Principal Mode Analysis for a structural model with numbers of natural modes
Challenge: Identify principal modes of a model with high density of natural mode
In the case of analysis for a large size FE model and/or in a higher frequency, it is often found difficulty to identify dominant modes to one single resonant peak because numbers of modes act on the single peak.
In addition, even though contribution ratio is obtained for the natural mode, it is not easy to analyze and find countermeasures for the phenomena since it is often hard to find outstanding modes which act on the peak.
How to resolve pains:
If the input condition is specified, it is not necessary to check up all the natural modes since dominant mode shapes for the resonant peaks are looked similar. The PMA option of ESTECH.NAST+ puts similar natural modes together and eliminates unnecessary natural modes to extract dominant mode. The dominant mode is named as "Principal Mode" which makes it easy to analyze resonant peaks of vibration.
Strength of the Software
- Simplifying the phenomenon makes it possible to understand its mechanism easily. Additionally, since strain energy of the principal mode is obtained, a specific study to improve the noise & vibration performance of a structure is the same procedure as one using natural modes.
- Even small numbers of principal modes are able to reproduce its frequency response since the principal mode is described by putting similar dominant natural modes together.
- Because of the reason mentioned above, the outstanding principal mode is identified
- Analysis of the phenomena is able to conduct by checking up the principal modes since the local modes are not extracted which have no relation to its response
