1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationNon-destructive testing Methods for absolute calibration of acoustic emission transducers by the reciprocity techniquePD CEN ISO/TR 13115:2011National forewordThis Published Docu
2、ment is the UK implementation of CEN ISO/TR13115:2011.The UK participation in its preparation was entrusted to Technical CommitteeWEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to incl
3、ude all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 70487 1ICS 19.100Compliance with a British Standard cannot confer immunity fromlegal obligations.This Publishe
4、d Document was published under the authority of theStandards Policy and Strategy Committee on 29 February 2012.Amendments issued since publicationAmd. No. Date Text affectedPUBLISHED DOCUMENTPD CEN ISO/TR 13115:2011TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN ISO/TR 13115 December 2011
5、 ICS 19.100 English Version Non-destructive testing - Methods for absolute calibration of acoustic emission transducers by the reciprocity technique (ISO/TR 13115:2011) Essais non destructifs - Mthodes dtalonnage absolu des capteurs dmission acoustique par la technique de rciprocit (ISO/TR 13115:201
6、1) Zerstrungsfreie Prfung - Methode zur Absolutkalibrierung von Schallemissionswandlern durch Reziproktechnik (ISO/TR 13115:2011) This Technical Report was approved by CEN on 20 September 2011. It has been drawn up by the Technical Committee CEN/TC 138. CEN members are the national standards bodies
7、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, Switzerland and United Kingdo
8、m. 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. No. CEN ISO/TR 13115:2011: E
9、PD CEN ISO/TR 13115:2011CEN ISO/TR 13115:2011 (E) 2 Contents Page Foreword 3PD CEN ISO/TR 13115:2011CEN ISO/TR 13115:2011 (E) 3 Foreword This document (CEN ISO/TR 13115:2011) has been prepared by Technical Committee ISO/TC 135 “Non-destructive testing“ in collaboration with Technical Committee CEN/T
10、C 138 “Non-destructive testing” the secretariat of which is held by AFNOR. 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 such patent rights. Endorsement
11、 notice The text of ISO/TR 13115:2011 has been approved by CEN as a CEN ISO/TR 13115:2011 without any modification. PD CEN ISO/TR 13115:2011ISO/TR 13115:2011(E) ISO 2011 All rights reserved iiiContents Page Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and definitions . 1 4 Preparation
12、 for calibration 3 4.1 Transfer medium and calibration signal . 3 4.2 Mounting of acoustic emission transducer 4 4.3 Calculation of reciprocity parameters . 5 5 Method for three-transducer calibration . 6 5.1 Apparatus to be used 6 5.2 Method of measurement . 6 5.3 Method for determination of absolu
13、te sensitivity 9 6 Method for two-transducer calibration 9 6.1 Apparatus to be used 10 6.2 Method of measurement . 10 6.3 Method for determination of absolute sensitivity 10 7 Method for impulse response calibration . 11 7.1 Apparatus to be used 11 7.2 Method of measurement . 11 7.3 Method for deter
14、mination of frequency response . 13 7.4 Method for determination of impulse response . 15 8 Method for representing calibration results . 16 8.1 Representation items for calibration results 16 8.2 Method for representing frequency response of absolute sensitivity . 16 8.3 Method for representing imp
15、ulse response of absolute sensitivity 17 Bibliography 18 PD CEN ISO/TR 13115:2011ISO/TR 13115:2011(E) ISO 2011 All rights reserved vIntroduction A standard method for primary calibration of acoustic emission transducers, ISO 12713:19981, introduced the seismic surface pulse method for Rayleigh surfa
16、ce wave calibration, wherein the breaking of a glass capillary is employed for the sound source and a standard capacitive transducer is used for the measurement of dynamic displacements of the surface. In ISO 12714:19992, on secondary calibration of acoustic emission sensors, a transducer which has
17、been calibrated by the seismic surface pulse method is employed for comparison of reception sensitivity. This Technical Report describes the methods for calibrating absolute sensitivity of acoustic emission transducers, both to Rayleigh surface waves and longitudinal waves, by means of a reciprocity
18、 technique. Since reciprocity parameters have been derived, absolute sensitivity can be determined by purely electrical measurements without the use of mechanical sound sources or reference transducers. Procedures of the seismic surface pulse method and reciprocity technique differ from each other;
19、however, there is a common theoretical basis in the two calibration methods. For the seismic surface pulse method, theoretical surface displacements were calculated on the basis of Lambs theory (Reference 7). For the reciprocity calibration, reciprocity parameters for the Rayleigh wave calibration w
20、ere also derived from Lambs theory. As for the Rayleigh surface wave calibration, a round robin experiment was carried out in a collaborative effort between the USA and Japan, and it was ascertained that absolute sensitivities as obtained by either method agreed well. The aim of both methods is the
21、same, namely, to establish uniformity of acoustic emission testing, to form a basis for data correlation, and to provide for the interpretation of results obtained by different laboratories at different times. This Technical Report describes methods for three-transducer calibration, two-transducer c
22、alibration, and impulse response calibration, respectively. In three-transducer calibration, three acoustic emission transducers of the same kind, which are reversible transducers, are prepared to configure three independent pairs of transmitting and receiving transducers on a solid transfer medium.
23、 Transmission signal current and reception signal voltage are measured on each pair as a function of frequency, and frequency responses of amplitude of absolute sensitivity both to the Rayleigh surface waves and longitudinal waves are determined on each transducer. Once three-transducer calibration
24、has been carried out, an optional transducer, which is not necessarily a reversible transducer, can be calibrated by a relatively simple procedure by using the calibrated transducer as a reference of transmission or reception. In two-transducer calibration, frequency responses of amplitude of absolu
25、te reception sensitivity are determined on an optional transducer by using one acoustic emission transducer, the transmission responses of which have been calibrated by the three-transducer calibration. In addition, by means of three-transducer calibration, impulse responses of each acoustic emissio
26、n transducer can also be determined. In the impulse response calibration, frequency responses of phase angle, in addition to amplitude, of absolute sensitivity are measured by three-transducer calibration on the basis of complex reciprocity parameters, and impulse responses are determined through in
27、verse Fourier transform of the frequency responses of amplitude and phase. PD CEN ISO/TR 13115:2011TECHNICAL REPORT ISO/TR 13115:2011(E) ISO 2011 All rights reserved 1Non-destructive testing Methods for absolute calibration of acoustic emission transducers by the reciprocity technique 1 Scope This T
28、echnical Report describes the method of three-transducer calibration for calibrating frequency responses of absolute sensitivity by means of a reciprocity technique using three reversible acoustic emission transducers of the same kind, the method of two-transducer calibration for calibrating frequen
29、cy responses of reception sensitivity of an optional acoustic emission transducer by using one acoustic emission transducer, the transmission responses of which have been calibrated by three-transducer calibration, the method for impulse response calibration for calibrating impulse responses of abso
30、lute sensitivity through inverse Fourier transform of the frequency responses measured by the three-transducer calibration, and the method for representing the calibration results. 2 Normative references The following referenced documents are indispensable for the application of this document. For d
31、ated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12716:2001, Non-destructive testing Acoustic emission inspection Vocabulary 3 Terms and definitions For the purposes of this document, the te
32、rms and definitions given in ISO 12716 and the following apply. 3.1 reciprocity technique calibration method on three reversible acoustic emission transducers of the same kind, wherein transducers are arranged on a solid transfer medium so that they configure three independent pairs of transmitting
33、and receiving transducers, and absolute sensitivity is determined only by electrical measurements of transmission current and reception voltage on each pair 3.2 reversible transducer transducer which can be used both for transmission and reception 3.3 absolute sensitivity quantity of reception volta
34、ge sensitivity or transmission current response of an acoustic emission transducer 3.4 reception voltage sensitivity ratio of the open-circuit output voltage of an acoustic emission transducer used for reception to the vertical component of displacement velocity at the position where the transducer
35、is to be placed PD CEN ISO/TR 13115:2011ISO/TR 13115:2011(E) 2 ISO 2011 All rights reserved3.5 transmission current response ratio of the vertical component of displacement velocity at the index point to the input current of an acoustic emission transducer used for transmission 3.6 index point posit
36、ion on the surface of the transfer medium, which is located at the specified distance in the specified direction from the acoustic emission transducer used for transmission, and used as the reference of transmission response 3.7 reciprocity parameter ratio of reception sensitivity to transmission re
37、sponse of an acoustic emission transducer which is a reversible transducer 3.8 transfer medium solid block on the surfaces of which transducers are placed in the calibration so that they configure a pair of transmitting and receiving transducers of the Rayleigh surface waves or longitudinal waves 3.
38、9 calibration signal electrical voltage signal which is applied to the transmitting transducer in the calibration 3.10 tone burst signal calibration signal consisting of sinusoidal waves with a specified frequency and a specified period modulated so that the envelope forms one squared cosine 3.11 ca
39、libration frequency frequency of sinusoidal waves of which a tone burst signal consists 3.12 squared-cosine signal calibration signal which trigonometrically increases from zero to a maximum and decreases to zero during a specified period 3.13 Hanning window cosine-type time window with a specified
40、period, which is used for Fourier transform of transmission and reception signals measured in the impulse response calibration 3.14 Rayleigh wave calibration calibration by which sensitivity to Rayleigh surface waves is determined by using Rayleigh waves for transmission and reception 3.15 longitudi
41、nal wave calibration calibration by which axial sensitivity to longitudinal waves is determined by using longitudinal waves for transmission and reception 3.16 three-transducer calibration calibration by a reciprocity technique, wherein frequency responses of amplitude of reception voltage sensitivi
42、ty and/or transmission current response are determined on each of the three acoustic emission transducers PD CEN ISO/TR 13115:2011ISO/TR 13115:2011(E) ISO 2011 All rights reserved 33.17 two-transducer calibration calibration on an optional acoustic emission transducer which is not necessarily a reve
43、rsible transducer, wherein frequency responses of amplitude of reception voltage sensitivity are determined by using one acoustic emission transducer for transmission, the transmission current response of which has been determined by three-transducer calibration 3.18 impulse response calibration cal
44、ibration on three reversible acoustic emission transducers of the same kind, wherein impulse responses of reception voltage sensitivity are determined through inverse Fourier transform of the frequency responses of amplitude and phase of absolute sensitivity measured by three-transducer calibration
45、4 Preparation for calibration 4.1 Transfer medium and calibration signal The transfer medium should be made of a material whose density and elastic moduli are as close as possible to those of the actual object on which acoustic emission transducers are intended for use. In this Technical Report, car
46、bon steel is principally assumed to be the material of possible objects. While any solid can be used for the transfer medium, forged steel is most recommended. The transfer medium should undergo ultrasonic testing in order to assure that detectable flaws or inclusions, which may affect the Rayleigh
47、wave or longitudinal wave calibration, are not included. Namely, in longitudinal ultrasonic testing at a frequency between 2 MHz and 5 MHz, the medium should contain no flaws which give a reflection greater than 10 % of the first back-wall reflection. The planes of the transfer medium, used for the
48、longitudinal wave calibration, should be parallel within 0,2. At the measurement of reception signals in the calibration, discrimination between the direct wave of the Rayleigh waves or longitudinal waves, which is the object of measurement, and other spurious waves is made on the basis of the propa
49、gation time of each wave. A larger dimension of the medium causes longer differences in the propagation time between waves, and consequently, the period Tof a tone burst signal used in three-transducer or two-transducer calibration, or the period Twof a Hanning window used in impulse response calibration, can be set longer. Figure 1 shows examples of setting on the period, T, in seconds, of a tone burst signal or the period, Tw, in seconds, of a Hanning window in relation to the dimension of a cylindrical transfer mediu
