BS EN 13554-2011 Non-destructive testing Acoustic emission testing General principles《无损检验 声发射检测 一般原理》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 13554:2011Non-destructive testing Acoustic emission testing General principlesBS EN 13554:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementati

2、on of EN 13554:2011. Itsupersedes BS EN 13554:2002 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee WEE/46, Non-destructive testing.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not

3、 purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 61011 0ICS 19.100Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStand

4、ards Policy and Strategy Committee on 28 February 2011.Amendments issued since publicationDate Text affectedBS EN 13554:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13554 January 2011 ICS 19.100 Supersedes EN 13554:2002English Version Non-destructive testing - Acoustic emission testing -

5、 General principles Essais non destructifs - mission acoustique - Principes gnraux Zerstrungsfreie Prfung - Schallemissionsprfung - Allgemeine Grundstze This European Standard was approved by CEN on 17 December 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which sti

6、pulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European

7、 Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are th

8、e national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, S

9、witzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref.

10、No. EN 13554:2011: EBS EN 13554:2011EN 13554:2011 (E) 2 Contents page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Personnel qualification .45 Principle of the acoustic emission method 45.1 The acoustic emission (AE) phenomenon 45.2 Advantages and features of AE 55.3 Limita

11、tions of AE .66 Applications of the acoustic emission method 67 Instrumentation 77.1 General 77.2 AE sensors .77.3 Signal conditioning and processing 87.4 Settings .97.5 External parameters inputs 98 Testing 98.1 General 98.2 Preliminary information 98.3 Preliminary preparation . 108.4 On-site prepa

12、rations . 108.5 Data acquisition 108.6 Presentation of results . 118.7 Subsequent operations 119 Data analysis . 129.1 General . 129.2 On-line analysis 129.3 Post test analysis 1210 Test instruction . 1311 Test documentation and test report . 14Bibliography . 15BS EN 13554:2011EN 13554:2011 (E) 3 Fo

13、reword This document (EN 13554:2011) has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the

14、 latest by July 2011, and conflicting national standards shall be withdrawn at the latest by July 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all su

15、ch patent rights. This document supersedes EN 13554:2002. The following summary of changes intends to identify the most significant changes made to the standard during the revision process. It does not necessarily contain all changes, and it is recalled that, while efforts have been made to highligh

16、t the relevance of the list, the user of this standard is responsible for recognizing any differences between this and the present edition. 6: Further applications were introduced; 7.3: Adoption on the new EN 13477-2 (signal processor); 7.5: New paragraph on external parameters input; 8: Examination

17、 was replaced by testing; 9: Clause divided in on-line and post test analysis; 9.3.3: Source severity grading was changed; 10: Examination procedure was replaced by test instruction; 11: Examination report was replaced by test documentation and test report and re-written. According to the CEN/CENELE

18、C Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

19、 Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 13554:2011EN 13554:2011 (E) 4 1 Scope This European Standard specifies the general principles required for the acoustic emission testing (AT) of industrial

20、 structures, components, and different materials under stress and for harsh environment, in order to provide a defined and repeatable performance. It includes guidelines for the preparation of application documents, which describe the specific requirements for the application of the AE method. Unles

21、s otherwise specified in the referencing documents, the minimum requirements of this European Standard are applicable. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated r

22、eferences, the latest edition of the referenced document (including any amendments) applies. EN 1330-1:1998, Non destructive testing Terminology Part 1: List of general terms EN 1330-2:1998, Non destructive testing Terminology Part 2: Terms common to the non-destructive testing methods EN 1330-9:200

23、9, Non-destructive testing Terminology Part 9: Terms used in acoustic emission testing EN 13477-2, Non-destructive testing Acoustic emission Equipment characterisation Part 2: Verification of operating characteristic 3 Terms and definitions For the purposes of this document, the terms and definition

24、s given in EN 1330-1:1998, EN 1330-2:1998 and EN 1330-9:2009 apply. 4 Personnel qualification It is assumed that emission testing is performed by qualified and capable personnel. In order to prove this qualification, it is recommended to certify the personnel in accordance with EN 473 or equivalent.

25、 Note that for pressure equipment in categories III and IV according to Directive 97/23/EC, Annex I, 3.1.3: the personnel shall be approved by a third-party organization recognized by a Member State. 5 Principle of the acoustic emission method 5.1 Acoustic emission (AE) phenomenon Acoustic emission

26、is a physical phenomenon whereby transient elastic waves are generated within a material or by a process. The application of load or harsh environment in a material produces internal structural modifications such as local plastic deformation, crack growth, corrosion, erosion and phase transformation

27、s. AE sources also arise from impact, leakage (turbulent flow), cavitation, electric discharge and friction. All these mechanisms and processes are generally accompanied by the generation of elastic waves that propagate in materials or into ambient liquids. The waves therefore contain information on

28、 the internal behaviour of the material and/or structure. BS EN 13554:2011EN 13554:2011 (E) 5 The waves are detected by the use of sensors that convert the particle motion at the surface of the material into electric signals. These signals can be of a burst or continuous nature and are processed by

29、appropriate instrumentation to detect, characterize and locate the AE sources. Figure 1 shows the schematic principle of AE. Key 1 growing discontinuity 5 signal out 2 surface waves 6 section view of the component material 3 preamplifier 7 wave packet 4 AE sensor 8 applied load inducing stress Figur

30、e 1 Schematic principle of Acoustic Emission and its detection 5.2 Advantages and features of AE The AE method has the following features: a) it is a passive detection method that monitors the dynamic response of the material to the applied load or environment; b) it allows detection of sources, dep

31、ending on the materials properties, up to several meters distance; c) it allows a 100 % volumetric monitoring of the test object; d) it is sensitive to growth of discontinuities and changes in the material structure rather than to the presence of static discontinuities; e) it is non invasive; f) it

32、offers a dynamic real time monitoring of any discontinuity that grows under the applied stress; g) it can be applied to monitor the structures during operation; h) it can be used to detect the effects of the application of load in order to prevent catastrophic failure of structures; i) it is capable

33、 of locating a growing discontinuity in the structure under test by the use of a sufficient number of sensors; j) its measurement frequency range extends from about 20 kHz to 2 MHz depending on the application. BS EN 13554:2011EN 13554:2011 (E) 6 The AE method can be applied only if the materials in

34、 the structures or components are adequately stressed. The difference between AE and most NDT methods stems from the above features. It is the material itself that releases the energy in consequence of structural degradation due to different source mechanisms. This is different to detecting existing

35、 geometrical discontinuities in a static condition. AE is a method which points out the presence and location of an evolving degradation process under a given stimulus. 5.3 Limitations of AE Limitations of the AE method are: a) non growing discontinuities may not generate AE; b) subsequent applicati

36、on of load to the previously applied maximum stress level will only identify discontinuities which are still active; c) it is sensitive to in-service or other extraneous noise. Prior to performing an acoustic emission testing (AT), it is very important to check for the presence of potential noise so

37、urces. Noise sources should be removed or action taken to insure they do not reduce the effectiveness of the AT. 6 Applications of the acoustic emission method AE is applied at the different phases of product life: materials and design optimisation; manufacturing (quality assurance); acceptance test

38、; initial proof test; requalification tests; in-service condition / health monitoring; leak detection. Furthermore, it is applicable to detection of: cavitation erosion; electric discharge; crack activity of rocks and concrete; etc. It is applied to: pressure equipment; pipe systems; BS EN 13554:201

39、1EN 13554:2011 (E) 7 atmospheric storage tanks; machinery; civil constructions (e.g. bridges, dams); power transformers; mines (e.g. rock salt mines for hazardous waste disposal); etc. These examples concern metallic materials, polymer composites, ceramics, concrete, rock, etc. 7 Instrumentation 7.1

40、 General The AE instrumentation shall fulfil the requirements of EN 13477-2 and the performance shall be checked periodically in accordance with this European Standard. 7.2 AE sensors 7.2.1 General Detection is the most important part of an AE measurement chain because any problem here (poor acousti

41、cal coupling, incorrect installation, incorrect frequency selection, cable mismatching, etc.) affects the rest of the measurements and hence the results. 7.2.2 AE sensor selection The sensors are normally of the resonant type, i.e. one frequency dominates the response; sensors with different resonan

42、t frequencies are available. The choice of the sensor and the operating frequency depends upon: the purpose of testing; the requirements of the referencing standard or specification; type and shape of structure or component; operating temperature and surface condition of the structure or component (

43、insulation, painting, coating, surface corrosion, etc.); environment; material properties; background noise; wave attenuation; material thickness. The signal waveform from the sensor is affected by multiple path propagation and multiple waves modes that are generated in the material. An example of a

44、 typical AE burst signal is shown in Figure 2. BS EN 13554:2011EN 13554:2011 (E) 8 Key 1 amplitude 2 time Figure 2 Example of AE burst signal from a sensor 7.2.3 Sensor installation The sensor shall be fixed to the test object using an acoustic couplant, a clamping device or an adhesive bond. In spe

45、cial applications, the AE sensor is installed on a waveguide. The surface at sensor positions shall be cleaned and sufficiently flat to ensure adequate and reproducible transmission of AE waves. Verification of installation with Hsu-Nielsen source and/or other method shall be performed. 7.2.4 Coupli

46、ng media Different coupling media can be used, but their type shall be compatible with the materials to be examined. Examples are: water soluble paste; reagent soluble paste; oil; grease; wax; adhesive bond, etc. 7.3 Signal conditioning and processing This includes signal transmission, amplification

47、, filtering and extraction of the AE signal features. The frequency filtering shall be appropriate for the sensor response. The preamplifier converts the signal from the sensor into a suitable low impedance signal for transmission over long distances, using suitable cables, up to the signal processi

48、ng and analysis system. The AE signal processor provides frequency band filtering for the rejection of noise, analogue to digital conversion, threshold controlled feature extraction, e.g. peak amplitude, rise time, duration, energy, counts and time driven measurements, e.g. RMS, in real time. The AE

49、 signal processor may acquire the wave form. The AE signal BS EN 13554:2011EN 13554:2011 (E) 9 processor normally provides the power supply for the preamplifier and a method for using AE sensors as a mechanical pulse generator (e.g. for the sensor coupling test). 7.4 Settings The detection threshold, gain, and real time display features shall be appro