WO2012172124A1 - Architecture électronique multicanal pour surveillance avancée de l'intégrité structurale par la technique des ondes ultrasonores guidées ou ondes de lamb - Google Patents

Architecture électronique multicanal pour surveillance avancée de l'intégrité structurale par la technique des ondes ultrasonores guidées ou ondes de lamb Download PDF

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Publication number
WO2012172124A1
WO2012172124A1 PCT/ES2011/070428 ES2011070428W WO2012172124A1 WO 2012172124 A1 WO2012172124 A1 WO 2012172124A1 ES 2011070428 W ES2011070428 W ES 2011070428W WO 2012172124 A1 WO2012172124 A1 WO 2012172124A1
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WIPO (PCT)
Prior art keywords
signals
structural integrity
monitoring
channel
signal
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PCT/ES2011/070428
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English (en)
Spanish (es)
Inventor
Valerijan Cokonaj
Gerardo Aranguren Aramendia
Luciano CASADO MARTÍNEZ
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Aernnova Engineering Solutions Iberica
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Priority to PCT/ES2011/070428 priority Critical patent/WO2012172124A1/fr
Publication of WO2012172124A1 publication Critical patent/WO2012172124A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/043—Analysing solids in the interior, e.g. by shear waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/025—Change of phase or condition
    • G01N2291/0258—Structural degradation, e.g. fatigue of composites, ageing of oils
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0425—Parallel to the surface, e.g. creep waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0427—Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/10—Number of transducers
    • G01N2291/106—Number of transducers one or more transducer arrays

Definitions

  • Structural serves to detect problems in structures that may arise during the useful life of the structure, or in manufacturing, assembly and transport. It can be applied to civil engineering structures and transport, mainly in aeronautics and aerospace, where volume and weight requirements are important. These techniques are known in English as SHM (Structural Health Monitoring) or Structural Integrity Monitoring.
  • the architecture of an integrated electronic SHM system is presented, which can be classified as an Ultrasound Imaging System, based on the transmission and acquisition of ultrasonic signals using a set of piezoelectric transducers.
  • the invention comes to solve the functional deficiencies, disadvantages and problems found in the architectures currently used to make SHM systems.
  • Structural Integrity Monitoring Systems arise from the need to control the integrity of structures throughout their life cycle under real service conditions and replace conventional methods of non-destructive testing, evaluation and inspection (NDT / NDE / NDI) of the English Non Destructive Testing / Non Destructive Evaluation / Non Destructive Inspection) used so far.
  • the systems of SHM aim to automate the processes of detection of defects in real time in structures of any material in which their correct state of functioning is a critical factor, with the minimum possible human interaction. This check is made through sensors / actuators, either embedded or fixed permanently on the surface of the structure to be monitored, without the need to require the manual action of an operator during the inspection.
  • the real-time realization of the structural inspections allows to reduce the maintenance times, executing the maintenance tasks only when it is determined to be really necessary (also known as CBM of the English Condition Based Maintenance).
  • the architecture of the invention makes it possible to build an SHM system that can be installed on an aircraft because it is lightweight and operates autonomously, automatically and in real time. In this way, it also comes to solve and facilitate maintenance operations in aeronautics, which require scheduled and unscheduled maintenance established by the competent authorities, which in most cases requires stopping the aircraft and disassembling the sections of the structure to analyze.
  • the present invention is directed to various fields of engineering, such as: structural integrity monitoring (SHM, Structural Health Monitoring), internal and external damage detection, temperature distribution mapping (TDM). ), stress distribution mapping (SDM), Stiffness Distribution Mapping (STDM), deformation distribution mapping (DDM), or mapping Vibration Distribution Mapping (VDM).
  • SHM structural integrity monitoring
  • TDM temperature distribution mapping
  • SDM stress distribution mapping
  • STDM Stiffness Distribution Mapping
  • DDM deformation distribution mapping
  • VDM mapping Vibration Distribution Mapping
  • the use of the invention is not only intended for aeronautical structures, but can also be used in ships, submarines, space vehicles, land vehicles, oil or gas pipelines, tanks, platforms, barrels with nuclear waste, etc.
  • Other potential fields of engineering and attractive fields of use are related to the monitoring of impacts, leak detection, mass loss or characterization of physical properties of structural materials during the life cycle of the structure, due to possible material degradation during the service in adverse environments.
  • Experts on SHM may come up with other useful and advantageous applications in the
  • the invention as a key component of SHM systems based on the technique of multiple guided ultrasonic waves with structural radar operation, named PAMELA SHM (from the English Phased Array Monitoring for Enhanced Life Assessment), is designed to work together with a PhA transducer ( of the English Phased array) integrated described in the patent application EP11382045.
  • PAMELA SHM from the English Phased Array Monitoring for Enhanced Life Assessment
  • PhA transducer of the English Phased array
  • CB English, Condition Based Maintenance
  • g) measure the structural aging and acquire the operational data of the structure, acquire the necessary data for the evaluation of the "consumed” structural life, thus enabling the prognosis of the remaining life and its possible extension in old aircraft or in aged structures, h) optimize (in mass and form) future structures using the design method to load last (FSD, of the English Fully Stressed Design) and the operational maps of distribution of efforts obtained during the different real conditions of service (important aspect for the engineers of design and calculation),
  • n significantly reduce the current effort of suppliers of maintenance tasks associated with the maintenance of structures or the evaluation of their structural integrity
  • n have at all times valuable information on structural integrity, consumed and remaining life, information which is important for insurance or leasing companies, buyers of structures, retailers or maintenance providers, etc.
  • the object of the invention raised in this document presents an electronic architecture of multiple real channels that allows advanced structural analysis to be carried out autonomously with a low weight and volume equipment, ideal for use in the aeronautical sector.
  • the patent US6996480 does not present an electronic architecture necessary to make this system possible, which means that the patent US6996480 encounters a series of problems / limitations for its implementation to be viable:
  • the generation of signals is limited to the excitation of a single sensor or, at least, to the generation of a single excitation signal, not being able to use multiple excitation channels.
  • the signal acquisition is also limited to a single channel, since it uses processing through an obviously sequential and non-concurrent signal processor.
  • E / M impedance technique is mainly used to detect defects in the near field.
  • This technique is not applicable to the far field because it does not provide sufficient resolution for the detection and localization of faults in the far field.
  • the Lamb wave technique on which the electronic architecture object of the invention is based can be used both in the near field and in the far field, so that the scope and the analytical techniques usable by the equipment proposed in the patent US7174255 and by the equipment object of invention are totally different.
  • this technique uses a single sensor and, therefore, it would be impossible to use the real multi-channel techniques described in this invention.
  • the integrated signal generator having a single excitation channel, can not transmit to the structure several signals at the same time using different piezoelectric transducers. Therefore, it can not implement advanced analysis techniques such as real Beamforming in transmission.
  • the acquisition system can only sample one signal at a time, so this limits the use of the device, not being able to apply advanced techniques such as real Beamforming in reception, Time Reversal, Focusing and Zooming, SHM, etc.
  • Advanced techniques that use several channels can monitor a surface with detail, but the use of a single channel at the same time limits the monitoring to analysis techniques that complicate the reconstruction of ultrasonic images of the structure, such as pitch-catch or pulse-tests. I make simple, round-robin tests, etc.
  • patent US7881881 is focused on its use in the laboratory with specific laboratory equipment, and not its onboard use (for example, in aircraft), so that patent US7881881 does not propose what electronic architecture would be necessary to build a Boating equipment, of small dimensions and weight, able to carry out the analysis of structural integrity in an autonomous, automatic and real time manner.
  • the patent US7881881 is, therefore, a document with a different approach to the object of invention, so that this document provides many novelties and differentiating features.
  • the patent application ES 201000242 entitled "Integrated system for monitoring structures by means of the ultrasound technique", in which several authors of this document participated, the electronic architecture of a basic SH system is described.
  • the differentiating objects make the architecture object of invention a fully configurable, autonomous system that can work automatically and in real time, without the attention of specialized personnel.
  • the differentiating or added elements in the present invention against the patent ES 201000242 are, among others:
  • Lamb wave technique on which the electronic architecture object of invention is based can be used both in the near field (with SAFT algorithms or Synthetic Aperture Focusing Technique, Adaptive Beamforming, triangulation algorithms, etc.) as in the far field, unlike the equipment proposed in the article, so the scope of application and the usable analysis techniques are very different in both cases.
  • SAFT algorithms Synthetic Aperture Focusing Technique, Adaptive Beamforming, triangulation algorithms, etc.
  • Patent ES2009070303 entitled “Procedure and apparatus for the correction of ultrasonic images by phase analysis”, in English “Method and apparatus for correcting ultrasound images by means of phase analysis”, describes a procedure for the correction of ultrasonic images by analysis phase, and comments on some features that should be included by an apparatus that puts this procedure into practice. It is evident that, although this document has to do with the taking of ultrasonic images by means of an array of transducers, it only describes an improvement for the correction of said ultrasonic images, and comments on the characteristics that an apparatus should have to apply said procedure, but not describes the electronic architecture that would be necessary to carry it out.
  • patent ES2302615 entitled “Digital defect detector by ultrasound and its applications”
  • patent WO2007128858A1 entitled “Digital device for detecting defects by means of ultrasound, and applications thereof”
  • Patent EP1715474A1 entitled “Coherent composition of signs by means of progressive focal correction” and patent ES2277473, entitled “Coherent composition of signals by progressive focal correction”
  • the patent discloses, on the one hand, the method to be used to perform beam shaping, and on the other hand, a system capable of implementing said method.
  • the described system only has the possibility of acquiring signals from the N transducers, not being able to generate the excitation signals by itself. Therefore, its use is limited to the technique of beam shaping in reception, making it impossible to use other advanced techniques of ultrasonic analysis, such as time-reversal, focusing and zooming, etc.
  • the fact of not being able to generate excitation signals makes necessary the presence of ultrasonic energy in the structure, generated by other means, either through other equipment, impacts, etc.
  • the patent ES2129004 entitled “Segmented architecture non-destructive testing system (SENDAS)" describes an architecture for the realization of systems of non-destructive tests by ultrasound, which allows the acquisition and subsequent processing of signals ultrasonic This architecture is solely dedicated to the acquisition of signals, so it does not include transducer excitation systems, impact detection systems, etc. Therefore, the architecture presented in patent ES2129004 can not implement advanced ultrasonic techniques such as time-reversal, beamforming in transmission, focusing and zooming, impact detection, etc. autonomously, automatically and in real time. Therefore, if you want to be able to use these techniques, it is necessary to use other external equipment that implements the functions that the patent ES2129004 lacks.
  • SENDAS Segmented architecture non-destructive testing system
  • the object of the present invention is a new electronic architecture that allows to build a high-performance integrated equipment for the field of structural integrity monitoring or SHM (Structural Health Monitoring) by the use of multiple ultrasonic waves.
  • This electronic architecture encompasses many useful functionalities and is planned and prepared to perform a wide variety of testing procedures.
  • a team designed on the basis of this architecture can be part of the equipment of an aircraft because it is capable of operating autonomously and because its weight and volume are reduced.
  • this new architecture allows a new mode of operation and methodology for SHM based on multiple ultrasonic waves, among others Lamb waves, since it allows to permanently incorporate a structure and carry out monitoring throughout the lifetime of the structure.
  • a series of ultrasonic wave transducers of piezoelectric material are attached to the surface and in turn the transducers are connected to the system of the invention.
  • the system of the invention allows to generate arbitrary signals in form, duration, amplitude, phase and frequency to excite all the desired piezoelectric devices.
  • the system acquires the response of all the transducers, stores and analyzes the received signals, and generates in real time a report, in the form of SHM maps, about the state of the structure, indicating the imperfections that may have arisen, such as fractures, cracks, delamination, deformations, corrosion, etc.
  • This parallel or concurrent architecture supposes a considerable advance on the systems SHM available at present.
  • the architecture integrates all the necessary electronic circuits in a small space, has various configuration options by the user such as frequencies used, signal types, number of channels, delays, etc. It also has a great power of calculation and operational flexibility and configuration, which allows you to implement advanced techniques of excitation, acquisition, processing and analysis, such as beam formation (in English Beamforming) both in transmission and reception, techniques of Time Reversal, Focusing, Zooming, Mapping, etc.
  • the invention as a key component of the PAMELA SHM system (Phased Array Monitoring for Enhanced Life Structural Health Monitoring System), is intended for real-time use or demand, in numerous and important applications such as: structural integrity monitoring , mapping of temperature distribution, deformation distribution mapping, stress distribution mapping, rigidity distribution mapping, vibration distribution mapping, characterization of physical properties of structural materials, impact detection, leak detection, etc. and all this during all the phases that make up the life cycle of the structures, such as in the manufacturing process, curing, assembly, certification tests, flight tests, maintenance and real service.
  • the invention is an important prerequisite for the future extensive use of systems for monitoring structural integrity distributed in common aeronautical structures, with on-site processing and rapid generation of reports on the state of structural integrity and the performance of the structure.
  • FIG. 1 constitutes the general block diagram of the Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 in relation to its environment.
  • the integrated monitoring equipment is composed of a digital block 102 and a 103. This unit receives the power supply from a power supply system 106, controlled by a Power Monitoring and Control Circuit 107. monitoring equipment communicates with an external control computer 101 via a guided communication system 105 and / or using a wireless communication system 104.
  • FIG. 2 shows the internal block diagram of the Multiple Electronic Architecture
  • the electrical supply of the equipment comes from the Power System 106, which generates the supply voltages from the External Power 112, being the Supervision and Power Control Circuit 107 the one that manages the use of energy.
  • the digital block 102 contains the Processing Module 203, the Arbitrary Signal Generation Module 200 (composed of the Digital Arbitrary Signal Generation Module 204 and the Arbitrary Signal Generation Analog Module 205), the Access Module for Memory 206, the Storage Module 209, the Adaptation Module 202, the piezoelectric actuators / sensors 108 mounted under the adapter module 110 and the Signal Acquisition Module 201 (comprised of the Analog Signal Acquisition Module 208 and the Digital Module of Acquisition of Signals 207).
  • the Processing Module 203 communicates with an external control computer 101 using the Communications Module 210, via guided communications 105 and / or wireless communications 104.
  • FIG. 3 shows the blocks that make up the Arbitrary Signal Generation Module 200 and its interconnection with the Processing Module 203 and the Adaptation Module 202.
  • the Processing Module 203 configures the parameters of the Arbitrary Signal Generation Module 200 and stores them in Generation Configuration and Control Block 311.
  • the Digital Module of Generation of Arbitrary Signals 204 is formed by the Block of Base Memories 300 (constituted by a natural number N of Base Memories 301), the Channel Multiplexer Block 302, the Block of Deprecated 303 (formed a number N of RFO Memories of Generation 304).
  • the output signals are sent to the Analog Arbitrary Signal Generation Module 205, formed by the Digital Analog Conversion Block 305 (which has a natural number N of High Speed Analog Digital Converters 306), the Anti-aliasing Filtering Block of Generation 307 (formed by N Anti-aliasing Filters of Generation 308) and the Amplification and Selection Block 309 (constituted by an N number of Channel 310 Amplifiers and Selectors), which sends the output signals to the Adaptation Module 202.
  • the Analog Arbitrary Signal Generation Module 205 formed by the Digital Analog Conversion Block 305 (which has a natural number N of High Speed Analog Digital Converters 306), the Anti-aliasing Filtering Block of Generation 307 (formed by N Anti-aliasing Filters of Generation 308) and the Amplification and Selection Block 309 (constituted by an N number of Channel 310 Amplifiers and Selectors), which sends the output signals to the Adaptation Module 202.
  • FIG. 4 shows the blocks forming the Signal Acquisition Module 201, and the interconnection with the Adaptation Module 202 and the Memory Access Module 206.
  • the analog signals collected from the transducers through the Adaptation Module 202 are sent to the Digital Signal Acquisition Module 208, formed the Impact Detection Block 400 (which includes N Voltage Level Detectors 401), the Acquisition Conditioning Block 402 (consisting of a number N of Low Noise, Gain Amplifier blocks Variable and Filter Anti-aliasing 403) and the Digital Analog Conversion Block 404, composed of a number N of High-Speed Digital Analog Converters 405.
  • the Impact Detection Block 400 which includes N Voltage Level Detectors 401
  • the Acquisition Conditioning Block 402 consisting of a number N of Low Noise, Gain Amplifier blocks Variable and Filter Anti-aliasing 403
  • the Digital Analog Conversion Block 404 composed of a number N of High-Speed Digital Analog Converters 405.
  • the signals are sent to the Signal Acquisition Analog Module 207, the trainer by the Digital Filtering Block 406 (containing an N number of configurable Digital Filters 407), the Digital Conditioning Block 408 and the Synchronization Block 409 (formed by N FIFO Acquisition Memory 410).
  • the output signals are sent to the Memory Access Module 206, which also controls the 411 Acquisition Control and Configuration Block.
  • FIG. 5 shows in greater detail a possible way of designing the Low Noise Amplifier, Variable Gain and Anti-aliasing Filter 403.
  • the signals that are sent from the Voltage Level Detector 401 pass through the Low Noise Amplifier 500, then through the Variable Gain Amplifier 501, and finally by the Anti-aliasing Filter of Acquisition 502.
  • FIG. 6 shows the connection between the integrated monitoring equipment 100 and the piezoelectric elements 108.
  • the connection is made in the Adaptation Module 202, through the electromechanical Connector of the Equipment 606.
  • the electromechanical Connector of the Equipment 606 is connected to the electromechanical Connector of the Adapter 109 by connecting lines 607.
  • the Adaptation Module 202 has the Transformation Block 600 (containing N sub-blocks Signal Transformer 601), the Suppression Block 602 (formed by N sub-blocks Transient Suppressor 603) and the Discharge Block 604 (formed by N sub-blocks Gas Discharger 605).
  • FIG. 7 represents the arrangement of two integrated monitoring equipment 100 for implementing the Pitch & Catch technique, located on either side of a welded, screwed or riveted joint 700. Both devices are connected to the transducers by means of the adapter 110 and are synchronized by a Dedicated Line of Communications 701.
  • FIG. 8 shows the Multi-Channel Electronic Architecture Performance Flow for Advanced Structural Integrity Monitoring 800 and the flow of external control computer 801.
  • the external control computer 101 using the configuration and control program 816, communicates with the preparation, timing, etc. program. 804, in addition to ordering the execution of the tests to the preparation program, timing, etc. 804.
  • the configuration program of a composite test 805 is executed, the configuration program of a simple test 806 is executed, the execution of a simple test by means of the electronic circuits 807 and the execution of the preprocessing program of the data 808.
  • the composite end-of-test bifurcation 809 is executed which decides whether to follow the flow of the realization loop of a composite test 812, or the composite test has been completed, in this case proceeding to the execution of the data processing program of the composite and processed test of the signals 810.
  • This program transmits the results to the external control computer 101 that receives them through the execution of the reception program of the test results 813, performs the assembly of the SHM 814 maps and visually presents the results 815.
  • FIG. 9a and 9b represent an example, not exclusive but if preferable, of the outside of a computer with the architecture object of this invention.
  • the electromechanical Connector 606 with the 905 systems to provide the mechanical coupling between the integrated equipment 100 and the electromechanical connector of the Adapter 109 in the Transducer Adapter Module 110, the connector for the dedicated communications lines 701, two electromechanical connectors for guided communications 903, the antenna for wireless communications 904, the extendable cable-extender antenna 907, the articulated support and screwed on antenna 908, the glued support of Antenna 909, an electromechanical power connector 901, the electromechanical connector for the autoharvesting system or alternative power systems 906, and a label identifying the 910 equipment.
  • a small screen is also shown 913 touch with the menus of co nfiguration 914 and display of SHM 902 maps or ultrasonic images, which can replace the external control computer 101.
  • Detail 911 illustrates the menus of co nfiguration 914 and display of SHM 902 maps or ultrasonic images, which
  • FIG. 10 shows a preferred mode of installation of several Adapter Modules of piezoelectric transducers 110 on the liner 114 of a typical aeronautical panel 113 with several integrated stiffeners 115.
  • the adapter modules 110 are coupled with their corresponding box 900.
  • each of the integrated equipment 110 117 wirelessly send the SHM maps to the external control computer 101.
  • three-dimensional assembly tools three-dimensional models are created 116.
  • the Electronic Architecture of Multiple Channels for Advanced Monitoring of Structural Integrity 100 is an electronic circuit where all the elements that make up a multi-channel system are integrated for the monitoring or advanced evaluation of the integrity of a structure throughout its life. In particular, it affects the aeronautical and aerospace fields, where it is important to use integrated equipment of great reliability and low weight and volume.
  • the Multi-Channel Electronic Architecture prototype for Advanced Structural Integrity Monitoring 100 uses 12 excitation and acquisition channels connected to each piezoelectric actuator / sensor 108, an Arbitrary Signal Generation Module 200, an Adaptation Module 202 between the system and the piezoelectric transducers, a Signal Acquisition Module 201, a Processing Module 203 that includes in its interior a processor for the processing of the acquired signals, a Memory Access Module 206 for storing the signals as quickly as possible in the memory Dynamic DDR2 SDRAM (dynamic type read and write memory) included within Storage Module 209, and other circuits in charge of system control, power and communications management.
  • SDRAM dynamic type read and write memory
  • FIGs. 9a and 9b show the preferred exterior design of the box that would contain the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100.
  • FIG. 9a shows a top view of the Box 900 containing the Electronic Architecture, where the guided communication connector 903, the antenna for wireless communications 904 and the mechanical coupling 905 for the electromechanical connector of the equipment 606, among others, can be seen.
  • section 2 the operating scenarios of the system are presented, a fundamental aspect to differentiate this invention from others referenced.
  • FIG. 1 you can see the elements of the structure analysis system described in section 3.
  • sections 4 to 11 each of the modules shown in FIG. 2, in FIG. 3, in FIG. 4, in FIG. 5 and in FIG. 6.
  • Section 12 describes aspects of internal functioning.
  • section 13 the techniques of analysis of structural integrity, based on the technique of guided ultrasonic waves, which can be put into practice by using the electronic architecture described.
  • section 14 the structural integrity analysis to be carried out is analyzed to determine the appearance of defects.
  • the use of multiple systems is extrapolated to large-sized material structures or that contain stiffening elements, an aspect shown further in FIG. 7.
  • the letter N will normally indicate the natural number of transmission / reception channels present in the Electronic Architecture of Multiple Channels for Advanced Monitoring of Structural Integrity 100 (preferably 12 channels).
  • the monitoring system based on Electronic Multiple Channel Architecture for
  • Advanced Monitoring of Structural Integrity 100 is planned to work in two different scenarios or spaces of use. In each of them, the configuration of the architecture and the mode of operation are very different. 2a. In the first place, it can be operated in a laboratory setting, where an operator configures the parameters of the electronic architecture using an external control computer 101 in which a human-machine interface or HMI (Human-Machine Interface) is executed. Using the same HMI, the operator can order the start of a structural integrity test.
  • HMI Human-Machine Interface
  • the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100 loads the configuration defined by the operator and starts a test, exciting all the desired piezoelectric transducers and acquiring the signals received by all transducers simultaneously.
  • the signals acquired are sent, using the Communications Module, to the external control computer 101, where the computer performs structural integrity analysis using a specific program for this task.
  • This particular operating scenario is mainly thought for the tasks of development and verification of all the SHM algorithms and optimal configurations, before recording all of them within the Storage Module 209 of the Multiple Channel Electronic Architecture for Structural Integrity Monitoring 100, of face its final installation in the host structure. 2b.
  • the other scenario, the preferred one for real aeronautical applications, is an on-board scenario. In this scenario, the system is assembled in an aeronautical structure or component, operating autonomously, in programmed intervals and modes, without external supervision by an operator. The methodology for the on-board system is similar.
  • the configuration parameters of the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100 can be configured before or after placing the system in the structure and joining it with the piezoelectric transducers that are attached to the structure to be monitored. At any time there is the possibility of modifying the system configuration using the Hybrid Communications Module 210 for downloading the results. This modification of the configuration is used to update the algorithms of image reconstruction or embedded software. The transfer of results through the Hybrid Communications Module 210 can be performed without having direct access to any of the SHM devices, without any dismantling in the structure or need for its ground parking.
  • the system When the system is shipped, periodically and autonomously, based on the configuration recorded by the user, it is responsible for performing the structural integrity tests, loading the configuration parameters stored inside, exciting the piezoelectric transducers, acquiring signal of them, applying advanced SHM techniques to determine the position of possible defects and generating images or SHM maps of the structure. At the end of these processes, it will generate information that can be stored to provide a maintenance service with the information when it is required, or it can be transmitted immediately to the pilot of the aircraft or to stations on the ground to warn about the status of the structure, for example. 3.
  • FIG. 1 you can see the electronic elements that are part of the Electronic Architecture of Multiple Channels for Advanced Monitoring of Structural Integrity 100 and its connection with other external elements. From the physical point of view, you can see four basic elements:
  • This adapter includes an electromechanical connection of the adapter 109 for connection with the electronic architecture .
  • the example of the adapter module would preferably be an integrated PhA (Phased Array) transducer, such as, for example, the one presented in the patent application EP11382045.
  • PhA PhA
  • These piezoelectric elements vibrate the structure by means of ultrasonic guided waves to subsequently capture the waves propagated by the structure and reflected in the limits of the same and in possible defects.
  • the possible disturbances of the waves are proof of defects, such as fissures or delaminations.
  • This technique can be used in both metallic materials and composite materials (also known as composites).
  • the attenuation of ultrasonic waves is very high.
  • the Electronic Architecture of Multiple Channels for Advanced Monitoring of Structural Integrity 100 has amplifiers capable of adequately counteracting this attenuation in propagation. It also has a signal generator that can adapt the shape, amplitude, duration and frequency of the excitation signals according to the characteristics of the propagation medium.
  • the electronic architecture receives the energy of a power system 106, which is fed from an external power 112 or by means of an energy accumulator which is recharged by means of Autoharvesting techniques or the like.
  • the power system 106 is managed by the Power Monitoring and Control Circuit 107.
  • the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100 is connected to an external control computer 101 by means of guided communications 105 and / or wireless communications 104.
  • guided communications 105 and / or wireless communications 104 Components dedicated exclusively to perform the structural analysis can be decomposed into:
  • a block of digital circuits 102 which, as will be shown below, must be built into a programmable logic device such as a PLD (Programmable Logic Device, in English) or an FPGA (Field-programmable Gate Array, in English) or similar, and
  • a programmable logic device such as a PLD (Programmable Logic Device, in English) or an FPGA (Field-programmable Gate Array, in English) or similar, and
  • analog circuits 103 which are responsible, among other things, for conditioning the analog signals that are sent and received from the piezoelectric actuators / sensors.
  • the digital circuit block 102 uses digital signals arranged on buses with a sufficient number of bits to provide adequate accuracy. For example, 10 or 12 bit buses have been used in the prototype for signal data buses.
  • the analog circuit block 103 after making the conversion from digital to analog, the signals are analog and with the necessary amplitude in each part of the circuit.
  • FIG. 2 the diagram of the Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 is appreciated in detail. The modules presented in said figure are discussed in detail in sections 4 to 11.
  • FIG. 3 the general scheme of the Arbitrary Signal Generation Module 200 is shown.
  • This module is used to generate a base signal of a certain form, duration, amplitude, phase and frequency independently for each of the piezoelectric N actuators / sensors.
  • the Arbitrary Signal Generation Module 201 can simultaneously excite the N piezoelectric elements and, moreover, each of the N channels can be set to high impedance after transmitting the excitation signals to the structure 111; this aspect allows to have a guard time between successive excitations, which allows to use the piezoelectric no only as actuators, but also as sensors, being able to capture the echoes that occur due to rebounds of the signals in the limits of the material, in the defects, etc.
  • All of the configuration parameters of the Arbitrary Signal Generation Module 200 are stored in the Configuration and Control Block 311 and are configurable by programming from the external control computer 101 in a laboratory setting, or from the Processing Module 203 in a Embarked scenario (for more details, see section 2 - Operating Scenarios).
  • the Arbitrary Signal Generation Module 200 is able to use integrity analysis techniques such as simple tests (pitch-catch or pulse-echo inspection), round-robin tests, etc., and more advanced techniques such as beam formation (from English Beamforming) in transmission, investment of time (from English Time Reversal) or the algorithm of autofocus (Focusing and Zooming), among others.
  • integrity analysis techniques such as simple tests (pitch-catch or pulse-echo inspection), round-robin tests, etc.
  • advanced techniques such as beam formation (from English Beamforming) in transmission, investment of time (from English Time Reversal) or the algorithm of autofocus (Focusing and Zooming), among others.
  • the parameters of the signals generated by the Arbitrary Signal Generation Module 200 can be varied very freely, the characteristics of the signals are approximately the following:
  • variable frequency in the range of 30 kilohertz to 1 megahertz
  • the signals generated by the Arbitrary Signal Generation Module 200 once transmitted to the structure with a certain shape, duration, amplitude, phase and frequency, create ultrasonic waves that propagate through the material to be monitored, called ultrasonic guided waves or Lamb waves.
  • Lamb waves are a type of elastic waves that propagate on thin surfaces and that have different modes of propagation.
  • the most interesting modes for structural integrity analysis are the lower order modes (Ao or antisymmetric 0 and So or symmetric 0), which are generated for specific frequencies that are in the range of 35 kilohertz to 500 kilohertz.
  • the position of the propagation modes depends on the type of material of the structure under monitoring and is described by curves known as dispersion curves.
  • the Arbitrary Signal Generation Module 200 is composed of two interconnected parts: the Digital Arbitrary Signal Generation Module 204, which sends the N signals to the Arbitrary Signal Generation Analog Module 205.
  • the Processing Module 203 loads, from the Storage Module 209 and using the Memory Access Module 206, the digital base signals in the Digital Arbitrary Signal Generation Module 204.
  • the Digital Arbitrary Signal Generation Module 204 is a highly configurable module. Thanks to this configuration flexibility, it is possible to generate the necessary signals in a large part of the monitoring analysis modes currently used and may even adapt to others that have not been considered in this document.
  • the Digital Module of Generation of Arbitrary Signals 204 is composed of the Base Memory Block 300, the Channel Multiplexer Block 302, the Phase 303 Block, the Analog Digital 305 Conversion Block, the Generation 307 Anti-aliasing Filtering Block and the Block of Amplification and Selection 309.
  • Block of Base Memories 300 is formed by a number N of Base Memories 301 that store individual signals so that they are subsequently transmitted to each channel.
  • the Base 300 Memory Block can be realized with dual port memories. On the left side of the memories there is access from the Processing Module 203 and on the right side there is a counter that generates the read addresses of the memory in order to reproduce the stored signal. This counter can be configured with a maximum value according to the size of the signal to be generated. The shape of the signal is implicit in the digital data that determines the amplitude of the signal at each moment.
  • Channel Multiplexer Block 302 this block is a multiplexer of N by N buses of a single direction, which allows to vary the position of the channels in the connection with the Phase Out Block 303.
  • the Channel Multiplexer Block 302 is formed internally by N multiplexers from N to 1 buses. This block adds flexibility to the system, allowing to vary the signals assigned to each channel dynamically. Other possibilities of this block are: to provide the signal of a Base Memory 301 to all or part of the channels (necessary for bemaforming), to apply the signal of the Base Memory 301 from one channel to another different channel (necessary in round-robin) , etc.
  • this block is formed by a number N of Generation FIFO Memories 304 of a certain number of memory positions, which allow each one of the signals of the N channels to be independently offset.
  • Each of the FIFO Memories of Generation 304 is connected, through a configurable multiplexer, with the output of the Channel Multiplexer Block 302 of the channel itself, with the FIFO memory of the previous channel and with the FIFO memory of the subsequent channel, of so that the phase shifts can be transmitted one way or the other. This allows applying the Beamforming technique for the two upper quadrants and for the two lower quadrants of a flat structure without modifying the data stored in the Base Memory Block 300.
  • the FIFO Generation 304 Memories and the Base 301 Memories can function in sets of X channels (where X and the sum of all X's are a natural number less than or equal to N), so that different signals can be transmitted, even with different phase shifts, in groups of X channels selected from among the N channels totals
  • the output signals of the Deprecated Block 303 are sent to the Analog Module of
  • Digital Analog Conversion Block 305 this block is formed by a number N of High Speed Analog Digital Converters 306, for example of 100 million samples per second (from English MSPS or Mega Samples Per Second) or higher.
  • the High Speed Analog Digital Converters 306 reproduce the excitation signals of the piezoelectric elements in the analog domain and with high resolution. Due to the high sampling frequency, a high resolution is achieved when applying the phase shifts chosen in the Out-of-Phase Block 303. These converters should preferably have differential output, in order to reduce the noise when amplifying the signals in the Block. Amplification and Selection 309.
  • Generation 307 Anti-aliasing Filtering Block composed of N Generation 308 Anti-aliasing Filters to prevent the aliasing effect due to the conversion process from appearing in generation signals.
  • Each of the Anti-aliasing Filters of Generation 308 is a low-pass filter of a certain type and order, for example a Butterworth filter of order 5, which eliminates the frequency components that are above the maximum frequency of the generable excitation signal.
  • 4h Amplification and Selection Block 309 formed by an N number of Blocks of the Amplifier and Channel Selector type 310.
  • Each of these blocks can be composed of a high-precision operational amplifier, which provides the output with a signal of sufficient amplitude to the application to piezoelectric transducers (for example, 40 volts peak-to-peak), and a channel selector or electronic switch for analog signals, which depending on the analysis technique to be used allows activating and deactivating each of the channels .
  • the amplifier is also capable of transmitting the excitation signal to a piezoelectric actuator / sensor without oscillating due to the high capacity of the piezoelectric elements (in the order of a few picofarads, depending on the model used).
  • the Arbitrary Signal Generation Module 200 includes a Generation Configuration and Control Block 311 where the Processing Module 203 introduces all the configuration parameters of the Arbitrary Signal Generation Module 200, configures the Base Memory Block 300, configures the state of each channel in the Channel Multiplexer Block 302, configures the delays of each signal in the Deprecated Block 303, controls and configures the analog-digital converters of the Digital Analog Conversion Block 305, the level of amplification and the selected channels in the Amplification and Selection Block 309, etc. All these configurable values allow to provide the Electronic Architecture of Multiple Channels for Advanced Monitoring of Structural Integrity 100 presented in this document of capacity to use the advanced analysis techniques used in structural integrity monitoring.
  • the variation of the configuration is introduced in the Processing Module 203 through the external control computer 101, prior to the installation in the structure of the equipment based on the electronic architecture. Based on this configuration, the Processing Module 203 modifies in a fraction of a second the parameters of the Generation Configuration and Control Block 311 to perform the different types of tests automatically. 5.
  • the Adaptation Module 202 is responsible for sending the signal generated by the Arbitrary Signal Generation Module 200 to the piezoelectric elements, performing the necessary adaptation for their interconnection. In addition, it is responsible for collecting signals from echoes, rebounds, etc. from piezoelectric actuators / sensors. in the structure and sends them to the Signal Acquisition Module 201.
  • the Adaptation Module 202 is formed by a series of adaptation, protection and isolation circuits. Since the piezoelectric elements are fixed on an aeronautical structure that is in contact with the environment, unwanted signals of great amplitude can be introduced into the system. These signals can damage the internal electronic circuits, and can damage any of the channels of Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100. Therefore, in addition to making the connection with the piezoelectric elements, this module includes for each of The N channels a series of circuits that provide electrical isolation and protection against surges and overcurrents.
  • each channel has galvanic isolation, which is achieved by one of the N Signal Transformer elements 601, all of which are contained in the Transformation Block 600.
  • the Signal Transformer 601 must be able to work with the maximum tensions generated by the Modulation Module.
  • Generation of Arbitrary Signals 200 which can be relatively high voltages for low power devices, and must do so in a sufficiently large bandwidth introducing the minimum distortion. Therefore, taking into account the voltages generated by the Arbitrary Signal Generation Module 200, it must support, for example, maximum voltages of 40 volts peak to peak of alternating signal without introducing an appreciable distortion.
  • Transient Suppressor 603 or TVS (from the English Transient Voltage Suppressor), which absorbs voltages greater than 40 volts peak to peak.
  • the invention has N devices of this type contained in the Suppression Block 602,
  • connection with the piezoelectric elements 108 is carried out by means of the Electromechanical Connection of the Equipment 606, which must have at least as many pairs of connections as number N of channels.
  • Connection Lines 607 of the same number of pairs of cables, are joined, which is used to join the equipment based on the electronic architecture with the Adapter Connection 109.
  • the Connection Lines 607 can be constructed in different ways:
  • the mechanical part of the Electromechanical Connection of the Equipment 606 (for example CMN series Nicomatic, female) with the Adapter Electromechanical Connector 109 (for example CMM series Nicomatic, male) be carried out with, at least, two screws.
  • the 606 connector be located in the center (gravity) of the printed circuit, in order to be able to better support the vibrations, forces and inertial moments during service, once fixed above the adapter module of piezoelectric transducers 110. of the structure in a real application environment, such as aeronautics.
  • the box 900 containing the integrated equipment 100 being fixedly connected on top of the Adapter Module 110 by means of the Electromechanical Connection of the Adapter 109, must not touch or touch the structure on which it is installed with any of its points. This is achieved by adjusting the heights of the two electromechanical connectors, that of the Integrated Equipment 606 and that of the Adapter 109, or correctly positioning the printed circuit board of the equipment with Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 inside the box 900. Thus, a minimum allowable distance of several millimeters can be ensured. This requirement is essential so that the box 900 with the integrated equipment 100 can not cause any damage by touching or rubbing the structure, or produce impacts or friction on it, which could hinder the correct interpretation of the signals and SHM maps. 6. Module of Acquisition of Signals 201
  • the Signal Acquisition Module 201 is responsible for adequately conditioning, filtering and sampling the signals collected from the N piezoelectric elements and sending them to the Storage Module 209, using the Memory Access Module 206 for this purpose.
  • Configuration of the Signal Acquisition Module 201 are stored in the Acquisition Control and Configuration Block 411 and are configurable by programming from an external control computer 101 in a laboratory setting, or from the Processing Module 203, previously configured, in an onboard stage.
  • the Signal Acquisition Module 201 contains sufficient circuits to deal in parallel or simultaneously with the signals of the N channels, and is composed of two interconnected parts: the Analog Signal Acquisition Module 208, which sends the N signals to the Module Digital Signal Acquisition 207. 6a.
  • the Analog Signal Acquisition Module 208 is responsible for collecting in parallel the signals of the N actuators / piezoelectric sensors and conditioning them using the following blocks:
  • - Impact Detection Block 400 formed by N blocks of type Voltage Level Detector 401 which, after adjusting a reference voltage level (for example, through a variable and programmable resistor), allow determining if produced an impact on the structure that is being monitored and thus activate the acquisition of data to be able to determine in which position of the structure the impact has happened.
  • a reference voltage level for example, through a variable and programmable resistor
  • each of these N elements is composed, firstly, by a Low Noise Amplifier 500 or LNA (from the English Low Noise Amplifier) that allows reducing the noise figure of the Signal Acquisition Module 201. Subsequently, each signal it passes through a Variable Gain Amplifier 501, which amplifies the signal with a gain that is selected from the Processing Module 203. This gain can be varied dynamically over time, so it can function as a TGC (from the English Time -Gain Compensation, or Compensation of Profit over Time.
  • LNA from the English Low Noise Amplifier
  • each signal goes through an Acquisition Anti-aliasing Filter 502, which can be done with a low-pass filter of a cutoff frequency of, for example, 8 megahertz, which is It eliminates the signal frequencies above said frequency, to avoid aliasing in the sampled signal in the subsequent sampling process.
  • the filter introduces the minimum possible distortion in the signal that is responsible for filtering.
  • MSPS samples per second
  • the already digitized signals that come out of the Signal Acquisition Analog Module 208 are sent to the Signal Acquisition Digital Module 207. 6b.
  • the Digital Signal Acquisition Module 207 is in charge of preparing digitalized signals, digitally filtering them, decimating them if necessary and storing them. Integrates the following blocks:
  • Digital Filtering Block formed by an N number of Digital Filters 407.
  • These digital filters can be either FIR (Finite Impulse Response or Finite Impulsive Response) or IIR (Infinite Impulse Response) Infinite). Its cutoff frequency can be very abrupt, given that they work in the digital domain, and are responsible for eliminating signal frequencies that are outside the range of interest and that could not be eliminated by the Block 502 Anti-aliasing Filter. of Acquisition Conditioning 402.
  • - Digital Conditioning Block 408 which is in charge of ordering, numbering and conditioning the N signals digitized by the Analog Module of Signal Acquisition 208, including in each sample the numbering of the channel to which it belongs and, if necessary, increasing the length from each of the samples of the signals up to a power value of two, so that the samples are easily manageable in the digital domain. In addition, it is responsible for modifying the format of each sample so that it is understandable by the following stages (for example, serial to parallel conversion, if necessary). Finally, in the Digital Conditioning Block 408 it is also possible to decimate the digitized signals, in order to reduce the size of the samples of the signals when they are stored in memory. The decimation values are selectable, which may be any multiple of two within a permissible range.
  • Synchronization Block 409 consisting of a number N of FIFO Acquisition Memories 410, which are FIFO buffer memories of a certain number of positions. Because access to the Storage Module 209 is shared by the Processing Module 203 and by the Signal Acquisition Module 201 through the Memory Access Module 206, and that those can use different operating frequencies, the the channels must be synchronized in the Synchronization Block 409 before being stored in memory through the Memory Access Module 206.
  • the Signal Acquisition Module 201 includes a Acquisition Control and Configuration Block 411, where the Processing Module 203 or the external control computer 101 enter all the configuration parameters of the Signal Acquisition Module 201: they configure the level voltage of the Impact Detection Block 400, the gain and filters of the Acquisition Conditioning Block 402, the sampling frequency of the digital analog converters of the Digital Analog Conversion Block 404, etc.
  • the Processing Module 203 is responsible for performing the relevant signal analysis. In a laboratory setting, samples of the ultrasonic signals are downloaded to the external control computer 101 for further analysis.
  • the Memory Access Module 206 manages the accesses to the Storage Module 209 by the Processing Module 203 and the Signal Acquisition Module 201, avoiding simultaneous access attempts.
  • the Memory Access Module 206 has a DMA block (from the English Direct Memory Access) that allows the signals digitized by the Signal Acquisition Module to be transferred to the Storage Module 209 at high speed. 201, without the Processing Module 203 having to intervene in the process.
  • the Memory Access Module 206 includes other devices and circuits necessary for the proper development of its functions.
  • Storage Module 209 This module is composed of storage memories that allow storing the data and programs necessary for the correct functioning of the system. Memories of various types are necessary:
  • Random Access Memory Random Access Memory
  • DDR SDRAM Double Data Rate Synchronous Dynamic Random Access
  • Memory or similar, of a sufficient capacity to store the data necessary for the execution of the analysis software executed by the Processing Module 203, as well as other data necessary for the operation of the equipment.
  • the size of volatile RAM storage must be at least 512 megabytes.
  • - ROM Read-Only Memory or Read Only Memory
  • Flash to store the results of structural integrity analysis in a non-volatile way, the program or operating system that will be executed by the Processing Module 203, and other configuration data of! system.
  • the size of ROM memory storage should preferably be several gigabytes or greater. The size of this memory depends to a great extent on the final application scenario of the integrated SHM system. In the aeronautical sector it is of great interest to store SHM data during several flights and / or days, before downloading the data in ground stations or on-line SHM systems by means of suitable methods.
  • PROM memory from English Programmable Read-Only Memory
  • EPROM from English Erasable Programmable Read-Only Memory
  • EEPROM from English Electrically-Erasable Programmable Read-Only Memory
  • the size of the PROM / EPROM / EEPROM memory should be sufficient to store the configuration of the FPGA or PLD device, or if desired, a bit larger to store several different configurations.
  • This module is responsible for carrying out the processing of signals acquired through the piezoelectric sensors / actuators. It is responsible for processing the samples of the signals stored in the Storage Module 209, and for carrying out a digital processing of said samples. In addition, he is in charge of controlling and configuring the rest of the modules of the Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 using different internal communication systems. For example, write the configuration of the Arbitrary Signal Generation Module 200 in the Configuration and Generation Control Block 311.
  • the Processing Module 203 is preferably based on a microprocessor or a DSP (of English, Digital Signal Processor or Digital Signal Processor) of great power and versatility, preferably integrated within the device FPGA, PLD or ASICS (of the English Application Specific Integrated Circuit or Integrated Circuit for Specific Applications) used.
  • a microprocessor or a DSP of English, Digital Signal Processor or Digital Signal Processor
  • FPGA field-programmable gate array
  • the Processing Module 203 accesses the Storage Module 209 using the Memory Access Module 206, uses different types of serial and parallel communications to communicate with other integrated circuits capable of accepting these communications. , and various input and output pins for controlling the Arbitrary Signal Generation Module 200, the Signal Acquisition Module 201, the Adaptation Module 202 and the Communications Module 210.
  • the Processing Module 203 After performing the analysis of the acquired signals, sends the maps or warnings about the state of the structure to an external control computer 101 operated by the operators that control or maintain the structure . It can also be operated remotely by the people who supervise the structure, to request or configure the equipment for a certain mode of operation. Even so, it should not be forgotten that the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100 can also work autonomously, without intervention by specialized personnel, in an on-board or installed scenario.
  • Hybrid Communications Module 210
  • This module is responsible for managing the communications of Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 with the outside, using two types of communications, thus creating a hybrid communications system:
  • a guided communications system 105 for example IEEE 802.3u, this being not the only admissible guided communications system, since others such as aeronautical standards A INC, MIL-STD-1553, USB, etc. can be used.
  • the preferable number of the 903 Guided Communications Connectors for aeronautical applications is two, in order to be able to connect several equipment with the Electronic Architecture of Multiple Channels for Structural Integrity Monitoring 100 in a chain (daisy-chain) creating a linear or ring topology.
  • a wireless communication system 104 for example WiFi (from English Wireless Fidelity), or any other wireless communication system, such as Infrared (IR), VLC (Visible Light Communications) or systems operating by radio frequency (RF) ) in free bands, among others.
  • WiFi from English Wireless Fidelity
  • IR Infrared
  • VLC Vehicle Light Communications
  • RF radio frequency
  • the team based on the Multiple Channel Electronic Architecture for Structural Integrity Monitoring 100 integrates a wireless communication system for reasons of redundancy, security and flexibility, to adapt the SHM system to real and complex aeronautical structures and application scenarios, such as the wings, the stabilizers, the fuselage, etc., where there are areas with a preference for guided communications and others where only wireless communications can be used. It is preferable that the wireless communication system supports communication protocols, such as protocols for mesh networks based on the IEEE 802.11s standard, its different updated versions and / or others.
  • the Communications Module 210 collects the orders that are sent by any of the communication systems to the program that is executes in the Processing Module 203, which subsequently writes the configuration in the elements of the Digital Block 102 and the Analog Block 103.
  • the Processing Module 203 finishes performing the integrity analysis of the structure and generates a report about it , it is connected to the Communications Module 210 to send the warning to the remote management systems, by any of the available communication systems.
  • the Power System 106 uses the external power 112 to generate the power supply voltages required for the Electronic Architecture for Multiple Channels. Advanced Monitoring of Structural Integrity 100.
  • the Power Monitoring and Control Circuit 107 manages the use of the energy consumed by the electronic architecture, shutting down circuits that are not necessary during certain time intervals, thus reducing the energy consumption of the architecture.
  • the operating capacity in low consumption mode is established in order to reduce the consumption of the device, and it is possible to work with electric energy accumulators or electricity generation systems from alternative energies.
  • the equipment based on the electronic architecture 100 is connected to the external power by the Electromechanical Power Connect 901. In an aircraft, the external system can be the main or auxiliary power system.
  • the connection must be electromechanical in order to ensure a reliable connection throughout the life of the aircraft and in all service environments.
  • the invention apparatus may include a rechargeable energy accumulator (battery, supercapacitor, etc.), previously charged, which may be used during the process of manufacturing and assembly of the structure in order to detect possible loads and deformations that occur during this phase of life of the structure, where there is an absence of external power.
  • the energy accumulator may be recharged during the life cycle of the structure using alternative energies, for example, by using Auto-Harvesting, although other methods are possible and it is understood that they are contemplated within the scope of this invention.
  • the equipment based on the electronic architecture 100 includes on the upper face an Electromechanical Connection 906 that allows an Autoharvesting device to be fixed on it to feed it. In addition, it is not ruled out that an Autoharvesting system is part of the Power System 106.
  • FIG. 8 shows the flow of operation of the Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 800, in addition to the flow of operation of the external control computer 801. The latter serves so that the user can control, receive and visualize the data of the monitoring system.
  • Multi-Channel Electronic Architecture for Advanced Structural Integrity Monitoring 800 begins when the electronic circuit is fed. At that time, the initialization process of the electronic circuits 802 and the initialization process of the internal processor 803. occurs. From this moment the execution of the preparation, timing, etc. program begins. 804.
  • This program works on the basis of the configuration introduced by the maintenance personnel of the aircraft, or the corresponding user, through the flow of operation of the external control computer 801, through the external configuration and control program 816.
  • This program can determine the type of test that must be done on a structure, the periodicity of the test, the control of the low consumption states and other parameters .
  • the execution of the configuration program of a composite test 805 is presented, which is responsible for preparing the configurable parameters of a composite test. Then, the execution of the configuration program of a simple test 806, the execution of a simple test by means of the electronic circuits 807 and the execution of the data preprocessing program 808, responsible for adapting the data received for its treatment in the Processing Module 203.
  • a simple test is considered the application of certain signals to the piezoelectric and the reception of the signals received by the piezoelectric. It is considered a composite test when the technique of integrity monitoring of a structure requires the execution of successive simple tests. That is, when it is required to apply signals to the piezoelectric, collect the piezoelectric data and return several times to apply and collect piezoelectric data by varying some parameter of the test, to finally process together the data collected in the various tests with algorithms that take into account the different tests.
  • the composite end-of-test bifurcation 809 is executed, which decides if more simple tests should be executed to complete the composite test and, therefore, the loop flow of a composite test must be followed. 812, or the composite test has been completed and the normal execution of the program must continue.
  • This program contains the functions of data processing in a system of monitoring structures and for all the test modes provided in the invention. Part of this program is in charge of transmitting the results of the tests to the external control computer 101, which receives them through the execution of the program of reception of the results of tests 813, performs the three-dimensional assembly 814 of all the SHM maps and presents the results through the execution of the results visualization program 815.
  • This visualization can have several manifestations: from showing the numerical data of the test in a laboratory scenario, to informing a pilot or the maintenance personnel of an aircraft by an alarm on the status of the monitored structure (on-board scenario). Using multiple units of the Multiple Channel Electronic Architecture for Advanced Structural Integrity Monitoring 100, the complete structure of a complex system such as an aircraft can be monitored.
  • Multi-Channel Electronic Architecture Performance Flow for Advanced Monitoring of Structural Integrity 800 returns to the execution of the preparation, timing, etc. program. 804 through the main loop flow of program 811.
  • the analysis round-robin consists of N x N simple tests determined by the simple test configuration 806, by which the excitation channel and the acquisition channel are alternated among the N available channels. For example, if we have 12 channels connected to piezoelectric transducers, we can find up to 144 pairs of excitation and reception.
  • a pre-processing of the data 808 is carried out and the next test is carried out.
  • the N x N tests are finished, the data processing and the signal processing 810 is performed, in order to generate the ultrasonic image of the structure.
  • the object of the invention allows to make all possible combinations automatically and periodically.
  • the results are sent to the external control computer 101, which receives the results 813, makes the three-dimensional assembly of the maps 814 and visualizes them 815, so that the results are easy to interpret.
  • This technique is based on transmitting the same ultrasonic signal on the N channels, but with a specific time lag between each of them, so that the piezoelectric elements act as an array of elements that has a directional transmission beam that is used to scan the entire structure. To do this, the piezoelectric units must be arranged in a linear array.
  • This method provides an improvement in the gain of signal reception with respect to the omnidirectional transmission, which is known as transmission gain. Making use of this technique, a greater resolution can be reached when analyzing the material and it is possible to work with larger materials or with materials in which Lamb waves have a great attenuation, such as composite materials.
  • this technique is carried out by adjusting the phase shift introduced in the Out-of-Phase Block 303 for each of the channels, and if necessary, modifying the arrangement of the channels in the Channel Multiplexer Block 302.
  • This technique is similar to the previous one, but in this case it is applied in the reception of signals. After sampling the signals of the N channels, a differential time difference with respect to the others is applied to them, which allows to improve the resolution of the analysis, the improvement index being known in this case as gain of reception.
  • This technique is applied by the Module of Processing 206 varying the phase shift of each channel sampled by the Signal Acquisition Module 201.
  • a simple test 806 with the Beamforming parameters must be configured in reception, to subsequently perform a preprocessing of the data 808 , data processing and signal processing 810, before sending the results for viewing 815.
  • This technique consists only in combining the operation of Beamforming mode in transmission and Beamforming in reception.
  • the approach and enlargement mode has the objective of concentrating the inspection or scanning by elastic waves in the defects present in the structure subject to monitoring.
  • the autofocus procedure measures the backscattered signals in a first transmission made by an element of the linear array of transducers.
  • the cross-correlation technique is used to determine the differences in flight times or TOFs (of the English Time-Of-Flig t) of the backscattered signals that are received in the piezoelectric elements of the array that is mounted on the adapter 110. These Time delays are used to adjust the moments of excitation of the elements to achieve focusing the transmission on a specific defect in a subsequent signal transmission.
  • the backscattered signals are aligned after the focused transmission to perform the focus on the reception.
  • the Processing Module 203 must analyze the signals acquired by the Signal Acquisition Module 201, which are stored in the Storage Module 209. The Processing Module 203 determines the optimal phase shift pattern. the signals to be applied to each channel in the next transmission, taking into account the delays of the signals previously acquired. Next he applies the calculated delays to the excitation signals of a new simple test in the Arbitrary Signal Generation Module 200, loading the signals in the Base Memory Block 300 and loading the configuration of the Out-of-Phase Block 303 in the Block Configuration and Control Generation 311.
  • This technique allows to focus the energy of the ultrasonic waves at a certain point of a non-homogeneous structure.
  • an ultrasonic wave is transmitted to the structure, which propagates through the material, bounces off possible defects and into the limits of the structure, and comes back to the piezoelectric.
  • the theory of this method raises the existence of a second ultrasonic wave, which could precisely retrace the steps of the first wave in terms of the complex phenomena of propagation, and that converges synchronously in the source of the wave, as if time was moving backwards. Therefore, if the first wave is acquired and stored and later transmitted to the piezoelectric inverted in time, the energy can be focused on a desired point of the structure.
  • the monitoring system must transmit a first wave using the Arbitrary Signal Generation Module 200, digitize the ultrasonic waves received by the Signal Acquisition Module 201, and store them in the Storage Module 209 through the Access Module to Memory 206.
  • the waves already stored in the Storage Module 209 are loaded into the Base Memory Block 300 and the transmission of this second wave is initiated.
  • the signals due to bounces in the structure are then acquired again by means of the Signal Acquisition Module 201. Repeating this procedure several times increases the accuracy of the detection of defects in the structure under analysis.
  • the Processing Module 203 is always responsible for eliminating any type of noise or distortion that may have been introduced in the acquired signals and that is not useful information to perform the analyzes.
  • a model or pattern of behavior of the structure is made by an algorithm that incorporates data such as the distance between the piezoelectric elements, the time of transmission of the signal between said elements, the type of material to analyze, the frequency of the signal, the type of signal transmitted, etc.
  • the operation can be repeated periodically, checking that the data received corresponds to the initial model or optimal conditions of the structure.
  • An ultrasonic map of the structure is also generated that graphically shows the position of the possible defects. If at any time there is a defect due to deterioration or accident, the data obtained will not correspond to the initial pattern and the difference between the models will serve to determine the type of defect, the severity or defect measurement, the location and its progression over time.
  • the invention 100 can also be used in passive mode to detect impacts in the structure under analysis.
  • the system continuously digitizes the signals received by the piezoelectric elements, and uses in each channel a Voltage Level Detector 401, present in the Impact Detection Block 400 within the Signal Acquisition Module 201, so that if the signals received in the piezoelectric sensors exceed a certain configurable threshold, the structure is considered to have suffered an impact and the system is responsible for saving samples of the signals before and after the impact in the Storage Module 209.
  • the team then processes them to determine the severity of the defects produced by the impact, and then applies any other analysis technique to more accurately determine the position of the defects that the impact has caused.
  • the results of the structural analysis can be downloaded to an external control computer 101 using guided communications 105 and / or wireless communications 104, to generate the corresponding maintenance notices.
  • more than one integrated system based on Multiple Channel Electronic Architecture for Advanced Monitoring of Structural Integrity 100 can be used to perform the monitoring, using a multipoint communication system that Allow to control all the equipment through a single remote control system. Everything discussed in the previous sections would extend to the operation of each monitoring equipment separately.
  • FIG. 7 shows a case that employs multiple teams. It is desired to analyze a structure having a welded or riveted joint 700 in the middle, and it is desired to analyze what happens in this joint when signals are transmitted from another area of the structure. Two computers of the invention 100 connected to each other by a Dedicated Communications Line should be used. 701. In this way, and in a synchronized manner, one of the teams starts a test by exciting the piezoelectric elements and acquiring the signals due to rebounds, and the other is also responsible for acquiring the signals that pass through the welded or riveted joint. 700 and they reach it. This technique is usually known as Pitch & Catch, where one team acts as Pitch (excitation and acquisition) and the other as Catch (acquisition only).
  • the first step consists of adhering several adapter modules 110 of piezoelectric elements (preferably integrated PhA transducers mentioned above) on each of the panel inspection sectors (IS1, IS2, IS3, IS4).
  • the corresponding 900 multi-channel Electronic Architecture boxes for Advanced Structural Integrity Monitoring 100 are firmly coupled in their interior by means of electromechanical connectors (109 and 606).
  • each of the integrated equipment wirelessly sends the SHM maps 117 to the external control computer 101, which also serves as a wireless receiver, data concentrator, assembler and viewer thereof.
  • the external control computer 101 which also serves as a wireless receiver, data concentrator, assembler and viewer thereof.
  • three-dimensional image assembly tools three-dimensional models 116 are created with the SHM maps assembled according to their position, proportional size and real orientation, so that they can be displayed on the screen in a simple way to interpret.
  • Each of the SHM maps corresponds to a panel inspection sector.
  • Electromechanical connector of guided communications 903.- Electromechanical connector of guided communications. 904. - Antenna for wireless communications.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

L'invention a pour objet une architecture électronique multicanal pour la surveillance avancée de l'intégrité structurale par la technique des ondes ultrasonores guidées ou ondes de Lamb, permettant la réalisation d'un dispositif intégré de surveillance de l'intégrité structurale. Ce dispositif peut être monté de manière permanente dans une structure aéronautique du fait qu'elle est capable de fonctionner de manière autonome en temps réel. Son poids et son volume sont réduits. Le système objet de l'invention génère des signaux destinés à exciter des transducteurs piézoélectriques intégrés dans la structure à surveiller ou collés sur cette dernière, et acquiert simultanément la réponse de tous les transducteurs et renseigne sur l'état de la structure. Cette architecture électronique permet de mettre en pratique tous types d'essais d'intégrité structurale, tels que Round Robin, formation de voies, retournement temporel. Son utilisation permet de réduire les coûts directs de maintenance et les risques de défaillance des structures, principalement aéronautique.
PCT/ES2011/070428 2011-06-15 2011-06-15 Architecture électronique multicanal pour surveillance avancée de l'intégrité structurale par la technique des ondes ultrasonores guidées ou ondes de lamb WO2012172124A1 (fr)

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