Mode-Selective Imaging Procedures of Acoustic Ultrasonic Data on Hollow Cylinder Geometries for Structural-Health-Monitoring

摘要

Nowadays most common ultrasonic transducers measure only one scalar quantity instead of an elastic displacement field. In the case of Lamb wave propagation, this lack of information is critical under conventional imaging conditions. For baseline based and baseline free crack detection will lead to incorrect localization and classification due to different dispersive phase velocities for each propagating mode. The presented approach provides an heuristic operator to identify and select certain Lamb modes in single component datasets measured by piezoelectric transducers. This allows for the suppression of undesired side-modes. A specific pre-processing step gives us the possibility to use single component imaging procedures like conventional Kirchhoff-, Fresnel- and Reverse-Time-Migration in the terms of physics in a more precise manner.