An FFT-based spectral analysis method for linear discrete dynamic systems with non-proportional damping

Article type: Research Article

Authors: Cho, Jooyong | Lee, Usik

Affiliations: Department of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Ku, Incheon 402-751, South Korea

Note: [] Corresponding author. Tel.: +82 32 860 7318; Fax: +82 32 866 1434; E-mail: ulee@inha.ac.kr

Abstract: This paper proposes a fast Fourier transforms (FFT)-based spectral analysis method for the dynamic analysis of linear discrete dynamic systems which have non-proportional viscous damping and are subjected to non-zero initial conditions. To evaluate the proposed FFT-based spectral analysis method, the forced vibration of a three degree-of-freedom (DOF) system is considered as an illustrative problem. The accuracy of the proposed FFT-based spectral analysis method is evaluated by comparing the forced vibration responses obtained by the present FFT-based spectral analysis method with those obtained by using the well-known Runge-Kutta method and modal analysis method.

Keywords: Spectral analysis method, linear discrete dynamic system, non-proportional damping, discrete Fourier transform (DFT), fast Fourier transform (FFT)

Journal: Shock and Vibration, vol. 13, no. 6, pp. 595-606, 2006