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Visualization of Frequency Response Using Nyquist Plots
Technical Paper
2022-01-0753
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Nyquist plots are a classical means to visualize a complex vibration frequency response function. By graphing the real and imaginary parts of the response, the dynamic behavior in the vicinity of resonances is emphasized. This allows insight into how modes are coupling, and also provides a means to separate the modes. Mathematical models such as Nyquist analysis are often embedded in frequency analysis hardware. While this speeds data collection, it also removes this visually intuitive tool from the engineer’s consciousness. The behavior of a single degree of freedom system will be shown to be well described by a circle on its Nyquist plot. This observation allows simple visual examination of the response of a continuous system, and the determination of quantities such as modal natural frequencies, damping factors, and modes shapes. Vibration test data from an auto rickshaw chassis are used as an example application. It is hoped that this return-to-fundamentals will help a new generation of engineers take advantage of this useful tool.
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Citation
Bhatnagar, A. and Malen, D., "Visualization of Frequency Response Using Nyquist Plots," SAE Technical Paper 2022-01-0753, 2022, https://doi.org/10.4271/2022-01-0753.Also In
References
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- Bhatnagar , A.V. , et al Mode Shape Analysis of Auto Rickshaw Chassis for Conversion to Electric. Paper ID 139 International Transportation Electrification Conference SAE and IEEE IAS India 16 Dec 2021