title: Enhanced method to reconstruct mode shapes of continuous scanning measurements using the Hilbert Huang transform and the modal analysis method.
abstract: Generally, it is time consuming to experimentally identify the operating deflection shape or mode shape of a structure. To overcome this problem, the Hilbert Huang transform (HHT) technique has been recently proposed. This technique is used to extract the mode shape from measurements that continuously measure the vibration of a region of interest within a structure using a non-contact laser sensor. In previous research regarding the HHT, two technical processes were needed to obtain the mode shape for each mode. The purpose of this study is to improve and complement our previous research, and for this purpose, a modal analysis approach is adapted without using the two technical processes to obtain an accurate un-damped impulse response of each mode for continuous scanning measurements. In addition, frequency response functions for each type of beam are derived, making it possible to make continuously scanned measurements along a straight profile. In this paper, the technical limitations and drawbacks of the damping compensation technique used in previous research are identified. In addition, the separation of resonant frequency (the Doppler effect) that occurs in continuous scanning measurements and the separation of damping phenomenon are also observed. The proposed method is quantitatively verified by comparing it with the results obtained from a conventional approach to estimate the mode shape with an impulse response.
authors.affiliation: School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
authors.forename: Jongsuh
authors.initials: J
authors.lastname: Lee
authors.affiliation: School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
authors.forename: Syed Hassaan
authors.initials: SH
authors.lastname: Hussain
authors.affiliation: School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
authors.forename: Semyung
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
authors.forename: Kyihwan
authors.initials: K
authors.lastname: Park