title: Nonlinear ultrasonic imaging of imperfectly bonded interfaces.
abstract: A nonlinear ultrasonic imaging system is developed for detecting and imaging damages and defects with nm order gaps in industrial materials, which were undetectable by conventional ultrasonic imaging systems. A high power pulser generating large amplitude incident waves and high gain receiver with high-pass or band-pass filters extracting the second harmonic signals are combined with a conventional C-scan imaging system. The system is applied to visualize fiber/matrix debondings or matrix crackings in CFRP plates. It also visualizes anomalous substructures in amorphous diffusion-bonded interfaces, spot-welded nuggets, and projection-welded interfaces. This system would be also useful to detect semi-closed cracks whose opening is in nm order.
authors.affiliation: Ultrasonic Materials Diagnosis Laboratory Limited, Gokiso, Showa, Nagoya, Aichi 466-8555, Japan. kkawas@nitech.ac.jp <kkawas@nitech.ac.jp>
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kawashima
authors.forename: Morimasa
authors.initials: M
authors.lastname: Murase
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Yamada
authors.forename: Masamichi
authors.initials: M
authors.lastname: Matsushima
authors.forename: Mituyoshi
authors.initials: M
authors.lastname: Uematsu
authors.forename: Fumio
authors.initials: F
authors.lastname: Fujita