Method and system for characterizing elongated media

Abstract

A method for characterizing the dynamic behavior of an elongated medium is disclosed. The method comprises the steps of: generating an input wave signal at an input position along the elongated medium; generating a first electrical signal by measuring a first output wave signal at a first position along the elongated medium; and generating a second electrical signal by measuring a second output wave signal at a second position along the elongated medium. The input wave signal includes a vibratory acoustic wave signal selected to excite a vibration mode of the elongated medium, the first electrical signal represents a first component of the first output wave signal, and the second electrical signal represents a second component of the second output wave signal. The method further comprises the steps of: comparing the first and second components of the vibration mode with respect to the first and second electrical signals; and calculating the dynamic response of the elongated medium based on the comparison step.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application claims priority to U.S. Patent Application No. 63 / 529,539, filed on 28 July 2023, and U.S. Patent Application No. 63 / 637,044, filed on 22 April 2024. The entire contents of these prior applications are incorporated herein by reference.

[0002] [Technical field] This application relates, as a whole, to the field of monitoring methods, and more particularly to the field of characterizing the vibroacoustic properties of elongated media. [Background technology]

[0003] Monitoring pressurized fluid systems is often challenging due to limited access to pipes, complex networks, and the varying sizes of defects being monitored and / or detected. Meanwhile, fluid loss can have negative environmental impacts (e.g., oil and natural gas pipelines, portable water waste) or lead to massive resource losses (as is the case with aging water networks worldwide), creating a growing need for systems that can adequately monitor the health of pressurized fluid systems. While traditional methods relied on manual inspections of structures, today's infrastructure demands more innovative approaches.

[0004] Methods relying on the detection of sound waves (acoustic waves) have been developed to identify defects in pipeline networks. Sound waves can be generated by a sound source at a given point on the outer wall of a pipe, and after the sound waves propagate through the pipe from the source to a detector, the acoustic detector can sense them at another point. By measuring the delta time it takes for the sound waves to propagate from the source to the detector, and by considering the pipe's characteristics, it is possible to estimate the structural integrity of a pipe segment between the sound source and the detector, or between two detectors. However, such methods often lack accuracy and may not adequately provide details such as the type, size, and severity of defects within the pipe. To improve the accuracy and number of defect details, other solutions utilizing electromagnetic systems for defect detection have also been developed. However, such methods are often invasive, destructive, costly, and / or limited to large-diameter pipe networks. [Overview of the project]

[0005] A method for characterizing the dynamic behavior of an elongated medium is provided according to a first embodiment. The method comprises the steps of: generating an input wave signal at an input position along the elongated medium; measuring a first output wave signal at a first position along the elongated medium spaced apart from the input position and generating a first electrical signal based thereon; measuring a second output wave signal at a second position along the elongated medium spaced apart from the input position and the first position and generating a second electrical signal based thereon, wherein the input wave signal includes a vibroacoustic wave signal selected to excite a vibration mode of the elongated medium; the first electrical signal represents a first component of the first output wave signal; and the second electrical signal represents a second component of the second output wave signal. The method further comprises the steps of: comparing the first and second components of the vibration mode with each other based on the first and second electrical signals; and calculating the dynamic response of the elongated medium based on the comparison step.

[0006] Furthermore, according to the above embodiment, for example, the input wave signal is selected to target the structural natural frequencies of the elongated medium so as to induce resonance in a predetermined frequency band.

[0007] Furthermore, according to the above embodiment, for example, the method further comprises the step of measuring the input wave signal at the input position and generating a third electrical signal based thereon, wherein the third electrical signal represents the third component of the input wave signal, and the comparison step further includes comparing the third component of the input wave signal on the third electrical signal with the first and second components of the first output wave signal and the second output wave signal on the first and second electrical signals.

[0008] Furthermore, according to the above embodiment, for example, the method further comprises the step of obtaining an analytical model of the elongated medium which includes at least the estimated acoustic characteristics of the elongated medium, and the input wave signal is defined by the estimated acoustic characteristics.

[0009] Furthermore, according to the above embodiment, for example, the method further comprises the steps of generating an experimental model of the elongated medium based on the first signal and the second signal, and updating the analytical model based on the experimental model, wherein the step of calculating the dynamic response is performed using the analytical model and / or the experimental model.

[0010] Furthermore, according to the above embodiment, for example, the method further comprises the step of associating a quality index with the generated experimental model, the quality index including a given value of the signal-to-noise ratio, the presence of the input signal in the output signal to be measured, and / or a given value of the coherence between the output signals.

[0011] Furthermore, according to the above embodiment, for example, the step of generating the experimental model includes the step of performing modal analysis of the elongated medium and the step of using the modal analysis during the step of acquiring the analysis model.

[0012] Furthermore, according to the above embodiment, for example, the step of performing the modal analysis includes the step of predicting the dynamic behavior of the elongated medium at a virtual position beyond the region demarcated between the input position and the first and second positions, using a nonlinear function.

[0013] Furthermore, according to the above embodiment, for example, the method further comprises the steps of dividing the dynamic response into a plurality of time windows and obtaining the dynamic response of the elongated medium for each of the plurality of time windows.

[0014] Furthermore, according to the above embodiment, for example, the step of obtaining the dynamic response for each of the plurality of time windows includes the step of calculating the signal average over a given frequency bandwidth.

[0015] Furthermore, according to the above embodiment, for example, the comparison step includes the steps of: calculating the cross-correlation between the first electrical signal and the second electrical signal; calculating the cross-correlation between the first electrical signal and the second electrical signal and the third electrical signal; calculating the transfer function between the first electrical signal and the second electrical signal and the third electrical signal; and / or calculating the predicted transfer function of the elongated medium between the first electrical signal and the second electrical signal based on the calculated transfer function.

[0016] Furthermore, according to the above embodiment, for example, the comparison step further includes a step of normalizing the predicted transfer function of the elongated medium with the calculated transfer function.

[0017] Furthermore, according to the above embodiment, for example, the method further comprises the steps of displaying the first output wave signal and the second output wave signal on a user interface, and / or displaying a visual representation on the user interface in response to the determination of the acquisition quality indicators of the measured first output wave signal and the second output wave signal.

[0018] Furthermore, according to the above aspect, for example, the step of generating the input signal includes the step of generating a set of timbres, and the set of timbres is continuously selected at a frequency or a predetermined pattern.

[0019] Furthermore, according to the above aspect, for example, the step of generating the input wave signal includes the step of selecting a first input wave signal for exciting the elongated medium in an axial shell-dominated wave frequency range and / or a fluid-dominated wave frequency range.

[0020] Furthermore, according to the above aspect, for example, the step of calculating the dynamic response is performed by solving a mathematical model including the following equation: JPEG2026528704000002.jpg18150 JPEG2026528704000003.jpg17150Here, k L 、k f 、k1, k2 are respectively the wave number of the compression wave, the wave number of the fluid wave, the wave number of the fluid-dominated wave, and the wave number of the axial shell-dominated wave, ν is the Poisson's ratio of the elongated medium, a is the radius of the elongated medium, B f is the bulk modulus of the external medium, E is the Young's modulus of the elongated medium, h is the wall thickness, ρ is the density of the shell material, and ω is the angular frequency.

[0021] Furthermore, according to the above aspect, for example, the method further includes the step of plotting a stiffness profile of the elongated medium, and the plotting step includes normalizing the stiffness profile based on the nominal stiffness of the elongated medium, plotting the normalized stiffness profile of the elongated medium to provide visualization means for identifying the stiffness difference between the nominal stiffness and the stiffness profile along the elongated medium, and / or plotting the Young's modulus, the density, the Poisson's ratio, the wall thickness, and / or the diameter of the elongated medium.

[0022] Furthermore, according to the above embodiment, for example, the calculation step includes the step of subtracting the third electrical signal from the first electrical signal and the second electrical signal.

[0023] Furthermore, according to the above embodiment, for example, the first component of the first output wave signal and / or the second component of the second output wave signal each include a mode frequency.

[0024] A system for characterizing an elongated medium is provided according to a second embodiment. The system comprises a wave generator configured to generate vibroacoustic waves, a plurality of sensing units mounted at different locations on the elongated medium, and a computing device communicated to the plurality of sensing units, wherein the vibroacoustic waves are selected to excite vibration modes of the elongated medium, and each sensing unit has a sensor for detecting and measuring an output wave signal at an output location along the elongated medium, and a processing unit for converting the measured output wave signal into an electrical signal, the computing device having a processing unit and a memory storing program commands executable by the processing unit for the following operations, the operations including receiving the telegraph signal from each of the plurality of sensing units when the input wave signal includes the excited vibration mode, generating an analysis model of the elongated medium, and calculating the dynamic behavior of the elongated medium by comparing the electrical signal from each of the plurality of sensing units with the analysis model.

[0025] Furthermore, according to the above embodiment, for example, each sensing unit further includes a geolocation classifier for identifying the geographic location of the sensing unit, and the operation targeted by the program instruction further includes receiving the geographic location of each sensing unit via the geolocation classifier and calculating the dynamic behavior using the geographic location of each sensing unit.

[0026] A system for characterizing an elongated medium is provided according to a third embodiment. The system comprises a wave generator configured to generate vibratory acoustic waves within the elongated medium, a plurality of sensing units mounted at different locations on the elongated medium, and a computing device communicated to the plurality of sensing units. Each sensing unit includes a geographic location identifier for identifying the geographic location of the sensing unit, a sensor for detecting and measuring the vibratory acoustic waves at output points along the elongated medium, and a processing unit for converting the measured vibratory acoustic waves into an output signal. The computing device includes a processing unit and a memory storing program commands executable by the processing unit for the following operations: the operations include receiving the output signals and geographic locations of each of the plurality of sensing units, generating an analysis model of the elongated medium, and calculating the dynamic behavior of the elongated medium by comparing the measured output signals and geographic locations with the analysis model.

[0027] A method for experimentally characterizing a pressurized fluid system is provided according to a fourth aspect. The method comprises the steps of: inputting one or more test input signals at an input point (the one or more test input signals having a duration at least longer than the time required to propagate throughout the pressurized fluid system); measuring output signals from a first output point and at least a second output point located away from the input point; calculating the cross-correlation of the output signals to obtain the dynamic response of the pressurized fluid system; dividing the dynamic response into a plurality of time windows; and obtaining the dynamic response of the pressurized fluid system for each of the plurality of time windows.

[0028] A data analysis method for a system for characterizing an elongated medium is provided according to a fifth aspect. The method comprises the steps of: receiving an input signal measured from an input position along the elongated medium; receiving a plurality of output signals from a selected position away from the input position along the elongated medium; processing the plurality of output signals to generate an experimental model of the elongated medium based on at least the plurality of output signals and the input signal; and calculating the dynamic behavior of the elongated medium from the experimental model.

[0029] A method for modifying an analytical model for characterizing an elongated medium is provided according to a sixth aspect. The method comprises the steps of: receiving analytical characteristics of the elongated medium; generating an analytical model of the elongated medium using the analytical characteristics; generating a vibroacoustic wave adapted to excite the elongated medium; propagating the generated vibroacoustic wave through the elongated medium; receiving a plurality of output signals extracted at selected positions along the elongated medium; processing the plurality of output signals and a measured input signal of the vibroacoustic wave from the input position to generate an experimental model of the elongated medium based on the plurality of output signals and the measured input signal; calculating the dynamic behavior of the elongated medium from the experimental model; and updating the analytical model using the calculated dynamic behavior, wherein the analytical model includes at least the estimated acoustic characteristics of the elongated medium, and the vibroacoustic wave is defined at least by the estimated acoustic characteristics of the analytical model of the elongated medium.

[0030] A method for experimentally characterizing a pressurized fluid system is provided according to a seventh aspect. The method comprises the steps of: inputting one or more test input signals at an input point; measuring the one or more test input signals from the input point; measuring output signals from a first output point and at least a second output point located away from the input point; calculating the cross-correlation of the output signals; calculating the cross-correlation of each output signal with respect to the measured one or more test input signals; calculating a transfer function between each output signal and the measured one or more test input signals; calculating a predicted transfer function of the pressurized fluid system between the output signal at the second output point and the output signal at the first output point based on the transfer function between the output signal at the first output point and the one or more test input signals; and normalizing the predicted transfer function of the pressurized fluid system with respect to the transfer function between the output signal at the second output point and the one or more test input signals.

[0031] A method for dynamically characterizing an elongated medium is provided according to an eighth aspect. The method comprises the steps of: selecting a first input signal that excites the elongated medium in at least an axial shell dominant wave frequency range; generating the first input signal via a wave generator operably coupled to the elongated medium; sensing the first input signal at an input position and sensing a first set of output signals at each output position along the elongated medium; processing the measured first set of output signals and the measured first input signal; solving a mathematical model; and generating a first experimental model of the elongated medium based on the solved mathematical model.

[0032] Many further features relating to the embodiments described herein, and combinations thereof, will be apparent to those skilled in the art by reading this disclosure. [Brief explanation of the drawing]

[0033] [Figure 1]Figure 1 is a schematic diagram of a system for characterizing elongated media according to one or more embodiments.

[0034] [Figure 2] Figure 2 is a schematic diagram of the sensing unit of the system shown in Figure 1, according to one embodiment.

[0035] [Figure 3] Figure 3 shows one embodiment of the system shown in Figure 1 for characterizing an elongated medium.

[0036] [Figure 4] Figure 4 shows another embodiment of the system of Figure 1 for characterizing an elongated medium, according to one embodiment.

[0037] [Figure 5] Figure 5 is a flowchart of a data analysis method that can be performed using the system in Figure 1 for characterizing an elongated medium, according to one embodiment.

[0038] [Figure 6] Figure 6 is a flowchart of a method for modifying an analysis model for characterizing an elongated medium, according to one embodiment.

[0039] [Figure 7] Figure 7 is a flowchart of a method for experimentally characterizing a pressurized fluid system according to one embodiment.

[0040] [Figure 8] Figure 8 is a block diagram of an exemplary computing device of the system shown in Figure 1, according to one exemplary embodiment.

[0041] [Figure 9] Figure 9 shows a first exemplary dynamic response profile according to one embodiment.

[0042] [Figure 10]Figure 10 shows a second exemplary dynamic response profile according to one embodiment.

[0043] [Figure 11] Figure 11 shows a third exemplary dynamic response profile according to one embodiment.

[0044] [Figure 12] Figure 12 shows a fourth exemplary dynamic response profile according to one embodiment. [Modes for carrying out the invention]

[0045] Referring to Figure 1, a schematic diagram of one embodiment of a system 100 for characterizing an elongated medium 102 is shown. During operation, the system 100 can characterize the dynamic behavior of the elongated medium 102 using the generation and measurement of vibroacoustic waves. The system 100 comprises a wave generator 104 configured to generate vibroacoustic waves within the elongated medium 102, and a plurality of sensing units 200a, b, c that are operably coupled to the elongated medium 102 at a plurality of select locations along the elongated medium 102 and sense the generated vibroacoustic waves propagating therein. The sensing units 200a, b, c are communicated to a computing device 106 for processing the measurements obtained by the sensing units 200a, b, c. In at least some embodiments, the computing device 106 is in communication with a user interface 108. In at least some embodiments, the computing device 106 is in wireless communication with the sensing units 200a, b, c via a wireless network 110. Wireless networks may include, for example, the Internet, a local area network (LAN), a personal area network (PAN), a metropolitan area network (MAN), or a wide area network (WAN). Wired communication between sensing units 200a, b, and c and the computing device 106 may also be considered. The features of the computing device 106 will be described later with reference to an exemplary computing device 800, with reference to Figure 8.

[0046] This technology is intended for the field of vibrational acoustics, which lies at the boundary between acoustics and structural dynamics. The generation, propagation, and measurement of vibrational acoustic waves can be carried out in both solid and fluid media. Therefore, this technology is not limited to fluids (which is generally the case for acoustic waves).

[0047] The elongated medium 102 is composed at least in part of a material that dynamically responds to the propagation of vibroacoustic waves, such as steel, iron, copper, and / or any suitable alloy. In at least some embodiments, the elongated medium 102 may include, as another possibility, plastics such as polyvinyl chloride (PVC). In at least some embodiments, the elongated medium 102 is a prestressed concrete pipe made of concrete and steel wires configured to optionally provide tensile stress to the pipe. The concrete pipe may be a wire-wrapped pipe, an asbestos cement pipe, or any other type of concrete pipe (e.g., a prestressed concrete pressure pipe (PCCP) having a steel core cylinder with concrete layers on the inside and outside). It will be understood that various other types of materials not enumerated herein may also be subject to the Art.

[0048] The elongated medium 102 can have various shapes depending on its application. In at least some embodiments, the elongated medium 102 has a tubular shape, which may have a cylindrical cross-section, or other possible cross-sections such as elliptical, oblong, square, circular, rectangular, hexagonal, or other polygonal. The diameter (or other lateral dimensions) and wall thickness may be constant or may vary along the elongation axis X. In at least some embodiments, the elongated medium 102 is configured to contain a pressurized fluid. In at least some embodiments, the elongated medium 102 is a pipe in a pressurized network such as a pipeline network or a water network. In other embodiments, the elongated medium 102 may be an acoustic propagation section or beam of an underground or surface structure.

[0049] The wave generator 104 is operably coupled to an elongated medium 102. The wave generator 104 is configured to generate an input signal 112 in the form of a vibratory acoustic wave that propagates within the elongated medium 102 when in use. The wave generator 104 is an electronic device capable of generating vibratory acoustic waves by selecting and / or controlling various characteristics of a wave signal, including amplitude, frequency, duration, and shape (waveform). The wave generator 104 may include function generators, arbitrary waveform generators, radio frequency (RF) generators, microwave generators, analog signal generators, audio frequency (AF) signal generators, vector signal generators, digital pattern generators, and the like. In at least some embodiments, the wave generator 104 may be portable. The compactness and weight of the wave generator 104 can be adapted (adjusted) to facilitate handling by the operator. This can be particularly advantageous for transporting the wave generator 104 between test sites with limited equipment or manpower. In some alternative examples, in addition to the wave generator 104, a modal hammer may be used to excite the elongated medium 102. As shown in Figure 1 and further described below, the wave generator 104 may be configured to produce vibratory acoustic waves 114 that propagate along the elongated medium 102. In response to the generated vibratory acoustic waves 114, the elongated medium 102 may enter a resonant state, thereby generating various harmonics or standing waves 114 or other propagating waves of a combination thereof.

[0050] The generated input signal 112 may be defined by a complex function including one or more sine waves or other waveforms having different timings, frequencies, and / or amplitudes. Generally, the input signal 112 has a duration longer than the time required to propagate through the elongated medium 102. The generated input 112 signal may also include one or more step functions and / or one or more impulse functions. In at least some embodiments, the wave generator 104 is configured to operate at frequencies in the range of 5 to 2000 Hz, which may be a suitable range for characterizing the tube. In other embodiments where the elongated medium 102 is a medium other than a tube, the frequency range may vary and may extend to a higher range, for example, above 10 kHz. The elongated medium 102 may function as a vibroacoustic filter. In other words, within some frequency bands, the elongated medium 102 may not affect the vibroacoustic waves. At some specific frequencies, or within a specific frequency band, the elongated medium 102 may cause changes in the vibroacoustic waves propagating through it. Vibrational acoustic waves propagate within the elongated medium 102 and can "store" or "carry" structural information associated with the vibrating elongated medium 102. The generated input signal 112 can therefore function as a carrier wave for the information extracted from the excited elongated medium 102. The generated input signal 112 can therefore be called a carrier signal. The vibrational acoustic properties and / or dynamic response of the elongated medium 102 may be considered when generating appropriate vibrational acoustic waves to most efficiently carry the information. In other words, the generated input signal 112 is considered to be adapted to the dynamic response of the elongated medium 102. The dynamic response of the elongated medium 102 can be determined via modal analysis. Modal analysis may allow for the identification of specific frequencies (or natural frequencies) of the elongated medium 102 and their associated deformation shapes. Modal analysis may be performed via finite element simulation or via experimental measurements, as will be further described later. The vibratory acoustic waves can be specifically selected ("tuned" or "constructed") to excite the elongated medium 102 by changing the frequency information of the excitation waveform, the type of excitation, the duration, etc.The generated vibroacoustic waves can be iteratively refined, as will be described later, until the desired quality of the signals sensed by sensing units 200a, b, and c is obtained. The term “vibroacoustic properties” used herein may refer to the properties of the dynamic response (which may be called “dynamic properties”) and vice versa.

[0051] The input signal 112 may include one or more sets of timbres (tones), i.e., one or more sets of given frequencies, as a method for dynamically exciting the elongated medium 102. Generally, the temporal length of the timbre is longer than the time required for the timbre to propagate through the elongated medium 102. In this case, the entire elongated medium 102 is excited by the timbre simultaneously. In practice, multiple timbres of different frequencies may be sequentially provided to the elongated medium 102 to create various types of excitation patterns. By measuring the correlation between the output signals measured by the sensing units 200a, b, and c, it is possible to obtain different structural information for each excitation pattern generated by the corresponding timbre. It will be understood that using timbres to excite the elongated medium 102 and measuring the output signals at multiple locations on the elongated medium 102 is generally suitable for characterizing nonlinear systems.

[0052] In at least some embodiments, timbres are obtained from a dictionary (also called a “library”) containing multiple timbres selected to create various excitation patterns for the elongated medium 102. If the elongated medium 102 is iteratively characterized and / or the vibroacoustic waves are iteratively refined (improved), the first iteration may include exciting the elongated medium 102 with vibroacoustic waves containing the entire dictionary. In subsequent iterations, it is not necessary to reproduce the entire dictionary, and timbres may be selected within the dictionary to extract specific structural information from the elongated medium 102 obtained in the first iteration. The dictionary may be general-purpose, i.e., not configured to create excitation patterns for a particular type of elongated medium, or it may be specific to the elongated medium 102 being characterized. In the latter case, the dictionary may be created based on analytical and / or experimental modeling of the elongated medium 102, as described below.

[0053] In one particular embodiment, the input signal 112 is a predefined signal formed by the successive execution of timbre intervals and periods of no signal. For example, the input signal 112 may include a signal in which a 20Hz timbre is played for 5 seconds, followed by 10 seconds of no signal, then a 40Hz timbre is played for 5 seconds, followed by 10 seconds of no signal, then a 60Hz timbre is played for 5 seconds, followed by 80Hz timbre is played for 5 seconds, followed by 10 seconds of no signal, then a 100Hz timbre is played for 5 seconds, followed by 10 seconds of no signal, then a 120Hz timbre is played for 5 seconds, followed by 10 seconds of no signal.

[0054] These predefined signals can be used for multiple elongated media and are therefore considered versatile.

[0055] Since the input signal 112 may include other types of signals, it will be understood that this disclosure is not limited to timbre. In one embodiment, the input signal 112 includes a broadband signal in which multiple timbres are convolved.

[0056] In other embodiments, the input signal 112 includes a sweep signal with a continuously increasing frequency. In this case, the time at each frequency is maintained in proportion to the wavelength at least in time. It is understood that the time at each frequency is at least longer than the time required for the input signal 112 to propagate through the elongated medium 102. In a particular embodiment, the input signal 112 may include a sweep signal that starts at 5 Hz and ends at 120 Hz, with an increment step of 5 Hz and a residence time of 5 seconds at each frequency. In another particular embodiment, the input signal 112 may include a chirp signal having a first sweep signal that starts at 5 Hz and ends at 10 Hz, a second sweep signal that starts at 5 Hz and ends at 15 Hz with an increment step of 5 Hz, a third sweep signal that starts at 5 Hz and ends at 20 Hz with an increment step of 5 Hz, and so on.

[0057] During operation, sensing units 200a, b, and c are dispersed along the elongation axis X, spaced apart by a fixed or varying distance. Such distances may be predetermined, as will be described later, or may be determined by geographical location. In at least some embodiments, sensing units 200a, b, and c are positioned at the same longitudinal position between adjacent sensing units, at different angular positions from one another, or at the same angular position. During operation, sensing units 200a, b, and c are configured to measure vibrational acoustic waves propagating within the elongated medium 102. The number of sensing units 200a, b, and c is not limited to the three shown in Figure 1, and it will be understood that any number of sensing units greater than one can be applied according to various embodiments. Sensing units 200a, b, and c are described further below.

[0058] Each of the sensing units 200a, b, and c is communicatively coupled to a computing device 106. The computing device 106 is configured to receive signals from the sensing units 200a, b, and c that indicate vibroacoustic characteristics or dynamic responses. Alternatively, the computing device 106 is configured to receive signals from the sensing units 200a, b, and c from which the vibroacoustic characteristics of the elongated medium 102 can be derived. Such signals are referred to herein as signal outputs that can be used as part of the single-input multiple-output (SIMO) characteristics of the elongated medium 102, and are described further below. The computing device 106 may be in wired communication with one or more of the sensing units 200a, b, and c, or it may be in wireless communication. In some embodiments in which the computing device 106 communicates with a user interface 108, the user interface 108 may be a mobile device such as a tablet or smartphone that can monitor and / or visualize the signals received from the sensing units 200a, b, and c. The visualization of the signal may take the form of one or more graphs, figures (e.g., cross-correlation spectrograms), or other visual representations, and / or visual indicators such as icons or other identifiers indicating the presence or absence of one or more output signals from sensing units 200a, b, c and / or acquired quality indicators. Signal quality indicators may be, for example, a given value of the signal-to-noise ratio, the presence of the input signal 112 in the measured signal, or a given value of coherence between signals measured at different outputs. If such indicators cannot be obtained by the computing device, a prompt indicating that the signal quality is insufficient for a representative measurement may be provided to the user interface 108. In at least some embodiments, the computing device 106 may form part of the user interface 108 (or vice versa), or part of at least one of the sensing units 200a, b, c.

[0059] Referring to Figure 2, a sensing unit 200, such as the sensing units 200a, b, and c described above, includes at least one sensor 202 and a processing unit 204. Optionally, the sensing unit 200 may include a geographic identifier 206. The sensing unit 200 is configured to acquire the dynamic response of an elongated medium 102 excited by an input signal 112 generated by a wave generator 104. In at least some embodiments, the sensor 202 is configured to generate impedance matching at the contact point between the sensing unit 200 and the elongated medium 102. In other embodiments, impedance matching is generated between the wave generator 104 and the elongated medium 102. The sensing unit 200 may have a data storage function for storing at least some of the data related to the measured dynamic response in the processing unit 204. Such data may be communicated via an output signal from the sensing unit 200. The sensor 202 and the processing unit 204 may be integrated, i.e., they do not necessarily have to be separate components of the sensing unit 200.

[0060] Sensor 202 is configured to detect and measure vibroacoustic waves. During operation, sensor 202 is configured to convert vibroacoustic waves, which propagate through the surface or interior of the elongated medium 102 and are measured at the output point, into an electrical signal. In at least some embodiments, sensor 202 may include a surface acoustic wave (SAW) sensor, a quartz crystal microbalance (QCM), and / or a thin-film bulk acoustic wave resonator (FBAR). In at least some embodiments, sensor 202 includes a micro-electromechanical system (MEMS). In at least some embodiments, sensor 202 includes an array of transducers. Other sensors 202 suitable for measuring vibroacoustic waves may be implemented in the sensing unit 200. For example, in at least some embodiments, sensor 202 includes an accelerometer such as a piezoelectric sensor. In other embodiments, sensor 202 includes dynamic response sensors such as a displacement sensor, a velocity sensor, or a strain gauge.

[0061] The vibration-acoustic waves measured by the sensor 202 are processed into an output signal (as described above), which can be stored in the processing unit 204 and / or transmitted to the computing device 106. The output signal represents the vibration-acoustic characteristics of the elongated medium 102, or allows for the derivation of such vibration-acoustic characteristics through processing. The output signal is then available to the computing device 106.

[0062] The geographical location of the sensing unit 200 may be required to obtain a geographical mapping of the dynamic behavior of the elongated medium 102. As previously stated, the sensing unit 200 may include a geographical location identifier 206, preferably a Global Positioning System (GPS) antenna or node for obtaining the geographical location coordinates of the sensing unit 200. The coordinates may allow for the measurement of distances between each location of the sensing unit 200. The sensing unit 200 may be configured, optionally, to transmit a geographical location signal indicating its location via the geographical location identifier 206. In at least some embodiments, the coordinates are stored in a processing unit 204 or a computing unit 106. In other embodiments, the coordinates are obtained by relating the location of the sensing unit 200 using a map. In other embodiments, the coordinates are referenced to the coordinates of other sensing units 200. In some modifications, the coordinates may be obtained by measuring the distance from a reference location, for example, using a measuring wheel or a laser rangefinder.

[0063] Figures 3 and 4 show embodiments of systems 300 and 400 for characterizing elongated media 302 and 402. Systems 300 and 400 and elongated media 302 and 402 may correspond to the aforementioned system 100 and elongated media 102. The features previously described for system 100 and elongated media 102 also apply to systems 300 and 400 and elongated media 302 and 402, and are therefore not repeated here for brevity. In Figure 3, system 300 includes a wave generator 304 connected to the outer surface of the elongated media 302. In the illustrated embodiment, the elongated media 302 is a tube (pipe) with pressurized fluid inside. Multiple sensing units 200 (two in this case) are each connected to a sensor 202. As shown in the figure, the elongated medium 302 may have a defect 306 and a leak 308, which are represented between two sensing units 200d and e along the elongation axis X. In practice, such defects 306 and leaks 308 may not be known before characterizing the elongated medium 302. As shown in the figure, the vibrational acoustic waves generated by the wave generator 304 may propagate through the elongated medium 302 and interact with the illustrated defects 306 and leaks 308. Such interactions may change the characteristics of the propagating waves, i.e., the wave's "signature". Therefore, the propagating vibrational acoustic waves measured by the sensing unit 200 may contain structural information of the elongated medium 302, including the changes caused by the defects 306 and leaks 308. It will be understood that using system 300, various other types of anomalies can be detected, such as deformation of the elongated medium 302, mineral accumulation inside and / or outside the elongated medium 302, and changes in stiffness in various parts of the elongated medium 302.

[0064] As shown in Figure 4, in the data acquisition application, system 400 is adapted to characterize a pipe network 402. In particular, the pipe network 402 may be a fire hydrant network. System 400 includes a plurality of sensing units 200f, g, h, i, j (five here, but other numbers are possible), each connected along the extensional axis X of the (multiple) pipes of the pipe network 402, and a wave generator 404 is connected to a fire hydrant of the pipe network 402. In other embodiments, the wave generator 404 may be connected to other interface components of the fire hydrant network, such as intermediate components between the wave generator 404 and the fire hydrant, pipe segments that fluidly communicate with the elongated medium 302, valves or access chambers, or other contact points on components connected in series with the elongated medium 302. The wave generator 404 may be connected to pipes or other interface components of the pipe network 402 as described above. System 400 is adapted for installation in pipe networks 402, such as fire hydrant networks, which typically consist of small pipes, but System 400 can also be installed in water supply mains, which consist of larger pipes. Therefore, this technology can be implemented in various types of pipe networks, regardless of pipe diameter.

[0065] The sensing units 200f, g, h, i, and j are connected to a computing device 406, such as the aforementioned computing device 106, to transmit output signals that represent (or from which these characteristics can be derived) the measured vibroacoustic characteristics of the pipe network 402. A user interface 408 may be connected to the computing device 406 to monitor and / or visualize the output signals received from the sensing units 200f, g, h, l, and j. The visualization of the signals may take the form of one or more graphs, figures, or other visual representations for visualizing the output signals or their characteristics, and / or visual indicators such as icons or other identifiers indicating the presence or absence of one or more output signals from the sensing units 200f, g, h, l, and j and / or acquisition quality indicators. Processing of the output signals by the computing device 406 may be part of the system characterization of the pipe network 402. The characterized system may be visualized on the user interface 408. The characterized system may include information (e.g., characteristics) about various parts of the pipe network 402, such as flow rate and pressure in the pipes, the presence of defects, mineral deposits and / or leaks in the pipe network 402, etc. In one embodiment, the user interface 408 may be a mobile device such as a tablet or smartphone. Other devices such as a portable computer or computer station may also be considered.

[0066] The output signals received from the sensing units 200a, b, and c may be calculated to create or at least modify an analytical model of the elongated medium 102 and / or to characterize the dynamic response of the elongated medium 102 to one or more input signals 112, as will be further described below. Methods for analyzing the vibroacoustic properties of the elongated medium 102 or a pressurized fluid system containing such an elongated medium 102 will also be described.

[0067] First, an analytical model of the elongated medium 102 or the pressurized fluid system can be calculated. The analytical model (or “simulation”) of the elongated medium 102 can help identify what input signals 112 should be generated to reveal information about the elongated medium 102. The analytical model can also be used to compare measured data or complete system characteristics, as described below, with the dynamic behavior expected from the physical properties of the dynamic behavior of the elongated medium 102. To construct the analytical model, information about the pressurized elongated medium 102 can be collected. Based on the collected information about the pressurized elongated medium (including the mechanical properties of the elongated medium), the analytical model can be obtained. The analytical model may include, for example, calculations of various coefficients and / or mechanical properties of the material of the elongated medium 102, such as geometry, tensile stress, mass, damping level, modulus of elasticity (E) (e.g., Young's modulus), stiffness level, sound absorption coefficient, thermal expansion coefficient, etc. If the elongated medium 102 is a prestressed concrete pipe, the tensile stress induced by the steel wire can be considered in the analytical model. The analytical model may include dimensional calculations and may also consider the geometry (constant or variable) of the elongated medium 102. In at least some embodiments, the analytical model includes calculations of coefficients of the fluid propagating inside and / or outside the elongated medium 102, such as density (p), specific heat, viscosity, compressibility (K), etc. A mathematical model recognized in the field of vibrational acoustics is established in the scientific paper entitled "Wavenumber Prediction of Waves in Buried Pipes for Leak Detection" by J. M. Guggleton, M. J. Rennan, and R. J. Innnington, published in the Journal of Sound and Vibration (2002) 249(5), pp. 939-954. The contents of this document are incorporated herein for reference. This publication presents the following formula derived from equilibrium relationships. This formula can be used to model the dynamic behavior of a cylindrical elongated medium. JPEG2026528704000004.jpg11170

[0068] Here, k L , k S , k f , k fsr , k d , k ds r , k r , k rs r are, respectively, the wave number of compression, the wave number of shear, the wave number of fluid, the internal radial wave number, the external longitudinal wave number, the internal longitudinal wave number, the external shear wave number, and the internal shear wave number, v is the Poisson's ratio, a is the radius, B f and B m are, respectively, the bulk modulus of the internal medium and the external medium, G m is the shear modulus of the external medium, E is the Young's modulus, h is the wall thickness, J O , J O ’, H O , H O ’ are, respectively, the Bessel function and the Hankel function of the 0th order. Using Equation (1), it is possible to solve the mathematical models of at least two types of waves, namely, s = 1 and s = 2. These correspond to the fluid-dominated wave and the axial shell-dominated wave, respectively.

[0069] In the cases of s = 1 (Equation (2)) and s = 2 (Equation (3)), the general mathematical formula (1) for the dynamic behavior of a cylindrical slender medium becomes as follows, respectively. JPEG2026528704000005.jpg16150 JPEG2026528704000006.jpg12150

[0070] Here, k1 is the wave number of the fluid-dominated wave, k2 is the wave number of the axial shell-dominated wave, p is the density of the shell material, and ω is the angular frequency. In at least some embodiments, the wave number k of compression L can be represented by the following mathematical formula. JPEG2026528704000007.jpg8170

[0071] The fluid-dominant wave (s=1) generally propagates along the longitudinal axis of the elongated medium 102 and oscillates perpendicular to this longitudinal axis. Therefore, it is sensitive to and highly dependent on the elastic and bulk moduli of the propagating materials, such as the fluid, the walls of the elongated medium 102, and, if underground, the surrounding soil. The axial shell-dominant wave (s=2) is typically confined within the walls of the elongated medium 102, and its propagation is typically less affected by and less dependent on the elastic and bulk moduli of the fluid and, if underground, the surrounding soil. Thus, in at least some embodiments, the sensing unit 200 can measure at least one, preferably both, of the fluid-dominant wave and the axial shell-dominant wave. It will be understood that both waves can coexist simultaneously and have different propagation velocities within the elongated medium 102. In such cases, frequency separation can occur (e.g., through data processing or filtering). In some cases, there may be overlap between frequency ranges, so the separation between frequency ranges may not be complete. When overlap occurs, a deconvolution algorithm may be used to separate the two waves from the measured signal. In other cases, the frequency ranges may not overlap, and the two waves can be extracted from the measured signal by separating the signal by time frame or by filtering the signal by frequency.

[0072] Subsequently, the dynamic behavior of the elongated medium 102 can be modeled using characteristics inferred from waves measured at input and output positions along the elongated medium 102. To model the dynamic behavior of the elongated medium 102, the elastic modulus, Poisson's ratio, and / or density of the walls of the elongated medium 102 can also be input into the model.

[0073] When the elongated medium 102 is a metal pipe, the fluid-dominant wave is generally dominant in the measured output signal because the elastic modulus of the pipe is substantially greater than that of the surrounding soil and fluid. In the case of such a metal pipe, the fluid-dominant wave can be measured in the frequency band of 0 Hz to 3,000 Hz. In such situations, the fluid-dominant wave tends to attenuate more slowly due to the high rigidity of such a pipe, so the fluid-dominant wave can be measured over long distances along the elongated medium 102. On the other hand, in the case of a metal pipe, the axial shell-dominant wave is rapidly attenuated by the pipe over relatively short distances, so the presence of the axial shell-dominant wave in the measured signal may be smaller or invisible at signal output locations along the elongated medium 102, unless the signal output locations are very close to each other, such as being several meters apart (e.g., less than 10 meters). Therefore, depending on the pipe configuration, it may be preferable to use the fluid-dominant wave to characterize the metal pipe.

[0074] In other cases, the elongated medium 102 may be a plastic or polymer pipe, or a network of plastic or polymer pipes, which generally have lower rigidity than metal. In such cases, when the fluid-dominant wave propagates through the plastic or polymer pipe, it is attenuated or "absorbed" more significantly by the pressurized fluid system compared to when the elongated medium is a metal pipe. Also, due to the dynamic properties of the plastic or polymer pipe, including lower elastic modulus and flexural modulus, the fluid-dominant wave may be measurable in a lower and narrower frequency band, for example, 0 Hz to 200 Hz. The elastic modulus of the pipe may be similar to that of soil. On the other hand, when propagating through the plastic or polymer pipe, the axial shell-dominant wave can propagate with less loss than when the elongated medium 102 is a metal pipe, because the dynamic properties of the walls of the plastic or polymer pipe result in less absorption (attenuation) of the axial shell-dominant wave within such a medium. Therefore, in the case of plastic or polymer pipes, the measurement of the axial shell-dominant wave in the output signal can be performed in a relatively low frequency band, for example, in the range of 200 Hz to 2,000 Hz. In contrast, in the case of a metal pipe, the axial shell-dominant wave is observed in a frequency band exceeding 3,000 Hz. In summary, depending on the properties of the elongated medium 102, the output signal may contain different types of waves in a given set of frequency bands.

[0075] However, if the elongated medium 102 is a prestressed concrete pressure pipe (PCCP) with a steel core cylinder having concrete layers on the inside and outside, the fluid-dominant wave may reveal the overall pipe hoop stiffness of the layered pipe design. On the other hand, the axial shell-dominant wave may reveal structural information regarding the integrity of the steel core cylinder.

[0076] In practice, an input signal 112 can be injected into the elongated medium 102, which can induce acoustic resonance or vibroacoustic resonance in response. This resonance may include harmonic oscillations that generate various types of waves across a wide range of frequency bands. In at least some embodiments, the resonance may generate fluid-dominant waves and axial-shell-dominant waves. In other words, amplification of various harmonics of the elongated medium 102 by vibroacoustic resonance can generate various types of waves within the elongated medium 102, including fluid-dominant waves and axial-shell-dominant waves. The signal measured by the sensor generally includes the input signal 112 and the generated resonance. By injecting an input signal 112 tuned based on the dynamic characteristics of the elongated medium, it may be permissible to induce more resonance and thereby cause more signal amplification, thereby extracting more reliable information about the elongated medium 102. Preferred excitations are those that target the structural natural frequencies of the elongated medium 102 to generate vibroacoustic resonances in the elongated medium 102 in order to obtain the dynamic response of the elongated medium 102. However, it will be understood that other types of excitations are also possible, such as excitations of vibrational modes that do not target the structural natural frequencies of the elongated medium 102. It will be understood that the vibrational modes can change, be in a stationary state or a propagating state, be longitudinal and / or transverse, and may include fundamental modes and / or harmonics. In at least some embodiments, a single vibrational mode may be excited in the elongated medium 102, but multiple modes may be excited.

[0077] In at least some embodiments, the parameters required to model the dynamic behavior of the elongated medium 102 are the modulus of elasticity, density, Poisson's ratio, wall thickness, and diameter. Thus, if the output signal contains information about fluid-dominant waves and axial-shell-dominant waves, it is possible to generate an experimental model using a mathematical model including equations (2) and (3). Due to the physical properties of these waves, assumptions must be made to reduce the number of parameters and leave one unknown parameter. In general, by assuming theoretical values ​​for the modulus of elasticity in the fluid-dominant wave equation and theoretical values ​​for the pipe thickness in the axial-shell-dominant wave, it is possible to use each equation independently to model the dynamic behavior of the pipe and derive the stiffness profile of the pipe. In other words, using assumptions, it may be possible to obtain the dynamic properties of the elongated medium 102 using only one of equations (2) or (3). Since assumptions are made about the wall properties of the elongated medium 102 instead of measuring these properties, using only one of equations (2) or (3) may be limiting in terms of analytical accuracy. However, by combining both equations (2) and (3) in a linear or nonlinear system, these assumptions can be eliminated, thereby making it possible to obtain dynamic behavior of the pipe that is not based on theoretical values, or is not based on theoretical values. As mentioned above, the proposed method requires a suitable elongated medium 102, such as a plastic pipe, polymer pipe, or metal pipe, with a short distance between the signal input position and the signal output position (or between adjacent signal output positions) so that both fluid-dominant waves and axial shell-dominant waves can be adequately measured. Thus, the positioning of the sensor can be selected according to the mechanical properties of the elongated medium 102, such as stiffness and size / dimensions.

[0078] In one embodiment, by exciting a plastic or polymer pipe, sensing the axial shell-dominant and fluid-dominant waves within the plastic or polymer pipe, and solving the mathematical model based on equations (2) and (3) described above, information regarding the stiffness and thickness of the pipe along its length, which cannot be obtained by relying solely on the fluid-dominant waves and associated signal data, can be provided. It has been found that, in the case of plastic or polymer pipes, the axial shell-dominant waves are in a lower frequency range than in the case of metal pipes, and therefore, exciting the elongated medium 102 to induce resonance in such a low frequency range can generate data that is reliable enough to dynamically characterize hundreds of meters of plastic or polymer pipe with sufficient accuracy based on the single-input, multiple-output characterization described above.

[0079] Measuring both the waves induced by resonance and the waves induced by other types of induced vibrations within the elongated medium 102 may provide separate datasets that can be processed to obtain the properties of the fluid and the walls of the elongated medium 102. These datasets may be combined before or after processing. As part of the characterization method, when generating the experimental model, each measured output signal may be normalized by the input signal, and the input signal may be removed from the experimental model.

[0080] At least one or more gear generators 104 coupled to the elongated medium 102 may be used to generate a vibroacoustic wave signal. The vibroacoustic wave signal may be selected to excite the elongated medium 102 in a frequency range of at least axial shell-dominant waves. Such a range may be known, for example, by analytical modeling and / or theoretical properties of the elongated medium 102. In applications of plastic or polymer pipes, a vibroacoustic wave signal may be generated and configured to induce resonance in the elongated medium 102, including fluid-dominant waves and axial shell-dominant waves. The first vibroacoustic wave signal, along with the induced resonance, may be sensed by a sensing unit 200 at input and output positions along the elongated medium 102. The acquired signal data may be stored in the sensing unit 200 and / or a computing device 106. By processing the signal data thus acquired, the mathematical models defined by equations (2) and (3) above can be solved. Based on the solved mathematical model, an experimental model of the elongated medium can be generated. Such an experimental model may represent the dynamic behavior of the elongated medium 102. Such a method of dynamically characterizing the elongated medium 102 may be repeated iteratively to compare the generated experimental models and verify their correlations. The correlations between successively generated experimental models may be used as a quality indicator of the input, output, and obtained experimental models. In at least some embodiments, the vibrational acoustic wave signal generated by the wave generator 104 may be subtracted from the signal sensed by the sensing unit 200. In such cases, the signal measured by the sensing unit 200 may represent the response of the elongated medium 102, rather than the excitation wave introduced into the elongated medium 102.

[0081] As mentioned above, once an experimental model is generated, it is possible to generate one or more additional experimental models by selecting a second input signal based on quality indicators of the first experimental model, which can be established, for example, by the signal-to-noise ratio or correlation of measured values ​​across a frequency band.

[0082] Therefore, a different vibroacoustic wave signal, distinct from that generated in the first pass or the first series of experimental model generation, may be generated via the wave generator 104 at the input position (the same input position as the first vibroacoustic wave signal) to induce resonance in the elongated medium 102. For example, such other vibroacoustic wave signals may be selected to target resonances corresponding to at least the frequency or frequency range of the fluid-dominant wave signal and / or the axial shell-dominant wave signal. The wave generator 104 may then generate such other vibroacoustic wave signals. Measurements of the signals made at the input and output positions along the elongated medium 102 may be processed to generate further experimental models. Once experimental models are generated, it is possible to compare (multiple) experimental models derived from some or all of the vibroacoustic wave signals iteratively generated and measured as described above. This step may be used, for example, to further refine the new input signal generated in the elongated medium 102.

[0083] As part of the dynamic characterization method described herein, the experimental model may be plotted as a stiffness profile. This may involve normalizing the stiffness profile based on the nominal stiffness of the elongated medium 102. Such nominal stiffness may be based on an analytical model, as further described below. The plot may also include visualization means for identifying the stiffness difference between the nominal stiffness and the stiffness profile.

[0084] In consideration of the foregoing, a method for dynamically characterizing the elongated medium 102 is provided. A first input signal is selected to excite the elongated medium 102 in a frequency range of at least an axial shell-dominant wave. The first input signal is generated via a wave generator operably coupled to the elongated medium 102. The first input signal is sensed at the input position, and a first set of output signals is sensed at each output position along the elongated medium 102. The measured / sensed first set of output signals and the measured first input signal are processed. This includes the step of solving a mathematical model. A first experimental model of the elongated medium 102 can then be generated based on the solved mathematical model. In at least some embodiments, the mathematical model is based on a combination of equations (2) and (3) as described above.

[0085] In at least some embodiments, the method may further include the step of selecting a second input signal for exciting the elongated medium 102 in at least one of the frequency ranges of an axial shell-dominant wave, a fluid-dominant wave, or a frequency range that overlaps with both the axial shell-dominant wave and the fluid-dominant wave. The second input signal may be generated via a wave generator operably coupled to the elongated medium 102. The second input signal may be measured at the input position, and a second set of output signals may be measured at each output position along the elongated medium 102. The measured second set of output signals and the measured second input signal may be processed. This includes the step of solving the mathematical model (described above) once again. A second experimental model of the elongated medium 102 may then be generated based on the solved mathematical model. The selection of the second input signal may be based on quality indicators of the first experimental model. The method may also include the step of comparing the experimental model obtained from the first input signal with the experimental model obtained from the second input signal. Comparisons of experimental models can be made by correlation or cross-correlation, but other types of treatments may also be considered.

[0086] In at least some embodiments, the method may also include the step of plotting the first experimental model as a stiffness profile of the elongated medium 102. The step of plotting the experimental model as a stiffness profile may include the step of normalizing the stiffness profile based on the nominal stiffness of the elongated medium 102. The nominal stiffness may be determined (provided as an assumption) based on an analytical model of the elongated medium 102.

[0087] In some cases, the method may also include the step of performing a modal analysis of the elongated medium 102 by finite element simulation or experimentally through measurement as described above, before selecting the first input signal. In such cases, the selection of the first input signal may be based on a selected frequency range corresponding to the frequency response of the axial shell-dominant wave of the elongated medium 102, the frequency response of the fluid-dominant wave of the elongated medium 102, or a frequency range that includes the responses of both.

[0088] In some cases, the step of plotting the experimental model as a stiffness profile may include the step of plotting the nominal stiffness of the elongated medium 102 and providing a visualization means for identifying the difference in stiffness between the nominal stiffness along the elongated medium 102 and the stiffness profile.

[0089] In at least some embodiments, the step of generating the first experimental model may include the step of normalizing each measured output signal with the first input signal.

[0090] In at least some embodiments, the step of comparing a first experimental model with a second experimental model may include the step of cross-correlating the respective experimental models.

[0091] In at least some embodiments, the step of plotting the experimental model as a stiffness profile may be based on the modeled elastic modulus, density, Poisson's ratio, wall thickness, and / or diameter of the elongated medium 102.

[0092] To characterize the elongated medium 102, other equations or models not described above may be considered, and other methods may also be used to generate the analytical model. In one embodiment, the analytical model may be generated at least in part using finite element analysis (FEA) and / or boundary element analysis (BEA). In one embodiment, the model is generated using the Monte Carlo method. In at least some embodiments, the model is generated using artificial intelligence (AI), such as machine learning techniques and / or deep learning techniques. Based on the analytical model, the estimated dynamic behavior of the pressurized elongated medium 102 or pressurized fluid system can be characterized.

[0093] Based on the estimated dynamic behavior and their ability to reveal several aspects (characteristics) of the pressurized elongated medium 102, one or more test input signals can be generated. These one or more test input signals can be input to the pressurized fluid system via a wave generator, such as the aforementioned wave generator 104. Output signals can then be measured at various locations along the pressurized fluid system. Such output signals are in response to the one or more test input signals propagating through the pressurized fluid system.

[0094] A complete system characterization may be performed with respect to the transmittance from one output point to another (i.e., the location of the sensing unit or the extraction point of the measured vibration-acoustic wave), the cross-correlation between the output signals (or any other type of comparison processing), the cross-correlation between the input signal and each output signal (or any other type of comparison processing), the transfer function between the input signal and each output signal, or a combination thereof. In at least some embodiments, dynamic time warping, root mean square error, instantaneous phase synchronization, cross-spectral density, coherence, and / or autocorrelation algorithms are performed to characterize the model.

[0095] In at least some embodiments, the dynamic behavior of an elongated medium can be segmented (discretized) by time-windowing the dynamic response. In this case, the dynamic response is divided into multiple time windows, each time window representing an elongated portion of the elongated medium. In other words, the dynamic response provided in the spatial domain is transformed into the time domain using a suitable algorithm, e.g., a Fourier transform function, and then segmented (discretized) into multiple time windows. The duration of the time windows is generally chosen such that the elongated portion has a length related to the wavelength of the vibrating acoustic wave. In some cases, the time windows may overlap. After separation, a given frequency bandwidth of each time window may be averaged to obtain a dynamic response value such as a root mean square (RMS) value, or another value representing the average or mean value over the time window. It varies as a function of position along the elongated member. Other algorithms suitable for obtaining frequency values ​​representing the dynamic behavior of each window may also be applied. It will be understood that the duration of the time windows represents the spatial resolution of the dynamic response. This complete characterization may provide the measured vibroacoustic properties of the pressurized fluid system, either through processing or post-processing. Once the complete characterization of the pressurized fluid system is calculated, the expected dynamic behavior of the analysis model can be compared with the measured vibroacoustic properties. Subsequently, updated information about the pressurized fluid system can be obtained.

[0096] Figure 5 is a flowchart of an example of a data analysis method 500 for systems such as systems 100, 300, and 400 described herein, for characterizing elongated media such as elongated media 102, 302, and 402. The method 500 is initiated in step 502, in which a vibroacoustic wave signal is generated by a wave generator such as the aforementioned wave generators 104, 304, and 404.

[0097] In step 504, a plurality of output signals (as defined above) are received. In at least some embodiments, geographic location data signals are also received. The plurality of output signals are extracted at selected locations along the elongated media 102, 302, 402 using the sensing unit 200, as described above. The reference to sensing unit 200 is for brevity and is intended to generally refer to the sensing units 200a, b, c, d, e, f, g, h, l, j described herein. The output signals may contain structural information of the elongated media 102, 302, 402. In other words, structural information of the elongated media 102, 302, 402 along the axial distance between adjacent sensing units 200 can be derived from the output signals. The geographic location data signals received in step 504 indicate the geographic location associated with each of the output points or selected locations of the sensing unit 200. By knowing the geographical location of the selected location, it is possible to obtain the geographical layout of the sensing units 200 distributed along the elongated media 102, 302, and 402.

[0098] In step 506, multiple output signals are processed. In at least some embodiments, geographic location data signals are also processed. Thus, characterization of the transfer functions between the output signals of multiple sensing units 200 can be performed in order to at least partially characterize the elongated media 102, 302, 402. In at least some embodiments, the systems 100, 300, 400 are characterized by calculating the transfer rate (or transfer rate coefficient) between the multiple output signals. By knowing the geographic location of each output signal and the difference between the signal strengths or "signatures," it is possible to calculate the attenuation that vibrational acoustic waves experience as they propagate through the elongated media 102, 302, 402 between the input point and the respective output point. It will be understood that this attenuation may correlate with the structural properties of the elongated media 102, 302, 402. The presence of surface defects, leaks, and / or mineral deposits on the elongated media 102, 302, and 402 between the sensing units 200 can alter the dynamic behavior of the elongated media 102, 302, and 402, and consequently alter the acoustic wave propagation within them. In at least some embodiments, as part of the processing, a cross-correlation function between each of the output signals is used to identify similarities or differences between them. As mentioned above, other types of comparison processing between different output signals may also be considered.

[0099] In at least some embodiments, a cross-correlation function can be performed between at least one of the output signals and an input signal measured at the input point of the vibratory acoustic wave generated by the wave generators 104, 304, and 404.

[0100] In at least some embodiments, a sensing unit 200 may be positioned in series with wave generators 104, 304, 404, for example, between the wave generators 104, 304, 404 and the input point, in order to acquire measurements of vibrational acoustic waves at the input point. Such measurements can be calculated as actual input signals transmitted to the system to be characterized. In other embodiments, the wave generators 104, 304, 404 may include such a sensing unit, i.e., the sensing unit is embedded within the wave generators 104, 304, 404. The number of possible combinations of transfer functions between multiple output signals is: In JPEG2026528704000008.jpg11170, N is the number of sensing units 200 that explore vibrational acoustic waves along the elongated media 102, 302, and 402. In other embodiments, N is the number of possible combinations of transfer functions between multiple output signals. It will be understood that various methods are applicable to process multiple output signals and geolocation data signals, and that multiple output signals paired with corresponding geolocation data signals are required to provide a complete characterization of the elongated media 102, 302, and 402. In one exemplary embodiment, five sensing units 200 are used to characterize the elongated media, with one pair of sensing units used on each side of the wave generators 104, 304, and 404, and one used near the input point. Such an arrangement may be suitable for characterizing the elongated media 102, 302, and 402 surrounding the input point.

[0101] Furthermore, in step 506, an experimental model of the elongated medium is generated based on at least a plurality of output signals and geographic location data signals. In at least some embodiments, structural properties extracted from the characterization of the elongated mediums 102, 302, and 402 may also be used to generate the experimental model. In at least some embodiments, an analytical model including the estimated dynamic behavior of the elongated mediums 102, 302, and 402 is used to generate the experimental model.

[0102] In step 508, the dynamic behavior of the elongated medium is calculated from the experimental model. The dynamic behavior may include the stiffness of the elongated medium under various conditions, from which structural information such as deformation, stress, brittleness, and wall thickness can be derived. The behavior of the fluid within the elongated mediums 102, 302, and 402 may affect sound propagation. In at least some embodiments, the dynamic behavior includes fluid properties, such as pressure, velocity, temperature, and density. Method 500 concludes in step 510.

[0103] Figure 6 is a flowchart illustrating an example of a method 600 for refining (improving) an analytical model of an elongated medium based on experimental characterization of the elongated medium. The method 600 is initiated in step 602.

[0104] In step 604, the analytical properties of the elongated media are received. The analytical model can be obtained based on various material coefficients of the elongated media 102, 302, and 402, or these coefficients can be calculated. Such analytical properties can be received via one or more analytical property inputs made by operators of systems 100, 300, and 400. The analytical properties can be stored in and / or retrieved from the data library of a computing device such as computing device 106.

[0105] In step 606, an analytical model of the elongated medium is generated using the received analytical characteristics. The estimated dynamic behavior can be derived from the analytical models of the elongated mediums 102, 302, and 402. In at least some embodiments, the analytical model or its iterations can be obtained by vibroacoustic measurements performed on the elongated mediums 102, 302, and 402 using the systems 100, 300, and 400 described herein. In method 600, the analytical model can function as a reference model. Throughout the iterative cycle, the analytical model can be refined (improved) using experimental models of the elongated mediums 102, 302, and 402, as described with respect to method 500 above. In this way, refined iterations of the analytical model can be obtained, forming a refined reference model on which subsequent iterations of the experimental model can be based at least in part, as will be further described below.

[0106] In step 608, vibroacoustic waves are generated that are adapted to excite the elongated media 102, 302, and 402. The vibroacoustic waves are defined by at least an estimated timbre characteristic, which may be derived from an analytical model of the elongated media 102, 302, and 402. Thus, the vibroacoustic waves can be generated to induce vibroacoustic resonance in the elongated media 102, 302, and 402 by matching a plurality of natural frequencies of the elongated media 102, 302, and 402. In at least some embodiments, the vibroacoustic waves include a frequency signature that includes frequencies that cause such resonance in at least some of the elongated media 102, 302, and 402. In at least some embodiments, the vibroacoustic waves may excite a plurality of harmonics of the natural frequencies of the elongated media 102, 302, and 402. Defects and / or leaks along the elongated media 102, 302, and 402 may affect the frequency characteristics of the elongated media 102, 302, and 402. In at least some embodiments, the vibroacoustic wave is a pulsed signal having a short duration and a large amplitude. In other embodiments, the vibroacoustic wave signal is a continuous signal.

[0107] In step 610, the generated vibratory acoustic waves are propagated within the elongated media 102, 302, and 402. The characteristics of the vibratory acoustic waves (e.g., amplitude, frequency, energy) are generally selected so that the vibratory acoustic waves can be transmitted to at least each sensing unit 200 without being excessively or completely attenuated by damping.

[0108] In step 612, multiple output signals are received, extracted at multiple selected locations along the elongated media 102, 302, and 402. Furthermore, in step 612, geolocation data signals indicating the geographical location associated with each of the multiple selected locations may be received, optionally. The output signals may correspond to modified (or "perturbed") versions of the generated vibroacoustic waves after they have propagated through the elongated media 102, 302, and 402 from the input point to the output point. The multiple output signals may include the input signals of the original vibroacoustic waves, whose amplitude, frequency, and phase have been modified by signal attenuation and external perturbations. Such external perturbations may be caused by at least defects and / or leaks.

[0109] In step 614, a plurality of output signals and their conversion to vibration-acoustic waves or input signals are processed. In at least some embodiments, geographic location data signals are also processed. By using the output signals (with or without their respective geographic locations) and input signals of each sensing unit 200, it is possible to compare the responses at each sensing unit 200. Such comparisons may contribute to the experimental modeling of some of the elongated media 102, 302, and 402. The processing may include calculating the transfer rates and / or cross-correlations between each of the plurality of output signals in several possible permutations, and / or calculating the transfer rates and / or cross-correlations between the input signal and at least one of each of the plurality of output signals. The processing may also include calculating the transfer functions between each of the plurality of output signals, and / or calculating the transfer functions between the input signal and at least one of each of the plurality of output signals. In at least some embodiments, the processing may include the deconvolution of a plurality of such signals. Based on the processing described above, experimental models of the elongated media 102, 302, and 402 are generated. The model can be generated according to step 506 described above.

[0110] In step 616, the dynamic behavior of the elongated media 102, 302, and 402 is calculated from the experimental model. The dynamic behavior may be generated according to step 508 described above. In a hypothetical scenario in the first iteration of method 600, where the desired dynamic behavior is not provided and / or the information sought on the elongated media 102, 302, and 402 is not revealed, for example, due to insufficient resolution of the acquired output signals, steps 608 to 616 may be reprocessed using different vibroacoustic waves. The different vibroacoustic waves may be arbitrary or may be selected / constructed to provide a higher resolution of the dynamic behavior, such as the SVAI signal (described later).

[0111] In step 618, the analysis model is updated using the acquired dynamic behavior. Step 618 may be processed if the dynamic behavior matches predefined requirements. Multiple iterations of method 600 may lead to obtaining a substantially refined (improved) analysis model. Method 600 terminates in step 620.

[0112] Figure 7 is a flowchart showing an example of method 700 for experimentally characterizing a pressurized fluid system according to the above.

[0113] The method is initiated in step 702. In step 704, one or more test input signals are input. These test input signals may be referred to as specific vibroacoustic input (SVAI) signals within the system at the input point.

[0114] In step 706, the SVAI signal at the input point is measured.

[0115] In step 708, the output signals at a first output point and at least a second output point are measured, each being located away from the input point and also away from each other. For clarity, it is understood herein that the first output point is located at a distance closer to the input point than at least the second output point.

[0116] In step 710, the cross-correlation of multiple output signals is measured.

[0117] In step 712, the cross-correlation of each output signal with respect to the measured SVAI signal is calculated.

[0118] In step 714, the transfer function between each output signal and the measured SVAI signal is calculated.

[0119] In step 716, the predicted transfer function of the system between the output signal at the second output point and the input signal at the input point is calculated. The calculation in step 716 is obtained based on the transfer function between the output signal at the first output point and the SVAI signal.

[0120] In step 718, the system's predicted transfer function is normalized. Normalization in step 718 may be performed using the transfer function between the output signal at the second output point and the SVAI signal. It is understood that in step 718, by generating transfer functions between multiple output responses to an input excitation, it is possible to use a nonlinear function to extrapolate (or predict) the dynamic behavior of an elongated medium to a virtual location beyond a region characterized by a comparative function, such as a region delimited between the input and output positions. This aspect (feature) is particularly relevant to nonlinear systems whose behavior cannot be extrapolated by conventional means, and therefore cannot be extrapolated with at least acceptable accuracy. In some cases, for example, due to structural defects or repairs, the dynamic behavior of an elongated medium differs significantly between regions. Therefore, the behavior between two sensors modeled using a transfer function may not apply to other regions. On the other hand, the predicted transfer function can be used to predict the behavior in these regions by normalizing the transfer function with the SVAI signal. The SVAI signal is assumed to be similar along the elongated medium. In some cases, the predictive transfer function can be used to obtain the dynamic behavior of an elongated medium in the region near the wave generator. This method concludes in step 720. The presented order of the computational steps is not intended to be restrictive, and these steps can be performed in various permutations.

[0121] Method 700 may optionally include the steps of displaying the output signal on a user interface, such as by displaying one or more graphs or figures (e.g., spectrograms), and / or displaying a visual indicator on the user interface in response to the determination of an acquisition quality indicator for the measured vibration-acoustic waves converted into the output signal. In response to the determination of the acquisition quality indicator, Method 700 may further include the step of triggering a request through the user interface to repeat the acquisition of vibration-acoustic waves at the first output point and / or the second output point. This step can ensure that the computing device receives reliable information and / or sufficient resolution regarding the vibration-acoustic waves measured at the first output point and / or the second output point. Method 700 may optionally include the step of displaying a cross-correlation spectrogram of the output signal on the user interface. Method 700 may optionally include the step of displaying a cross-correlation spectrogram of at least one of the output signals and the SVAI signal on the user interface.

[0122] Referring to Figure 8, some or all embodiments of the apparatus, systems, and methods described herein may be implemented in combination of both hardware and software.

[0123] Figure 8 shows exemplary computing devices that may be used to implement methods 500, 600, and 700 of Figures 5, 6, and 7, respectively. Computing device 800 may correspond to computing device 106 described herein (or vice versa). Computing device 800 has a processing unit 802 and a memory 804 in which computer executable instructions 806 are stored. Processing unit 802 may include any suitable device configured to implement the functions of sensing systems 100, 300, 400 and / or methods 500, 600, and / or 700, and the instructions 806, when executed by computing device 800 or other programmable device, may cause functions / operations / processes to be performed by sensing systems 100, 300, 400 and / or methods 500, 600, and / or 700 as described herein. The processing unit 802 may include, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field-programmable gate array (FPGA), a reconfigurable processor, other appropriately programmed or programmable logic circuits, custom-designed analog and / or digital circuits, or any combination thereof.

[0124] Memory 804 may include any suitable known machine-readable storage medium or other machine-readable storage medium. Memory 804 may include non-temporary computer-readable storage medium, which may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Memory 804 may include any suitable combination of computer memory of any type located inside or outside the device, such as random access memory (RAM), read-only memory (ROM), compact disk read-only memory (CD-ROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferroelectric RAM (FRAM), etc. Memory 804 may include any storage means (e.g., a device) suitable for acquiringly storing machine-readable instructions 806 that can be executed by the processing unit 802.

[0125] The computing device 800 may be any suitable computing device, such as a desktop computer, laptop computer, mainframe, server, distributed computing system, portable computing device, mobile phone, or tablet.

[0126] Figures 9 to 12 show exemplary embodiments of vibroacoustic characteristic profiles obtained using the methods and systems presented herein. Thus, the vibroacoustic characteristic profiles in Figures 9 to 12 may represent an image of the dynamic behavior of the characterized pipe.

[0127] Figure 9 shows the dynamic response of the pipe after measurements were taken at six different positions 900a, b, c, d, e, and f using one or more sensors, such as sensor 202. As illustrated, vibrational acoustic waves are induced at five positions 902a, b, c, d, and e using one or more wave generators, such as wave generator 104. Using the measurements, the dynamic properties of the pipe are modeled and divided into five sections 904a, b, c, d, and e. In each section 904a, b, c, d, and e, the size of the bottom of the profile represents the dominant level of stiffness of the pipe. Thus, sections with a smaller size of the bottom of the profile generally have more desirable stiffness, and sections with a larger size of the bottom of the profile generally have less desirable stiffness. In the profile of Figure 9, sections 904a and b are sections that have been repaired using carbon fiber, which results in increased stiffness. Sections 904c, d, and e have not been repaired and are reflected by a more undesirable stiffness, as shown in the profile of Figure 9.

[0128] Figure 10 shows another exemplary dynamic response profile of a pipe. The profile in Figure 10 includes five sections 1000a, b, c, d, and e. Three larger sections 1000a, c, and e correspond to segments of the pipe, while two smaller sections 1000b and d have vibroacoustic waves introduced into the pipe to induce a dynamic response. As shown, sections 1000b and d do not contain vibroacoustic properties because the measurements obtained in these regions are primarily the introduced vibroacoustic waves themselves, which mask the dynamic response of the pipe. If multiple wave generators are installed in the pipe, it is possible to obtain vibroacoustic property profiles of the regions near the wave generators by operating the wave generators alternately. In the profile shown in Figure 10, dark spots in the larger portions at the bottom of the profile represent damaged areas within the pipe's stiffness profile corresponding to known wire breaks.

[0129] Figure 11 shows a profile including a dynamic response curve 1100a representing the vibroacoustic energy change (VAEV) of the dynamic response as a function of position within the pipe. In this exemplary profile, the VAEV can be obtained using a cross-correlation function between outputs in a specific frequency band. It will be understood that the VAEV distribution can be obtained by windowing the dynamic behavior of the pipe in time and averaging the frequencies in each time window. It will be understood that the VAEV measurement level increases with the number of defects in the pipe section. Masked regions 1100b and 1100c are regions where vibroacoustic waves were introduced to induce the dynamic response of the pipe.

[0130] Figure 12 shows the stiffness profile of the pipe. This stiffness profile has four regions 1200a, b, c, and d, each of which can be divided into stages according to the level of pipe condition. For example, regions 1200a and d have high stiffness and correspond to desirable pipe condition levels, region 1200b has low stiffness and corresponds to undesirable pipe condition levels, and region 1200c has very high stiffness and corresponds to a more desirable pipe condition level. Furthermore, defects can be detected in the stiffness profile because they correspond to regions with relatively low stiffness.

[0131] In at least some embodiments, the vibroacoustic characteristic profiles shown in Figures 9 to 12 may be displayed on a processing device used by an inspector of the pipe. In this case, the inspector can identify sections of the pipe that require repair without using invasive inspection means.

[0132] Considering the various aspects (characteristics) described above, a method for characterizing the dynamic behavior of an elongated medium is described below. The method comprises the step of generating an input wave signal at an input position along the elongated medium. The input wave signal includes a vibratory acoustic wave signal and is selected to excite at least one vibration mode of the elongated medium. As described above, the generated input wave signal is configured to excite the elongated medium and induce vibration within it. The vibration mode may include components such as a mode frequency representing the frequency at which the vibration occurs and a mode shape representing the pattern of vibration displacement. These components may also include the phase of the vibration and the amplitude of the vibration.

[0133] The method also comprises the steps of: measuring a first output wave signal at a first position along the elongated medium, spaced apart from the input position, and generating a first electrical signal based thereon; and measuring a second output wave signal at a second position along the elongated medium, spaced apart from the input position and the first position, and generating a second electrical signal based thereon, wherein the first electrical signal represents a first component of the first output wave signal, and the second electrical signal represents a second component of the second output wave signal. As described above, the output wave signal may be measured by a suitable sensor, such as an accelerometer or piezoelectric transducer, as described with respect to Figures 1 and 2. The sensor may be configured to convert the mechanical vibrations of the output wave signal into an electrical signal, which is then provided to a processing unit. The vibrations measured by the sensor may be acoustic vibrations or vibroacoustic vibrations, depending on the embodiment. It will be understood that the calculation process of the method is performed using the electrical signal generated by the sensor.

[0134] The method also comprises the steps of comparing the first and second components of the vibration mode with respect to the first and second electrical signals, and calculating the dynamic response of the elongated medium based on the comparison step.

[0135] In at least some embodiments, the input wave signal is selected to target the structural natural frequencies of the elongated medium in order to induce resonance in a predetermined frequency band. Various vibrational modes can be excited using the generated input signal, but in this embodiment, the input signal is configured to generate resonance within the elongated medium, which can increase the amplitude of the output signal.

[0136] In at least some embodiments, the method further comprises the steps of measuring the input wave signal at the input location and generating a third electrical signal thereon, wherein the third electrical signal represents a third component of the input wave signal, and the comparison step further includes comparing the third component of the vibration mode on the third electrical signal with the first and second components of the vibration mode on the first and second electrical signals. In some cases, as described above, the input wave signal is measured near the wave generator using a suitable sensor. It will be understood that the first electrical signal, the second electrical signal, and the third electrical signal represent wave signals measured at the first position, the second position, and the input position, respectively.

[0137] In at least some embodiments, the method further comprises the step of obtaining an analytical model of the elongated medium, which includes at least the estimated acoustic characteristics of the elongated medium, and the input wave signal is defined by the estimated acoustic characteristics.

[0138] In at least some embodiments, the method further comprises the steps of generating an experimental model of the elongated medium based on the first and second signals, updating the analytical model based on the experimental model, and the step of calculating the dynamic response is performed using the analytical model and / or the experimental model.

[0139] In at least some embodiments, the method further comprises the step of associating a quality index with the generated experimental model, the quality index including a given value of the signal-to-noise ratio, the presence of the input signal in the output signal being measured, and / or a given value of the coherence between the output signals.

[0140] In at least some embodiments, the step of generating the experimental model includes the step of performing modal analysis of the elongated medium and the step of using the modal analysis in the step of obtaining the analysis model.

[0141] In at least some embodiments, the step of performing the modal analysis includes the step of using a nonlinear function to predict the dynamic behavior of the elongated medium at a virtual position beyond the region demarcated between the input position and the first and second positions.

[0142] In at least some embodiments, the method further comprises the steps of dividing the dynamic response into a plurality of time windows and obtaining the dynamic response of the elongated medium for each of the plurality of time windows.

[0143] In at least some embodiments, the step of obtaining the dynamic response for each of the plurality of time windows includes the step of calculating the signal average over a given frequency bandwidth.

[0144] In at least some embodiments, the comparison step includes the steps of: calculating the cross-correlation between the first electrical signal and the second electrical signal; calculating the cross-correlation between the first electrical signal and the second electrical signal and the third electrical signal; calculating the transfer function between the first electrical signal and the second electrical signal and the third electrical signal; and / or calculating the predicted transfer function of the elongated medium between the first electrical signal and the second electrical signal based on the calculated transfer function.

[0145] In at least some embodiments, the comparison step further includes the step of normalizing the predicted transfer function of the elongated medium with the calculated transfer function.

[0146] In at least some embodiments, the method further comprises the steps of displaying the first output wave signal and the second output wave signal on a user interface, and / or displaying a visual representation on the user interface in response to the determination of an acquisition quality index of the measured first output wave signal and the second output wave signal.

[0147] In at least some embodiments, the step of generating the input signal includes the step of generating a set of timbres, the set of timbres being selected sequentially by frequency or a predetermined pattern.

[0148] In at least some embodiments, the step of generating the input wave signal includes the step of selecting a first input wave signal for exciting the elongated medium in an axial shell dominant wave frequency range and / or a fluid dominant wave frequency range.

[0149] In at least some embodiments, the process of calculating the dynamic response is performed by solving a mathematical model that includes the following equation: JPEG2026528704000009.jpg18150 JPEG2026528704000010.jpg17150

[0150] Here, k L , k f k1 and k2 are the wavenumber of the compression wave, the wavenumber of the fluid wave, the wavenumber of the fluid-dominant wave, and the wavenumber of the axial shell-dominant wave, respectively, ν is the Poisson's ratio of the elongated medium, a is the radius of the elongated medium, and B f ρ is the bulk modulus of the external medium, E is the Young's modulus of the elongated medium, h is the wall thickness, ρ is the density of the shell material, and ω is the angular frequency.

[0151] In at least some embodiments, the method further comprises the step of plotting the stiffness profile of the elongated medium, the plotting step of normalizing the stiffness profile based on the nominal stiffness of the elongated medium, plotting the normalized stiffness profile of the elongated medium to provide a visualization means for identifying the difference in stiffness between the nominal stiffness and the stiffness profile along the elongated medium, and / or plotting the Young's modulus, density, Poisson's ratio, wall thickness, and / or diameter of the elongated medium. In at least some embodiments, the nominal stiffness may be determined based on an analytical model of the elongated medium. It will be understood that the diameter (or other cross-sectional dimensions) of the elongated medium may be obtained from a structural design of the elongated medium, from an analytical model, or measured by an operator or any suitable autonomous device.

[0152] In at least some embodiments, the calculation step includes subtracting the third electrical signal from the first electrical signal and the second electrical signal.

[0153] In at least some embodiments, the first component of the first output wave signal and / or the second component of the second output wave signal include a mode frequency.

[0154] Taking into consideration the various aspects (features) described above, a system for characterizing an elongated medium is described below. The system comprises a wave generator configured to generate vibroacoustic waves, a plurality of sensing units mounted at different locations on the elongated medium, and a computing device. The vibroacoustic waves are selected to excite vibration modes (e.g., one or more modes) of the elongated medium. Each sensing unit has a sensor that detects and measures an output wave signal at an output location along the elongated medium, and a processing unit that converts the measured output wave signal into an electrical signal. The computing device is communicated to the plurality of sensing units and has a processing unit and a memory storing program commands that can be executed by the processing unit for the following operations, which include receiving the telegraph signals from each of the plurality of sensing units when the input wave signal includes the excited vibration mode, generating an analysis model of the elongated medium, and calculating the dynamic behavior of the elongated medium by comparing the electrical signals from each of the plurality of sensing units with the analysis model. It will be understood that a system of this embodiment can correspond to the aforementioned systems 100, 300, and 400.

[0155] In at least some embodiments, each sensing unit further includes a geolocation classifier for identifying the geographic location of the sensing unit, and the operation targeted by the program instruction further includes receiving the geographic location of each sensing unit via the geolocation classifier and calculating the dynamic behavior using the geographic location of each sensing unit.

[0156] Considering the various embodiments (features) described above, a system for characterizing an elongated medium is described below. The system comprises a wave generator configured to generate vibration-acoustic waves within the elongated medium, a plurality of sensing units attached to different locations on the elongated medium, and a computing device communicated to the plurality of sensing units. Each sensing unit has a geographic location identifier for identifying the geographic location of the sensing unit, a sensor for detecting and measuring the vibration-acoustic waves at output points along the elongated medium, and a processing unit for converting the measured vibration-acoustic waves into an output signal. The computing device has a processing unit and a memory storing program commands that can be executed by the processing unit for the following operations. These operations include receiving the output signals and geographic locations of each of the plurality of sensing units, generating an analysis model of the elongated medium, and calculating the dynamic behavior of the elongated medium by comparing the measured output signals and geographic locations with the analysis model. It will be understood that such an embodiment of the system can correspond to the systems 100, 300, and 400 described above.

[0157] Taking into consideration the various aspects (features) described above, a method for experimentally characterizing a pressurized fluid system is described below. The method comprises the steps of: inputting one or more test input signals at an input point (the one or more test input signals having a duration at least longer than the time required to propagate throughout the pressurized fluid system); measuring output signals from a first output point and at least a second output point located away from the input point; calculating the cross-correlation of the output signals to obtain the dynamic response of the pressurized fluid system; dividing the dynamic response into a plurality of time windows; and obtaining the dynamic response of the pressurized fluid system for each of the plurality of time windows.

[0158] Taking into consideration the various aspects (features) described above, a data analysis method for a system for characterizing an elongated medium is described below. The method comprises the steps of: receiving an input signal measured from an input position along the elongated medium; receiving a plurality of output signals from a selected position away from the input position along the elongated medium; processing the plurality of output signals and generating an experimental model of the elongated medium based on at least the plurality of output signals and the input signal; and calculating the dynamic behavior of the elongated medium from the experimental model.

[0159] Taking into consideration the various aspects (features) described above, a method for modifying an analysis model for characterizing an elongated medium is described below. The method comprises the steps of: receiving the analysis characteristics of the elongated medium; generating an analysis model of the elongated medium using the analysis characteristics; generating a vibratory acoustic wave adapted to excite the elongated medium; propagating the generated vibratory acoustic wave through the elongated medium; receiving a plurality of output signals extracted at selected positions along the elongated medium; processing the plurality of output signals and a measured input signal of the vibratory acoustic wave from the input position to generate an experimental model of the elongated medium based on the plurality of output signals and the measured input signal; calculating the dynamic behavior of the elongated medium from the experimental model; and updating the analysis model using the calculated dynamic behavior, wherein the analysis model includes at least the estimated acoustic characteristics of the elongated medium, and the vibratory acoustic wave is defined at least by the estimated acoustic characteristics of the analysis model of the elongated medium.

[0160] Taking into consideration the various aspects (features) described above, a method for experimentally characterizing a pressurized fluid system is described below. The method comprises the steps of: inputting one or more test input signals at an input point; measuring the one or more test input signals from the input point; measuring output signals from a first output point and at least a second output point located away from the input point; calculating the cross-correlation of the output signals; calculating the cross-correlation of each output signal with respect to the measured one or more test input signals; calculating the transfer function between each output signal and the measured one or more test input signals; calculating the predicted transfer function of the pressurized fluid system between the output signal at the second output point and the output signal at the first output point based on the transfer function between the output signal at the first output point and the one or more test input signals; and normalizing the predicted transfer function of the pressurized fluid system with respect to the transfer function between the output signal at the second output point and the one or more test input signals.

[0161] Taking into consideration the various aspects (features) described above, a method for dynamically characterizing an elongated medium is described below. The method comprises the steps of: selecting a first input signal that excites the elongated medium in at least the axial shell dominant wave frequency range; generating the first input signal via a wave generator operably coupled to the elongated medium; sensing the first input signal at an input position and sensing a first set of output signals at each output position along the elongated medium; processing the measured first set of output signals and the measured first input signal; solving a mathematical model; and generating a first experimental model of the elongated medium based on the solved mathematical model.

[0162] The terms “communicatively connected” or “communicatively coupled” can include both direct communicative coupling (two elements communicatively coupled to each other and communicating without an interface component) and indirect communicative coupling (at least one additional element communicatively interfaces with the two elements). For example, the terms “communicatively connected” or “communicatively coupled” can include wireless connections over communication networks such as the Internet or 5G networks.

[0163] To be understood, the embodiments described and illustrated herein are for illustrative purposes only. The scope of the present invention is defined by the appended claims. While the embodiments presented herein generally relate to pressurized fluid systems, it will be understood that the art is not limited to the characterization of pressurized fluid systems. This is because it can also be applied to the characterization of various other fields, such as railway tracks, bridges, wind turbines, cables, buildings, platforms, and any other types of structures subjected to stress, which can induce defects and be excited acoustically or vibroacoustically using methods and systems as described herein.

Claims

1. A method for characterizing the dynamic behavior of an elongated medium, A step of generating an input wave signal at an input position along the elongated medium, A step of measuring a first output wave signal at a first position along the elongated medium, spaced apart from the input position, and generating a first electrical signal based thereon, A step of measuring a second output wave signal at a second position along the elongated medium, spaced apart from the input position and the first position, and generating a second electrical signal based thereon, Equipped with, The input wave signal includes a vibratory acoustic wave signal and is selected to excite the vibration mode of the elongated medium. The first electrical signal represents the first component of the first output wave signal, The second electrical signal represents the second component of the second output wave signal, This method further, A step of comparing the first and second components of the vibration mode with each other based on the first and second electrical signals, A step of calculating the dynamic response of the elongated medium based on the comparison step, A method characterized by comprising:

2. The input wave signal is selected to target the structural natural frequencies of the elongated medium in order to induce resonance in a predetermined frequency band. The method according to claim 1, characterized by the features described above.

3. A process of measuring the input wave signal at the input position and generating a third electrical signal based thereon. Furthermore, The third electrical signal represents the third component of the input wave signal, The comparison step further includes comparing the third component of the input wave signal on the third electrical signal with the first and second components of the first and second output wave signals on the first and second electrical signals, respectively. The method according to 1 or 2, characterized by the features described above.

4. A step of obtaining an analytical model of the elongated medium that includes at least the estimated acoustic characteristics of the elongated medium. Furthermore, The input wave signal is defined by the estimated acoustic characteristics. The method according to any one of 1 to 3, characterized by the features described herein.

5. A step of generating an experimental model of the elongated medium based on the first signal and the second signal, A step of updating the analysis model based on the experimental model, Furthermore, The step of calculating the dynamic response is performed using the analytical model and / or the experimental model. The method according to feature 4.

6. Steps to associate quality indicators with the generated experimental model. Furthermore, The aforementioned quality indicator includes a given value of the signal-to-noise ratio, the presence of the input signal in the output signal being measured, and / or a given value of the coherence between the output signals. The method according to specification 5.

7. The step of generating the experimental model includes the step of performing modal analysis of the elongated medium and the step of using the modal analysis during the step of acquiring the analysis model. The method according to any one of 4 to 6, characterized by...

8. The step of performing the modal analysis includes a step of predicting the dynamic behavior of the elongated medium at a virtual position beyond the region demarcated between the input position and the first and second positions, using a nonlinear function. The method according to feature 7.

9. The process of dividing the dynamic response into multiple time windows, A step of acquiring the dynamic response of the elongated medium for each of the plurality of time windows, The method according to any one of 1 to 8, further comprising the above.

10. The step of obtaining the dynamic response for each of the plurality of time windows includes the step of calculating the signal average over a given frequency bandwidth. The method according to feature 9.

11. The aforementioned comparison step is, A step of calculating the cross-correlation between the first electrical signal and the second electrical signal, A step of calculating the cross-correlation between the first electrical signal, the second electrical signal and the third electrical signal, A step of calculating the transfer function between the first electrical signal, the second electrical signal and the third electrical signal, and / or, A step of calculating the predicted transfer function of the elongated medium between the first electrical signal and the second electrical signal based on the calculated transfer function, including The method according to feature 3.

12. The comparison step further includes a step of normalizing the predicted transfer function of the elongated medium with the calculated transfer function. The method according to 11, characterized by the features described above.

13. A step of displaying the first output wave signal and the second output wave signal on a user interface, and / or a step of displaying a visual representation on the user interface in response to the determination of the acquisition quality indicators of the measured first output wave signal and the second output wave signal. The method according to 11 or 12, further comprising the above.

14. The process of generating the input signal includes the process of generating a set of timbres, The aforementioned set of timbres is selected sequentially by frequency or a predetermined pattern. The method according to any one of 1 to 13, characterized by the features described herein.

15. The step of generating the input wave signal includes the step of selecting a first input wave signal for exciting the elongated medium in the axial shell dominant wave frequency range and / or the fluid dominant wave frequency range. The method according to any one of 1 to 14, characterized by the features described herein.

16. The process of calculating the dynamic response is carried out by solving a mathematical model that includes the following equation: Here, k L , k f , k 1 , k 2 These are the wavenumber of the compression wave, the wavenumber of the fluid wave, the wavenumber of the fluid-dominant wave, and the wavenumber of the axial shell-dominant wave, respectively. ν is the Poisson's ratio of the elongated medium, a is the radius of the elongated medium, B f This is the bulk modulus of the external medium, E is the Young's modulus of the elongated medium, h is the wall thickness, ρ is the density of the shell material, ω is the angular frequency. The method according to the present invention, characterized by the present invention.

17. Steps to plot the stiffness profile of the elongated medium. Furthermore, The aforementioned plotting step is, A step of normalizing the stiffness profile based on the nominal stiffness of the elongated medium, A step of plotting the normalized stiffness profile of the elongated medium and providing a visualization means for identifying the difference in stiffness between the nominal stiffness along the elongated medium and the stiffness profile, and / or A step of plotting the Young's modulus, density, Poisson's ratio, wall thickness, and / or diameter of the elongated medium, including The method according to 16, characterized by...

18. The calculation step includes subtracting the third electrical signal from the first electrical signal and the second electrical signal. The method according to feature 3.

19. The first component of the first output wave signal and / or the second component of the second output wave signal each include a mode frequency. The method according to any one of 1 to 18, characterized by the features described herein.

20. A system for characterizing elongated media, A wave generator configured to generate vibrational acoustic waves, Multiple sensing units attached to different positions on the elongated medium, A computing device connected to the aforementioned plurality of sensing units via communication, Equipped with, The vibrational acoustic wave is selected to excite the vibrational mode of the elongated medium. Each sensing unit is: A sensor for detecting and measuring the output wave signal at the output position along the elongated medium, A processing unit that converts the measured output wave signal into an electrical signal, It has, The aforementioned computing device is Processing unit and A memory containing program commands that can be executed by the processing unit for the following operations, It has, The aforementioned operation is, When the input wave signal includes the excited vibration mode, the telegraph signal of each of the plurality of sensing units is received. To generate an analytical model of the aforementioned elongated medium, and The dynamic behavior of the elongated medium is calculated by comparing the electrical signals of each of the plurality of sensing units with the analysis model. including A system characterized by the following features.

21. Each sensing unit further includes a geolocation classifier for identifying the geographic location of the sensing unit. The operation intended by the aforementioned program instruction is further, The geographic location of each sensing unit is received via the geographic location identifier, and The dynamic behavior is calculated using the geographical location of each sensing unit. including The system according to claim 20, characterized in that it is as described above.

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