1、STD.BS1 BS EN 13477-1-ENGL 2001 111 1b24bbS 090L7b3 b2T BRITISH STANDARD Non-destruct ive testing - Acoustic emission - Equipment characterization - Part 1: Equipment description The European Standard 13477-1:2001 has the status of a British Standard ICs 17.140.01; 19.100 I BS EN 1347 7-1 :200 1 NO
2、COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD.BSI BS EN L3477-1-ENGL 200% Lb24bb9 090L7b4 5bb BS EN 13477-1:2001 Amd. No. National foreword Date Comments This British Standard is the official English language version of The UK participation in its preparation was entrusted
3、to Technical Committee WEW46, Non-destructive testing, which has the responsibility to: EN 13477-1:2001. - - aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor r
4、elated international and European developments and promulgate them in the UK. - A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this documen
5、t may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of Brit
6、ish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. This British Standard, having been prepared under the irection of the Engineering Sector Committee, was published under the authority of the Stan
7、dards Committee and comes into effect on 15 March 2001 Summary Of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued sin
8、ce publication 8 BSI 03-2001 EUROPEAN STANDARD NORME EUROPEENNE EUROPISCHE NORM EN 13477-1 January 2001 ICs 19.100 English version Non-destructive testing - Acoustic emission - Equipment characterization - Part I : Equipment description Essais non destructifs - Emission acoustique - Caractrisation d
9、e IYquipement - Partie 1: Description de Iquipement Zerstrungsfreie Prfung - Schallemissionsprfung - Gertecharakterisienmg - Teil 1 : Gertebeschreibung This European Standard was approved by CEN on 28 December 2000. CEN members are bound to comply with the CENICENELEC Internal Regulations which stip
10、ulate 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 CEN member. This European Standard exi
11、sts in three ofilcial 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 members are the national standards bodi
12、es of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Klngdom. EUROPEAN CO-E FOR STANDARDIZATION COMITE EUROPEEN DE NORMALISATION EUROPISCHES KOMITEE FUR NORMUNG Man
13、agement Centre: rue de Stassart, 36 B-1050 Brussels O 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13477-1:2001 E STD.BSI BS EN 23477-2-ENGL 200% M Lb24bb9 090L7bb 339 Page 2 EN 13477-1 12001 Contents Page Foreword . 3 1 Sc
14、ope . 4 2 Normative references . 4 3 Terms and definitions . 4 4 Detection 4 4.1 Sensing element 5 4.2 Sensor case . 5 4.3 Sensor characteristics 5 5 Signal conditioning . 6 5.1 Preamplifier 6 5.2 Cables 6 5.3 Post-amplification and frequency filtering 7 6 Signal measurement . 7 6.1 Continuous signa
15、l . 7 6.2 Burst signal 7 6.3 Waveform . 8 7 Analysis and output of results . 8 8 Automated system 9 8.1 Automated analysis 9 8.2 Feedback to a control or alarm system 9 8 BSI 03-2001 STD.BSI BS EN 13477-L-ENGL 2OOL Lb24669 090L7b7 275 Page 3 EN 13477-112001 Foreword This European Standard has been p
16、repared 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 latest by July 2001, and conflicting national s
17、tandards shall be withdrawn at the latest by July 2001. This European Standard has been prepared under a mandate 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 standard
18、s which in themselves support an essential safety requirement of a New Approach Directive and which make normative reference to this European Standard. This standard about “Non destructive testing - Acoustic emission - Equipment characterization” consists of the following parts: Part 1 : Equipment d
19、escription Part 2: Verification of operating characteristics Part one of this standard gives a description of 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 met
20、hods and acceptance criteria are used to routinely check and verify the performance of an AE monitoring system composed of one or more channels during its life time. According to the CENKENELEC Internal Regulations, the national standards organizations of the following countries are bound to impleme
21、nt this European Standard: Austria, Belgium, Czech .Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. O BSI 03-2001 Page 4 EN 13477-1 12001 I Scope This European standard describ
22、es the main components that constitute an acoustic emission (AE) monitoring system comprising: - detection; - signal conditioning; - signal measurement; - analysis and output of results. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other p
23、ublications. These normatives references are cited at the appropriate places in the text and the publications are listed hereafter. 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 re
24、vision. For undated references, the latest edition of the publication referred to applies (including amendments). EN 1330-1, Non-destructive testing - Terminology - Part 1: List of general terms EN 1330-2, Non-destructive testing - Terminology - Patt 2: Terms common to the non-destructive testing me
25、 thods EN 1330-9, Non-destructive testing - Terminology - Part 9: Terms used in acoustic emission testing 3 Terms and definitions 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:
26、 average signal level (ASL) rectified, time averaged AE signal. 4 Detection A piezoelectric sensor is the most commonly used device for detecting acoustic emission. It provides the most effective conversion of elastic waves (acoustic emission) into an electrical signal in the frequency range most co
27、mmonly used for AE detection, 20 kHz - 1 MHz. In its simplest form it consists of a piezoelectric crystalline or ceramic element, mounted in a protective case. The sensor detects a combination of wave types: compressional, shear, surface (Rayleigh), plate (Lamb), arriving from any direction. O BSI 0
28、3-2001 Page 5 EN 13477-1 2001 4.1 Sensing element The sensing material affects the conversion efficiency, operating temperature range and cable drive capability. Lead zirconate titanate (Pa), a ceramic, is the most commonly used material. It can be manufactured in a wide range of sizes and shapes. T
29、he size, shape and containment affect the sensitivity, directionality, frequency response and wave-mode response. Several elements may be combined to achieve a desired performance. 4.2 Sensor case The sensor case (usually metallic) determines the overall size and mechanical characteristics of the se
30、nsor. It may have an integral cable or a connector. The case provides a total electrical screening of the sensing element and is usually common to one poie of the sensing element. A faceplate of ceramic or epoxy between the sensor element and test object provides electrical isolation from the struct
31、ure to avoid ground loop and induced electromagnetic noise. Depending on the method of assembly, the sensor can be made single ended or differential. 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 devi
32、ce, a screened twisted pair cable is used and the sensing element is usually split or machined so that the screen does not conduct the electrical output signal. Differential sensors have normally improved immunity to electromagnetic noise compared with single-ended sensors. The case may contain a lo
33、w noise preamplifier. Incorporating the preamplifier inside the sensor case, eliminates the cable link between the sensor element and the preamplifier. This reduces signal loss and improves immunity to electromagnetic noise. The drawbacks are that the sensor case becomes larger, the maximum temperat
34、ure rating is limited by the electronics, and the preamplifier is not interchangeable, see also 5.1. 4.3 Sensor characteristics 4.3.1 Frequency response Piezoelectric acoustic emission sensors are either resonant with a peak in a certain frequency range, .e. the frequency content of the transient si
35、gnal is mostly determined by the resonant frequency of the sensing element, or broad-band with a rather flat frequency response if properly damped. 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 piezoelectri
36、c sensors their response will be different to continuous and transient stimuli. Most piezoelectric devices will be characterised by surface velocity (volts per metre per second) as a function of frequency for a transient input. An exception is the qat response” device that is often characterised in
37、terms of surface displacement (volts per unit displacement). Continuous signal response may be characterised in the same way or in pressure 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 a
38、long 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 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 par
39、ticular wave mode, such as: shear, compressional or other waves. O BSI 03-2001 STD.BSI BS EN 13477-1-ENGL 2001 1b24bb9 0903770 bT W Page 6 EN 13477-1 2001 4.3.4 Operating temperature This depends on the construction materials and the characteristics of the sensor element. It shall be used within the
40、 temperature range specified by the manufacturers. 5 Signal conditioning Included in this section is preamplification, cables and post amplification. 5.1 Preamplifier The main preamplifier characteristics are the input impedance, noise, gain, bandwidth, filter characteristics such as roll-off rate,
41、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, usually a high impedance low-level signal, to a low impedance high-level signal for the transmission
42、 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 R output impedance to drive a coaxial cable. The D.C. power supply to the preamplifier is commonly supplied on the same cab
43、le 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 applications, preamplifiers are an integral part of the AE sensor, providing greater ruggedness, reliabi
44、lity, 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 purposes. Charge preamplification eliminates the effect of cable capacitance on the signal but i
45、s 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 ( 1 m) where voltage preamplification is used. 5.2.2 Preamplifier to instrument cable This is n
46、ormally a screened coaxial 50airnpedance cable matched to the preamplifier and measurement instrument. Care shall be taken to avoid crosstalk problems with multi-conductor cables, particularly if individual conductors are used to transmit a wide band pulser signal for periodic calibration during a t
47、est. 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. Q BSI 03-2001 Page 7 EN 13477-1 12001 5.3 Post-amplification and frequency filtering Post-amplification and further analogue filter
48、ing is used at the measurement instrumentation to increase the signal level and remove unwanted low or high frequency signais for measurement purposes. The input impedance, dynamic range, filter characteristics, gain or attenuation are relevant to this section. The input stage usually provides D.C.
49、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 and leak detection. The measured characteristics and their dynamic range define this type of system. 6.2 Burst signal Burst signal measurement systems identify a
