Ultrasonic guided wave-based damage identification with split spectrum processing algorithm

A split spectrum processing(SSP) algorithm was proposed to estimate the time of flight(ToF) of the damage-scattered fundamental symmetrical(S0) mode by comparing the instantaneous amplitude variation degree(IPVD) of a captured wave signal and that of a benchmark signal in a damage case,so as to realize the ultrasonic guided wave-based damage identification.Wave signals captured from an intact aluminum plate were firstly acquired in ideal environment(without noise) as a benchmark one.Then,a notch was artificially introduced into an aluminum plate and the wave signals captured from the notched aluminum plate(damage case) were acquired in different environments(without and with noise).Test results demonstrated that even though the captured wave signal from the damage case has a lower signal-to-noise ratio(SNR),the IAVD of the captured wave signal extracted with SSP algorithm is almost not influenced by noise.As result,the proposed SSP algorithm was capable of estimating the ToF of the damage-scattered S0 mode with higher precision,regardless of very strong noise disturbance,so as to identify successfully the notch in an aluminum plate further combining with the triangulation algorithm.