1、Designation: E1888/E1888M 12E1888/E1888M 17Standard Practice forAcoustic Emission Examination of Pressurized ContainersMade of Fiberglass Reinforced Plastic with Balsa WoodCores1This standard is issued under the fixed designation E1888/E1888M; the number immediately following the designation indicat
2、es the yearof original 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*1.1 This practice covers guidelines for acoustic
3、 emission (AE) examinations of pressurized containers made of fiberglassreinforced plastic (FRP) with balsa cores. Containers of this type are commonly used on tank trailers for the transport of hazardouschemicals.1.2 This practice is limited to cylindrical shape containers, 0.5 m 20 in. to 3 m 120
4、in. in diameter, of sandwich constructionwith balsa wood core and over 30 % glass (by weight) FRP skins. Reinforcing material may be mat, roving, cloth, unidirectionallayers, or a combination thereof. There is no restriction with regard to fabrication technique or method of design.1.3 This practice
5、is limited to containers that are designed for less than 0.520 MPa 75.4 psi (gage) above static pressure headdue to contents.1.4 This practice does not specify a time interval between examinations for re-qualification of a pressure container.1.5 This practice is used to determine if a container is s
6、uitable for service or if follow-up NDT is needed before thatdetermination can be made.1.6 Containers that operate with a vacuum are not within the scope of this practice.1.7 Repair procedures are not within the scope of this practice.1.8 The values stated in either SI units or inch-pound units are
7、to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.9 This standard does not purport to address all
8、 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 applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 8.1.10 Thi
9、s international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TB
10、T) Committee.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestructive TestingE750 Practice for Characterizing Acoustic Emission InstrumentationE976 Guide for Determining the Reproducibility of Acoustic Emission Sensor ResponseE1067 Practice for Acoustic Em
11、ission Examination of Fiberglass Reinforced Plastic Resin (FRP) Tanks/VesselsE1106 Test Method for Primary Calibration of Acoustic Emission SensorsE1316 Terminology for Nondestructive ExaminationsE1781 Practice for Secondary Calibration of Acoustic Emission Sensors1 This practice is under the jurisd
12、iction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic EmissionMethod.Current edition approved June 15, 2012June 1, 2017. Published July 2012June 2017. Originally approved in 1997. Last previous edition approved in 20072012 asE1888/E
13、1888M - 07.E1888/E1888M - 12. DOI: 10.1520/E1888_E1888M-12.10.1520/E1888_E1888M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary pag
14、e on the ASTM website.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 may not be technically possible to adequately depict all changes accurately, ASTM recommends that u
15、sers 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 the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
16、hohocken, PA 19428-2959. United States1E2374 Guide for Acoustic Emission System Performance Verification2.2 SPI/CARP Standards:3Recommended Practice for Acoustic Emission Testing of Fiberglass Reinforced Plastic Resin (FRP) Tanks/VesselsRecommended Practice for Acoustic Emission Testing of Fiberglas
17、s Reinforced Plastic Piping Systems2.3 ANSI/ASNT Standards:4SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive TestingANSI/ASNT CP-189 Standard for Qualification and Certification of NDT Personnel2.4 AIA Standard:5NAS-410 Nondestructive Testing Personnel Q
18、ualification and Certification2.5 ASME Standard:6Section V, Article 11, Boiler and Pressure Vessel Code2.6 ISO Standard:7ISO 9712 Non-Destructive Testing: Qualification and Certification of NDT Personnel3. Terminology3.1 DefinitionsWith the exception of terms defined in 3.2, this practice incorporat
19、es by reference all terminology inTerminology E1316 and Practice E1067. First occurrences of terms defined herein are italicized.3.2 Definitions of Terms Specific to This Standard:3.2.1 AE trend numbera number used to designate trends in AE activity which are exhibited by structures during a set ofr
20、epeated loading cycles (see 9.2).3.2.2 Minimum AE activity levelthat level of activity below whichAE trend numbers are not robust indicators of the trend (see9.1)3.2.3 Examination pressurethe highest pressure used while examining a given container. The examination pressure is 1.1times the maximum al
21、lowable working pressure, MAWP (see Section 8).4. Significance and Use4.1 This practice does not rely on absolute quantities of AE parameters. It relies on trends of cumulative AE counts that aremeasured during a specified sequence of loading cycles. This practice includes an example of examination
22、settings and acceptancecriteria as a nonmandatory appendix.4.2 Acoustic emission (AE) counts were used as a measure of AE activity during development of this practice. Cumulative hitduration may be used instead of cumulative counts if a correlation between the two is determined. Several processes ca
23、n occurwithin the structure under examination. Some may indicate unacceptable flaws (for example, growing resin cracks, fiber fracture,delamination). Others may produce AE but have no structural significance (for example, rubbing at interfaces). The methodologydescribed in this practice prevents con
24、tamination of structurally significant data with emission from insignificant sources.4.3 Background NoiseBackground noise can distort interpretations of AE data and can preclude completion of anexamination. Examination personnel should be aware of sources of background noise at the time examinations
25、 are conducted. AEexaminations should not be conducted until such noise is substantially eliminated.4.4 Mechanical Background NoiseMechanical background noise is generally induced by structural contact with the containerunder examination. Examples are: personnel contact, wind borne sand or rain. Als
26、o, leaks at pipe connections may producebackground noise.4.5 Electronic NoiseElectronic noise such as electromagnetic interference (EMI) and radio frequency interference (RFI) canbe caused by electric motors, overhead cranes, electrical storms, welders, etc.4.6 Airborne Background NoiseAirborne back
27、ground noise can be produced by gas leaks in nearby equipment.4.7 Accuracy of the results from this practice can be influenced by factors related to setup and calibration of instrumentation,background noise, material properties, and structural characteristics.5. Basis of Application5.1 The following
28、 items are subject to contractual agreement between the parties using or referencing this practice.5.2 Personnel Qualification:3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4 Available from American Society for Nondes
29、tructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.5 Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http:/www.aia-aerospace.org.6 Available from American Society of
30、 Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.7 Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,Switzerland, http:
31、/www.iso.org.E1888/E1888M 1725.2.1 If specified in the contractual agreement, personnel performing examinations to this practice shall be qualified inaccordance with a nationally or internationally recognized NDT personnel qualification practice or standard such as ANSI/ASNT CP-189, SNT-TC-1A, NAS-4
32、10, 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 contractual agreement between theusing parties.5.2.2 Also, it is required that personnel performing acoustic emis
33、sion examination of containers be trained, by attending adedicated training course on the subject and passing a written examination. The training course shall include appropriate materialfor NDT Level II qualification in accordance with a recognized NDT personnel qualification practice or standard p
34、er 5.2.1.Personnel shall be trained/examined on the following topics:5.2.2.1 Container construction and terminology,5.2.2.2 Mechanisms of AE generation in FRP including containers within the scope of this practice,5.2.2.3 AE instrumentation,5.2.2.4 Container examination procedures, including loading
35、 requirements,5.2.2.5 Data collection and interpretation, and5.2.2.6 Examination report and permanent record requirements.5.3 Qualification of Nondestructive AgenciesIf specified in the contractual agreement, NDT agencies shall be qualified andevaluated as described in Practice E543. The applicable
36、edition of Practice E543 shall be specified in the contractual agreement.5.4 Timing of ExaminationThe timing of examination shall be in accordance with 1.4 1.7 unless otherwise specified.5.5 Procedures and TechniquesThe procedures and techniques to be utilized shall be specified in the contractual a
37、greement.5.6 Extent of ExaminationThe extent of examination shall be in accordance with paragraph 1.2, unless otherwise specified.5.7 Reporting Criteria/Acceptance CriteriaReporting criteria/acceptance criteria shall be in accordance with Sections 9 and10 unless otherwise specified.5.8 Reexamination
38、 of Repaired/Reworked ItemsReexamination of repaired/reworked items is not addressed in this practiceand if required shall be specified in the contractual agreement.6. Apparatus6.1 Recommended features of the apparatus required for this practice are provided in Fig. 1. Full specifications are in Ann
39、exA1.6.2 Couplant must be used to acoustically connect sensors to the vessel surface. Adhesives that have acceptable acousticproperties and adhesives used in combination with traditional couplants are acceptable.6.3 Sensors may be held in place with elastic straps, adhesive tape, or other mechanical
40、 means.FIG. 1 Recommended Features of the ApparatusE1888/E1888M 1736.4 Sensor spacing shall be such that a standard 0.5 mm 0.02 in., 2H pencil lead break (See Guide E976) on any part of a liquidfilled container is detected by at least oneAE sensor.A0.3 mm 0.012 in., 2H pencil lead break may be used
41、which would reducethe sensor spacing. Presence of heads, manholes, and nozzles shall be considered when sensor locations are selected. Fig. 2 showsa typical sensor location scheme for a vessel of 10.8 m 424 in. length and 1.8 m 72 in. diameter.6.4.1 Attenuation CharacterizationTypical signal propaga
42、tion losses shall be determined according to the followingprocedure. This procedure provides a relative measure of the attenuation but may not be representative of a genuine AE source.It should be noted that the peak amplitude from a mechanical pencil lead break may vary with surface hardness, resin
43、 conditionand cure. Select a representative region of the vessel with clear access along the cylindrical section. Mount anAE sensor and markoff distances of 15 cm 6 in. and 30 cm 12 in. from the center of the sensor along a line parallel to the principal direction ofthe surface fiber. Select two add
44、itional points on the surface of the vessel at 15 cm 6 in. and 30 cm 12 in. along a line inclined45 and 90 to the principal direction of the surface fiber, break pencil leads (0.3 mm 0.012 in. 2H, rather then 0.5 mm 0.02 in.to avoid possible saturation due to larger signal output) and record peak am
45、plitude. All lead breaks shall be done at an angle ofapproximately 30 to the surface with a 2.54 mm 0.1 in. lead extension. The attenuation data shall be retained as part of theoriginal experimental record.6.4.2 In addition, record the distances from the center of the sensor to the points where hits
46、 are no longer detected. Repeat thisprocedure along lines inclined 45 and 90 to the direction of the original line. The data shall be retained as part of the originalexperimental record. The minimum distance from the sensor at which the pencil lead break can no longer be detected is knownas the thre
47、shold distance.6.5 Acoustic emission sensors are used to detect strain induced stress waves produced by discontinuities. Sensors must be heldin contact with the vessel wall to ensure adequate acoustic coupling.6.6 A preamplifier may be enclosed in the sensor housing or in a separate enclosure. If a
48、separate preamplifier is used, cablelength between sensor and preamplifier must not exceed 2 m 78 in.6.7 Power/signal cable length (that is, cable between preamplifier and signal processor) shall not exceed 150 m 500 ft.6.8 Signal processors are computerized instruments with independent channels tha
49、t filter, measure and convert analoginformation into digital form for display and permanent storage. A signal processor must have sufficient speed and capacity toindependently process data from all sensors simultaneously. The signal processor should provide capability to filter data for replay.6.9 A video monitor should display processed data in various formats. Display format may be selected by the examiner.6.10 Adata storage device, such as a hard disc or removable media (CD, DVD, or other), device, may be used to provide
