Applications of higher-order statistics to ground vibration testing of aircraft structures

Abstract

Nonlinearity in GVT (ground vibration test) data causes force-dependence in the FRF (frequency response function) and linear-coherence estimates. Application of higher-order statistics with a GVT offers one possible method for studying structural nonlinearity. In this paper, a third-order frequency-domain orthogonal Volterra-like model is used to decompose GVT data from a Star-Lite aircraft into constituent linear, quadratic, and cubic components. The results indicate cubic effects significantly account for regions of low linear coherence.