1、BS EN 15857:2010ICS 19.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDNon-destructive testing Acoustic emission Testing of fibre-reinforced polymers Specific methodologyand general evaluationcriteriaThis British Standardwas published under theauthority of th
2、e StandardsPolicy and StrategyCommittee on 31 January2010 BSI 2010ISBN 978 0 580 59537 0Amendments/corrigenda issued since publicationDate CommentsBS EN 15857:2010National forewordThis British Standard is the UK implementation of EN 15857:2010.The UK participation in its preparation was entrusted to
3、 TechnicalCommittee WEE/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 include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance wi
4、th a British Standard cannot confer immunityfrom legal obligations.BS EN 15857:2010EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15857 January 2010 ICS 19.100 English Version Non-destructive testing - Acoustic emission - Testing of fibre-reinforced polymers - Specific methodology and general
5、evaluation criteria Essais non destructifs - mission acoustique - Essai des polymres renforcs par des fibres - Mthodologie spcifique et critres dvaluation gnraux Zerstrungsfreie Prfung - Schallemissionsprfung - Prfung von faserverstrkten Polymeren - Spezifische Vorgehensweise und allgemeine Bewertun
6、gskriterien This European Standard was approved by CEN on 4 December 2009. CEN members are bound to comply with the CEN/CENELEC 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 bibliog
7、raphical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN 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
8、 a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Icela
9、nd, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue
10、Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15857:2010: EBS EN 15857:2010EN 15857:2010 (E) 2 Contents Page Foreword 3Introduction . 41 Scope 52 Normative references 53 Terms and definitions . 64
11、Personnel qualification . 75 AE sources and acoustic behaviour of FRP . 75.1 AE source mechanisms 75.2 Wave propagation and attenuation characterisation . 85.3 Test temperature 85.4 Source location procedures . 85.5 Analysis of AE from FRP 96 Instrumentation and monitoring guidelines .106.1 General
12、106.2 Sensors .106.3 Sensor location and spacing 106.4 Sensor coupling and mounting 106.5 Detection and evaluation threshold .116.6 Application of load 116.7 Graphs for real-time monitoring.117 Specific methodology .127.1 General 127.2 Testing of specimens 137.3 Testing of components and structures
13、.137.3.1 Preliminary information 137.3.2 Test preparation .147.3.3 Load profiles 147.3.4 Written test instruction .167.3.5 Evaluation criteria 177.3.6 Stop criteria 207.4 Health monitoring 208 Interpretation of AE results / source mechanisms.209 Documentation .21Annex A (informative) Recommended sta
14、ndard formats for presentation of AE data (examples) 22A.1 AE testing of specimens .22A.1.1 Example 1: AE data from static tensile testing of UD Carbon-fibre/Epoxy composite 22A.1.2 Example 2: AE data from mode I DCB delamination test of UD Glass-fibre/Epoxy composite .27A.2 AE testing of components
15、 and structures, example 3: AE data from pressure testing.34A.3 Advanced analysis methods 41A.3.1 General 41A.3.2 Waveform/wave mode analysis 41A.3.3 Frequency spectrum (FFT) analysis 41A.3.4 Pattern recognition of AE sources 41A.3.5 Modelling of AE sources .42Bibliography 43BS EN 15857:2010EN 15857
16、:2010 (E) 3 Foreword This document (EN 15857:2010) 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 endor
17、sement, at the latest by July 2010, and conflicting national standards shall be withdrawn at the latest by July 2010. 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
18、 any or all such patent rights. According to the CEN/CENELEC 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, G
19、reece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15857:2010EN 15857:2010 (E) 4 Introduction The increasing use of fibre-reinforced polymer materi
20、als (FRP) in structural (e.g. aerospace, automotive, civil engineering) and infra structural applications (e.g. gas cylinders, storage tanks, pipelines) requires respective developments in the field of non-destructive testing. Because of its sensitivity to the typical damage mechanisms in FRP, AE te
21、sting is uniquely suited as a test method for this class of materials. It is already being used for load test monitoring (increasing test safety) and for proof-testing, periodic inspection and periodic or continuous, real-time monitoring (health monitoring) of pressure vessels, storage tanks and oth
22、er safety-relevant FRP structures. AE testing shows potential where established non-destructive test methods (e.g. ultrasonic or water-jacket tests) are not applicable (e.g. “thick“ carbon-fibre reinforced gas cylinders used for the storage and transport of compressed natural gas (CNG), gaseous hydr
23、ogen, etc.). The general principles outlined in EN 13554 apply (as stated) to all classes of materials but the document in fact emphasises applications to metal components (see Clause 6 “Applications of the acoustic emission method“). However, the properties of FRP relevant to AE testing are distinc
24、tly different from those of metals. FRP structures are inherently inhomogeneous and show a certain degree of anisotropic behaviour, depending on fibre orientation and stacking sequence of plies, respectively. Material composition and properties, and geometry affect wave propagation, e.g. mode, veloc
25、ity, dispersion, and attenuation, and hence the AE signals recorded by the sensors. Composites with a distinct viscoelastic polymer matrix (e.g. thermoplastics) possess a comparatively high acoustic wave attenuation which is dependent on wave propagation parallel or perpendicular to direction of fib
26、re orientation, plate-wave mode, frequency and temperature dependent relaxation behaviour. Therefore, successful AE testing of FRP materials, components and structures requires a specific methodology (e.g. storage of complete waveforms, specific sensors and sensor arrays, specific threshold settings
27、, suitable loading patterns, improved data analysis, etc.), different from that applied to metals. Most evaluation criteria for AE tests on FRP components and structures to date are either empirical (derived from comparative tests on a limited number of specimens) or else classified (proprietary, un
28、published data banks). The time and effort to establish qualified evaluation criteria for specific AE test applications may be too costly to make it worthwhile. Generally applicable evaluation criteria for a class of materials FRP will help to pave the way for the development of new applications. Th
29、ere are recent developments in AE testing, e.g. “modal AE“ (wave and wave mode analysis in time and frequency domain) and “pattern recognition analysis“. In particular, feature extraction and pattern recognition techniques seem promising for achieving, among others, improved source location and dama
30、ge mechanism discrimination in materials that show complex wave propagation behaviour and signals originating from multiple mechanisms acting simultaneously, such as FRP. BS EN 15857:2010EN 15857:2010 (E) 5 1 Scope This European Standard describes the general principles of acoustic emission (AE) tes
31、ting of materials, components and structures made of FRP with the aim of: materials characterisation; proof testing/manufacturing quality control; retesting/in-service inspection; health monitoring. When AE testing is used to assess the integrity of FRP materials, components or structures or identif
32、y critical zones of high damage accumulation or damage growth under load this standard further describes the specific methodology (e.g. suitable instrumentation, typical sensor arrangements, location procedures, etc.). It also describes available, generally applicable evaluation criteria for AE test
33、ing of FRP and outlines procedures for establishing such evaluation criteria in case they are lacking. NOTE The structural significance of the AE may not in all cases definitely be assessed based on AE evaluation criteria only but may require further inspection and assessment (e.g. with other non-de
34、structive test methods or fracture mechanics calculations). This standard also recommends formats for the presentation of AE test data that allow the application of qualitative and quantitative evaluation criteria, both on-line during testing and by post test analysis, and that simplify comparison o
35、f AE test results obtained from different test sites and organisations. 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 references, the latest edition of the referenced
36、 document (including any amendments) applies. EN 473, Non-destructive testing Qualification and certification of NDT personnel General principles 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
37、 to the non-destructive testing methods EN 1330-9:2009, Non-destructive testing Terminology Part 9: Terms used in acoustic emission testing EN 13477-1, Non-destructive testing Acoustic emission Equipment characterisation Part 1: Equipment description EN 13477-2, Non-destructive testing Acoustic emis
38、sion Equipment characterisation Part 2: Verification of operating characteristic EN 13554, Non-destructive testing Acoustic emission General principles EN 14584, Non-destructive testing Acoustic emission Examination of metallic pressure equipment during proof testing Planar location of AE sources EN
39、 15495, Non-destructive testing Acoustic emission Examination of metallic pressure equipment during proof testing Zone location of AE sources BS EN 15857:2010EN 15857:2010 (E) 6 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 1330-1:1998, EN 1330-2:19
40、98 and EN 1330-9:2009 and the following apply. 3.1 fibre slender and greatly elongated solid material NOTE Typically with an aspect ratio greater than 5 and tensile modulus greater than 20 Gpa. The fibres used for continuous (filamentary) or discontinuous reinforcement are usually glass, carbon or a
41、ramide. 3.2 polymer matrix surrounding macromolecular substance within which fibres are embedded NOTE Polymer matrices are usually thermosets (e.g. epoxy, vinylester polyimide or polyester) or high-performance thermoplastics (e.g. poly(amide imide), poly(ether ether ketone) or polyimide). The mechan
42、ical properties of polymer matrices are significantly affected by temperature, time, ageing and environment. 3.3 fibre laminate two-dimensionally element made up of two or more layers (plies of the same material with identical orientation) from fibre-reinforced polymers NOTE They are compacted by se
43、aling under heat and/or pressure. Laminates are stacked together by plane (or curved) layers of unidirectional fibres or woven fabric in a polymer matrix. Layers can be of various thicknesses and consist of identical or different fibre and polymer matrix materials. Fibre orientation can vary from la
44、yer to layer. 3.4 fibre-reinforced polymer material FRP polymer matrix composite with one or more fibre orientations with respect to some reference direction NOTE Those are usually continuous fibre laminates. Typical as-fabricated geometries of continuous fibres include uniaxial, cross-ply and angle
45、-ply laminates or woven fabrics. FRP are also made from discontinuous fibres such as short-fibre, long-fibre or random mat reinforcement. 3.5 delamination intra- or inter-laminar fracture (crack propagation) in composite materials under different modes of loading NOTE Delamination mostly occurs betw
46、een the fibre layers by separation of laminate layers with the weakest bonding or the highest stresses under static or repeated cyclic stresses (fatigue), impact, etc. Delamination involves a large number of micro-fractures and secondary effects such as rubbing between fracture surfaces. It develops
47、 inside of the composite, without being noticeable on the surface and it is often connected with significant loss of mechanical stiffness and strength. 3.6 micro-fracture (of composites) occurrence of local failure mechanisms on a microscopic level, such as matrix failure (crazing, cracking), fibre/
48、matrix interface failure (debonding) or fibre pull-out as well as fibre failure (breakage, buckling) NOTE It is caused by local overstress of the composite. Accumulation of micro-failures leads to macro-failure and determines ultimate strength and life-time. BS EN 15857:2010EN 15857:2010 (E) 7 4 Per
49、sonnel qualification It is assumed that acoustic 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. 5 AE sources and acoustic behaviour of FRP 5.1 AE source mechanisms Damage of FRP as a result of micro- and macro-fractur
