Medium-range magnetostrictive ultrasonic guided wave scanner systems and methods

#The disclosed systems and methods relates to the non-destructive inspection of sections of pipes, plates, and shells using ultrasonic guided waves.

#Ultrasonic guided wave techniques are utilized in a wide range of non-destructive inspection applications including those for pipes, plates, and shells comprised of metals, composites, and other materials. Guided waves are elastic waves propagating in a bounded structure that is utilized as a waveguide to efficiently transmit one or more wave modes along the structure. One of the foremost benefits of guided waves over other non-destructive inspection techniques is the ability of said waves to propagate over long distances, in many cases hundreds of feet, and to inspect inaccessible or hidden structures from a single probe position.

#Long-range guided wave techniques are often utilized for the inspection of pipelines, plates, and shells. However, due to the nature of the guided waves and associated electronics used in such applications, there are inherent limitations of this technology. Two of these limitations are the existence of an uninspectable region, i.e. ‘dead zone’, around the transducer and a lack of axial and lateral resolution in many applications. Due to these limitations, guided waves are often used as a screening tool for large sections of a structure. However, there exist many opportunities for guided wave applications over short and medium ranges that require greater axial and lateral resolution. Several examples of these opportunities include the detection of corrosion, cracks, and other flaws in close proximity to structural features such as supports, welds, flanges, and air-soil interfaces as well as inspection of short, inaccessible regions such as corrosion under pipe supports (CUPS). The disclosed magnetostrictive ultrasonic guided wave scanner system advantageously yields two-dimensional scan images featuring improved axial and lateral resolution and featuring a small dead zone compared to conventional guided wave inspection systems.

#FIG. 1 is a conceptual illustration of the differences between ultrasonic bulk waves and ultrasonic guided waves.

#FIG. 2 is an illustration of a complex section of piping with a typical dead zone for a conventional long-range ultrasonic guided wave tool superimposed.

#FIG. 3 is an illustration of a complex section of piping with one example of a reduced dead zone that can be achieved using the disclosed system in accordance with some embodiments.

#This description of the exemplary embodiments is non-limiting and is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description.

#The disclosed medium-range magnetostrictive ultrasonic guided wave scanner system generates two-dimensional scan images for the purposes of non-destructive inspection of pipes, plates, and shells by sending and receiving shear horizontal-type guided waves in said structures. The system includes at least one pulser/receiver/processor, at least one sensor coil, at least one ferromagnetic strip, at least one biasing magnet, a position encoder, and a probe body upon which at least the coil and encoder are mounted. The pulser/receiver/processor electronics sub-system and software to perform data analysis and hardware control also can be mounted in or on the probe body.

#In some embodiments, the sensor coil is a flat flexible cable (FFC), although the sensor coil also can be implemented as a flexible printed circuit board (FPCB) or other flexible structure. The sensor coil can be configured to provide at least one of directional control and wave focusing. The sensor coil may be interchangeable to generate and receive guided waves across a wide range of frequencies between 10 kHz and 2 MHz. In some embodiments, the sensor coil includes at least two separate coil elements that are utilized to achieve at least one of improved focusing, aperture control, directional control, probe calibration, and decreased dead zone extent. The sensor coil may be arranged such that at least one coil element generates the outgoing guided waves and subsequently detects guided wave reflections. Alternatively, the sensor coil may be arranged such that at least one coil element generates the outgoing guided waves and at least one additional coil element detects guided wave reflections.