, element internal forces - and rigid
element forces
- Element centroidal strains in the orthotropic direction of each
layer
- Element stresses in orthotropic direction at Gauss points and
node
- points of each layer
- Element stress resultants in the direction of top layer at each
Gauss point and node point
- Average stress resultants in the top layer direction at each node
of the structure
- Largest magnitude of displacement vector
- Highest stresses and stress resultants in descending order of
magnitude
Post-Processing
Extensive post-processing features of DISPLAY III can be utilized to
contour and interpret the results of the analysis. Some of the
outstanding and frequently used capabilities are:
- Layer stresses
- Stress resultants
- Displacements
- Original and deformed geometry
- Stress survey plots
- Mode shapes
- Multiple load case deformed plots
Filtering the Output
Interpreting the results of a composite structural analysis can be a
cumbersome task for various reasons such as:
- The volume of stress output increased with the number of layers.
- Maximum stresses may not necessarily occur at the top, middle or
bottom surface of the shell.
- Strength of a composite lamina is direction-dependent and
stresses must be transformed into a material coordinate system,
which is different for each layer, before their significance can be
measured.
- To overcome the above difficulties, filtering of output is very
essential in composite structural analysis.
Filtering Stress Output
NISA II/ COMPOSITES incorporates a number of unique output
features. For each layer, stress components are automatically
computed in the local material axes. The stress values, including
transverse shea r components, and the ratios of actual to allowable
stresses are computed at the midsurface of each layer. The user may
choose to print all stresses and stress ratios or may specify a threshold
stress ratio and suppress printout of all stresses less than that fraction
of allowable.
In addition to filtering the stress output using the threshold stress
ratio, the output can also be filtered using the NISA II print control
options. These options may be used to control the bulk of printout for
the output quantities such as displacements, reactions, stresses,
strain, energy, etc.
Stress survey plot
A special survey plot is available which searches for the most critical
stress ratio in all layers of each element. This plot prints an integer
number, representing the most critical percentage of allowable stress
and the layer numbers in each element. Guided by a stress survey
plot, the analyst may then use the stress printout and contour plots of
layer stresses or stress resultants to examine structural response in
more detail.
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