6533b873fe1ef96bd12d57be
RESEARCH PRODUCT
Ultrasonic detection by photo-EMF sensor and by wideband air-coupled transducer
B. Boro DjordjevicDonatella Cernigliasubject
Materials scienceMechanical EngineeringAcousticsUltrasonic testingDetectorAir-coupled transducerNon-contact ultrasoundCondensed Matter PhysicsLaserlaw.inventionTransducerMechanics of MaterialslawContinuous waveLaser.General Materials ScienceUltrasonic sensorWidebanddescription
Two non-contact remote ultrasonic detection systems are compared. The first consists of a continuous wave (CW) Nd:YVO4 laser operating at 532 nm used in conjunction with a photo-induced electromotive-force (EMF) sensor. The second system employs an air-coupled capacitance transducer that has a bandwidth from 100 kHz up to 2 MHz. Both systems exhibit higher sensitivity to out-of-plane than in-plane measurements of stress wave signals. Ultrasound generation is carried out by an Nd:YAG pulsed laser at 532 nm in the thermoelastic regime in a 1.6 mm aluminum plate. A0 Lamb mode is generated at frequency-thickness product with strong out-of-plane displacements. Ultrasonic waveforms acquired are reported and the performance advantages of the two remote non-contact detectors are compared with each other. For lower frequency tests (up to 2 MHz), better results have been achieved with the air-coupled transducer that also has superior overall performance and benefits. The tests enabled direct comparison of air-coupl...
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-07-01 |