Acoustics Tutorials
Function Filter on Data Sources TutorialObjective:The goal of
this tutorial is to explain the use of the Function Filter on the
Data sources of a function set to eliminate unwanted functions, and
keep only useful or needed functions for the analysis.
Acoustics Tutorials Function Filter on Data Sources Tutorial BEM
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Prerequisites:Software Configurations and Options that are
needed to run the tutorial: Configuration: Desktop
Tutorial Data Files:LMS CADA-X project 'AR' (5 files: AR.idx,
AR.mtx, ar.ix0, ar.ix1, ar.dat) [All data files can be found on the
Windows-DVD, on LMSGETTSTDataVAM-Tutorial-DataMODSubframe. For ease
of use, it is best to copy all files to a local folder.]
Step-by-Step Tutorial:Step 1 of 4: Import Transfer Functions
from CADA-X We will first import the transfer functions from the
CADA-X project. 1. Start LMS Virtual.Lab, select: Start Noise &
Vibration System Analysis from the main menu bar. Transfer Function
Set. The Transfer Function Set
A new document will be created. 2. Select Insert Function Sets
Definition dialog will appear.
3. Keep the default settings and click the OK button. This will
insert a Transfer Function Set.1 feature in the Specification Tree.
4. Expand the Transfer Function Set.1 feature in the Specification
Tree, and right click on the Data sources feature and select Add a
Data File from the contextual menu. Open a Data Source window will
open. 5. Select the file type LMS CADA-X Project (*.idx). Browse
for the folder where the CADA-X project, ar can be found. Select
the file AR.idx.
6. Click the Open button. The File Data Source window will
appear. 7. Keep all tests in the Selected Subcases/Tests in the
list. Check the Create Input and Output Points in this dialog
box.
8. Click the OK button. The transfer functions and the IO Points
are added under the Transfer Function Set.1. Step 2 of 4:
Investigate the Transfer Function Set In this step we will find out
which transfer functions are available in the Data Sources. 1.
Double-click the Transfer Function Set.1 feature in the
Specification Tree. The Transfer function Set Definition window
opens.
2. For this exercise, we are not interested in the
Velocity/Force transfer functions. Select Velocity under the Output
Physical Types. Click the Remove button under the Output Physical
Types. This removes Velocity from the Output Physical Types field.
Click the OK button. This will remove the corresponding IO Points
Set from under the function set. 3. Expand the Transfer Function
Set.1 in the Specification Tree, and right click the Data sources
LMS CADA-X Project AR.idx feature and select List Functions from
the contextual menu. This will open the List of Functions in
Database dialog which shows a list of all 252 transfer functions in
the file. Other functions than transfer functions (like loads or
coherence functions) will not be shown because the file is attached
to a Transfer Function Set.
4. Click the Close button. 5. Right-click on the Transfer
Function Set.1 feature and select Check Transfer Function Set
Status from the contextual menu. 632 functions are shown as
missing.
6. Click the Close button. 7. Right-click the Transfer Function
Set.1 feature and click New Function Display from the contextual
menu. The New Function Display dialog will appear.
8. Select Check transfer Function Set Status and click the
Finish button. The graph window opens. 9. For each of the different
Output Physical types, you can have an overview of the available
and missing transfer functions for all relevant IO Points.
Right-click on the graph select Views Top from the contextual menu.
10. The top view is shown as follows:
11. Close the graph. Step 3 of 4: Define the Function Filter In
this step, we will use the capability of Add Function Filter so
that we keep only the following transfer functions:
The one of type Acceleration/force% %
For input/excitation points on the "bar" component Of test
section "Impact01"
1. Right-click the Data Sources feature and select Add Function
Filterfrom the contextual menu. This opens the dialog box for
Function Filter. The title window frame shows that we start with
252 functions:
2. First filter out the transfer functions that are not
Acceleration / force. For this select the other ones, and move them
to the rejected list. Set the Matching fields as follows:
3. Click the Apply Matching button. Then click the
button.
4. Now keep only the FRFs for excitation points on component
bar. Set the Matching fields as follows:
5. Click the Apply Matching button. This selects the functions
that we want to keep, not reject. 6. Now click the Invert Selection
button. Then push the button.
7. The manual operation of inverting the selection has broken
the associativity, as indicated in the window title frame (see Add
Function Filter for more details):
8. But for this exercise, we want to keep the associativity.
Click the Undo button. 9. Use the negative logic so that the
associativity is not broken. Select any one of the two
possibilities given below:
OR 10. Click the Apply Matching button. Then click the
button.
11. Inspect the list of 57 Kept records. You will see that there
are only two FRFs for excitation point bar:20: +X, at the bottom of
the list. You can select these manually with the mouse to reject
them, but this would again break the associativity. You can use one
of the following settings to select them:
OR 12. Click the Apply Matching button. Then click the 13. Close
the Function Filter dialog box. Step 4 of 4: Check the Transfer
Function Set
OR button. This will keep 55 functions.
In this step we will check the transfer functions that are
available, now that we have applied the filter on the functions. 1.
Double click the Check Transfer Function Set Status Matrix Display
feature. The graph window opens. Note: this feature is not changed
by the function filter operations, since it still checks the
availability of functions for all of the IO Points in the Transfer
Function Set. These IO Points have not changed by applying the
Function Filter. 2. Close the graph. 3. Right-click on the Transfer
Function Set.1 feature and select Regenerate IO Points from the
contextual menu. The Feature Selection dialog will appear.
4. Check Remove Existing Points and Create Input and Output
Points in the intermediate dialog box.
If you don't get this intermediate dialog box, go to Tools
Options, section General, tab Data Source, and
un-check:
5. Click the OK button. 6. Again double-click the Check Transfer
Function Set Status Matrix Display feature. 7. Right-click on the
graph and select Select Data. This will now show that no functions
are missing.
If the function filter stays associative (check the window title
frame to be sure), then the same filtering operation will be
applied even when the source file is updated. In the above example:
if the CADA-X user moves transfer functions from one test section
to another, or adds transfer functions for another excitation point
(e.g. "acc:24:+Z"), the Transfer Function Set will still expose the
same 55 functions. 8. Right-click Input points [Force] and select
Create Single IOPoint New IOPoint from the contextual menu. The
Single Node IOPoint Definition dialog will appear. 9. Fill in the
details as shown below:
10. Double-click the Function Filter feature. The Function
Filter dialog will still show that 55 functions are kept.
11. Close the graph. This ends the tutorial on using a function
filter on a function set. Note: More complex filter operations are
possible. You can also use Wildcards to define such complex filter
operations (see Add Function Filter for more details). A few
examples are given below.%
To match only response points 5 through 12 on component bar:
%
To not match half orders (in loads):