1、Designation: E2191/E2191M 10E2191/E2191M 16Standard Practice forExamination of Gas-Filled Filament-Wound CompositePressure Vessels Using Acoustic Emission1This standard is issued under the fixed designation E2191/E2191M; the number immediately following the designation indicates the yearof original
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This practice provides guidelines for acoustic emission (AE)
3、examination of filament-wound composite pressure vessels, forexample, the type used for fuel tanks in vehicles which use natural gas fuel.1.2 This practice requires pressurization to a level equal to or greater than what is encountered in normal use. The tankspressurization history must be known in
4、order to use this practice. Pressurization medium may be gas or liquid.1.3 This practice is limited to vessels designed for less than 690275 bar 10,0004,000 psi maximum allowable workingpressure and water volume less than 1 m3 or 1000 L 35.4 ft3.1.4 AE measurements are used to detect emission source
5、s. Other nondestructive examination (NDE) methods may be used togain additional insight into the emission source. Procedures for other NDE methods are beyond the scope of this practice.1.5 This practice applies to examination of new and in-service in-service, Type II, filament-wound composite pressu
6、re vessels.1.6 This practice applies to examinations conducted at ambient temperatures above 20C 70F. This practice may be used atambient temperatures below 20C 70F if provision has been made to fill to the tanks rated pressure at 20C 70F. Also thatthe test temperature must not exceed the glass tran
7、sition temperature of the matrix material.1.7 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. The values statedin each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining valuesfrom t
8、he two systems may result in non-conformance with the standard.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applic
9、ability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestructive TestingE650 Guide for Mounting Piezoelectric Acoustic Emission SensorsE976 Guide for Determinin
10、g the Reproducibility of Acoustic Emission Sensor ResponseE1316 Terminology for Nondestructive ExaminationsE2374 Guide for Acoustic Emission System Performance Verification2.2 Natural Gas Vehicle Standard:3American National Standard for Basic Requirements for Compressed Natural Gas Vehicle (NGV) Fue
11、l Containers ANSI/AGA/NGV22.3 Compressed Gas Association Standard:4Pamphlet C-6.4, Methods for Visual Inspection of AGA NGV2 Containers1 This practice is under the jurisdiction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic Emission
12、Method.Current edition approved June 1, 2010Feb. 1, 2016. Published July 2010February 2016. Originally approved in 2002. Last previous edition approved in 20082010 asE2191 - 08.E2191 - 10. DOI: 10.1520/E2191_E2191M-10.10.1520/E2191_E2191M-16.2 For referencedASTM standards, visit theASTM website, www
13、.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www
14、.ansi.org.4 Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5th Floor, Chantilly, VA 20151-2923, http:/.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit
15、 may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at
16、 the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.4 U.S. Department of Transportation Reference:5NHTSA Federal Motor Vehicle Safety Standard No. 304, March 27, 19952.5 ASNT Standards:6ANSI/ASNT CP-189, Standar
17、d for Qualification and Certification of Nondestructive Testing PersonnelSNT-TC-1A, Recommended Practice for Nondestructive Testing Personnel Qualification and Certification2.6 International Standards Organization (ISO) Standards:7ISO 9712 Nondestructive TestingQualification and Certification of NDT
18、 Personnel3. Terminology3.1 DefinitionsSee Terminology E1316 for general terminology applicable to this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 AE test pressure, n110 % of the greatest pressure that the examination article contains during previous service. Usually125 % of t
19、he filling pressure is an acceptable AE examination pressure. (Normally, gas is heated when compressed during thefilling process; hence, tanks are filled to more than rated service pressure). After filling, pressure should settle to rated servicepressure as gas temperature within the tank becomes eq
20、ual to ambient temperature.3.2.2 detectability distance, nthe maximum distance from a sensor at which a defined simulated AE source can be detectedby the instrumentation with defined settings and using appropriate pressurization medium.4. Summary of Practice4.1 AE sensors are mounted on a vessel and
21、 emission is monitored while the vessel is pressurized to the “AE examinationpressure.”4.2 This practice provides guidelines for the detection of AE from structural flaws in the composite overwrap in gas-filled,filament-wound composite pressure vessels. Damage mechanisms which produceAE include: res
22、in cracking, fiber debonding, fiberpullout, fiber breakage, delamination and bond failure. Flaws in liner portions of a vessel may not be detected.4.3 This practice and others found in ASTM, ASME, ASNT, SPI relate Acoustic Emission to applied load on the compositematerial. At relatively low load (sa
23、fe operating conditions) the acoustic emission from the composite material is low. At higherloads (unsafe operating conditions) the slope of the AE versus load curve changes drastically. In some cases this phenomenon canbe identified and quantified by a single AE parameter (that is, AE counts).4.4 S
24、tructurally insignificant flaws or processes (for example, leaks) may produce emission.4.5 This practice is convenient for periodic examination of vessels in-service.4.6 Gas-filled filament-wound pressure vessels which exhibit unacceptable levels ofAE should be examined by other methods;for example,
25、 visual, ultrasound, dye penetrant, etc., and may be repaired and re-examined in accordance with governmentregulations and manufacturers guidelines. Repair and repair examination procedures are outside the scope of this practice.4.7 Any number of pressure vessels may be examined simultaneously as lo
26、ng as the appropriate number of sensors andinstrumentation channels are used.5. Significance and Use5.1 Due to safety considerations, the Compressed Gas Association (CGA) and others have produced guidelines which addressin-service inspection of NGV fuel containers (see 2.2 2.4). AE examination is li
27、sted as an alternative to the minimum three-yearvisual examination which generally requires that the container be removed from the vehicle to expose the entire container surface.The AE method allows “in-situ” examination of the container.5.1.1 Slow-fill pressurization must proceed at flow rates that
28、 do not produce background noise from flow of the pressurizingmedium. Acoustic emission data are recorded throughout a pressurization range (that is, 50 % to 100 % of AE examinationpressure).5.1.2 Fast-fill pressurization can be used if hold periods are provided.Acoustic emission data are recorded o
29、nly during the holdperiods.NOTE 1Fast-fill pressurization is less appropriate for carbon (or graphite) composites due to the lower sensitivity of carbon fibers to stress rupturecompared to other fibers.5.1.3 Background noise above the threshold will contaminate the AE data and render them useless. U
30、sers must be aware of thefollowing common causes of background noise: high fill rate (measurable flow noise); mechanical contact with the vessel by5 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.m
31、il.6 Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.7 Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernie
32、r, Geneva,Switzerland, http:/www.iso.org.E2191/E2191M 162objects; electromagnetic interference (EMI) and radio frequency interference (RFI) from nearby broadcasting facilities and fromother sources; leaks at pipe or hose connections and airborne particles, insects, rain and snow. This practice shoul
33、d not be usedif background noise cannot be eliminated or controlled.5.2 Sensitivity is influenced by factors that affect elastic wave propagation, sensor coupling and signal processor settings.5.3 It is possible to measure AE from AE sources that cannot be verified by other NDE methods.6. Basis of A
34、pplication6.1 The following items are subject to contractual agreement between the parties using or referencing this practice.6.2 Personnel QualificationIf specified in the contractual agreement, personnel performing examinations to this practice shallbe qualified in accordance with a nationally or
35、internationally recognized NDT personnel qualification practice or standard suchas ANSI/ASNT-CP-189, SNT-TC-1A, ISO 9712, or a similar document and certified by the employer or certifying agency, asapplicable. The practice or standard used and its applicable revision shall be identified in the contr
36、actual agreement between theusing parties.6.3 Qualification of Nondestructive Test AgenciesIf specified in the contractual agreement, NDT agencies shall be qualifiedand evaluated as described in Practice E543. The applicable edition of Practice E543 shall be specified in the contractualagreement.6.4
37、 Extent of ExaminationThe extent of examination shall be in accordance with 4.2 unless otherwise specified.6.5 Reporting Criteria/Acceptance CriteriaReporting criteria for the examination results shall be in accordance with Section11 unless otherwise specified.6.6 Personnel Training/Test Requirement
38、sNDE personnel (examiner) shall be familiar with CGAPamphlet C6 and shall haveattended a training course and passed a written test which cover the following topics.6.6.1 Basic technology of acoustic emission.6.6.2 Failure mechanisms of reinforced plastics.6.6.3 Acoustic emission instrumentation.6.6.
39、4 Instrumentation verification.6.6.5 Vessel filling requirements.6.6.6 Data collection and interpretation.6.6.7 Examination report generation.7. Apparatus7.1 Essential features of the apparatus required for this standard are shown in Fig. 1. Specifications are provided in Annex A1.7.2 Couplant must
40、be used to acoustically couple sensors to the vessel surface. Adhesives that have acceptable acousticproperties and traditional couplants are acceptable.7.3 Sensors may be held in place with elastic straps, adhesive tape, or other mechanical means.7.4 On small vessels (that is, where less than 1.3 y
41、d3 1 m3 (where 100 % coverage can be achieved with two sensors) thesensor locations on the vessel wall will be determined by accessibility. Ideally they should be placed 180 apart at opposite endsof the container on the shoulders.7.5 On larger vessels (that is, where two sensors cannot provide 100 %
42、 coverage) sensors are positioned on the vessel wall soas to provide complete coverage. Sensor spacings are governed by the attenuation of the material. If attenuation characteristics arenot available from previous examinations of similar vessels follow the directions found below.FIG. 1 Essential Fe
43、atures of the ApparatusE2191/E2191M 1637.5.1 Attenuation CharacterizationTypical signal propagation losses shall be determined in accordance with the followingprocedure. This procedure provides a relative measure of the attenuation but may not be representative of a genuine AE source.It should be no
44、ted that peak amplitude caused by a mechanical pencil lead break may vary with surface hardness, resin conditionand cure. Select a representative region of the vessel with clear access along the cylindrical section. Mount anAE sensor and markoff 15-cm 6-in. intervals from the center of the sensor al
45、ong a line parallel to the principal direction of the surface fiber. Selectadditional points on the surface of the vessel at 15-cm 6-in. intervals along lines angled 45 and 90, respectively, to the principaldirection of the surface fiber. Break pencil leads (see Guide E976) and record peak amplitude
46、. All lead breaks shall be done at anangle of approximately 30 to the surface with a 2.5-mm 0.1-in. lead extension. The attenuation data shall be retained as part ofthe test report.7.5.2 Record the distances from the center of the sensor to the points where hits are no longer detected. Repeat this p
47、rocedurealong lines angled 45 and 90 to the direction of the original line.The data shall be retained as part of the test report.The minimumdistance from the sensor at which the pencil lead break can no longer be detected is known as the detectability distance; thisdistance shall be recorded. Use th
48、e same threshold during testing that was used to determine the detectability distance.NOTE 2Detectability distance may be reduced to achieve greater sensitivity to sources at farther distance.7.5.3 Sensor spacing (distance between adjacent sensors) shall not be greater than 1.5 times the detectabili
49、ty distance.7.6 AE sensors are used to detect stress waves produced by flaws. Sensors must be held in contact with the vessel wall to ensureadequate acoustic coupling.7.7 A preamplifier may be enclosed in the sensor housing or in a separate enclosure. If a separate preamplifier is used, cablelength, between sensor and preamplifier, must not result in a signal loss of greater than 3 dB (typically 2 m 6 ft is acceptable).7.8 Power/signal cable length (that is, cable between preamplifier and signal processor) shall
