Reviewing Your Model
Importing Vibration Results
You can import a previously generated results file and attach it to a vibration analysis. This enables you to plot vibration data generated from the eigen and state matrices in the results file. The imported results file and the vibration analysis must be from the same model.
To import vibration results:
1. From the Vibration menu, point to Review, and then select Import Vibration Results.
2. Complete the dialog box as described in Importing Vibration Results.
3. Select OK.
Displaying Eigenvalues
The Eigenvalue table displays the eigenvalue of a given analysis.
To display eigenvalues:
1. From the Vibration menu, point to Review, and then select Display Eigenvalue Table.
2. Complete the dialog box as described in Eigen Information.
3. Select OK.
Displaying Modal Information
In the Modal Information Table dialog box, you can view the Modal Coordinates, Modal Participation, or Modal Energy table and Marker Mode Shape table. The Modal Coordinates and Modal Participation tables are always available when a forced vibration analysis is performed. The Modal Energy table and Marker Mode Shape table is available when modal energy computation is turned on before performing a forced vibration or normal mode analysis.
To display modal information:
1. From the Vibration menu, point to Review, and then select Display Modal Info Table.
2. Complete the dialog box as described in Modal Information.
Note: | You can display the same modal information from Adams PostProcessor by selecting the Modal Info button in the dashboard. |
Animating Your Results
Adams Vibration supports animation of three types of analysis:
2. Normal Modes
Animating Forced Vibration Analyses
For general information on animating, see the Adams PostProcessor online help.
To animate a forced vibration analysis:
1. Display the Adams PostProcessor in Animation mode.
2. Right-click the animation window, and then select Load Vibration Animation.
3. From the Database Navigator, select the vibration analysis you want to plot.
4. Select Forced Vibration Animation.
5. Specify values as described in Animation Dashboard - Vibration Animation.
6. Select the Play tool.
Animating Normal Modes Analyses
You can animate the model to inspect and relate mode shapes with mode numbers. Remember, doing a normal modes animation outside of Adams Vibration is called a frequency-domain animation. So, if you’re referring to the online help for Adams PostProcessor for more information on normal modes animation, read the sections on frequency-domain animations.
To animate a normal modes analysis:
1. Display Adams PostProcessor in Animation mode.
2. Right-click the animation window, and then select Load Vibration Animation.
3. From the Database Navigator, select the vibration analysis you want to display.
4. Select Normal Mode Animation.
5. Specify values as described in Animation Dashboard - Vibration Animation.
6. Select the Play tool 
.
.Animating Operating Deflection Shape Analyses
You can animate the operating deflection shape of transient simulations. Part Frequency Response Functions (FRF) are created of the time-based simulation to view operating deflection shapes at a specified frequency. Before you can animate you have to create an ODS Analysis
To create an ODS analysis:
1. Run a time-based simulation if one does not exist
2. Load Vibration plugin and Select Vibration – Create ODS Analysis to create an ODS analysis if one does not exist for the time-based solution of interest
3. From the Database Navigator, select the time-based simulation you want to perform an ODS analysis on.
4. Specify values as described in Operational Deflection Shape Analysis dialog box.
To animate an ODS analysis:
1. Display Adams PostProcessor in Animation mode.
2. Right-click the animation window, and then select Load ODS Animation.
3. From the Database Navigator select the ODS analysis you want to display.
4. Specify values as described in Animation Dashboard - Vibration Animation.
5. Select the Play tool .
.Plotting Your Results
Plotting Adams Vibration Output in Adams PostProcessor
To perform a complete vibration analysis, you first pre-process your model using Adams View and Adams Car. Then, you use Adams Vibration to set up and perform vibration analysis. Finally, you post-process the results using Adams PostProcessor. Post-processing involves animating forced vibrations and plotting frequency response functions, generating modal coordinates tables, and displaying other time and frequency data (see table below).
Note: | Doing a normal modes animation outside of Adams Vibration is called a frequency-domain animation. So, if you’re referring to the Adams PostProcessor online help for more information on animation, read the sections on frequency-domain animations. |
Note: | Adams PostProcessor displays charts using three types of transformations: linear (no transformation of the displayed values), logar (logarithmic transformation of the displayed values), or dB (decibel transformation of the displayed values.) When using the dB option, the formula: db = 20*log10( x ) is used to transform the value of 'x'. |
You can validate Adams Vibration results using Adams PostProcessor. Using Adams PostProcessor you can plot several key pieces of data, including:
■3D
The following table outlines how you can view Adams Vibration results:
Vibration Results: | View as: |
|---|---|
System Modes | Complex Scatter Normal Modes Animation Forced Vibration Animation |
PSD | Plots |
Frequency Response | Plots |
Modal Coordinates | Plots and Tables |
Modal Participation Factors | Plots and Tables |
Transfer Function | Plots |
Modal Energy Distribution | Tables |
Vibration Animation | Normal Modes Animation Forced Vibration Animation ODS Animation |
For general information plotting, refer to the online help for Adams PostProcessor.
Plotting Operational Defection Shape (ODS) Data
You can generate X-Y plots of ODS data or other types of frequency =based data such as auto spectrum, cross correlation, and transfer function.
To plot ODS data:
1. Display Adams PostProcessor in Plot mode.
2. Load the Vibration plugin if not loaded
3. Select the Plot → Operational Deflection Shape menu option
4. Specify values in the Operational Deflection Shape Plot dialog box.
Plotting in Three Dimensions
You can generate three-dimensional plots of frequency response functions (FRF) in the Adams Vibration postprocessing environment. This feature enables you to show multiple FRFs from a Design study in frequency domain within the same three-dimensional plot, and better visualize the effect of a design change on the frequency response function. The three-dimensional plots feature allows additional complex representations of results. For example, plot FFTs of a time domain signal obtained with different windowing parameters and display them in a waterfall format.
To plot frequency response in three dimensions:
1. In Adams PostProcessor, set the pulldown menu located in the menu bar below the File menu to Plot3D.
2. In the Vibration Analysis text box, select all analyses you wish to include in your plot.
3. Select your input channels.
4. Select your output channels.
5. Select Add Surface to create the three-dimensional plot.
For more information on setting the display of three-dimensional plots, see Controlling the Display of Three-Dimensional Plots.
Plotting Frequency Response
You can plot the frequency response, change the scale for plotting, and split the Adams PostProcessor plotting window to compare plots of frequency response functions to see the phase shift.
To plot the frequency response:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to Frequency Response.
3. From the Vibration Analysis list, select the vibration analysis you want to plot.
4. From the Input Channels list, select the input channels you want to reference.
5. From the Output Channels list, select the output channels you want to reference.
6. Select one of the following:
♦Use Individually: Computes and displays a curve for each selected input channel/output channel pair.
♦Sum All Input Channels: Computes and displays a curve for each output channel selected. The curve is the sum of the response for all the input channels.
♦Sum Selected Input Channels: Works like Sum All Input Channels, but only uses the selected inputs.
7. Select Add Curves.
Adams PostProcessor plots the frequency response in the default scale (dB).
8. To plot the phase angle of the response, select Phase.
Learn more about Frequency Response.
To change the scale for plotting the frequency response:
1. Right-click the horizontal axis of the plot, point to Axis: haxis, and then select Select. (This selects the horizontal axis.)
2. Set the Scale to Logar, dB, or Linear.
Note: | If you change the axis limits, the upper and lower limits will have different meanings. For example, in the logarithmic scale, the limit values are the exponent. So, if the values are 2 and 3, the limits are 102 and 103 or 100 and 1000, respectively. In a linear scale, values of 2 and 3 actually mean limits of 2.0 and 3.0, respectively. |
3. Right-click the vertical axis of the plot, point to Axis: vaxis, and then select Select.
4. Set the Scale to either Logar, dB, or Linear.
To split the Adams PostProcessor plotting screen:
■Right-click the Page Layout tool 
, and select the 2 Views-over & under tool 
.
, and select the 2 Views-over & under tool .The plotting area of the screen splits into two plots, one containing the frequency response plot, and the other containing a blank plot. You can then create a new plot in the blank region.
Plotting Modal Coordinates
To plot modal coordinates:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to Modal Coordinates.
3. From the Vibration Analysis list, select the vibration analysis you want to plot.
4. From the Input Channels list, select the input channels you want to reference.
5. Set Modal Coordinates By to one of the following:
♦Mode - How the modal coordinate value changes with frequency.
♦Frequency - What modal coordinates are active at a frequency.
6. Complete one of the following:
♦If you selected Mode, select the mode whose coordinate value you want to plot.
♦If you selected Frequency, select the frequencies at which coordinates are to be plotted.
7. Select Add Curves.
Learn more about Modal Coordinates.
Plotting Modal Participation
Modal Participation is the absolute contribution of model modes to the transfer function for the model.
To plot modal participation:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to Modal Participation.
3. From the Vibration Analysis list, select the vibration analysis you want to plot.
4. From the Input Channels list, select the input channels you want to reference.
5. Select the mode whose participation value you want to plot.
6. Select Add Curves.
Plotting Power Spectral Density (PSD)
To plot PSD:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to PSD.
3. From the Vibration Analysis list, select the vibration analysis you want to plot.
4. From the Output Channels list, select the output channels you want to reference.
5. Select Add Curves.
Learn more about Power Spectral Density (PSD).
Plotting System Modes
To plot system modes:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to System Modes.
3. From the Simulation list, select the simulation you want to plot.
4. From the Eigen list, select the Eigen you are interested in examining.
5. Select Add Scatters.
To display a table of eigenvalues next to your scatter plot:
1. Split the plotting area by selecting the Page Layout: 2 Views, side by side tool 
.
. 2. Right-click the left view, and then select Load Vibration Animation.
3. Select Table of Eigenvalues.
4. Select Save to File and save as eigen.txt.
5. Right-click the right view, and then select Load Report.
6. Select eigen.txt.
Plotting Transfer Function
You can plot the transfer function, change the scale for plotting, and split the Adams PostProcessor plotting window to compare plots of frequency response functions to see the phase shift.
To plot the transfer function:
1. Display Adams PostProcessor in Plotting mode.
2. Set Source to Transfer Function.
3. From the Vibration Analysis list, select the vibration analysis you want to plot.
4. From the Input Channels list, select the input channels you want to reference.
5. From the Output Channels list, select the output channels you want to reference.
6. Select Add Curves.
Adams PostProcessor plots the transfer function in the default scale (dB).
7. To plot the phase angle of the response, select Phase.
To change the scale for plotting the transfer function:
1. Right-click the horizontal axis of the plot, point to Axis: haxis, and then select Select. (This selects the horizontal axis.)
2. Set the Scale to Logar, dB, or Linear.
Note: | If you change the axis limits, the upper and lower limits will have different meanings. For example, in the logarithmic scale, the limit values are the exponent. So, if the values are 2 and 3, the limits are 102 and 103 or 100 and 1000, respectively. In a linear scale, values of 2 and 3 actually mean limits of 2.0 and 3.0, respectively |
3. Right-click the vertical axis of the plot, point to Axis: vaxis, and then select Select.
4. Set the Scale to either Logar, dB, or Linear.
To split the Adams PostProcessor plotting screen:
■Right-click the Page Layout tool , and select the 2 Views-over & under tool .
, and select the 2 Views-over & under tool .The plotting area of the screen splits into two plots, one containing the transfer function plot, and the other containing a blank plot. You can then create a new plot in the blank region.
Nastran Modal Export
You can export modal coordinates of flexible body in MDF file format to recover stress and strain information in MSC Nastran. You need restart run in Nastran to recover stress and strain information. In brief, first create flexible body using Nastran, then do vibration analysis in Adams on model that use this flexible body, export modal coordinates for this flexible body in MDF file format, re-start Nastran run to recover element stress and strain information.
To export modal coordinates:
1. From the Vibration menu, point to Review, and then select Nastran Modal Export.
2. Complete the dialog box as described in Nastran Modal Export.
3. Select OK.