Nonlinear local wave-direction estimation for in-sight and out-of-sight damage localization in composite plates

In this study, a novel wave processing algorithm: “local wave-direction estimation (LWDE)”, is proposed to localize sources of guided waves using full-field scanning laser Doppler (SLDV) measurements. The LWDE algorithm uses angular bandpass filters in the wavenumber domain determine local propagation direction wave. obtained map converted into an error by use virtual map. resulting reveals as minima. exploitation directional information provides opportunity scan only small part component for localization out-of-sight waves. source performance illustrated multiple piezoelectric quasi-isotropic CFRP plate. further coupled nonlinear vibrations view damage (NL-LWDE). second higher harmonic extracted from SLDV measurement and are localized. Damages behave harmonics thus localized NL-LWDE approach. This demonstrated cross-ply plate with low velocity impact damage. combination (i) vibration filtering, (ii) filtering (iii) construction results robust baseline-free NDT technique. It can be used accurate in-sight or damages composite plates unknown material properties layup.