AIR COUPLED ULTRASONICS
Air Coupled Ultrasonics is an option in cases where it is not practical to use piezoelectric transducers since it is couplant free. Research is being conducted on using this technique on composites, aircraft wings and other complicated profiles.
We conduct research on the use of artificially structured media in achieving unusual phenomena such negative refraction. Our interests range from achieving selective transmission of waves to resolution beyond the diffraction limit. Under this umbrella of metamaterials, we work in an interdisciplinary manner by collaborating with other groups within and outside CNDE.
Electromagnetic acoustic transducer, also known as EMAT, are contactless transducers that produce ultrasonic waves. EMATs are inceasingly viewed as an viable alternative to piezoelectric transducers especially in applications where couplant cannot be used. We conduct research on a variety of applications ranging thickness monitoring to guided wave propagation on plates and pipes.
Laser ultrasonics (LU) uses a pulsed or modulated laser to generate ultrasound. In addition, laser inteferometers based on a Doppler effect and two-wave mixing in a photo refractive crystal are used to detect the ultrasonic displacements. LU offers a non-contact mode of inspection with broadband generation of ultrasound. In CNDE, we particularly research on applying LU for in-situ inspection of additively manufactured components.
CNDE has a set of multi scale immersion ultrasonic systems having equipment compatibility with a wide range of ultrasonic instruments. The gantry's are reconfigurable and can also be used as a scanning bench for research applications.