Hilbert-Huang Transform-Based Stability Spectral Analysis

摘要

The Hilbert Huang transform (HHT) has been applied to analyze flight flutter data. The analysis shows the yielding of the test wing after the onset of flutter, but just before breaking off at the wingtip. Based on HHT, research using a new stability spectrum shows both positive (stable) and negative (unstable) damping. Flutter occurs in a different frequency range than that determined by modal analysis and identification. Both HHT- and the Teager Energy Operator-based nonlinearity indicator show that structural dynamics are nonlinear throughout the flight-test flutter maneuver.