Discriminating linear from nonlinear elastic damage using a nonlinear time reversal DORT method

摘要: The DORT method is a selective detection and focusing technique originally developed to detect defects damages which induce linear changes of the elastic moduli. It based on time reversal (TR) where signal collected from an array transducers reversed then back-propagated into medium obtain selected targets. TR principle spatial reciprocity. Attenuation, dispersion, multiple scattering, mode conversion, etc. do not break presence or damage, may cause materials show nonlinear wave propagation behavior that will spacial Therefore allow scatterers. This paper presents new for identification scatterers by combining spectroscopy, method. In hysteretic scatterers, forcing solid with harmonic excitation, operator can be obtained only at fundamental frequency but also odd harmonics. At harmonic, either inhomogeneities individually harmonics exist. A procedure was decomposing harmonics, it possible focus differentiate them inhomogeneities. complete mathematical formulation 1 2D structures presented. To model Preisach-Mayergoyz (PM) material constitutive used. Results relative 2 dimensional are reported showing capability discern selectively Furthermore, analysis conducted study influence number sources their location imaging process using higher numbers sensors does automatically bring minor uncoupled behaviour between