Air-Coupled and Resonant Pulse-Echo Ultrasonic Technique

Ultrasonic Pulse-Echo Subwavelength Defect Detection Mechanism: Experiment and Simulation

The ultrasonic pulse-echo backscattered amplitude integral (BAI)-mode imaging technique [IEEE Trans. UFFC, 45:30 (1998)] has demonstrated sensitive detection of subwavelength channel defects (38m diameter reliably and 6m diameter occasionally) in flexible 220m-thick food package seals (17.3 MHz, 86 m). However, the underlying subwavelength defect detection mechanism is poorly understood. In thi...

Elastic properties of Gd5Si2Ge2 studied with an ultrasonic pulse-echo technique

We present the results of a study of the elastic properties of Gd5Si2Ge2, an alloy with giant magnetocaloric, magnetostrictive, and colossal magnetoresistive properties. Sound wave velocities measured in a number of different geometries allowed us to determine the whole elastic tensor for the monoclinic phase of this material. The anisotropy of the crystal is explored using the polar plots of t...

Air-coupled Ultrasonic Testing of Materials

NDE Applications of Air-Coupled Ultrasonic Transducers

Abslract In recent years, several new NDE applications of air-coupled, as opposed to liquid-coupled, ultrasonics have been seriously pursued. The applications range from throughtransmission testing of aerospace laminates and various honeycomb or foam filled materials, and solar cells, to pulseecho flaw detection in plastic electronic packaging materials and in-line inspection of large-diameter ...

Near Real Time Ultrasonic Pulse Echo Holographic Imaging System