1、Designation:E1888/E1888M07 Designation: E1888/E1888M 12Standard 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 designa
2、tion indicates 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
3、for acoustic 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.
4、 to 3 m 120 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 Th
5、is practice 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 co
6、ntainer is suitable 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-poun
7、d units are 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
8、 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 applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Sectio
9、n 8.2. 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 Emission Ex
10、amination of Fiberglass Reinforced Plastic Resin (FRP) Tanks/VesselsE1316 Terminology for Nondestructive ExaminationsE2374 Guide for Acoustic Emission System Performance Verification2.2 SPI/CARP Standards:3Recommended Practice for Acoustic Emission Testing of Fiberglass Reinforced Plastic Resin (FRP
11、) Tanks/VesselsRecommended Practice for Acoustic Emission Testing of Fiberglass 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 Certificatio
12、n of NDT Personnel1This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.04 on Acoustic EmissionMethod.Current edition approved July 1, 2007.June 15, 2012. Published July 2007.2012. Originally approved in 1997. La
13、st previous edition approved in 20022007 asE1888/E1888M - 027. DOI: 10.1520/E1888_E1888M-0712.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Documen
14、t Summary page on the ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/ww
15、w.asnt.org.1This 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 users consu
16、lt 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 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
17、 PA 19428-2959, United States.2.4 AIA Standard:NAS-410 Nondestructive Testing Personnel Qualification and Certification52.5 ASME Standard:Section V, Article 11, Boiler and Pressure Vessel Code63. Terminology3.1 DefinitionsWith the exception of terms defined in 3.2, this practice incorporates by refe
18、rence 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 ofrepeated lo
19、ading cycles (see 9.2).3.2.2 Minimum AE activity levelthat level of activity below which AE trend numbers are not robust indicators of the trend(see 9.1)3.2.3 Examination pressurethe highest pressure used while examining a given container. The examination pressure is 1.1times the maximum allowable w
20、orking 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 settings
21、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 can occurwi
22、thin 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 contaminatio
23、n 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 are cond
24、ucted. 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. Also, leaks
25、at pipe connections may producebackground noise.5Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http:/www.aia-aerospace.org.6Available from American Society of Mechanical Engineers (ASME), ASME International Headquarte
26、rs, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.FIG. 1 Recommended Features of the ApparatusE1888/E1888M 1224.5 Electronic NoiseElectronic noise such as electromagnetic interference (EMI) and radio frequency interference (RFI) canbe caused by electric motors, overhead cranes, electr
27、ical storms, welders, etc.4.6 Airborne Background NoiseAirborne background 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
28、 structural characteristics.5. Basis of Application5.1 The following items are subject to contractual agreement between the parties using or referencing this practice.5.2 Personnel Qualification:5.2.1 If specified in the contractual agreement, personnel performing examinations to this practice shall
29、 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-410, or a similar document and certified by the employer or certifying agency, as applicable.The practice or standard used and its appl
30、icable revision shall be identified in the contractual agreement between the using parties.5.2.2 Also, it is required that personnel performing acoustic emission examination of containers be trained, by attending adedicated training course on the subject and passing a written examination. The traini
31、ng course shall include appropriate materialfor NDT Level II qualification in accordance with a recognized NDT personnel qualification practice or standard per 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 ge
32、neration 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 requirements,5.2.2.5 Data collection and interpretation, and5.2.2.6 Examination report and permanent record requirements.5.3 Qualification of
33、Nondestructive AgenciesIf specified in the contractual agreement, NDT agencies shall be qualified andevaluated as described in Practice E543. The applicable edition of Practice E543 shall be specified in the contractual agreement.5.4 Timing of ExaminationThe timing of examination shall be in accorda
34、nce 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 agreement.5.6 Extent of ExaminationThe extent of examination shall be in accordance with paragraph 1.2, unless otherwise specified.5.7 Reporting
35、 Criteria/Acceptance CriteriaReporting criteria/acceptance criteria shall be in accordance with Sections 9 and10 unless otherwise specified.5.8 Reexamination of Repaired/Reworked ItemsReexamination of repaired/reworked items is not addressed in this practiceand if required shall be specified in the
36、contractual agreement.6. Apparatus6.1 Recommended features of the apparatus required for this practice are provided in Fig. 1. Full specifications are in AnnexA1.6.2 Couplant must be used to acoustically connect sensors to the vessel surface. Adhesives that have acceptable acousticproperties and adh
37、esives used in combination with traditional couplants are acceptable.6.3 Sensors may be held in place with elastic straps, adhesive tape, or other mechanical means.6.4 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 co
38、ntainer is detected by at least one AE sensor. A 0.3 mm 0.012 in., 2H pencil lead break may be used 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
39、 m 424 in. length and 1.8 m 72 in. diameter.6.4.1 Attenuation Characterization Typical signal propagation 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.FIG. 2 Typical
40、Examination Configuration Showing AE Sensor Location on a Road TankerE1888/E1888M 123It should be noted that the peak amplitude from 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 cylind
41、rical section. Mount an AE sensor and markoff distances of 15 cm (6 in.)6 in. and 30 cm (12 in.)12 in. from the center of the sensor along a line parallel to the principaldirection of the surface fiber. Select two additional points on the surface of the vessel at 15 cm (6 in.)6 in. and 30 cm (12 in.
42、)12in. along a line inclined 45 and 90 to the principal direction of the surface fiber, break pencil leads (0.3 mm 0.012 in. 2H, ratherthen 0.5 mm 0.02 in. to avoid possible saturation due to larger signal output) and record peak amplitude. All lead breaks shallbe done at an angle of approximately 3
43、0 to the surface with a 2.54 mm 0.1 in. lead extension. The attenuation data shall beretained as part of the original experimental record.6.4.2 In addition, record the distances from the center of the sensor to the points where hits are no longer detected. Repeat thisprocedure along lines inclined 4
44、5 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 threshold distance.6.5 Acoustic emission sensors are used to detect stra
45、in 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 separate preamplifier is used, cablelength between sensor and preamp
46、lifier 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 that filter, measure and convert analoginformation into digital form fo
47、r 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. Dis
48、play format may be selected by the examiner.6.10 Adata storage device, such as a hard disc or removable media (CD, DVD, or other), may be used to provide data for replayor for archives.6.11 Hard copy capability should be available from a printer or equivalent output device.7. Calibration and System
49、Performance Verification7.1 Perform annual calibration and verification of pressure transducer,AE sensors, preamplifiers (if applicable), signal processor(particularly the signal processor time reference) and AE electronic waveform generator. Adjust equipment so that it conforms toequipment manufacturers specifications. Instruments used for calibrations must have current accuracy certification that is traceableto the National Institute for Standards and Technology (NIST).7.2 Perform routine electronic evaluations on a monthly
