What is GWUT?
What is GWUT?
Guided wave ultrasonic testing (GWUT) is a viable alternative for non-piggable pipelines that are located in hard-to-reach areas where launching and receiving the pig is difficult. This technique has the ability to detect and measure the change in the pipeline’s cross section from a single test location.
How do guided waves work?
Guided wave testing (GWT) is a non-destructive evaluation method. The method employs acoustic waves that propagate along an elongated structure while guided by its boundaries. This allows the waves to travel a long distance with little loss in energy.
What is meant by Guided Wave?
guided wave: A wave having (a) energy concentrated near a boundary, or between substantially parallel boundaries, separating materials of different properties and (b) a direction of propagation effectively parallel to these boundaries. (
What is a bulk wave?
Bulk waves exist in infinite homogeneous bodies and propagate indefinitely without being interrupted by boundaries or interfaces. These waves can be decomposed into infinite plane waves propagating along an arbitrary direction g within the solid. Generally speaking, three types of waves are possible.
What is a bulk acoustic wave?
Bulk acoustic waves (BAWs) are elastic waves propagating in solids. They are categorized into a longitudinal wave shown in Fig. The longitudinal wave is also called a pressure wave whereas the transverse wave is also called a shear wave.
Is waveguide a transmission line?
A waveguide is a special form of transmission line consisting of a hollow, metal tube. Waveguides are practical only for signals of extremely high frequency, where the wavelength approaches the cross-sectional dimensions of the waveguide. Below such frequencies, waveguides are useless as electrical transmission lines.
What is the difference between SAW and BAW filter?
SAW filters are used for lower frequencies (up to 2.7GHz) and BAW filters are used at higher frequencies (2.7GHz-6GHz.)
What is a BAW resonator?
A BAW resonator is an electromechanical device in which a standing acoustic wave is generated by an electrical signal in the bulk of a piezoelectric material. In the simplest configuration, a device will consist of a piezoelectric material (typically quartz, AlN, or ZnO) sandwiched between two metallic electrodes.
Why is waveguide used?
Rectangular and circular waveguides are commonly used to connect feeds of parabolic dishes to their electronics, either low-noise receivers or power amplifier/transmitters. Waveguides are used in scientific instruments to measure optical, acoustic and elastic properties of materials and objects.
What is a waveguide antenna?
A beam waveguide antenna is a particular type of antenna dish, at which waveguides are used to transmit the radio beam between the large steerable dish and the equipment for reception or transmission, like e.g. RF power amplifiers.
What can gwut be used for in a pipeline?
Additionally, GWUT can be used to inspect hard-to-reach areas such as railway or river crossings that are difficult with conventional NDT methods. GWUT is composed of a ring of piezoelectric and magnetostrictive transducers that are coupled around the entire circumference of the pipeline.
When did guided wave ultrasonic testing start for pipelines?
Since 1998 pipeline operators began inspecting hard to reach pipelines or non-piggable pipelines with a technique known as guided wave ultrasonic testing (GWUT). This technique has the ability to detect and measure the change in the pipeline’s cross section from a single test location.
How is gwut used to measure wall thickness?
Although GWUT uses the same principles as the conventional ultrasonic testing (UT) that is used to measure the pipe wall thickness or to detect cracks if an angled probe is used, GWUT has several advantages (Table 1). Estimates wall loss in some test stations.
What are the three modes of gwut waves?
In GWUT, the waves exist in three modes: longitudinal, torsional and flexural. More than one mode could be available at the pipe under inspection at one frequency. This can lead to a response that is much more difficult to analyze than conventional UT.
