Designation:E1067–01
Standard Practice for
Acoustic Emission Examination of Fiberglass Reinforced Plastic Resin(FRP)Tanks/Vesls1thenumberof
This standard is issued under thefixed designation E1067;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope
1.1This practice covers acoustic emission(AE)examina-tion or monitoring offiberglass-reinforced plastic(FRP)tanks-vesls(equipment)under pressure or vacuum to determine structural integrity.
1.2This practice is limited to tanks-vesls designed to operate at an internal pressure no greater than0.44MPa absolute(65psia)above the static pressure due to the internal contents.It is also applicable for tanks-vesls designed for vacuum rvice with differential pressure levels between0and
0.06MPa(0and9psi).
1.3This practice is limited to tanks-vesls with glass contents greater than15%by weight.
1.4This practice applies to examinations of new and in-rvice equipment.
1.5The values stated in SI units are to be regarded as standard.The inch-pound units in parenthes may be approxi-mate.
1.6This standard does not purport to address all of the safety concerns,if any,associated with its u.It is the responsibility of the ur of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to u.(For more specific safe
ty precautionary information e8.1.)
2.Referenced Documents
2.1ASTM Standards:
D883Terminology Relating to Plastics2
E543Practice for Agencies Performing Nondestructive Testing3
E650Guide for Mounting Piezoelectric Acoustic Emission Sensors3
E750Practice for Characterizing Acoustic Emission Instru-mentation3
E1316Terminology for Nondestructive Examinations3
2.2ANSI/ASNT Standards:
SNT-TC-1A Recommended Practice for Nondestructive Testing Personnel Qualification and Certification4
ANSI/ASNT CP-189Standard for Qualification and Certi-fication of Nondestructive Testing Personnel4
2.3Military Standard:
MIL-STD-410Nondestructive Testing Personnel Qualifica-tion and Certification5
3.Terminology
3.1Complete definitions of terms related to plastics and acoustic emission will be found in Terminology D883and E1316.
3.2Definitions of Terms Specific to This Standard:
3.2.1count value N c—an evaluation criterion bad on the total number of AE counts.(See A2.4of Annex A2.)天津保卫战
3.2.2FRP—fiberglass reinforced plastic,a glass-fiber poly-mer composite with certain mechanical properties superior to tho of the ba resin.
3.2.3high-amplitude threshold—a threshold for large am-plitude AE events.(See A2.3of Annex A2.)
3.2.4low-amplitude threshold—the threshold above which AE counts(N)are measured.(See A2.2of Annex A2.)
3.2.5operating pressure—the pressure at the top of a vesl at which it normally operates.It shall not exceed the design pressure and it is usually kept at a suitable level below the tting of the pressure-relieving devices to prevent their frequent opening.
3.2.6pressure,design—the pressure ud in design to determine the required minimum thickness and minimum mechanical properties.
3.2.7processor—a circuit that analyzes AE waveforms. (See Section7and A1.8.)
3.2.8summing amplifier(summer,mixer)—an operational amplifier that produces an output signal equal to a weighted sum of the input signals.
3.2.9zone—the area surrounding a nsor from which AE can be detected by that nsor.
1This practice is under the jurisdiction of ASTM Committee E07on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.04on Acoustic Emission.
Current edition approved July10,2001.Published September2001.Originally published as E1067–85.Last previous edition E1067–96.
2Annual Book of ASTM Standards,V ol08.01.
3Annual Book of ASTM Standards,V ol03.03.
4Available from American Society for Nondestructive Testing,1711Arlingate Plaza,P.O.Box28518,Columbus,OH43228-0518.
5Available from Standardization Documents Order Desk,Bldg.4,Section D, 700Robbins Ave.,Philadelphia,PA19111-5094,Attn:NPODS.
1
Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
freestyle是什么意思4.Summary of Practice
4.1This practice consists of subjecting equipment to in-creasing pressure or vacuum while monitoring with nsors that are nsitive to acoustic emission(transient stress waves) caud by growingflaws.The instrumentation and techniques for nsing and analyzing AE data are described.
4.2This practice provides guidelines to determine the loca-tion and verity of structuralflaws in FRP equipment.
4.3This practice provides guidelines for AE examination of FRP equipment within the pressure range stated in 1.2. Maximum test pressure(or vacuum)for an FRP vesl will be determined upon agreement among ur,manufacturer,or test agency,or a combination thereof.Pressure vesls having an internal operating pressure exceeding0.2MPa absolute(30 psia),will normally be tested to 1.53operating pressure. Atmospheric storage vesls will normally be tested under maximum operating conditions.Pressure vesls having an internal pressure between0.1and0.2MPa absolute(15and30 psia),and vacuum vesls having an external differential pressure between0and0.06MPa(0and9psi),will normally be tested to pressures in the range from1.0to1.53operating pressure.
5.Significance and U
5.1The AE examination method detects damage in FRP equipment.The damage mechanisms that are detected in FRP are as follows:resin cracking,fiber debonding,fiber pullout,fiber breakage,delamination,and bond failure in asmbled joints(for example,nozzles,manways,etc.).Flaws in un-stresd areas andflaws that are structurally insignificant will not generate AE.
5.2This practice is convenient for on-line u under oper-ating stress to determine structural integrity of in-rvice equipment usually with minimal process disruption.
5.3Flaws located with AE should be examined by other techniques;for example,visual,ultrasound,dye penetrant,etc., and may be repaired and tested as appropriate.Repair proce-dure recommendations are outside the scope of this practice.
6.Basis of Application
6.1Personnel Qualification—If specified in the contractual agreement,personnel performing examinations to this standard shall be qualified in accordance with a nationally recognized NDT personnel qualification practice or standard such as ANSI/ASNT-CP-189,SNT-TC-1A,MIL-STD-410,NAS-410, or a similar document and certified by the employer or certifying agency,as applicable.
The practice or standard ud and its applicable revision shall be specified in the contractual agreement between the using parties.
6.2Qualification of Nondestructive Agencies—If specified in the contractual agreement,NDT agencies shall be qualified and evaluated in accordance with Practice E543.The appli-cable edition of Practice E543shall be specified in the contractual agreement.
6.3Procedures and Techniques—The procedures and tech-niques to be utilized shall be in accordance with this practice unless otherwi specified.Specific techniques may be speci-fied in the contractual agreement.
7.Instrumentation
7.1The AE instrumentation consists of nsors,signal processors,and recording equipment.Additional information on AE instrumentation can be found in Practice E750.
7.2Instrumentation shall be capable of recording AE counts and AE hits above the low-amplitude threshold,AE hits above the high-amplitude threshold within specific frequency ranges, and having sufficient channels to localize AE sources in real time.It may incorporate(as an option)peak-amplitud
e detec-tion for each input channel or for groups of channels.Hit detection is required for each channel.An AE hit amplitude measurement is recommended for nsitivity verification(e Annex A2).Amplitude distributions are recommended forflaw characterization.It is preferred that AE instrumentation acquire and record count,hit,and amplitude information on a per channel basis.The AE instrumentation is further described in Annex A1.
7.3Capability for measuring parameters such as time and pressure shall be provided.The pressure-vacuum in the vesl should be continuously monitored to an accuracy of62%of the maximum test value.
8.Examination Preparations
8.1Safety—All plant safety requirements unique to the examination location shall be met.
8.1.1Protective clothing and equipment that is normally required in the area in which the examination is being conducted shall be worn.
8.1.2Afire permit may be needed to u the electronic instrumentation.
again8.1.3Precautions shall be taken to protect against the conquences of catastrophic failure when pre
ssure testing,for example,flying debris and impact of escaping liquid.Pressur-izing under pneumatic conditions is not recommended except when normal rvice loads include either a superpod gas pressure or gas pressure only.Care shall be taken to avoid overstressing the lower ction of the vesl when liquid test loads are ud to simulate operating gas pressures.
8.1.4Special safety precautions shall be taken when pneu-matic testing is required;for example,safety valves,etc.
8.2Vesl Conditioning—The operating conditions for ves-ls that have been stresd previously shall be reduced prior to examining in accordance with the schedule shown in Table1. The maximum operating pressure or load in the vesl during the past year must be known in order to conduct the AE examination properly.
8.3Vesl Stressing—Arrangements should be made to stress the vesl to the operating pressure-load where possible. TABLE1Requirements for Reduced Operating Pressure-Load
Immediately Prior to Examining
%of Operating
Pressure or
Load,or Both
Time at Reduced
Pressure or
Load,or Both
10or less12h
2018h
3030h
402days
504days压强与浮力
607
days
The stress rate shall be sufficient to expedite the examination with minimum extraneous noi.Holding stress levels is a key aspect of an acoustic emission examination.Accordingly, provision must be made for holding the pressure-load at designated check points.
8.3.1Atmospheric Tanks—Process liquid is the preferredfill medium for atmospheric tanks.If water must replace the process liquid,the designer and ur shall be in agreement on the procedure to achieve acceptable stress levels.
8.3.2Vacuum-Tank Stressing—A controllable vacuum-pump system is required for vacuum tanks.
8.3.3Pressure-Vesl Stressing—Water is the preferred me-dium for pressure tanks.Safe means for hydraulically increas-ing the pressure under controlled conditions shall be provided.
8.4Tank Support—The tank shall be examined in its oper-ating position and supported in a manner consistent with good installation practice.Flat-bottomed tanks examined in other than the intended location shall be mounted on a pad(for example,rubber on a concrete ba or equivalent)to reduce structure-borne noi between the tank and ba.
8.5Environmental—The normal minimum acceptable ves-l wall temperature is4°C(40°F).
8.6Noi Reduction—Noi sources in the examination frequency and amplitude range,such as rain,spargers,and foreign objects contacting the tank,must be minimized since they mask the AE signals emanating from the structure.The inlet should be at the lowest nozzle or as near to the bottom of the vesl as possible,that is,below the liquid level.Liquid falling,swirling,or splashing can invalidate data obtained during thefilling pha.
8.7Power Supply—A stable grounded power supply,meet-ing the specification of the instrumentation,is required at the examination site.
8.8Instrumentation Settings—Settings will be determined as described in Annex A2.
9.Sensors六级准考证号
9.1Sensor Mounting—Refer to Practice E650for addi-tional information on nsor mounting.Location and spacing of the nsors are discusd in9.5.Sensors shall be placed in designated locations with a couplant between the nsor and examination article.One recommended couplant is silicone-stopcock grea.Care must be exercid to assure that ad-equate couplant is applied.Sensors shall be held in place utilizing methods of attachment which do not create extraneous signals.Methods of attachment using crosd strips of pressure-nsitive tape or suitable adhesive systems,may be considered.Suitable adhesive systems are tho who bond-ing and acoustic coupling effectiveness have been demon-strated.The attachment method should provide support for the signal cable(and preamplifier)to prevent the cable(s)from stressing the nsor or pulling the nsor away from the examination article causing loss of coupling.
9.2Surface Contact—Reliable coupling between the nsor and tank surface shall be assured and the surface of the vesl in contact with the nsor shall be clean and free of particulate matter.Sensors should be mounted directly on the tank surface unless integral waveguides shown by test to be satisfactory are ud.Preparation of the contact surface shall be compatible with both nsor and structure modification requirements. Possible caus of signal loss are coatings such as paint and encapsulants,surface curvature,and surface roughness at the contact area.
9.3High-Frequency Sensor—(See Annex A1.)Several high-frequency channels are ud for zone location of emission sources.Greater attenuation of stress waves at higher frequen-cies result in smaller zones of nsitivity for high-frequency nsors.
9.4Low-Frequency Sensor—(See Annex A1.)Low-frequency channels are less affected by attenuation;therefore, they can be ud to identifyflaws in a large zone.If significant activity is detected on the low-frequency channels,and not on high-frequency channels,consideration should be given to relocating high-frequency nsors.It should be noted,however, that low-frequency channels are more susceptible to back-ground noi.
emmy rossum
9.5Locations and Spacings—Locations on the vesl shell are determined by the need to detect structuralflaws at critical ctions;for example,high-stress areas,geometric discontinui-ties,nozzles,manways,repaired regions,support rings,and visibleflaws.Spacings are governed by the attenuation of the FRP material.
9.5.1Attenuation Characterization—Typical signal propa-gation loss shall be determined according to one of the following procedures.The procedures provide a relative measure of the attenuation,but may not be reprentative of genuine AE activity.It should be noted that the peak am
plitude from a mechanical pencil lead break may vary with surface hardness,resin condition,and cure.In both cas the attenua-tion characterization should be made above the liquid line. 9.5.1.1For acoustic emission instrumentation with ampli-tude analysis:Select a reprentative region of the vesl away from manways,nozzles,etc.Mount a high-frequency AE nsor and locate points at distances of150mm(6in.)and300 mm(12in.)from the center of the nsor along a line parallel to one of the principal directions of the surfacefiber(if applicable).Select two additional points on the surface of the vesl at150mm(6in.)and300mm(12in.)along a line inclined45°to the direction of the original points.At each of the four points,break0.3mm2H leads6and record peak amplitude.All lead breaks shall be done at an angle of approximately30°to the surface with a2.5mm(0.1in.)lead extension.The data shall be retained as part of the original experimental record.
9.5.1.2For Systems Without Amplitude Analysis—Select a reprentative region of the vesl away from manways, nozzles,etc.Mount a high-frequency AE nsor and break0.3 mm2H leads along a line parallel to one of the principal directions of the surfacefibers.
9.5.1.3Record the distances from the center of the nsor to the points at which the high-amplitude threshold and low-amplitude threshold are no longer detected(e Annex A2). Repeat this procedure along a line inclined45°to the direction 6Pentel0.3(2H)lead or its equivalent has been found satisfact
ory for this
purpo.
of the original line.The data shall be retained as part of the original experimental record.
9.5.2Sensor Spacings—The recommended high-frequency nsor spacing on the vesl shall be not greater than33the distance at which detected signals from the attenuation char-acterization equal the low-amplitude threshold.
9.5.3Sensor Location—Sensor location guidelines for the following tank types are given in the Annex.Other tank types require an agreement among the owner,manufacturer,or examination agency,or combinations thereof.
9.5.3.1Ca I:Atmospheric Vertical Tank—flat bottom,flanged and dished head,typical nozzle and ma
nway configu-ration,cylindrical shell fabricated in two ctions with cond-ary bond-butt joint,dip pipe.
9.5.3.2Ca II:Atmospheric Vertical Tank—flat bottom, 2:1elliptical head,typical nozzle and manway configuration, agitator with baffles,cylindrical shell fabricated in one ction.
9.5.3.3Ca III:Atmospheric-Pressure Vertical Tank—flanged and dished heads top and bottom,typical nozzle and manway configuration,packing support,legs attached to cy-lindrical shell,cylindrical shell fabricated in one ction.
9.5.3.4Ca IV:Atmospheric-Pressure Vertical Tank—cone bottom,2:1elliptical head,typical nozzle and manway con-figuration,cylindrical shell fabricated in two ctions,body flange,dip pipe,support ring.
9.5.3.5Ca V:Atmospheric-Vacuum Vertical Tank—flanged and dished heads top and bottom,typical nozzle and manway configuration,packing support,stiffening ribs,sup-port ring,cylindrical shell fabricated in two ctions with condary bond-butt joint.
9.5.3.6Ca VI:Atmospheric-Pressure Horizontal Tank—flanged and dished heads,typical nozzle an
d manway configu-ration,cylindrical shell fabricated in two ctions with cond-ary bond-butt joint,saddle supports.
10.Instrumentation System Performance Check
10.1Sensor Coupling and Circuit Continuity Verification—Verification shall be performed following nsor mounting and system hookup.The respon of each nsor-preamplifier combination to a repeatable simulated acoustic emission source should be taken prior to the examination.evasion
10.1.1When using systems with amplitude analysis,the peak amplitude of the simulated event at a specific distance from each nsor should not vary more than6dB from the average of all the nsors.Any nsor-preamplifier combina-tion failing this check should be investigated and replaced or repaired as necessary.
10.1.2When using systems without amplitude analysis, verification is accomplished by recording the distance from each nsor at which the respon from the repeated simulated source falls below the low-amplitude threshold.This distance should not vary more than30cm(12in.)from the average of all nsors.Any nsor-preamplifier combination failing this check should be investigated and replaced or repaired as necessary.
冒险精神10.2Background Noi Check—Recommended to identify and determine level of spurious signals.This is done following the completion of the verification described in10.1and prior to stressing the vesl.A recommended time period is10to30 min.
11.Examination Procedure
11.1General Guidelines—The tank-vesl is subjected to programmed increasing pressure-load levels to a predeter-mined maximum while being monitored by nsors that detect acoustic emission(stress waves)caud by growing structural flaws.
cet 411.1.1Fill and pressurization rates shall be controlled so as not to exceed a strain rate of0.005%/min bad on calculated values or actual strain gage measurements of principal strains. Normally,the desired pressure will be attained with a liquid (e8.1.3and8.1.4).Pressurization with a gas(air,N2etc.)is not recommended.A suitable manometer or other type gage shall be ud to monitor pressure.
11.1.2Vacuum should be attained with a suitable vacuum source.A quick relea valve shall be provided to handle any imminent catastrophic failure condition.
11.1.3Background noi shall be minimized and identified (e also8.6).Excessive background noi is cau for suspension of the pressurization.In the analysis of examination results,background noi should be properly discounted. Sources of background noi include the following:liquid splashing into a tank,afill rate that is too high,pumps,motors, agitators and other mechanical devices,electromagnetic inter-ference,and environmental factors,such as rain,wind,etc.
11.2Loading—Atmospheric tanks that operate with liquid head and pressures of0.2MPa(30psia)or less,and vacuum vesls that operate at pressures below atmospheric,shall be loaded in a ries of steps.Recommended load procedures are shown in Fig.1and Fig.2.The algorithmflow chart for this class of tanks is given in Fig.3.
11.2.1For tanks that have been stresd previously,the examination can begin with the liquid level as high as60%of the operating or maximum test level(e8.2).Fig.1should be modified for vesls that are partially full at the beginning of an examination.The background noi baline determination is important for this class of examination and should be provided for.Many vesls operate with liquid contents and partial vacuum;however,vacuum vesls are normally examined empty.
11.2.2Pressure vesls that operate with superimpod pressures greater than0.2MPa(30psia)shall be loaded as shown in Fig.4.The algorithmflow chart for this class of tanks is given in Fig.5.
11.2.3The initial hold period is ud to determine a baline of the background noi.This data provides an estimate of the total background noi contribution during the examination. Background noi shall be discounted in thefinal data analysis.
11.2.4Intermittent load holds shall be for4min.As shown in Fig.4,pressure vesls shall be loaded in steps up to30% of the maximum test pressure.Thereafter,the pressure shall be decread by10%of the maximum test pressure before proceeding to the next hold level.Following a decrea in pressure,the load shall be held for4min before
reloading.
11.2.5For all vesls,the final load hold shall be for 30min.The vesl should be monitored continuously during this period.
11.3Felicity Ratio Determination —The Felicity ratio is not measured during the first loading of atmos
pheric tanks and vacuum vesls.The Felicity ratio is obtained directly from the ratio of the stress at the emission source at ont of significant emission and the maximum prior stress at the same point.11.3.1The Felicity ratio is measured from the unload-reload cycles during the first loading of pressure vesls.For sub-quent loadings,the Felicity ratio is obtained directly from the ratio of the stress at the emission source at ont of emission and the previous maximum stress at the same point.A condary Felicity ratio is determined from the unload-reload cycles.
11.4Data Recording —Prior to an examination,the signal propagation loss (attenuation)data,that is,amplitude as a function of distance from the signal source,shall be recorded in accordance with the procedure detailed in 9.5.
11.4.1During an examination,the sum of counts above the low-amplitude threshold from all low-frequency channels shall be monitored and the sum of counts above the low-amplitude threshold from all the high-frequency channels shall be pa-rately monitored and recorded.The number of hits from
all
FIG.1Atmospheric Tank Examination,Stressing
Sequence
FIG.2Vacuum Tank Examination,Stressing
Sequence
