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Full-Text Articles in Mechanical Engineering
Study Of An Axial Fan Combined With A Microperforated Duct, Seungkyu Lee
Study Of An Axial Fan Combined With A Microperforated Duct, Seungkyu Lee
Seungkyu Lee
The fans used in the ventilation duct systems usually fall into two categories: (i) axial, and (ii) centrifugal. These types of fans are distinguished by having different performance characteristics. For instance, centrifugal fans are capable of generating high static pressures compare to axial fans. However, an axial fan can deal with higher air volume flow rates than a centrifugal fan, and, more importantly, an axial fan produces relatively low fan noise compared to a centrifugal fan. Thus, even though axial fans may be advantageous from a noise point-of-view, they are generally avoided in duct systems when relatively high static pressures …
Hilbert-Huang Transform Transient Analysis Of Composite Panel Undergoing High-Velocity Impact, Seungkyu Lee
Hilbert-Huang Transform Transient Analysis Of Composite Panel Undergoing High-Velocity Impact, Seungkyu Lee
Seungkyu Lee
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 …