ASTM E2478-11(2022)
(Practice)Standard Practice for Determining Damage-Based Design Stress for Glass Fiber Reinforced Plastic (GFRP) Materials Using Acoustic Emission
Standard Practice for Determining Damage-Based Design Stress for Glass Fiber Reinforced Plastic (GFRP) Materials Using Acoustic Emission
SIGNIFICANCE AND USE
5.1 The damage-based design approach will permit an additional method of design for GFRP materials. This is a very useful technique to determine the performance of different types of resins and composition of GFRP materials in order to develop a damage tolerant and reliable design. This AE-based method is not unique, other damage-sensitive evaluation methods can also be used.
5.2 This practice involves the use of acoustic emission instrumentation and examination techniques as a means of damage detection to support a destructive test, in order to derive the damage-based design stress.
5.3 This practice is not intended as a definitive predictor of long-term performance of GFRP materials (such as those used in vessels). For this reason, codes and standards require cyclic proof testing of prototypes (for example, vessels) which are not a part of this practice.
5.4 Other design methods exist and are permitted.
SCOPE
1.1 This practice details procedures for establishing the direct stress and shear stress damage-based design values for use in the damage-based design criterion for materials to be used in GFRP vessels and other GFRP structures. The practice uses data derived from acoustic emission examination of four-point beam bending tests and in-plane shear tests (see ASME Section X, Article RT-8).
1.2 The onset of lamina damage is indicated by the presence of significant acoustic emission during the reload portion of load/reload cycles. “Significant emission” is defined with historic index.
1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2478 − 11 (Reapproved 2022)
Standard Practice for
Determining Damage-Based Design Stress for Glass Fiber
Reinforced Plastic (GFRP) Materials Using Acoustic
Emission
This standard is issued under the fixed designation E2478; the number immediately following the designation indicates the year of
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 D790 Test Methods for Flexural Properties of Unreinforced
and Reinforced Plastics and Electrical Insulating Materi-
1.1 This practice details procedures for establishing the
als
direct stress and shear stress damage-based design values for
D4255/D4255M Test Method for In-Plane Shear Properties
use in the damage-based design criterion for materials to be
of Polymer Matrix Composite Materials by the Rail Shear
used in GFRPvessels and other GFRPstructures. The practice
Method
uses data derived from acoustic emission examination of
D3846 Test Method for In-Plane Shear Strength of Rein-
four-point beam bending tests and in-plane shear tests (see
forced Plastics
ASME Section X, Article RT-8).
E543 Specification forAgencies Performing Nondestructive
1.2 Theonsetoflaminadamageisindicatedbythepresence
Testing
of significant acoustic emission during the reload portion of
E976 GuideforDeterminingtheReproducibilityofAcoustic
load/reload cycles. “Significant emission” is defined with
Emission Sensor Response
historic index.
E1316 Terminology for Nondestructive Examinations
E2374 Guide for Acoustic Emission System Performance
1.3 Units—The values stated in inch-pound units are to be
regarded as standard. The values given in parentheses are Verification
mathematical conversions to SI units which are provided for
2.2 ASME Documents:
information only and are not considered standard.
ASMESectionX,ArticleRT-8 TestMethodforDetermining
1.4 This standard does not purport to address all of the Damage-Based Design Criterion
safety concerns, if any, associated with its use. It is the ASMESectionV,Article11 AcousticEmissionExamination
responsibility of the user of this standard to establish appro-
of Fiber-Reinforced Plastic Vessels
priate safety, health, and environmental practices and deter-
2.3 Other Standards:
mine the applicability of regulatory limitations prior to use.
ANSI/ASNT-CP-189 Qualification and Certification of
1.5 This international standard was developed in accor- 4
Nondestructive Testing Personnel
dance with internationally recognized principles on standard-
SNT-TC-1A Recommended Practice for Personnel Qualifi-
ization established in the Decision on Principles for the 4
cation and Certification in Nondestructive Testing
Development of International Standards, Guides and Recom-
NAS-410 Certification and Qualification of Nondestructive
mendations issued by the World Trade Organization Technical 5
Test Personnel
Barriers to Trade (TBT) Committee.
3. Terminology
2. Referenced Documents
3.1 Definitions of terms related to conventional acoustic
2.1 ASTM Standards:
emission are in Terminology E1316, Section B.
3.2 Definitions of Terms Specific to This Standard:
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.04 on
Acoustic Emission Method.
Current edition approved Dec. 1, 2022. Published December 2022. Originally Available from American Society of Mechanical Engineers (ASME), ASME
approved in 2006. Last previous edition approved in 2016 as E2478 – 11(2016). International Headquarters, Three Park Ave., New York, NY 10016-5990, http://
DOI: 10.1520/E2478-11R22. www.asme.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Standards volume information, refer to the standard’s Document Summary page on Available fromAerospace IndustriesAssociation ofAmerica, Inc. (AIA), 1000
the ASTM website. WilsonBlvd.,Suite1700,Arlington,VA22209-3928,http://www.aia-aerospace.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2478 − 11 (2022)
3.2.1 historic index—a measure of the change in MARSE used and its applicable revision shall be identified in the
(or other AE feature parameter such as AE Signal Strength) contractual agreement between the using parties.
throughout an examination.
6.1.2 Qualification of Nondestructive Agencies—Ifspecified
in the contractual agreement, NDT agencies shall be qualified
3.2.2 knee in the curve—a dramatic change in the slope of
and evaluated as described in Practice E543. The applicable
the cumulative AE (MARSE or Signal Strength) versus time
revision of Practice E543 shall be specified in the contractual
curve.
agreement.
3.2.3 measured area of the rectified signal envelope
6.1.3 Procedure and Techniques—The procedures and tech-
(MARSE)—a measure of the area under the envelope of the
niques to be utilized shall be as specified in the contractual
rectified linear voltage time signal from the sensor. (seeASME
agreement.
Section V, Article 11)
6.1.4 Timing of Examination—The timing of examination
3.2.4 significant emission—a level of emission that corre-
shall be in accordance with 12.4 unless otherwise specified.
sponds to the first time during reloading that the historic index
6.1.5 Extent of Examination—The extent of examination
attains a value of 1.4.
shall be in accordance with Sections 9 and 10 unless otherwise
specified.
4. Summary of Practice
6.1.6 Reporting Criteria—Reporting criteria for the exami-
4.1 This practice uses acoustic emission instrumentation
nationresultsshallbeinaccordancewith15.1unlessotherwise
and examination techniques during load/reloading of materials
specified.
being examined, to determine the onset of significant acoustic
emission. The onset of significant emission is related to the
6,7 7. Apparatus
damage-based design stress by the Felicity ratio.
NOTE 1—Refer to Fig. 1 for AE system block diagram showing key
components of the AE system. It is recommended to use two AE sensors
5. Significance and Use
to monitor the specimen, evaluated on a per channel basis.
5.1 The damage-based design approach will permit an
7.1 AE Sensors
additional method of design for GFRPmaterials.This is a very
7.1.1 AE sensors shall be resonant in a 100 to 300 kHz
useful technique to determine the performance of different
frequency band.
types of resins and composition of GFRP materials in order to
7.1.2 Sensors shall have a peak sensitivity greater than –77
develop a damage tolerant and reliable design. This AE-based
dB (referred to 1 volt per microbar, determined by face-to-face
method is not unique, other damage-sensitive evaluation meth-
ultrasonic examination) within the frequency range 100 to 300
ods can also be used.
kHz.Sensitivitywithinthe100to300kHzrangeshallnotvary
5.2 This practice involves the use of acoustic emission
more than 3 dB within the temperature range of intended use.
instrumentation and examination techniques as a means of
7.1.3 Sensors shall be shielded against electromagnetic
damage detection to support a destructive test, in order to
interference through proper design practice or differential
derive the damage-based design stress.
(anti-coincidence) element design, or both.
5.3 This practice is not intended as a definitive predictor of
7.1.4 Sensors shall have omni-directional response, with
long-term performance of GFRP materials (such as those used
variations not exceeding 2 dB from the peak response.
in vessels). For this reason, codes and standards require cyclic
7.2 Couplant
prooftestingofprototypes(forexample,vessels)whicharenot
7.2.1 Commercially available couplants for ultrasonic flaw
a part of this practice.
detection may be used. Silicone-based high-vacuum grease has
5.4 Other design methods exist and are permitted.
been found to be particularly suitable. Adhesives may also be
used.
6. Basis of Application
7.2.2 Couplant selection should be made to minimize
6.1 The following items are subject to contractual agree-
changesincouplingsensitivityduringacompleteexamination.
ment between the parties using or referencing this practice:
Consideration should be given to the time duration of the
6.1.1 Personnel Qualification—If specified in the contrac-
examination and maintaining consistency of coupling through-
tual agreement, personnel performing examinations to this
out the examination.
practice shall be qualified in accordance with a nationally or
7.3 Sensor-Preamplifier Cable
internationally recognized NDT personnel qualification prac-
tice or standard such as ANSI/ASNT-CP-189, SNT-TC-1A, 7.3.1 The cable connecting the sensor to the preamplifier
NAS-410, or a similar document and certified by the employer shall not attenuate the sensor peak voltage in the 100 to 300
or certifying agency, as applicable. The practice or standard kHz frequency range more than 3 dB (6 ft (1.8 m) is a typical
length). Integral preamplifier sensors meet this requirement.
They have inherently short, internal, signal cables.
Ramirez, G., Ziehl, P., Fowler, T., 2004, “Nondestructive Evaluation of FRP
7.3.2 Thesensor-preamplifiercableshallbeshieldedagainst
Design Criteria with Primary Consideration to Fatigue Loading”, ASME Journal of
electromagnetic interference. Standard low-noise coaxial cable
Pressure Vessel Technology, Vol. 126, pp. 1–13.
Ziehl, P. and Fowler, T., 2003, “Fiber Reinforced Polymer Vessel Design with
is generally adequate.
a Damage Approach”, Journal of Composite Structures, Vol. 61, Issue 4, pp.
395-411. 7.4 Preamplifier
E2478 − 11 (2022)
FIG. 1 AE System Block Diagram
7.4.1 The preamplifier shall have a noise level no greater 7.7.2 Electroniccircuitryshallbestablewithin 61dBinthe
thanfivemicrovoltsrms(referredtoashortedinput)withinthe temperature range 40 to 100°F (4 to 38°C).
100 to 300 kHz frequency range.
7.7.3 Threshold shall be accurate within 61 dB.
7.4.2 Preamplifier gain shall vary no more than 61dB
7.7.4 MARSE shall be measured on a per channel basis and
within the 100 to 300 kHz frequency band and temperature
shall have a resolution of 1 % of the value obtained from a one
range of use.
millisecond duration, 150 kHz sine burst having an amplitude
7.4.3 Preamplifiers shall be shielded from electromagnetic
25dBabovethedataanalysisthreshold.Usabledynamicrange
interference.
shall be a minimum of 40 dB.
7.4.4 Preamplifiers of differential design shall have a mini-
NOTE 2—Instead of MARSE, other AE feature parameters such as
mum of 40 dB common-mode rejection.
“Signal Strength” may be used.
7.4.5 Preamplifiers shall include a bandpass filter with a
minimum bandwidth of 100 kHz to 300 kHz. Note that the
7.7.5 Amplitude shall be measured in decibels referenced to
crystal resonant characteristics provide additional filtering as
0 dB as 1 microvolt at the preamplifier input. Usable system
does the bandpass filter in the signal conditioner.
dynamic range shall be a minimum of 60 dB with 1 dB
7.4.6 It is preferred that the preamplifier be mounted inside
resolution over the frequency band of 100 to 300 kHz, and the
the sensor housing.
temperature range of 40 to 100°F (4 to 38°C). Not more than
61 dB variation in peak detection accuracy shall be allowed
7.5 Power-Signal Cable
over the stated temperature range.
7.5.1 The cable and connectors that provide power to
preamplifiers, and that conduct amplified signals to the main 7.7.6 Hit duration (AE signal duration) shall be accurate to
processor, shall be shielded against electromagnetic interfer- 65 µs and is measured from the first threshold crossing to the
ence. Signal loss shall be less than 3 dB over the length of the last threshold crossing of the AE signal.
cable.
7.7.7 Hit arrival time shall be recorded globally for each
channel accurate to within one millisecond, minimum.
7.6 Power Supply
7.6.1 Astable,grounded,powersupplythatmeetsthesignal 7.7.8 The system deadtime of each channel of the system
processor manufacturer’s specification shall be used. shall be no greater than 200 µs.
7.7.9 The hit definition time shall be 400 µs.
7.7 Main Signal Processor
7.7.1 Themainprocessorshallhavecircuitrythroughwhich 7.7.10 The examination threshold shall be set at 40 dB
sensor data will be processed. It shall be capable of processing (depending on background noise of the system setup when
hits, hit arrival time, duration, counts, peak amplitude, and subjected to a constant load of 10 % or less of the estimated
MARSE (or similar AE feature parameters such as Signal failure load). Threshold should remain constant during the
Strength) on each channel. entire examination.
E2478 − 11 (2022)
8. Calibration and Verification 10.1.1 Flexural Specimens—The specimens shall be fabri-
cated as facing lamina on a random mat carrier. The random
8.1 Annual calibration and verification of AE sensors,
matcarriershallhave1.5oz(44.4mL)persquarefootchopped
preamplifiers (if applicable), signal processor, and AE elec-
orrandomfiber,shallbe0.25 60.063in.(6.35 61.6mm)and
tronic waveform generator (or simulator) should be performed.
shall be faced on each side with a minimum thickness of 0.063
Equipmentshouldbeadjustedsothatitconformstoequipment
in. (1.6 mm) of the lamina to be evaluated.
manufacturer’s specifications. Instruments used for calibra-
10.1.2 Shear Specimens—Thespecimensshallbeentirelyof
tions must have current accuracy certification that is traceable
the lamina construction being evaluated. For a lamina with
to the National Institute for Standards and Technology (NIST).
unidirectional fibers, specimens shall be prepared and evalu-
8.2 Routine electronic evaluations must be performed any
atedwiththeloadappliedinboththedirectionofthefibersand
time there is concern about signal processor performance. An
perpendicular to the fibers.
AEelectronicwaveformgeneratororsimulator,shouldbeused
in making evaluations. Each signal processor channel must
11. Examination Temperature
respond with peak amplitude reading within 62dBofthe
11.1 For applications with a design operating temperature
electronic waveform generator output.
between 0°F (-18°C) and 120°F (49°C), the temperature of the
8.3 A system performance verification must be conducted
examination shall be within the range of 0°F (-
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