Arrangement for Excitation of Guided Waves, Apparatus and Methods

Description

1 / 31 Arrangement for Excitation of Guided Waves, Apparatus and Methods TECHNICAL FIELD

[0001] The present invention relates to an arrangement for guided wave excitation and, more particularly, to an arrangement for guided wave excitation that utilizes a high-power ultrasonic transducer to generate guided waves in a test structure. The present invention also relates to associated guided wave testing apparatus and methods. More particularly, the present invention relates to guided wave excitation arrangements, apparatus, and methods for non-destructive testing applications, such as for detecting defects, such as corrosion (but not limited to) in a variety of structures, such as elongated metal structures (such as tendons, bars, pipes, rods, or rails) or metal plates, particularly when these test structures are embedded in highly attenuating materials such as concrete, earth, gravel, sand, or rock, to name just a few examples.The present invention also relates to infrastructure (such as columns, bridges or the like) comprising said arrangements, or said devices, for example, for continuous monitoring of structural integrity. TECHNICAL BACKGROUND

[0002] Mechanically guided waves are typically excited in test structures using one of three types of transducers: a) Piezoelectric transducers, which can be used in dry contact with a test structure, or closely coupled to the test structure by means of a coupling gel, which is usually an ultrasound transmitting gel; b) magnetostrictive transducers, which use the magnetostrictive properties of a material to generate vibration; and, c) Electromagnetic transducers (or EMATs), which use the Lorentz force principle. Petition 870250113100, dated 09 / 12 / 2025, page 9 / 51 2 / 31

[0003] These transducers, however, can only generate very limited guided wave amplitudes (typically on the order of nanometers or even picometers) in the test structure, meaning that only a very small amount of energy is associated with the guided waves propagating along the test structures. The standard approach for guided wave testing is to inspect using a pulse-echo system. Pulse-echo systems use guided wave reflections generated by the presence of defects in the test structures to detect their possible presence. In this way, defects such as corrosion, fatigue cracks, or defects of different types can be detected in the components under examination.The reason existing guided wave transducers use very low excitation power is so that the type of guided waves excited in the test structure can be precisely controlled, resulting in guided waves with abundantly submicrometer amplitudes (as mentioned above, typically on the order of nanometers or even picometers).

[0004] Furthermore, the electronics typically associated with pulse-echo guided wave test systems serve both the excitation and reception sides of the test, and this means that it necessarily provides a limited dynamic range of measurement for the received guided waves, which typically have smaller amplitudes than the amplitudes of the excited guided waves by one or more orders of magnitude.

[0005] Due to the low power of the guided wave excitation methods mentioned above, a known limitation of guided wave inspection methods is their range, i.e., the space (more specifically, the length, in the case of elongated test structures) that the guided waves can cover for testing purposes. This happens, for example, when a metallic component, such as a tendon, a bar, a tube, or some other elongated structural form, such as a rail, is embedded in an attenuating medium, such as concrete, is buried underground, or Petition 870250113100, dated 09 / 12 / 2025, page 10 / 51 3 / 31 coated with attenuating coatings. The excited guided waves (which, as explained above, can already be considered to have relatively low amplitudes) 'leak' into the external attenuating material, which exacerbates the problem of the limited inspection range.

[0006] In addition, all the above transducers have difficulty achieving uniform excitation when the transducers are coupled to the test structures via irregular surfaces (for example, an irregular surface, such as can be found in steel tendons).

[0007] Consequently, there is a need to improve guided wave inspection methods in relation to the state of the art.

[0008] At least one of the solutions presented addresses at least some of the limitations or disadvantages mentioned above in relation to the state of the art.

[0009] Furthermore, at least one of the solutions presented allows the use of enhanced attenuation-based non-destructive testing methods, where amplitude or energy loss (or a combination thereof) can be used to determine the possible presence of damage or defects, especially in the form of distributed damage, such as widespread corrosion (rather than highly localized), within the test structures. SUMMARY OF THE INVENTION

[0010] According to an implementation described in this disclosure, an ultrasonic excitation arrangement is provided comprising a high-power ultrasonic transducer and a housing. The housing defines a space volume to accommodate an ultrasonic transmitting medium, such as a gel or other liquid or semi-liquid medium (although, in principle, any medium capable of effectively transmitting ultrasound may be accommodated in said housing and on, around, or in close proximity to the test structure). The housing is adapted Petition 870250113100, dated 09 / 12 / 2025, page 11 / 51 4 / 31 so that, in use, the ultrasound transmitter medium can receive the ultrasound emitted by the high-power ultrasonic transducer. The housing is also adapted so that, in use, the test structure can receive the ultrasound from the ultrasound transmitter medium.

[0011] Advantageously, the housing helps to concentrate the high-power ultrasound level in the volume of space occupied by the ultrasound transmission medium. The ultrasound transmission medium will be subject to ultrasound received directly from the high-power ultrasonic transducer, as well as ultrasound reverberating from the housing.

[0012] Advantageously, the ultrasound transmission medium excites the test structure uniformly, due to its uniformity of distribution around and / or near the test structure.

[0013] The above effects, in combination, advantageously determine the uniform excitation of high-amplitude guide waves in the test structure. The excited guide waves were measured with amplitudes 40 decibels (dB) greater than the corresponding amplitudes obtained using state-of-the-art guided wave ultrasonic transducers; these values ​​were measured using a standard ultrasonic receiver on the end face of a bar – under similar conditions. The guide waves can therefore travel in the test structure over extended ranges, allowing for enhanced testing and inspections.

[0014] The high-power ultrasonic transducer can be adapted to excite ultrasound with one or more frequency components in the spectrum between about 20 kHz and about 100 kHz. This range is chosen in the low-frequency ultrasonic spectrum. The low-frequency ultrasonic spectrum can be chosen to provide high vibration amplitudes in the desired waveguide vibration modes in the test structures.

[0015] To reinforce the high-powered nature of Petition 870250113100, dated 09 / 12 / 2025, page 12 / 51 5 / 31 implementations described, the high-power ultrasonic transducer may comprise a mechanical resonator. The mechanical resonator may have at least one nominal resonant frequency in the spectrum between about 20 kHz and about 100 kHz, so as to be matched with excitation frequencies excitable by the high-power ultrasonic transducer.

[0016] The housing may be provided as a substantially rigid compartment. Alternatively, the housing may comprise at least a substantially rigid compartment portion. Optionally, the compartment or substantially rigid compartment portion is made of a metal, such as, but not limited to, steel.

[0017] Similarly, the housing may be provided as a substantially flexible compartment or may comprise a portion of a substantially flexible compartment. Optionally, said compartment or portion of a substantially flexible compartment is made of a thin plastic material, such as a film or a metallic foil. Optionally, said compartment or portion of a substantially flexible compartment is provided as a pouch made of a thin film or thin foil of plastic material.

[0018] In a preferred embodiment, the housing comprises a substantially rigid compartment portion to which a substantially flexible compartment portion can be attached, such that the ultrasound transmitting medium can fill a space volume shared between the substantially rigid and flexible compartment portions of the housing (i.e., the space volume filled with the ultrasound transmitting medium is defined by the substantially rigid and flexible compartment portions). In a preferred embodiment, a pouch or pocket made of a thin film or sheet of plastic material is attached to a Petition 870250113100, dated 09 / 12 / 2025, page 13 / 51 6 / 31 a substantially rigid compartment portion, such as a metal box, metal cylinder, or metal cone, to cite just a few examples of shape, so as to project outward from said rigid compartment portion. An advantage of this configuration is that the projecting pouch or pocket, filled with ultrasound transmitting medium, can then be shaped, for example, around a suitable metallic test component, such as an elongated metallic test component. The inventors recognized that it is not necessary for the test structure to occupy the volume of space filled with ultrasound transmitting medium within a substantially rigid compartment.Alternatively, the substantially flexible compartment or portion of a compartment may be adapted to conform to the test structure, for example, but not limited to, by enclosing said test structure, which is particularly, but not exclusively, suitable for elongated test structures. In this preferred configuration, the test structure remains outside the volume of space filled with ultrasound transmitting medium.

[0019] The substantially rigid compartment or portion of the housing may generally be provided in the form of a parallelepiped, or a cone, or a cylinder. Optionally, said substantially rigid compartment or portion of the housing may comprise two or more mountable parts, which may be useful for filling or replenishing said space volume with the ultrasound transmitting medium. Optionally, the two or more mountable parts may comprise a receiving part and a covering part, for practicality and ease of use. Optionally, said two or more mountable parts may also be demountable, i.e., they may be disassembled for removal or for maintenance in connection with the ultrasound transmitting medium.

[0020] Advantageously, the accommodation may include a Petition 870250113100, dated 09 / 12 / 2025, p. 14 / 51 7 / 31 orifice to receive the high-power ultrasonic transducer, so that at least a part, such as a tip (i.e., a distal end), of the ultrasonic transducer, or of the mechanical resonator, when present, can directly occupy said space volume to accommodate the ultrasound transmission medium. This means that, in use, the tip of the high-power ultrasonic transducer, or resonator, can be in direct contact with the ultrasound transmission medium. However, a different way of transmitting the ultrasound generated by the high-power ultrasonic transducer can be implemented. For example, the housing can be provided integrally as part of the mechanical resonator. Alternatively, the mechanical resonator can be placed directly in contact with the housing, externally to it, or internally.

[0021] It is preferable, however, that the orifice be in direct communication with the said volume of space to accommodate the ultrasound transmission medium.

[0022] The arrangement may further comprise a seal for sealing between the housing and the high-power ultrasonic transducer, so that the ultrasonic transmission medium is contained in a watertight manner within the provided space volume inside the housing. The seal may be adapted to fit within or around the orifice for the high-power ultrasonic transducer. However, it is not necessary for the ultrasonic transmission medium to be confined within the housing. For example, depending on the implementation, a flow of ultrasonic transmission medium through the housing may be implemented.

[0023] The test structure itself may form part of the arrangement. However, it is anticipated that the arrangements described herein may be sold independently of the test structure, for example, as a parts kit including the high-power ultrasonic transducer and housing. The housing may Petition 870250113100, dated 09 / 12 / 2025, p. 15 / 51 8 / 31 can be adapted to fit specific test structures at the point of sale, or it can be adapted on-site, or in any case before or in preparation for an inspection or monitoring campaign.

[0024] The arrangements described here are particularly suitable for test structures in the form of elongated metal components. However, as we shall see below, other test structures can be tested using the arrangements described here.

[0025] In specific implementations, some of which are described here, the metal component may be a bar, a rod, a tendon, a rail, or a tube.

[0026] Consequently, the housing may comprise at least one opening to receive a portion of said elongated metallic component in said space volume to accommodate the ultrasound transmission medium.

[0027] In some implementations described herein, the housing may comprise one and only one opening to receive one end of said elongated metal component.

[0028] The said orifice and said opening may be positioned relative to the housing so that, in use, the high-power ultrasonic transducer and the end of the elongated metal component may be generally arranged opposite each other. Optionally, the high-power ultrasonic transducer and the end of the elongated metal component may be generally arranged face to face. Optionally, the high-power ultrasonic transducer and said end of the elongated metal component may be generally arranged along a common straight line. However, other geometric configurations may be possible.

[0029] For example, the housing may comprise at least two openings to receive a length of said elongated metal component. Consequently, said Petition 870250113100, dated 09 / 12 / 2025, page 16 / 51 9 / 31 The orifice and said openings may be positioned relatively in the housing so that, in use, the high-power ultrasonic transducer and said end of the elongated metal component are arranged along intersecting or non-intersecting directions. For example, the high-power ultrasonic transducer and said length of the elongated metal component may be arranged substantially parallel to each other. Alternatively, the high-power ultrasonic transducer and said end of the elongated metal component may be arranged substantially perpendicular to each other, or at another angle.

[0030] Alternatively, the test structure may be a metal plate, such as a flat plate, such as the base (or floor) of a storage tank, or a curved wall, such as a cylindrical wall of said storage tank. Optionally, said plate or wall may define a complete circle, for example, as in the case of a whole cylindrical tank, for example, for storing fuel.

[0031] The housing can be specifically configured to test non-elongated metal structures, such as the plate or wall above. For example, the housing may comprise at least one outlet for the ultrasound output received by the test structure from the ultrasound transmitter medium. This outlet may be installed on a wall or side of the housing that is flat or curved, to adapt to the shape of the aforementioned plate or wall.

[0032] Advantageously, said outlet may comprise a barrier to prevent the ultrasound transmission medium from overflowing from the housing into the test structure. Optionally, said barrier may comprise, or may be in the form of, a film. Alternatively, said barrier may be in the form of a glove, such as a designed glove. Petition 870250113100, dated 09 / 12 / 2025, p. 17 / 51 10 / 31 into the accommodation, to accommodate part of the test structure.

[0033] In an alternative arrangement, the substantially flexible compartment or portion of a compartment is adapted to conform, at least partially, to an elongated metallic component, for example, by enclosing it. Optionally, the elongated metallic component is one of the following: a bar, a rod, a tendon, a rail, or a tube. Optionally, said substantially flexible compartment or portion of a compartment is provided as a pouch made of a thin film or a thin sheet made of a plastic material. This configuration may be particularly advantageous when there is not much space available around the test structure to access it with the excitation arrangement.Consequently, instead of fitting a rigid housing around the test structure so that the test structure is disposed within the housing, a flexible, suitably shaped pouch or pocket filled with ultrasound transmitting medium, which may optionally be attached to a rigid housing, may be provided for better access to the test structure, while the test structure remains outside the housing and outside the volume of space filled by the medium defined by the housing.

[0034] It is understood that the arrangements described may also include the ultrasound transmission medium. For example, a suitable ultrasound transmission gel may be sold as part of the aforementioned parts kit.

[0035] In some implementations described herein, the high-power ultrasonic transducer may be piezoelectric. This lends itself well to the use of a simple housing (i.e., a housing with a simple geometric shape), as also described herein. However, at least in principle, it is not necessary to specify the use of a piezoelectric transducer, provided that the excited guided waves are of sufficient amplitudes. Petition 870250113100, dated 09 / 12 / 2025, p. 18 / 51 11 / 31 highs to improve defect detection and / or inspection range compared to prior art methods, as discussed herein.

[0036] Advantageously, the arrangement may also comprise one or more ultrasound receivers, which may optionally also be piezoelectric transducers, such as standard acoustic emission transducers, adapted to receive and thus measure any received guided waves at the excited frequencies and amplitudes.

[0037] In addition, the arrangement may also comprise electronic components for operating the high-power ultrasonic transducer and one or more ultrasound receivers in transmission mode. The transmission mode may be continuous ultrasonic transmission, or the ultrasound may be generated by the high-power ultrasonic transducer in bursts, in transient transmission mode. In this mode, it will also be possible to measure the time of flight, between the moment the emitted ultrasonic burst is generated by the high-power ultrasonic excitation arrangement and the moment the ultrasonic burst is received, in the form of a guided wave packet, by the receiving ultrasound transducer, as one skilled in the art would recognize.

[0038] The present disclosure, therefore, also presents non-destructive testing methods comprising exciting ultrasonic guided waves in a test structure using ultrasonic excitation arrangements as described herein.

[0039] Ultrasound receptors can be arranged in the test structure itself or in a material that embeds said test structure. In a typical example, the test structure might be a tendon embedded in concrete.

[0040] The methods described herein may also include the calculation of a peak amplitude and / or a frequency spectrum and / or an attenuation parameter and / or a parameter representative of the energy of the received guided waves, which are received and Petition 870250113100, dated 09 / 12 / 2025, p. 19 / 51 12 / 31 measurements by ultrasound receivers.

[0041] A particular strength of the methods described here is that the presence or absence of distributed defects (such as widespread, rather than localized, corrosion) in a test structure can be assessed solely from the calculation of the attenuation parameter of the measured guided waves. This is particularly useful in monitoring applications, where the potential deterioration of the test structure is assessed continuously or periodically over time by observing changes in an attenuation parameter. However, in other testing applications, the attenuation level between ultrasonic excitation and reception at two arbitrarily selected points a fixed distance apart can also be examined using the attenuation parameter. By changing the location of the arbitrarily selected points on the test structure, baseline attenuation values ​​that likely correspond to the improbable presence of defects can be assessed.Therefore, the measurement of additional attenuation on top of the base attenuation can be considered as the likely presence of, for example, widespread corrosion, between the two specific points used for, respectively, the excitation and reception of guided waves.

[0042] In some implementations described herein, the test structure is a metallic tendon and the method may also include estimating a tension in said metallic tendon, since the properties of the excited guided waves depend on this tension. One application, for example, could be the detection of the presence of any tension in the tendon, or its absence.

[0043] When the methods described herein are applied to non-destructive guided wave testing on metal plates or similar, the methods may further comprise the arrangement of a plurality of ultrasound receivers on a metal plate, the excitation of ultrasonic guided waves on the metal plate from a first selected position on the metal plate, the Petition 870250113100, dated 09 / 12 / 2025, p. 20 / 51 13 / 31 Excitation of ultrasonic guided waves on the metal plate from at least one other selected position on the metal plate and measurement of the excited guided waves on a plurality of ultrasound receivers. Consequently, not only the presence but also the position of a defect on the plate can be estimated.

[0044] Furthermore, the method may also involve the excitation of guided ultrasonic waves on the metal plate from a plurality of positions, respectively close to the plurality of ultrasound receivers arranged on said metal plate. In this way, a complete map of defects in the area of ​​the plate delimited by the plurality of ultrasound receivers can be calculated and represented graphically.

[0045] It would be possible to permanently or semi-permanently place the arrangements described herein in infrastructures such as reinforced concrete columns, highways, bridges, railways, fuel storage tanks and the like. For this, it may be necessary to prepare said infrastructure (which may comprise one or more test structures in the form of elongated metallic components coated with attenuating material, such as concrete) for non-destructive ultrasonic testing, removing a portion of said attenuating material to expose one or more parts of the elongated metallic components and placing one or more ultrasonic excitation arrangements, as described herein, on one or more exposed parts of said metallic components.

[0046] One or more ultrasound receivers may then also be arranged in one or more exposed parts of said metallic components. However, they may alternatively be arranged on an external surface of the attenuating material itself, such as on a concrete face of the infrastructure.

[0047] The present implementations will now be described, by way of example only, with reference to the attached drawings, Petition 870250113100, dated 09 / 12 / 2025, page 21 / 51 14 / 31 in which: LIST OF DRAWINGS:

[0048] Figure 1 is a schematic representation of a first ultrasonic excitation arrangement as disclosed herein; Figure 2 is a schematic representation of a second ultrasonic excitation arrangement, as also disclosed here; Figure 3 is a schematic representation of a third ultrasonic excitation arrangement, as also disclosed here; Figure 4 is a schematic representation of a fourth ultrasonic excitation arrangement, as also disclosed here; Figure 5 is a schematic representation of a fifth ultrasonic excitation arrangement, as also disclosed here; Figure 6 is a top view of a sixth ultrasonic excitation arrangement, as also disclosed here, similar to that in Figure 1, immediately before use; Figure 7 is a top view, slightly in perspective, of a seventh excitation arrangement, also shown here, similar to that in Figure 2, immediately before use; Figure 8 is a perspective view of an eighth excitation arrangement, also shown here, similar to that in Figure 5, in use on a metallic tendon; Figure 9 is a schematic representation of a ninth excitation arrangement, also shown here, applied to the floor of a storage tank; Figure 10 is a schematic close-up view of the excitation arrangement in Figure 9; Figure 11 schematically represents an ultrasonic testing method for testing the floor of storage tanks. Petition 870250113100, dated 09 / 12 / 2025, page 22 / 51 15 / 31 figures 9 and 10; Figure 12 schematically represents an ultrasonic testing method for testing a wall of the storage tank shown in Figures 9, 10, and 11; Figure 13 is a perspective view of a test bar with a simulated distributed defect; Figure 14 shows the results of the tests performed on the bar in Figure 13, using an ultrasonic testing setup as described in this document; Figure 15 shows an ultrasound receiver placed on a reinforced concrete surface of a sample reinforced concrete infrastructure; Figure 16 shows the results of the tests performed on the infrastructure shown in Figure 15; Figure 17 is a wider perspective view of the arrangement in Figure 8, where tests are performed to detect tension in a tendon; Figure 18 shows the results of the tests performed on the tendon shown in Figures 8 and 17; Figure 19 shows, comparatively, two frequency spectra obtained from guided waves excited using a high-power ultrasonic excitation array, as described herein, and measured on a fault-free structure and a faulty structure, respectively; and Figure 20 shows an alternative excitation arrangement comprising a metallic cone and a plastic bag, which is filled with ultrasound transmitting medium and adapted to enclose an elongated test structure. DESCRIPTION

[0049] This disclosure arises from the desire to generate guided waves that produce relatively high wave displacements in the test structure, well above the order of magnitude of nanometers, typical of the state of the art. With guided waves of this Petition 870250113100, dated 09 / 12 / 2025, p. 23 / 51 16 / 31 type, it would be possible to achieve desirable inspection ranges even for test structures embedded in highly attenuative materials. It is a known problem that test structures embedded in highly attenuative materials have very limited guided wave inspection ranges, which depend on the attenuation characteristics of the highly attenuative materials. When it is only possible to test short segments or areas of a test structure at a time (i.e., when the possible inspection ranges are very small), it becomes difficult or—in any case—at least expensive and therefore potentially commercially unviable to test long (and / or large) structures, such as tendons embedded in concrete.

[0050] Although high-power ultrasonic transducers exist, they have not typically been applied to guided wave generation due to difficulties in controlling excitation (i.e., difficulties in making the excited modes reproducible). Careful selection of excited modes and modeling the interaction of these guided waves with defects has traditionally been the focus of research and development in the field of guided waves. On the other hand, high-power ultrasound has traditionally been used in various applications such as ultrasonic cleaning, cavitation, welding, cutting, and infrared imaging.

[0051] This disclosure proposes the use of high-power ultrasonic transducers for guided wave excitation, in a manner that makes it possible to reliably and uniformly excite guided waves in test structures at relatively high vibration amplitudes, which in turn allows for the detection of defects with enhanced inspection ranges, using said guided waves.

[0052] Figure 1 schematically illustrates a first high-power ultrasonic excitation arrangement 100 disclosed herein. The ultrasonic excitation arrangement 100 comprises, Petition 870250113100, dated 09 / 12 / 2025, page 24 / 51 17 / 31 in its essence, a high-power ultrasonic transducer 10 and a housing 20. The housing 20 defines a space volume 21 to accommodate an ultrasound transmission medium 22. In Figure 1, the space volume 21 is filled with the ultrasound transmission medium 22, or the ultrasound transmission medium 22 may be introduced later into the housing 20.

[0053] Importantly, the housing 20 is adapted in such a way that, in use, the ultrasound transmission medium 22 can receive the ultrasound 1 emitted by the high-power ultrasonic transducer 10 (in this case, the high-power ultrasonic transducer directly injects the ultrasound 1 into the ultrasound transmission medium 22, which in the described implementations is a gel). The housing 20 is also adapted to interact with a test structure 30, so that the test structure 30 can receive the ultrasound 1, which was injected by the high-power ultrasonic transducer 10 into the gel 22 – from the gel 22. As a result, high-amplitude guided waves 2 can be uniformly excited in the test structure 30.

[0054] Figures 2 to 5 show variations of the high-power excitation arrangement 100 of Figure 1. The same or similar test structures 30 are used in the configurations shown in Figures 1 to 5. Furthermore, the high-power ultrasonic transducer 10 is powered by the same electronics 13, part of which can be seen, for example, in Figure 1. However, in Figures 1, 2, 4 and 5, the high-power ultrasonic transducer 10 comprises a mechanical resonator 11 (or horn 11), which is not present (and therefore not shown) in the configuration of Figure 3. In Figure 3, the arrangement 100 comprises only a ready-to-use high-power ultrasonic transducer 10, which in this case is a conventional 50-Watt ultrasonic cleaner (although other similar transducers could be used).

[0055] The configurations in figures 1 and 2 differ with respect to the insertion lengths of one end 32 of the structure. Petition 870250113100, dated 09 / 12 / 2025, p. 25 / 51 18 / 31 test 30 in the volume of space 21 filled with gel 22, inside housing 20: in Figure 1, the test structure 30, in this case a metal rod measuring approximately 15 mm in diameter (as an example), projects a few centimeters into the volume of space 21 filled with gel 22; in Figure 2, the end face of the test structure 30 projects only marginally into said space 21. Furthermore, the projections of the resonator 11 in said volume of space 21 are slightly different between Figures 1 and 2, as can be seen. This, however, did not alter the result of the uniform induction of high-amplitude guided waves in the test structure 30.

[0056] In Figure 5, an entire length 33 of the test structure 30 is accommodated within the housing 20 and in contact with the gel 22. The mechanical resonator 11 is almost entirely inserted into the volume of the space 21 that accommodates the gel 22. The respective longitudinal axes defined by the transducer 10 and the test structure 30 itself are substantially perpendicular to each other, although it is possible to have different angles, including a 'zero' angle, corresponding to a parallelism relationship between the longitudinal axes of the elongated test structure 30 and the horn 11. Again, this did not alter the result of the uniform induction of high-amplitude guided waves in the test structure 30.

[0057] In Figure 4, the mechanical resonator 11 is further retracted towards the outer part of the housing 20, compared to the configurations shown in Figures 1 and 2. In Figure 4, the mechanical resonator 11 has its distal face almost flush, i.e., coplanar with an inner surface of the housing 20, as can be seen. Again, this did not alter the result of the uniform induction of high-amplitude guided waves in the test structure 30.

[0058] Despite the differences described above, in all configurations of figures 1 to 5, the ultrasonic transducer of Petition 870250113100, dated 09 / 12 / 2025, page 26 / 51 19 / 31 high power 10 (with or without mechanical resonator 11), regardless of the configuration of the test structure 30 within the housing 20, was able to excite guided waves 2 with the desired amplitudes in the test structures 30, as schematically represented in each of figures 1 to 5.

[0059] Figures 6, 7 and 8 show actual implementations of prototype high-power ultrasonic excitation arrays 100, in principle similar to those shown in Figures 1, 2 and 5, respectively. The high-power ultrasonic arrays 100 shown in these figures are all designed using a parallelepiped-shaped box to provide the housing 20 mentioned above. It is anticipated that commercial versions of the high-power ultrasonic excitation arrays 100 will, however, comprise cylindrical compartments 20, to better suit the geometry of the elongated metal structures 30, which are of particular interest here. Other shapes may, however, be considered and implemented, depending on the applications.Figure 20 described below shows, for example, an alternative excitation configuration comprising a relatively rigid housing portion and a relatively flexible housing portion, which cooperate to define the volume of space occupied by the gel.

[0060] The high-power ultrasonic excitation arrangement 100 of figure 6 closely follows the schematic ultrasonic excitation arrangement 100 shown in figure 1. However, in addition, in figure 6, a seal 25 in the form of a sealing ring is provided, which serves to prevent the spillage of ultrasonic transmitter gel 22 out of the housing 20, from the excitation opening 23, between the resonator 11 and the housing wall from where the resonator 11 is received.

[0061] The high-power ultrasonic excitation arrangement 100 in Figure 7 is, in fact, a real-world implementation of the arrangement. Petition 870250113100, dated 09 / 12 / 2025, page 27 / 51 The schematic ultrasonic excitation arrangement 100 illustrated in Figure 2 is shown. The high-power ultrasonic excitation arrangement 100 of Figure 8 is, in fact, essentially consistent with the schematic ultrasonic excitation arrangement 100 shown schematically in Figure 5: in particular, it can be noted that in both arrangements 100 the longitudinal axes defined by the high-power ultrasonic transducer 10 and the test structure 30, respectively, do not intersect and are substantially at 90 degrees to each other. After filling the volume of the space 21 defined within the housing 20 with the ultrasonic transmitting medium 22, the housing 20 (which in the arrangement 100 described currently has the form of a square container with walls or a receptacle) can be closed using a lid 27 (shown in Figure 8). The cover 27 can be removed or replaced, as appropriate, for example, if and when the ultrasound transmission medium 22 needs to be replaced or replenished.

[0062] Figures 7 and 8 also show other parts of the electronics 13 used to drive the high-power ultrasonic transducer 10. It is not within the scope of this disclosure to describe in detail such electronic components 13, as these components will be entirely consistent with readily available components in the state of the art.

[0063] Before proceeding to Figures 9 to 12, - which demonstrate the use of high-power ultrasonic arrays 100, as described herein, adapted to excite high-amplitude guided waves 2 in test structures 30 other than the elongated metallic components shown in Figures 1 to 8 (i.e., in essentially two-dimensional structures such as floors, plates or walls, such as floors and walls of fuel storage tanks or the like) - some additional attention will now be given to the housing features 20 that effectively enable the high-power ultrasonic transducer Petition 870250113100, dated 09 / 12 / 2025, page 28 / 51 21 / 31 power 10 inject ultrasound 1 into the ultrasound transmitter medium 22 on one side, and that any elongated metal test structure 30 receives most of said ultrasound 1 (part of its energy will inevitably dissipate due to friction or dispersion, for example, in the housing 20) from the ultrasound transmitter medium 22.

[0064] More specifically, the ultrasonic excitation arrangements 100 of figures 1 to 8 provide for the presence of an orifice 23 formed in a wall of the housing 20 to receive the high-power ultrasonic transducer 10 and / or its resonator 11, if present, and the presence of one or more openings 24 also formed in a wall of the housing 20 (which may be the same or a different wall compared to the wall of the housing 20 where the orifice 23 is provided) to allow one end 32 of the elongated metal structure 30, or an entire length 33 thereof, as the case may be, to be accommodated in the housing 20, to be immersed and surrounded by the ultrasound transmission medium 22 when this is present within the housing 20.

[0065] Different adaptations of housing 20, in addition to those described herein, may occur to the qualified professional. This disclosure teaches that housing 20 should be adapted so that ultrasound 1 is able to be transferred from the high-power ultrasonic transducer 10 to the ultrasound transmission medium 22 present in housing 20 first and then, from the ultrasound transmission medium 22, the ultrasound 1 is transferred to the test frame 30, so that high-amplitude guided waves 2 are generated uniformly in the test frame 30. It is convenient that the high-power ultrasonic transducer 10 (with its horn 11, when supplied) and the test frame 30 are in direct contact with the ultrasound transmission medium 22, since this configuration requires minimal and inexpensive adaptations to housing 20. However, other adaptations may be devised in which such direct contact is not necessary. Petition 870250113100, dated 09 / 12 / 2025, page 29 / 51 22 / 31 is required, as shown in Figures 9 and 10. In the case of Figure 20, only the transducer / horn is in direct contact with the ultrasound transmission medium, but not the test component, as described later.

[0066] Figure 9 is a schematic representation of an additional ultrasonic excitation arrangement 100 disclosed herein, for the inspection of a floor 30 (i.e., a plate) of a fuel storage tank. Arrangement 100 of Figures 9 and 10 (which shows a close-up view of arrangement 100 of Figure 9) is in many respects similar to that of Figures 1 to 8. However, housing 20, instead of defining an opening 24 to receive part of the test structure 30, defines an ultrasound outlet 28 which is still in the form of an opening similar to that or those shown in Figures 1 to 8, but is used to transmit ultrasound 1 from gel 22 to plate 30, which is now located outside housing 20. In this described arrangement 100, the ultrasound outlet 28 also comprises a barrier 26 (provided in the described arrangement 100 in the form of a film, but other materials may be used).This barrier 26 not only prevents the ultrasound transmission medium 22 from leaking out of the housing 20, but also allows ultrasound 1 to be transmitted to the floor 30 of the fuel storage tank through the barrier 26, so that guided waves 2 are generated, as shown in figure 10.

[0067] In a variation of the arrangement described above, the film 26 could be provided in the form of a sleeve extending inwards, for use with the configuration of any of Figures 1, 3, 4 and 5. By using such a sleeve, contact between the test structure 30 and the ultrasound transmitting gel 22 can be advantageously avoided, which may be desirable in some implementations. In the case of the excitation arrangement of Figure 20 (which is described further below), the plastic sleeve projects outwards from a metal cone, which plays a Petition 870250113100, dated 09 / 12 / 2025, p. 30 / 51 23 / 31 function similar to that of the box in figures 1 to 10.

[0068] We will now describe some test results obtained on sample test structures 30, using the guided wave excitation arrangements 100 described herein. We will then return to figures 11 and 12, since figures 11 and 12 conceptually represent the extension of testing from essentially one-dimensional (i.e., predominantly linear) test structures (such as rods, bars, tendons, rails or tubes) to essentially two-dimensional test structures, such as plates or walls.

[0069] Remaining, therefore, for the time being, in the domain of testing predominantly linear test structures 30, Figure 13 is a perspective view of a test rod 30 with a simulated defect 31. The test rod 30 was specifically prepared to validate the use of the high-power ultrasonic excitation arrangements 100 described herein. The tests were initially performed on the test rod 30 in the absence of the defect 31. The defect 31 was artificially introduced by removing a portion (a few millimeters) of the rod material from its circumference, only on one side of the test rod 30, for a length of about 10 to 15 centimeters. The experiments were then performed using the configurations of Figures 1 to 5. All configurations were able to excite similar guided waves 2 on the test rod 30. However, the results presented below are obtained from experiments using the configuration of Figure 1.Consequently, the high-power ultrasonic excitation arrangement 100 was used at one end of the test rod 30, and a standard acoustic emission receiver 12 (an example of which is shown in Figure 15) was used at the other end to receive the guided waves 2, directly in contact with an end face of the test rod 30.

[0070] With reference now to figure 14, three tests were initially performed with the metal test rod 30 in Petition 870250113100, dated 09 / 12 / 2025, page 31 / 51 24 / 31 absence of a defect 31. Both the peak amplitude 51 and the energy values ​​53 of the measured ultrasonic signal 50 received by the receiver 12 were repeatable, as shown by: Figure 14 b), representing the response signal 50 measured by the ultrasound receiver 12; Figure 14 a) showing on the left the peak amplitude values ​​51 of the three initial tests; and, Figure 14 d) also showing on the left the values ​​of an energy parameter 53 also associated with the three initial tests.

[0071] With continuous reference to Figure 14, the defect 31 described above was introduced to simulate general corrosion. Three more tests were performed under equivalent conditions. The simulated corrosion 31 caused attenuation in both the measured peak amplitude values ​​52 and the energy parameter values ​​54 in these three subsequent tests. Figure 14c) shows a spectrum associated with the signal measured in one of the tests of the test rod 30 with the defect 31.

[0072] Regarding Figure 15, it shows an ultrasound receiver 12 placed directly on a reinforced concrete surface 35. Tests were performed to verify whether the guided waves 2, as excited here, would be detected by the ultrasound receiver 12. The results of these tests are summarized in Figure 16. Figures 16 a) and b) on the left represent, respectively, the peak amplitude values ​​and the values ​​associated with an energy parameter as a function of time, in a first test. Figures 16 b) and c) on the right represent, respectively, the same peak amplitude values ​​and the same energy parameter values ​​as a function of time, in a second test. The tests show that the excited guided waves 2 have sufficient energy for the ultrasound receiver 12 to be able to capture them from the reinforced concrete surface 35. This would not be possible with guided waves Petition 870250113100, dated 09 / 12 / 2025, p. 32 / 51 Conventional 25 / 31, according to the state of the art: the ultrasound receiver 12 would exhibit only noise or, in any case, a borderline signal level (e.g., with a peak amplitude of only 40 dB), which would make defect detection really difficult or even impossible. It is expected that, in the presence of a defect, for example, a defect similar to the artificial defect 31 in Figure 13, in the test structure 30 in Figure 15, the peak amplitude values ​​and the values ​​of the energy parameters observed in Figure 16 would consistently drop with the drops observed in Figures 14 a) and ed), i.e., by a few decibels (dB). These drops undoubtedly represent a viable sensitivity to defects.

[0073] Figure 17 shows, at a wider angle, the high-power ultrasonic excitation array 100, previously shown in Figure 8. Here, tests are performed with or without tension in the tendon 30, and the results are plotted in Figure 18, respectively. The tension was between 1000N and 1500N in a 14 mm diameter tendon in the first three tests, which returned higher peak amplitude values ​​55. The tension was completely released in the following three tests (this is what would happen in real life with a ruptured tendon, for example, within a layer of concrete), with lower peak amplitude values ​​56. Given the relationship between tension and signal amplitude, it would also be possible to use this technique to measure tension in a tendon.

[0074] Figure 19 shows a comparative view of two frequency spectra 57, 58 obtained from excited guided waves using an arrangement as described herein and measured on a fault-free structure and a faulty structure, respectively. The difference in frequency content of the two spectra is indicative of the presence of a defect.

[0075] With regard now to figures 11 and 12, figure 11 shows 16 positions from XD1 to XD16 in which receptors of Petition 870250113100, dated 09 / 12 / 2025, page 33 / 51 26 / 31 ultrasound 12 similar to that shown in Figure 15 can be positioned. The test structure is a metal plate 30, as shown in Figures 9 and 10, and the corresponding high-power ultrasonic excitation arrangement 100, also seen in Figures 9 and 10, is used. Guided waves 2 are initially generated on the metal plate 30 from a first selected position on the surface of the metal plate 34, for example, near position XD1. Then, the process is repeated with excitation from a second selected position on the surface of the metal plate 34, for example, near XD2. Parameters such as time of flight or attenuation are then calculated for each of the ultrasound receivers 12. By comparing these values ​​and plotting them as a function of space, it is possible to visualize a map showing the location of potential defects on the plate, and not just their possible presence.To increase the accuracy of the map thus obtained, the process can be repeated, exciting, in turn, from positions close to each ultrasound receiver 12, as shown in figure 11. Furthermore, instead of using 16 locations around the circular plate 30, as shown in figure 11, more locations could be added (or fewer).

[0076] Figure 12 schematically describes a method for inspecting the outer cylindrical wall 30 of the fuel storage tank mentioned in connection with Figures 9 and 10. Two robots R1 and R2 are designed, adapted to move in circumferences, respectively, at the base and top of the cylindrical wall 30 to be inspected, as shown in Figure 12. The method comprises providing a high-power ultrasonic excitation arrangement of the type shown in Figures 9 and 10 in one of the two robots, for example, R1. The method also comprises providing at least one ultrasonic receiver 12 (similar in principle to that shown in Figure 15) in the second robot D2. When moving robots R1 and R2 Petition 870250113100, dated 09 / 12 / 2025, page 34 / 51 27 / 31 simultaneously along the aforementioned circumferences, it is possible to inspect the entire area of ​​the cylindrical wall for defects, preferably using detection parameters such as time of flight or attenuation. Moving robots R1 and R2 simultaneously is not the only applicable strategy. Alternatively, one robot, for example, R1, carrying a high-power ultrasonic excitation array 100, as described here, can be kept in a fixed location, and robot R2 carrying the ultrasound receiver can be moved to measure the guided waves 2 at various locations around the respective circumference, or vice versa. In either case, maps similar in principle to those obtained using the arrangement in Figure 11 can be obtained.

[0077] An inspector wishing to use the present high-power ultrasonic excitation arrangements 100 must use ear protection, as in other high-power ultrasonic applications such as ultrasonic cleaning, welding, cutting or ultrasonic infrared imaging. Noises not discernible to the human ear (because they arise from frequencies well above 20 kHz), but with high intensity levels (e.g., 80 dB or more), can otherwise damage the auditory tissues. Conversely, this is not a necessary requirement in guided wave applications.

[0078] Although various applications have been discussed in this disclosure with the aim of illustrating one or more advantages related to the introduction of the present high-power ultrasonic excitation arrangements 100, the list of these applications should not be considered exhaustive. Those skilled in the art would be able to utilize the present teachings in a wide range of applications, for example, in non-destructive testing.

[0079] One of these applications is illustrated, for example, with reference to Figure 20. Figure 20 a) shows a compartment Petition 870250113100, dated 09 / 12 / 2025, page 35 / 51 A hollow conical metal tube 20R is coupled to a substantially flexible housing portion 20F, which in this case is implemented as a plastic bag 29 made of a thin plastic material. The conical compartment 20R and the plastic bag 29 together define a space volume 21 which, in use, is occupied by an ultrasound transmission medium (not shown in Figure 20). The cone 20R is substantially rigid or, in any case, relatively more rigid than the bag 29; the cone 20R could alternatively be made of a rigid plastic material. In Figure 20b), the ultrasonic horn 10 is inserted into the space 21 delimited by the hollow cone. This serves to generate ultrasound, for example, in gel previously supplied to fill the conical cavity 21. As the gel also occupies the volume of space 21 defined by the plastic bag 29, the ultrasound propagates to the internal volume of the bag 29.In Figure 20c, the bag 29 is at least partially enclosed around a test structure 30, which in this case is a metallic tube, and the ultrasonic transducer / horn 10 is powered by electrical connections as needed before excitation can be applied to the test structure 30 and tests can be performed. The test structure 30, in this configuration, is not disposed within the housing 20, but it is the flexible portion 20F of the housing 20 that is conformed (more particularly, in this case, fully enclosed) to the test structure 30, with similar excitation results. This is possible because the ultrasound 1 is still able to reverberate within the ultrasound transmission medium, and the thin walls of the plastic bag 29 are able to significantly transmit the ultrasound 1 externally, directly to the test structure 30, thus generating the desired guided waves 2.

[0080] The excitation arrangement in Figure 20 is more suitable for test structures 30, which are more difficult to access, given the flexibility of the bag 29, which can be easily Petition 870250113100, dated 09 / 12 / 2025, p. 36 / 51 29 / 31 adapted to the format of the test structure 30. It will also be observed that, although in figure 20 the plastic bag 29 defines only a part of the volume of space 21 of the entire housing 20 filled with an ultrasound transmitting medium (not shown), in principle, the housing 20 can be entirely made of a substantially flexible and / or shape-compatible material, just as the housing can be entirely made using a relatively rigid material, such as a metal (as described above) or a relatively rigid plastic material, such as a thermosetting plastic. The test structure can therefore be arranged internally or externally to the housing, depending on the intended application and the configurations suitable for it – provided that it can eventually receive the ultrasonic waves that have developed in the volume of space filled with the ultrasound transmitting medium defined by the housing.

[0081] This disclosure focuses on mechanical aspects related to the excitation of high-amplitude guided waves in test structures and, as such, does not disclose details regarding any electronic components that may be used to drive the transducers on the excitation side or to measure the excited guided waves on the receiving side. Those skilled in the art would find suitable electronic components for the present purposes in the prior art.

[0082] Furthermore, although the calculation of certain parameters related to the excited guided wave has been mentioned here, again the list of these mentioned parameters should not be interpreted exhaustively. Depending on the specific applications, certain other parameters may be more suitable for detecting the investigated defects, and one skilled in the art would be able to select the appropriate parameters based on the teachings of the state of the art. LIST OF REFERENCE NUMBERS: Petition 870250113100, dated 09 / 12 / 2025, page 37 / 51 30 / 31 Ultrasound Guided waves High-power ultrasonic transducer Mechanical resonator Ultrasound receiver Electronics Accommodation 20R Substantially and / or relatively rigid part of the housing 20F A substantially and / or relatively flexible part of the accommodation Space volume in accommodation Ultrasound transmission medium Hole Opening Sealer Barrier Cover Ultrasound output (from the housing) Plastic bag or pocket Test structure Defect to be detected End of test structure Test frame length Test structure surface Attenuating material Infrastructure Ultrasonic signal measured at the ultrasound receiver. Peak amplitude (without defect) Peak amplitude (defect) Power parameter (no defect) Power parameter (defect) Peak amplitude (voltage) Petition 870250113100, dated 09 / 12 / 2025, pages 38 / 51 31 / 31 Peak amplitude (without voltage) Frequency spectrum (defect-free) Frequency spectrum (defect) 100 Ultrasonic excitation arrangement XD1, XD2, XD3,..., XD16 Positions of the ultrasound receivers in the R1 test structure. First robot. R2 Second robot Petition 870250113100, dated 09 / 12 / 2025, pp. 39 / 51

Claims

1 / 9 CLAIMS 1. Ultrasonic excitation arrangement, characterized in that it comprises: a high-power ultrasonic transducer; and a housing, the housing defining a space volume to accommodate an ultrasound transmission medium, wherein the housing is adapted so that, in use, the ultrasound transmission medium receives the ultrasound emitted by the high-power ultrasonic transducer, and a test structure receives the ultrasound from the ultrasound transmission medium.

2. Arrangement according to claim 1, characterized in that the high-power ultrasonic transducer is adapted to excite ultrasound with one or more frequency components in the spectrum between about 20 kHz and about 100 kHz.

3. Arrangement according to claim 1 or 2, characterized in that the high-power ultrasonic transducer comprises a mechanical resonator; optionally, wherein the mechanical resonator has at least one nominal resonant frequency in the spectrum between about 20 kHz and about 100 kHz.

4. Arrangement according to claim 1, 2 or 3, characterized in that the high-power ultrasonic transducer is selected to generate displacements on an active transducer surface measuring 1 micrometer or more; more preferably, 2 micrometers or more; more preferably, 5 micrometers or more; most preferably, 10 micrometers or more.

5. Arrangement, according to any of the preceding claims, characterized in that the housing is provided as a substantially rigid compartment, or in that the housing comprises a substantially rigid compartment portion; optionally, in that said compartment or substantially rigid compartment portion is made of metal.

6. An arrangement according to any of the preceding claims, characterized in that the housing is provided as a substantially flexible compartment, or in that the housing comprises a substantially flexible compartment portion; optionally, in that said compartment or substantially flexible compartment portion is made of a thin plastic material, such as a film or a sheet; optionally, in that said compartment or substantially flexible compartment portion is provided as a pouch made of a thin film or thin sheet of plastic material.

7. Arrangement according to claim 5 or 6, characterized in that the housing comprises a substantially rigid compartment portion and a substantially flexible compartment portion; optionally, wherein the substantially flexible compartment portion is provided as a pocket or pouch of a thin plastic material attached to and projecting outward from the substantially rigid compartment portion of said housing.

8. Arrangement according to claim 5, 6 or 7, characterized in that the substantially rigid compartment and / or portion of the compartment is generally in the form of a parallelepiped, a cone or a cylinder; optionally, wherein said substantially rigid compartment and / or portion of the compartment comprises two or more mountable parts; optionally, wherein said two or more mountable parts comprise a receiving part and a covering part; optionally, wherein said two or more mountable parts are also demountable. Petition 870250089980, dated 02 / 10 / 2025, p. 23 / 31 3 / 9 9. Arrangement, according to any of the preceding claims, characterized in that the housing comprises an orifice for receiving the high-power ultrasonic transducer.

10. Arrangement according to claim 9, characterized in that the orifice is in communication with said space volume.

11. Arrangement according to claim 9 or 10, characterized in that the arrangement further comprises a seal for sealing between the housing and the high-power ultrasonic transducer.

12. An arrangement according to any of the preceding claims, characterized in that the arrangement further comprises said test structure.

13. Arrangement according to claim 12, characterized in that said test structure is an elongated metallic component.

14. Arrangement according to claim 13, characterized in that the metallic component is one of the following: a bar, a rod, a tendon, a rail or a tube.

15. Arrangement, according to claim 13 or 14, characterized in that the housing comprises at least one opening to receive a portion of said elongated metallic component in said space volume to accommodate an ultrasound transmission medium.

16. Arrangement according to claim 9 or 15, characterized in that the housing comprises one and only one opening to receive one end of said elongated metallic component, and in which said orifice and said opening are positioned relatively such that, in use, the high-power ultrasonic transducer and said end of the elongated metallic component are generally arranged opposite each other; Petition 870250089980, dated 02 / 10 / 2025, page 24 / 31 4 / 9 optionally, in which the high-power ultrasonic transducer and said end of the elongated metallic component are generally arranged face to face; optionally, in which the high-power ultrasonic transducer and said end of the elongated metallic component are generally arranged along a common straight line.

17. Arrangement according to claim 9 or 15, characterized in that the housing comprises at least two openings for receiving a length of said elongated metallic component, and wherein said orifice and said openings are positioned so that, in use, the high-power ultrasonic transducer and said end of the elongated metallic component are arranged along non-intersecting directions; optionally, wherein the high-power ultrasonic transducer and said extension of the elongated metallic component are arranged substantially parallel to each other; optionally, wherein the high-power ultrasonic transducer and said end of the elongated metallic component are arranged substantially perpendicular to each other.

18. Arrangement according to claim 12, characterized in that the test structure is a metal plate, such as a flat plate or a curved wall, such as a cylindrical wall; optionally, wherein said plate and / or wall define a circle.

19. Arrangement according to claim 18, characterized in that the housing comprises at least one outlet for emitting ultrasound received by the test structure from the ultrasound transmission medium.

20. Arrangement, according to claim 19, characterized in that said outlet comprises a barrier to prevent the ultrasound transmission medium from leaking from the housing to the test structure.

21. Arrangement according to claim 20, characterized in that the barrier comprises, or is in the form of, a film, such as a thin film or thin sheet, made of a plastic material.

22. Arrangement according to claim 7 or 13, characterized in that the substantially flexible compartment or portion of a compartment is adapted to at least partially enclose said elongated metal component; optionally, wherein the elongated metal component is one of the following: a bar, a rod, a tendon, a rail or a tube; optionally, wherein said substantially flexible compartment or portion of a compartment is provided as a pouch made of a thin film or a thin sheet of a plastic material.

23. An arrangement according to any of the preceding claims, characterized in that the arrangement further comprises the ultrasound transmission medium; optionally, wherein the ultrasound transmission medium is a gel.

24. An arrangement, according to any of the preceding claims, characterized in that the high-power ultrasonic transducer is piezoelectric.

25. Non-destructive testing apparatus, characterized in that it comprises the ultrasonic excitation arrangement, as defined in any of the preceding claims, and one or more ultrasound receivers, which optionally are also piezoelectric.

26. Non-destructive testing apparatus, according to claim 25, characterized in that it further comprises electronic components for operating the high-power ultrasonic transducer and at least one ultrasound receiver in transmission mode; optionally, wherein said transmission mode operates using continuous ultrasonic transmission; or, wherein said transmission mode operates using transient or burst ultrasonic transmission.

27. Non-destructive testing method, characterized in that it comprises: exciting guided ultrasonic waves on a test structure using the ultrasonic excitation arrangement as defined in any one of claims 1 to 23, or the apparatus as defined in claim 24 or 25.

28. Method according to claim 27, when dependent on claim 25 or 26, characterized in that the method further comprises: measuring said excited guided waves using said one or more ultrasound receivers.

29. Method according to claim 28, characterized in that the method further comprises: arranging at least one or more ultrasound receptors in the test structure.

30. Method according to claim 28 or 29, characterized in that the method further comprises: arranging at least one or more ultrasound receptors in a material incorporating said test structure.

31. Method, according to claim 28, 9 or 30, characterized in that the method further comprises: calculating a peak amplitude and / or an energy parameter and / or a frequency spectrum and / or an attenuation parameter and / or a time of flight of said measured guided waves.

32. Method according to claim 31, characterized in that the method comprises calculating only the said attenuation parameter of the measured guided waves. Petition 870250089980, dated 02 / 10 / 2025, p. 27 / 31 7 / 9 33. A method, according to any one of claims 28 to 32, characterized in that the test structure is a metallic tendon and the method further comprises: estimating a tension in said metallic tendon and / or detecting the presence or absence of tension in said metallic tendon.

34. Method according to claim 27, when dependent on claim 22, characterized in that the method further comprises: enclosing said substantially flexible compartment or portion of compartment at least partially around said elongated metallic component; optionally, wherein the elongated metallic component is one of the following: a bar, a rod, a tendon, a rail or a tube; optionally, wherein the substantially flexible compartment or portion of compartment is provided as a pouch made of a thin film or a thin sheet of a plastic material.

35. A method according to any one of claims 28 to 32, characterized in that the test structure is a metal plate and the method further comprises: arranging a plurality of ultrasound receivers on the metal plate; exciting ultrasonic guided waves on the metal plate from a first selected position on the metal plate; exciting ultrasonic guided waves on the metal plate from at least one other selected position on the metal plate; and measuring the excited guided waves at the plurality of ultrasound receivers.

36. Method according to claim 35, characterized in that the method further comprises: exciting guided ultrasonic waves on the metal plate from a plurality of positions respectively proximal to the plurality of ultrasound receivers arranged on said metal plate.

37. A method according to any one of claims 28 to 33, characterized in that the method further comprises: providing the ultrasonic excitation arrangement in a first robot; providing at least one or more ultrasound receivers in a second robot; moving at least one of the first and second robots.

38. Infrastructure, characterized in that it comprises an ultrasonic excitation arrangement, as defined in any one of claims 1 to 24.

39. Infrastructure, according to claim 38, characterized in that the ultrasonic excitation arrangement is installed permanently or semi-permanently in said infrastructure.

40. Infrastructure, according to claim 38 or 39, characterized in that the infrastructure further comprises one or more ultrasound receivers.

41. Infrastructure, according to claim 40, characterized in that one or more ultrasound receivers are installed permanently or semi-permanently in said infrastructure.

42. A method for preparing a test structure, characterized in that it comprises a metallic component covered with attenuating material for non-destructive ultrasonic testing, the method comprising: removing a portion of said attenuating material to expose one or more parts of the metallic component; and arranging the ultrasonic excitation arrangement, as defined in any one of claims 1 to 24, on at least one of the exposed parts of said metallic component. Petition 870250089980, dated 02 / 10 / 2025, pp. 29 / 31 9 / 9 43. Method according to claim 42, characterized in that the method further comprises: arranging one or more ultrasound receptors in one or more exposed parts of said metallic component, or arranging one or more ultrasound receptors in the attenuating material. Petition 870250089980, dated 02 / 10 / 2025, pp. 30 / 31

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