Seung Kyu Lee, Yong Woo Kim, Man Hoi Koo, Hak In Gimm, Hong Hee Yoo*
The Journal of Mechanical Science and Technology, vol. 24, no. 12, pp.2395-2400, 2010

Abstract : Fast Fourier transform (FFT) has been widely used to analyze distribution patterns of frequency components in dynamic response signals. Given a stationary dynamic response signal, a fixed frequency distribution pattern can be obtained efficiently using FFT. If the system of concern is not stationary, however, the frequency distribution pattern varies with time, and the variation in that pattern cannot be effectively determined via FFT. To overcome this weakness, time-frequency dual-domain signal analysis methods such as wavelet transform and Hilbert-Huang transform (HHT) have been introduced. HHT has been shown to be particularly effective in analysis of nonstationary signals obtained from non-linear as well as linear systems. In the present study, the transient characteristics of a composite panel undergoing high-velocity impact were investigated. The composite panel, along with the colliding bullet, were modeled using the finite element method. To verify the reliability of the analysis model, an impact experiment was carried out, which proved that the model provides reliable, similar-to-experimental results.

Keyword : Composite panel; High-velocity impact; Transient characteristic; Hilbert-Huang transform; Experimental verification