Create and view contour plots by selecting various scales, grids, and
grid IDs for the specified Structure or Fluid grid participation.
Load Files and Select Result Options
From the NVH-Utilities > Grid Participation tab, click the Load sub-tab.
Under File selection, use the file browsers to select the file(s) that you
would like to load.
Option
Description
Result
Select the result file using the file browser
(.h3d, .pch,
.res, or .op2).
Attention: A PCH file cannot be read directly into HyperView, therefore it has to be converted
into the RES format. The translation process includes running a
special version of HMNast to convert the PCH file into the RES file,
which is then used for plotting.
Cavity
Select the model file which contains the solid elements for the
cavity (.fem, .dat, or
.bdf).
Note: This file is not required if an
OptiStruct.h3d or Nastran (MSC).op2 file is loaded into the Result file
field.
Structure
Select the model file which contains the solid elements for the
structure (.fem, .dat, or
.bdf).
Note: This file is not required if an
OptiStruct.h3d or Nastran (MSC).op2 file is loaded into the Result file
field.
Interface
Select the model file which contains the elements on the interface
of the cavity and structure interaction (.interface).
Note: This file is
not required if an OptiStruct.h3d or Nastran (MSC).op2 file is loaded into the Result file
field.
Click the Load button to load the files designated in
the File selection section of the tab.
Upon reading the file, the Result selection fields are populated (see
below).
Under Result selection, select the options that will be used to investigate the
participations.
Option
Description
H3D output
The H3D output option.
Contour = Yes
The grid participation results are output in a format that
is ready for contouring (which reduces the amount of
processing required for HyperView).
Contour = No
The grid participation results are output in a raw,
unprocessed format.
Subcase
Displays the various subcases and their scale types available for
selection from the drop-down menu - (s) indicates a scalar-type result,
(c) indicates complex results, (t) indicates a tensor-type result, and
(v) indicates a vector-type result.
Note: There is a Fluid Grid ID raw
data result type generated by OptiStruct
which can also be viewed by using the various options in the Contour
panel.
Response ID
Grid ID of the response for which Grid participation results are
available. Select one from the drop-down menu.
Response label
(optional)
Enter a label that describes the response, for example
"Driver’s Ear".
Result set
Select either a Structure Grid Participation
plot or a Fluid Grid Participation plot.
Click the Display Options button to customize the plot,
including scale, weighting, and the plot layout.
The Display Options dialog is displayed.
Click the Load Response button to apply the grid
participation plot in the modeling window.
Figure 1. A Response Study Example
The response study is meant to accomplish two goals:
Find the upper limit of the selected nodes’ impact on the response. If
it is too small, you may decide not to bother with optimizing the local
structure there.
Identify the impact of the selected nodes over the entire frequency
range analyzed. This is beneficial because it is often the case in
solving NVH problems that improvement in one frequency is accompanied by
degradations at others. Therefore, knowing the impact over the whole
frequency ranges helps you to ensure that the solution created by
modifying the structure at the selected nodes is a good overall
solution.
See the HyperGraph User's Guide for
additional information on plotting.
Display a Grid Participation Contour Plot
From the NVH-Utilities tab, click the Display
sub-tab.
Note: To activate this tab, you must first load a file from the Load tab.
Select an option from the Direction component drop-down menu.
Option
Description
X
Grid participation results from the X component of grid
vibration.
Y
Grid participation results from the Y component of grid
vibration.
Z
Grid participation results from the Z component of grid
vibration.
Sum of XYZ
Arithmetic sum of the grid participation results from the X, Y, and
Z components of grid vibration.
Select an option from the Complex component drop-down menu.
Option
Description
Projected
Complex grid participation results are first projected to the
response, and the resulting scalar values are then contoured.
Real
Real parts of the complex grid participation results are
contoured.
Imaginary
Imaginary parts of the complex grid participation results are
contoured.
Magnitude
The magnitudes of the complex grid participation results are
contoured.
Phase
The phases of the complex grid participation results are
contoured.
Select an option from the Frequency option drop-down menu.
Option
Description
Specific frequency
Select a specific frequency to contour grid participation
results.
Sum of frequencies
Select multiple frequencies and sum the results corresponding to
these frequencies to generate one contour plot.
Select an option from the Sum by option drop-down menu.
Option
Description
Arithmetic
Select how grid participation results from different frequencies are
to be summed together to generate one contour plot.
Select an option from the Frequency weighting option drop-down menu.
Option
Description
A
Use to scale sum grid participation results from different
frequencies. 'A weighting' is used to define equal loudness sound
pressure levels.
Equal
Use to sum grid participation results from different
frequencies.
Select frequencies from the Frequency List which will be included in the sum
response.
Tip: Use the Display All, Display None, or Reverse Display buttons
(located on the right side of the list) to quickly select/deselect
frequencies.
Click the Display Options button to customize the plot,
including scale, weighting, and the plot layout.
The Display Options dialog is displayed.
Once the result selection options and display options are complete, click
Display to apply the fluid or structure grid
participation contour plot to the model.
This will allow you to look for the particular area of the structure which has
the most positive (in-phase) contributions and also the area that has the most
negative (out-of-phase) contributions. You can then effectively reduce the
acoustic response at a grid point by reducing the vibration/contribution coming
from the positive/in-phase area, or by increasing the vibration/response in the
negative contribution area.
In addition, you can also view and move through
the various frequencies from the grid participations (in order to determine
the positive and negative contributions) by clicking on the various
frequencies located in the Frequency List.
You can then apply
additional fluid or structure grid plots, using log or linear or linear
scale types, in order to isolate the most significant areas (see the example
below): Figure 2. The change in vibration results in reduced Structure
participation and Fluid participation
Perform a Partial Grid Sum or Phaseless Sum Response Study
From the NVH-Utilities tab, click the Study
sub-tab.
Note: To enable this option, you must first load a grid participation contour
plot.
Under Response studies, enter in your custom frequency band in the
Frequency Range: 3.00 Hz to 203.00 HzFrom and To fields.
The frequency indicates the available range, based on the file loaded.
Select the type of response study from the Type drop-down menu.
Option
Description
Partial grid sum
Select a number of grids to exclude from the partial sum response,
with an optional percentage to exclude.
Phaseless sum
Participation results from various grids are summed based on the
magnitude only (without considering phase). Normally, both magnitude and
phase are taken into consideration when grid participations are summed
to calculate the response.
Optional: In the % to exclude field, enter the percentage of the
contributors that you would like to exclude from the response.
Select an option from the Sum by drop-down menu.
Option
Description
Arithmetic sum
Participation results from various grids are summed based on the
arithmetic sum of the complex grid participation.
Magnitude RSS
Participation results from various grids are summed based on the
root sum of squares of the magnitude of the complex grid
participation.
Under Select grids to exclude, select the grid that you would like to exclude
from the response study by selecting nodes.
Activate the Node input collector and pick an nodes directly from the
model in the modeling window.
The model is animated with respect to the selected entity. A new node can be
defined and tracked at any time during animation by picking different nodes in
the modeling window.
Select an option from the Show difference curve as drop-down menu.
Option
Description
% of Response
Plot the difference curve using a percentage of response scale and a
new axis on the right hand side of the plot.
Scale same as Response
Plot the difference curve using the same scale as the one used to
plot the response and a new axis on the right hand side of the
plot.
Click the Display Options button to customize the plot,
including scale, weighting, and the plot layout in the Display Options
dialog.
Once your selections are complete, click Display to
display the response study plot.
Note: See the HyperGraph User's Guide for additional
information.
Grid Participation - Display Options Dialog
The Display Options dialog allows you to customize the response plot using various
display and scaling options.
Figure 3. Load Tab and Study Tab - Display Options Dialog Figure 4. Display Tab - Display Options Dialog
The following options are available:
Display
The following options are available from the Display
drop-down menu:
Do not show phase
Hides the phase values on the plot.
Show phase
Displays the phase values on the plot.
Single perspective view
Attention: Available for the Display Tab
only.
Displays a contour plot using only the isometric perspective.
Multiple perspective view
Attention: Available for the Display Tab
only.
Displays multiple contour plots using the isometric, top, and bottom
perspectives.
Scale
Displays the scale types available.
Be sure to
review the various scaling types in order to determine which type gives you the
best spatial location of the contributions.
For example, the Linear scale
type is not very useful when looking at a Structure grid participation (the very
localized red contributions displayed on the model) because it makes it
extremely difficult to see the contributions. In many instances this
contribution can be concentrated at one single point, and if there is only one
grid contributing, then you essentially will not be seeing a very clear picture
of where it is contributing. If that is the case, you will need to use another
kind of scaling in order to make the area larger so that you will actually see a
patch of the surface that contributes. You therefore want to find a scaling type
which localizes the contribution without making the area too small to easily
locate.
Note: The Log extreme scaling versions are available for review
(essentially everything on the model is displayed in red or blue); however
these results are usually not very useful because they show that everything is
equally effective in fixing the problem.
Linear
Plots the linear values.
Logarithmic
Plots the values in logarithmic scale. With this scale, data points are
spread out more, which makes it easier to view.
Log 0.1
Attention: Available for the Display Tab
only.
Logarithmic scale with a reference value of 0.1.
Log 0.01
Attention: Available for the Display Tab
only.
Logarithmic scale with a reference value of 0.01.
Log 0.001
Attention: Available for the Display Tab
only.
Logarithmic scale with a reference value of 0.001.
Log 0.0001
Attention: Available for the Display Tab
only.
Logarithmic scale with a reference value of 0.0001.
% Plot
Plots the contribution of the selected modes as a percentage of the total
response. Percentage plot is a good option to use when comparing contributors
versus the total response.
dB10
10 logarithmic of the participation value over the reference value.
dB20
20 logarithmic of the participation value over the reference value. For
acoustic responses, the reference pressure is 20E-12 MPa.
Weighting
Select a weighting option from the drop-down menu:
A
B
C
U
A, B, C, and U-weighting are used to define equal loudness sound pressure
levels.
Unit
Activate the Unit check box and make selections from
the following drop-down menus:
Time (s, ms)
Length (mm, m, ft, km, mile, inch)
Force (N, KN, lbf)
Plot Layout
Select how the plot window will appear.
New windows on current page
Plot is placed into a new window on the current page.
