Time-Frequency Analysis of Multi-Mode Lamb Waves by Improved HHT

Hilbert-Huang transform is a new method to analyze non-stationary and non-linear signals. The multi-mode Lamb wave signals were analyzed by an improved HHT method, which combined band-pass filter group with HHT analysis. Using this technique, the Intrinsic Mode Function, IMF components were separated efficiently and the noise was suppressed dramatically, which suggested that this method was feasible and effective for Lamb wave analysis.