For elastic wave propagation in plate, with the increase of propagation
distance, the energy and the amplitude of vibration reduce
gradually. It is the attenuation phenomenon and main contains
dispersion, scattering and absorption [11]. The acoustic signals
caused by artificial defect (Hsu–Nielsen method of pencil lead
breaking) were acquired at four spatially separate points using
acoustic sensors mounted on the plate in rectangular array as
shown in Fig. 1. The sensors captured signals are mathematically
modeled as