7D-2 3D PSTD Simulations of NEWS-TR and TR-NEWS Methods: Application to Nonclassical Nonlinearity Ultrasonic Imaging

Nonlinear elastic wave spectroscopy with pretreatment and post-treatment of time reversal, called NEWS-TR and TR-NEWS, respectively, have been investigated numerically in this work. Ultrasonic Imaging of a localized 3D damaged region, modeled by a nonclassical nonlinear behavior has been demonstrated. With NEWS-TR localization is performed with a rebroadcast of the nonlinear signature after TR signal processing. Chirp-coded excitation has also been introduced as an alternative for excitation. With TR-NEWS, 3D reciprocity has been numerically demonstrated and nonlinear ultrasonic imaging is performed with classical NEWS analysis after local focusing of ultrasound generated by TR tool.