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1、NF EN 13477-1 juillet 2001 Ce document est usage exclusif et non collectif des clients Saga Web. Toute mise en rseau, reproduction et rediffusion, sous quelque forme que ce soit, mme partielle, sont strictement interdites. This document is intended for the exclusive and non collective use of Saga We
2、b customers. All network exploitation, reproduction and re-dissemination,even partial, whatever the form (hardcopy or other media), is strictly prohibited. Saga Web Pour THALES CORPORATE SERVICES SAS - EPM Client 04988312 le 22/7/2009 03:43 AFNOR 2001AFNOR 20011st issue 2001-07-P AFNOR 2001 All righ
3、ts reserved FE019331ISSN 0335-3931 NF EN 13477-1 July 2001 Classification index: A 09-353-1 European standard French standard Published and distributed by Association Franaise de Normalisation (AFNOR French standard institute) 11, avenue Francis de Pressens 93571 Saint-Denis La Plaine Cedex Tel.: +
4、33 (0)1 41 62 80 00 Fax: + 33 (0)1 49 17 90 00 www.afnor.fr ICS: 19.100 Non-destructive testing Acoustic emission Equipment characterisation Part 1: Equipment description F : Essais non destructifs mission acoustique Caractrisation de lquipement Partie 1 : Description de lquipement D : Zerstrungsfre
5、ie Prfung Schallemissionsprfung Gertecharakterisierung Teil 1: Gertebeschreibung French standard approved by decision of the Director General of AFNOR on June 20, 2001 taking effect on July 20, 2001. Replaces, together with the approved standard NF EN 13477-2 (classification index: A 09-353-2), the
6、approved standards NF A 09-353 and NF A 09-354 dated August 1985. CorrespondenceThe European standard EN 13477-1:2001 has the status of French standard. AnalysisThis document specifies the main components of a acoustic emission monitoring system: dtection ; signal conditioning; measuring of signals;
7、 analysis and result output. DescriptorsTechnical International Thesaurus: nondestructive tests, acoustic emission, detection, sensors, coaxial cables, acoustic signals, characteristics. ModificationsWith respect to documents replaced, resumption of the European standard. Corrections NF EN 13477-1:2
8、001 2 National foreword References to French standards The correspondence between the standards figuring in the clause “Normative references“ and the identical French standards is as follows: EN 1330-1: NF EN 1330-1 (classification index: A 09-020-1) EN 1330-2: NF EN 1330-2 (classification index: A
9、09-020-2) EN 1330-9: NF EN 1330-9 (classification index: A 09-020-9) EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13477-1 January 2001 ICS 19.100 English version Non-destructive testing - Acoustic emission - Equipment characterisation - Part 1: Equipment description Essais non destructifs -
10、Emission acoustique - Caractrisation de lquipement - Partie 1: Description de lquipement Zerstrungsfreie Prfung - Schallemissionsprfung - Gertecharakterisierung - Teil 1: Gertebeschreibung This European Standard was approved by CEN on 28 December 2000. CEN members are bound to comply with the CEN/CE
11、NELEC Internal Regulations which stipulate 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 Management Centre or to any C
12、EN member. This European 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 Management Centre has the same status as the official versions. CEN me
13、mbers are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISA
14、TION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2001 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13477-1:2001 E Page 2 EN 13477-1:2001 Contents Page Foreword.3 1 Scope4 2 Normative refe
15、rences4 3 Terms and definitions.4 4 Detection4 4.1 Sensing element.4 4.2 Sensor case .5 4.3 Sensor characteristics5 5 Signal conditioning.5 5.1 Preamplifier6 5.2 Cables 6 5.3 Post-amplification and frequency filtering.6 6 Signal measurement.6 6.1 Continuous signal.6 6.2 Burst signal.7 6.3 Waveform.7
16、 7 Analysis and output of results.8 8 Automated system 8 8.1 Automated analysis8 8.2 Feedback to a control or alarm system8 Page 3 EN 13477-1:2001 Foreword This European Standard has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing“, the secretariat of which is held by AFNOR.
17、 This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2001, and conflicting national standards shall be withdrawn at the latest by July 2001. This European Standard has been prepared under a manda
18、te given to CEN by the European Commission and the European Free Trade Association . This European Standard is considered to be a supporting standard to those application and product standards which in themselves support an essential safety requirement of a New Approach Directive and which make norm
19、ative reference to this European Standard. This standard about “Non destructive testing - Acoustic emission - Equipment characterisation” consists of the following parts: Part 1: Equipment description Part 2: Verification of operating characteristics Part one of this standard gives a description of
20、the main components of an AE monitoring system. Part two of this standard gives methods and acceptance criteria for verifying the electronic performance of an AE monitoring system. These methods and acceptance criteria are used to routinely check and verify the performance of an AE monitoring system
21、 composed of one or more channels during its life time. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Icela
22、nd, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Page 4 EN 13477-1:2001 1 Scope This European standard describes the main components that constitute an acoustic emission (AE) monitoring system comprising: -detection, -signal conditioni
23、ng, -signal measurement, -analysis and output of results. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normatives references are cited at the appropriate places in the text and the publications are listed hereafte
24、r. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies (including amendments). EN 1330-1, Non
25、destructive testing - Terminology - Part 1: List of general terms EN 1330-2, Non destructive testing - Terminology - Part 2: Terms common to the non destructive testing methods EN 1330-9, Non destructive testing - Terminology - Part 9: Terms used in acoustic emission testing 3 Terms and definitions
26、For the purpose of this standard the definitions given in EN 1330-1, EN 1330-2, EN 1330-9 and IEC 60050 International Electrotechnical Vocabulary and the following apply: average signal level (ASL) rectified, time averaged AE signal. 4 Detection A piezoelectric sensor is the most commonly used devic
27、e for detecting acoustic emission. It provides the most effective conversion of elastic waves (acoustic emission) into an electrical signal in the frequency range most commonly used for AE detection, 20 kHz - 1 MHz. In its simplest form it consists of a piezoelectric crystalline or ceramic element,
28、mounted in a protective case. The sensor detects a combination of wave types: compressional, shear, surface (Rayleigh), plate (Lamb), arriving from any direction. 4.1 Sensing element The sensing material affects the conversion efficiency, operating temperature range and cable drive capability. Lead
29、zirconate titanate (PZT), a ceramic, is the most commonly used material. It can be manufactured in a wide range of sizes and shapes. The size, shape and containment affect the sensitivity, directionality, frequency response and wave-mode response. Several elements may be combined to achieve a desire
30、d performance. Page 5 EN 13477-1:2001 4.2 Sensor case The sensor case (usually metallic) determines the overall size and mechanical characteristics of the sensor. It may have an integral cable or a connector. The case provides a total electrical screening of the sensing element and is usually common
31、 to one pole of the sensing element. A faceplate of ceramic or epoxy between the sensor element and test object provides electrical isolation from the structure to avoid ground loop and induced electromagnetic noise. Depending on the method of assembly, the sensor can be made single ended or differe
32、ntial. In a single-ended device, the screen of a coaxial cable is connected to the sensor case and to one side of the sensing element. In a differential device, a screened twisted pair cable is used and the sensing element is usually split or machined so that the screen does not conduct the electric
33、al output signal. Differential sensors have normally improved immunity to electromagnetic noise compared with single-ended sensors. The case may contain a low noise preamplifier. Incorporating the preamplifier inside the sensor case, eliminates the cable link between the sensor element and the pream
34、plifier. This reduces signal loss and improves immunity to electromagnetic noise. The drawbacks are that the sensor case becomes larger, the maximum temperature rating is limited by the electronics, and the preamplifier is not interchangeable, see also 5.1. 4.3 Sensor characteristics 4.3.1 Frequency
35、 response Piezoelectric acoustic emission sensors are either resonant with a peak in a certain frequency range, i.e. the frequency content of the transient signal is mostly determined by the resonant frequency of the sensing element, or broad-band with a rather flat frequency response if properly da
36、mped. The response of a sensor is given in terms of its output voltage versus frequency for a standard mechanical stimulus. Due to the inertia of piezoelectric sensors their response will be different to continuous and transient stimuli. Most piezoelectric devices will be characterised by surface ve
37、locity (volts per metre per second) as a function of frequency for a transient input. An exception is the “flat response“ device which is often characterised in terms of surface displacement (volts per unit displacement). Continuous signal response may be characterised in the same way or in pressure
38、 terms (volts per microbar). 4.3.2 Directionality The directionality is a measure of the uniformity of the device response to signals coming from any direction along the surface of the object to which the device is attached. It is usually called the polar response and quoted as a deviation about the
39、 mean in dB. Sensors may be intentionally directional to preferentially monitor a specific area. 4.3.3 Wave mode response Sensors may be made responsive to a particular wave mode, such as: shear, compressional or other waves. 4.3.4 Operating temperature This depends on the construction materials and
40、 the characteristics of the sensor element. It shall be used within the temperature range specified by the manufacturers. 5 Signal conditioning Included in this section is preamplification, cables and post amplification. Page 6 EN 13477-1:2001 5.1 Preamplifier The main preamplifier characteristics a
41、re the input impedance, noise, gain, bandwidth, filter characteristics such as roll-off rate, output impedance, operating temperature range, common-mode rejection ratio (CMRR) and dynamic range. Preamplification can be of voltage or charge. Voltage preamplification converts the sensor output, usuall
42、y a high impedance low-level signal, to a low impedance high-level signal for the transmission over long signal lines to the measurement instrumentation, which may be up to several hundred metres away. A typical preamplifier has a high input impedance, 40 dB gain and 50 ? output impedance to drive a
43、 coaxial cable. The D.C. power supply to the preamplifier is commonly supplied on the same cable as the signal output and decoupled at each end using a filter network. The preamplifier input may be single-ended, differential or switchable to fit different sensor types. For some industrial applicatio
44、ns, preamplifiers are an integral part of the AE sensor, providing greater ruggedness, reliability, reduced signal loss due to cable impedance and reduced susceptibility to electromagnetic noise. The design of the preamplifier may allow the sensor to be used as a pulser transducer for calibration pu
45、rposes. Charge preamplification eliminates the effect of cable capacitance on the signal but is not widely used. 5.2 Cables 5.2.1 Sensor to preamplifier cable This is the most important cable in the system and should be of low-capacitance, ( 100 pF/m), fully screened, and kept as short as possible (
46、 1 m) where voltage preamplification is used. 5.2.2 Preamplifier to instrument cable This is normally a screened coaxial 50 ?impedance cable matched to the preamplifier and measurement instrument. Care shall be taken to avoid crosstalk problems with multi-conductor cables, particularly if individual
47、 conductors are used to transmit a wide band pulser signal for periodic calibration during a test. 5.2.3 Screen A single-point ground for all the screens is normally used at the measurement instrumentation. The screens of the cables shall not form ground loops. 5.3 Post-amplification and frequency f
48、iltering Post-amplification and further analogue filtering is used at the measurement instrumentation to increase the signal level and remove unwanted low or high frequency signals for measurement purposes. The input impedance, dynamic range, filter characteristics, gain or attenuation are relevant
49、to this section. The input stage usually provides D.C. power for the preamplifier and, sometimes, may control pulser operation. 6 Signal measurement 6.1 Continuous signal A continuous signal is characterised by the measurement of RMS (Root Mean Square) or ASL (Average Signal Level) with a particular time constant. Continuous signal measurement systems are used where there is no requirement to identify and characterise individual emissions (bursts), e.g., process monitoring a