Acoustic resonance technology (ART) is an acoustic inspection technology developed by

Det Norske Veritas DNV (formerly DNV GL) is an international accredited registrar and classification society headquartered in Høvik, Norway. The company currently has about 12,000 employees and 350 offices operating in more than 100 countries, and provides serv ...

over the past 20 years. ART exploits the phenomenon of half-wave resonance, whereby a suitably excited resonant target (such as a pipeline wall) exhibits longitudinal resonances at certain frequencies characteristic of the target's thickness. Knowing the speed of sound in the target material, the half-wave resonant frequencies can be used to calculate the target's thickness. ART differs from traditional

ultrasonic testing Ultrasonic testing (UT) is a family of non-destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. In most common UT applications, very short ultrasonic pulse-waves with center frequencies ...

: although both are forms of

nondestructive testing Nondestructive testing (NDT) is any of a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), n ...

based on acoustics, ART generally uses lower frequencies and has a wider bandwidth. This has enabled its use in gaseous environments without a liquid couplant.

has licensed the technology for use in on-shore water pipes worldwide to

Breivoll Inspection Technologies AS Breivoll Inspection Technologies (BIT) have in close collaboration with Det Norske Veritas (DNV) and other partners developed a system for condition assessment of water pipelines. The company is the first world-wide to perform condition assessment ...

. Breivoll has proven the efficiency of the technology in assessing the condition of metallic water pipes, both with and without coating. The company has since 2008 successfully developed a method to enter and inspect water mains, and is a world-leader in their market. ART has also been used in field tests at

Gassco Gassco is a Norwegian state owned company that operates of natural gas pipes transporting annually of 100 billion cubic meter (bcm) of natural gas from the Norwegian continental shelf to Continental Europe and Great Britain. 15% of the t ...

Kårstø Kårstø is an industrial facility located near the village of Susort, along the Boknafjorden, in the municipality of Tysvær in Rogaland county, Norway. The site features a number of natural gas processing plants that refine natural gas and cond ...

facility. In 2012 DNV's ART activities were spun out into a subsidiar
HalfWave

Main features

* Uses lower frequencies than

* Effective in gases and liquids (i.e. requires no liquid couplant) * Can be used to characterize multi-layered media (e.g. pipelines with coatings) * Can penetrate coatings * Can measure inside and outside metal loss

RUV (resonance ultrasonic vibrations)

In a closely related technique, the presence of cracks in a solid structure can be detected by looking for differences in resonance frequency, bandwidth and resonance amplitude compared to a nominally identical but non-cracked structure. This technique, called RUV (Resonance Ultrasonic Vibrations), has been developed for use in the photovoltaics industry by a group of researchers from the University of South Florida
Ultrasonic Technologies Inc.
(Florida, US), and Isofoton S.A. (Spain). The method was able to detect mm-size cracks in as-cut and processed silicon wafers, as well as finished solar cells, with a total test time of under 2 seconds per wafer.

References

{{Reflist Quality Nondestructive testing Casting (manufacturing) Ultrasound