Identification of unstable modes caused by self-induced vibration
Challenge: Display output of self-induced vibration clearly to analyze the phenomenon
It is not easy to find countermeasures to improve self-induced vibration caused by a frictional phenomenon, even if the phenomenon is simulated by MSC Nastran transient response (time history response) analysis.
Therefore, in general, it is necessary to conduct complex eigenvalue analysis and display its outputs clearly to study the phenomenon.
Additionally, it takes significant amount of man-hour to analyze the phenomenon.
How to resolve pains:
Applying ESTECH.Squeal displays the following output from MSC Nastran complex eigenvalue analysis.
- Complex plane plots of complex eigenvalues
- Contribution ratio distribution plots of real eigenvalue modes vs. complex eigenvalue modes
- Eigenvalue shift plots due to changes in friction coefficient
- Instability index (Squeal Index) plots
By plotting contribution ratio distribution of each real eigenvalue modes to the complex eigenvalue modes, modes and parts of a structure to be fixed can be identified.
The instability index helps to understand tendency to occur self-induced vibration and its generating factors.
ESTECH.Squeal mainly applies to brake squeal phenomenon but it is also applicable to self-induced vibration caused by continuous sliding of parts.
Strength of the Software
- Designer by himself/herself is able to do design study to find its direction because the software generates the plots form the output of MSC Nastran automatically.
