1、Designation: E2983 14Standard Guide forApplication of Acoustic Emission for Structural HealthMonitoring1This standard is issued under the fixed designation E2983; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 Structural Health Monitoring (SHM) is a field of engi-neering that deals with diagnosis and monitoring of structuresduring the
3、ir operation. The primary goal of SHM is detection,identification, assessment, and monitoring of flaws or faultconditions that affect or may affect the future safety orperformance of structures. SHM combines elements of nonde-structive testing and evaluation, condition/process monitoring,statistical
4、 pattern recognition, and physical modeling.1.2 The acoustic emission (AE) method uniquely fits theconcept of SHM due to its capabilities to periodically orcontinuously examine structures and assess structural integrityduring their normal operation.1.3 In this guide, the definitions and fundamental
5、principlesfor applying theAE method for SHM tasks are elaborated. Thisincludes:1.3.1 Terminology and definitions of SHM by the AEmethod,1.3.2 Outline the recommended process of AE-SHM, and1.3.3 Fundamental requirements regarding development ofthe SHM procedures, including selection of appropriate AE
6、apparatus, data acquisition and analysis methods, diagnosis,monitoring and prediction.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices a
7、nd determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE1316 Terminology for Nondestructive Examinations2.2 ISO Standards3ISO/DIS 10303226 Industrial Automation Systems andInteg
8、rationProduct Data Representation and ExchangeISO 9712 Non-destructive TestingQualification and Cer-tification of NDT Personnel2.3 Other Referenced DocumentsANSI/ASNT CP-189 Standard for Qualification and Certifi-cation of Nondestructive Testing Personnel4NAS-410 NDT Certification5SNT-TC-1A Personne
9、l Qualification and Certification inNondestructive Testing63. Terminology3.1 Definitions: See E1316 for terminology related to thispractice.3.2 Definitions of Terms Specific to This Standard:3.2.1 diagnosis, na process of detection, identification,and assessment of flaws, and identifying properties
10、or condi-tions that may affect the future safety or performance of astructure.3.2.2 diagnostic AE, nan acoustic emission methodologycapable of achieving the goals of diagnosis.3.2.3 fault, nan abnormal condition or defect at thecomponent, equipment, or sub-system level which may lead toa failure. Wo
11、rden et al.73.2.4 monitoring, na process of observing or detectingchanges in the condition of a structure.3.2.5 prediction, na process of estimation of the possiblefuture flaw or fault deterioration based on results ofmonitoring, diagnostics, or numerical modeling, or a combi-nation thereof.1This te
12、st method is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic Emission Method.Current edition approved Oct. 1, 2014. Published October 2014. DOI: 10.1520/E2983-14.2For referenced ASTM standards, visit the ASTM we
13、bsite, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, CP 56, CH-1211
14、Geneva 20, Switzerland, http:/www.iso.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http
15、:/www.aia-aerospace.org.6Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.7K. Worden, C. Farrar, G. Manson, G. Park, “The fundamental axioms ofstructural health monitoring“, Proceedings of the Royal Socie
16、ty A, Vol. 463, 2007,p. 1639-1664.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.6 sensinga process of detection of acoustic emissionand conversion of measurements into data used during diag-nosis.3.2.7 structural health monitori
17、ng (SHM), na process ofdiagnosis and monitoring the condition of structures, normallyperformed during their operation.4. Summary of Guide4.1 The guide describes the AE-SHM process and providesa set of fundamental assumptions recommended in the appli-cation of the AE method in SHM tasks.5. Significan
18、ce and Use5.1 This guide can be used in the development of acousticemission applications for structural health monitoring.5.2 Accuracy, robustness, and efficiency of AE-SHM can beenhanced by following the steps and fundamental principlesdescribed in the guide.6. Basis of Application6.1 The following
19、 items are subject to contractual agree-ment between the parties using or referencing this guide.6.2 Personnel Qualification:6.2.1 If specified in the contractual agreement, personnelperforming examinations to this standard shall be qualified inaccordance with a nationally and internationally recogn
20、izedNDT personnel qualification practice or standard such asANSI/ASNT CP-189, SNT-TC-1A, NAS-410, ISO 9712, or asimilar document and certified by the employer or certifyingagency, as applicable. The practice or standard used and itsapplicable revision shall be identified in the contractual agree-men
21、t between the using parties.6.2.2 Qualification of Nondestructive Testing AgenciesIfspecified in the contractual agreement, NDT agencies shall bequalified and evaluated as described in Specification E543. Theapplicable edition of Specification E543 shall be specified inthe contractual agreement.7. T
22、he Process of Structural Health Monitoring by theAcoustic Emission Method7.1 The process of AE structural health monitoring can bedivided into the following typical stages:7.1.1 AE-SHM procedure development,7.1.2 Sensing,7.1.3 Diagnosis,7.1.4 Monitoring, and7.1.5 Prediction.7.2 AE-SHM Procedure Deve
23、lopmentThe first stage ofprocedure development starts with the collection of all neces-sary information regarding the structure, its design andmaterials, operational conditions, statistics of failures, etc. Inaddition, laboratory or full scale tests, or both, are conductedon structures with known fl
24、aws or faults, at a known stage ofdevelopment in order to develop the ability to detect, identify,and assess specific flaws or faults. Based on the collectedinformation, the optimal instrumentation, methods of dataacquisition and data analysis, and loading procedures areestablished.NOTE 1Results of
25、laboratory testing of small scale specimens, andespecially signal features derived therefrom, are not directly applicable tofull scale structures due to such influences as sensor frequency and sensormounting or spacing; wave propagation or reflections in small specimensversus large plate structures;
26、 noise backgrounds not replicated on smallspecimens; complex emission mechanisms that involve stress corrosioncracking, hydrogen embrittlement cracking, creep development, and thelike that involve difficulttocontrol environments in the lab. Specimentesting may be used to model the behavior and relat
27、ive emissivity ofmechanisms in materials, but may not be directly transferred to full scalestructures for life prediction.7.3 SensingSensing is a process of data capture andmeasurement. It involves measurement of AE as well asparametric data such as pressure, temperature, strain, and otherinformatio
28、n according to the developed SHM procedure. Thereare several important aspects to address during the sensingstage. It is important to check that data collected during thedata acquisition process is valid and can be satisfactorily usedfor the purposes defined in the developed SHM procedure. Ifthis is
29、 not the case, additional measurements with a differentsetup or loading, operational or environmental conditions orboth, may be required.Also, during the sensing process, a shortevaluation of the structure should be performed to identify, orrule out, possible conditions that may threaten the structu
30、reimmediately or in the short term.7.4 DiagnosisDiagnosis is one of the primary tasks of theSHM process. It effectively distinguishes typical noise-relatedAE from SHM-related AE. The objectives of the diagnosisprocess are not only to detect and locate flaws or faults as intypical NDE but also to ide
31、ntify and assess them. Diagnosis isperformed based on collected data, numerical modeling includ-ing finite element analysis, history of the inspected structure,local application of different NDE methods, material and otherrelevant investigations.7.5 MonitoringMonitoring is performed to assess thecon
32、dition of a structure over time. It is performed periodicallyor continuously, depending on the particular application. Forbest results, it is recommended to identify quantitative orqualitative AE characteristics, or both, that are changing withthe flaw or fault development. It is important to perfor
33、mmonitoring under normal operational and environmental con-ditions of a structure. If a change in stress or operational orenvironmental conditions occurs for any reason, or a structurehas been subjected to extreme conditions and trauma, it mayrequire a change in the monitoring policy. Another import
34、antgoal of monitoring is to identify conditions causing flaw orfault origination and development in the inspected structure.Examples of such conditions are fatigue, mechanical andthermal overstresses, etc.7.6 PredictionThe goals of prediction can include:7.6.1 Assessment of suitability for continued
35、 service ofstructures when a proven and statistically valid experience ordatabase is gathered.7.6.2 Defining an appropriate re-inspection or monitoringpolicy based on diagnostic and monitoring results.7.6.3 Providing information necessary for condition-basedmaintenance decisions.E2983 1427.6.4 Predi
36、ction, which is normally carried out based ondiagnostic results, several monitoring cycles, and in conjunc-tion with information about the structure, its history and allknown measurable or non-measurable risk factors.8. Fundamental Assumptions of AE Structural HealthMonitoring8.1 AE-based structural
37、 health monitoring, as with anyother scientific concept, is based on a set of fundamentalassumptions that are normally self-evident and do not neces-sarily have to be scientifically proven. The role of assumptionsis to define a systematic basis for a concept or theory. A set ofsuch fundamental assum
38、ptions of SHM by the AE method isproposed. It cannot be claimed at this moment that the set ofassumptions is complete and thus further modifications andcorrections over time could be required. Fundamental assump-tions are divided into four groups: AE-SHM proceduredevelopment, structure diagnosis and
39、 monitoring, dataanalysis, and prediction and recommendations.8.2 Assumption Group 1: AE-SHM Procedure Development8.2.1 An optimal SHM procedure is one that ensures amaximum probability of flaw or fault detection while minimiz-ing false negative findings.8.2.2 Development of new AE-SHM applications
40、is essen-tially based on a learning process. This includes collection andanalysis of information about:8.2.2.1 Structural design, history of operation, repairs andresults of previous inspections,8.2.2.2 Material properties,8.2.2.3 Applied loads, operational and environmentalconditions,8.2.2.4 Typica
41、l flaws or faults that can develop in theinspected structure,8.2.2.5 AE characteristics of flaws or faults to be detected,assessed, and monitored,8.2.2.6 Wave propagation characteristics in the material andgeometry of the inspected structure including propagationmodes, attenuation, dispersion, scatt
42、ering, and othercharacteristics,8.2.2.7 AE instrumentation appropriate for the particularapplication, and8.2.2.8 Optimal loading or environmental conditions, orboth, for performing SHM, are considered those under whichflaws or faults naturally originate and develop in the inspectedstructure.8.3 Assu
43、mption Group 2: Structure Diagnosis and Monitor-ing8.3.1 A specific AE methodology can be considered diag-nostic if essentially it allows:8.3.1.1 Detection,8.3.1.2 Location,8.3.1.3 Identification, and8.3.1.4 Assessment (qualitatively or quantitatively) of flawsor faults in the inspected structure.8.
44、3.2 Acoustic emission (AE activity and AE waves them-selves) can be flaw- or fault-stage-material specific, i.e. differ-ent flaws and faults at different stages of their development indifferent materials may have different AE waveform character-istics as well as different AE rates.8.3.3 During flaw
45、or fault assessment, a conservative ap-proach should be taken in case of uncertain results.8.3.4 Comparison of loading, operational or environmentalconditions or both, with AE activity or AE characteristicsreflecting kinetic characteristics of flaws or faults developmentcan be used to identify condi
46、tions causing flaw or faultorigination, development, acceleration, or arrest.8.3.5 Flaw or fault monitoring is possible when quantitativeor qualitativeAE characteristics, or both, changing with flaw orfault development are identified.8.3.6 Reliable comparison of data collected during differentmonito
47、ring periods is possible when monitoring is performedunder similar stress, operational, environmental, and sensingconditions.8.4 Assumption Group 3: Data Analysis8.4.1 The process of data analysis in AE-SHM necessarilyincludes the following steps:8.4.1.1 Analog or digital signal filtering, or both,8
48、.4.1.2 Initial feature extraction,8.4.1.3 Feature selection and dimension reduction,8.4.1.4 Clustering (unsupervised classification) or discrimi-nation (supervised classification), or both, and8.4.1.5 Interpretation.8.4.2 Signal features selected for data analysis should be aminimum set of statistic
49、ally significant features necessary forthe specific SHM application; filtered whenever possible sothat the influence of background noise is minimized and datameasured at different times and different locations is compa-rable.8.4.3 Features used in data analysis should have an estab-lished relationship with physical phenomena being measuredduring AE-SHM in order to assure correct diagnosis of theinspected structure.8.4.4 AE activity distinguishable from AE backgroundnoise should be considered as flaw or fault related activityunless proven otherwise.8.4.5 All dete
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