Non-contact ultrasonic non-destructive techniques : state of the art and their use in civil engineering
Résumé
Ultrasonic methods of testing of civil engineering materials in air where both transmission of waves into materials and reception of signals are contactless are reviewed. Short history, technical details and examples of applications of currently available methods are discussed. Keywords: ultrasound, NDT, non-contact, air-coupled, cement based materials, degradation, flaws 1. Introduction For effective and reliable non-destructive testing (NDT) of materials and structures in civil engineering (CE) new possibilities based on non-contact ultrasonic methodology are developed. The non-contact (NC) methods in air, where both transmission of waves into tested materials and reception of signals are contactless are interesting because they may be used for fast scanning of large surface objects avoiding problems with wet or dry coupling between contact ultrasonic transducers and ...