ASTM E2982-14
(Guide)Standard Guide for Nondestructive Testing of Thin-Walled Metallic Liners in Filament-Wound Pressure Vessels Used in Aerospace Applications
Standard Guide for Nondestructive Testing of Thin-Walled Metallic Liners in Filament-Wound Pressure Vessels Used in Aerospace Applications
SIGNIFICANCE AND USE
4.1 The COPVs covered in this guide consist of a metallic liner overwrapped with high-strength fibers embedded in polymeric matrix resin (typically a thermoset). Metallic liners may be spun formed from a deep drawn/extruded monolithic blank or may be fabricated by welding formed components. Designers often seek to minimize the liner thickness in the interest of weight reduction. COPV liner materials used can be aluminum alloys, titanium alloys, nickel-chromium alloys, and stainless steels, impermeable polymer liner such as high density polyethylene, or integrated composite materials. Fiber materials can be carbon, aramid, glass, PBO, metals, or hybrids (two or more types of fiber). Matrix resins include epoxies, cyanate esters, polyurethanes, phenolic resins, polyimides (including bismaleimides), polyamides and other high performance polymers. Common bond line adhesives are; FM-73, urethane, West 105, Epon 862 with thicknesses ranging from 0.13 mm (0.005 in.) to 0.38 mm (0.015 in.). Metal liner and composite overwrap materials requirements are found in ANSI/AIAA S-080 and ANSI/AIAA S-081, respectively. Pictures of representative COPVs are shown in E07’s forthcoming Guide for Nondestructive Testing of Composite Overwraps in Filament-Wound Pressure Vessels Used in Aerospace Applications.
4.2 The operative failure modes COPV metal liners and metal PVs, in approximate order of likelihood, are: (a) fatigue cracking, (b) buckling, (c) corrosion, (d) environmental cracking, and (e) overload.
Note 2: For launch vehicles and satellites, the strong drive to reduce weight has pushed designers to adopt COPVs with thinner metal liners. Unfortunately, this configuration is more susceptible to liner buckling. So, as a precursor to liner fatigue, attention should be paid to liner buckling.
4.3 Per MIL-HDBK-340, the primary intended function of COPVs as discussed in this guide will be to store pressurized gases and fluids where one or more of the following apply:
4.3.1 Co...
SCOPE
1.1 This guide discusses current and potential nondestructive testing (NDT) procedures for finding indications of discontinuities in thin-walled metallic liners in filament-wound pressure vessels, also known as composite overwrapped pressure vessels (COPVs). In general, these vessels have metallic liner thicknesses less than 2.3 mm (0.090 in.), and fiber loadings in the composite overwrap greater than 60 percent by weight. In COPVs, the composite overwrap thickness will be of the order of 2.0 mm (0.080 in.) for smaller vessels, and up to 20 mm (0.80 in.) for larger ones.
1.2 This guide focuses on COPVs with nonload sharing metallic liners used at ambient temperature, which most closely represents a Compressed Gas Association (CGA) Type III metal-lined COPV. However, it also has relevance to (1) monolithic metallic pressure vessels (PVs) (CGA Type I), and (2) metal-lined hoop-wrapped COPVs (CGA Type II).
1.3 The vessels covered by this guide are used in aerospace applications; therefore, the examination requirements for discontinuities and inspection points will in general be different and more stringent than for vessels used in non-aerospace applications.
1.4 This guide applies to (1) low pressure COPVs and PVs used for storing aerospace media at maximum allowable working pressures (MAWPs) up to 3.5 MPa (500 psia) and volumes up to 2 m3 (70 ft3), and (2) high pressure COPVs used for storing compressed gases at MAWPs up to 70 MPa (10,000 psia) and volumes down to 8000 cm3 (500 in.3). Internal vacuum storage or exposure is not considered appropriate for any vessel size.
1.5 The metallic liners under consideration include but are not limited to ones made from aluminum alloys, titanium alloys, nickel-based alloys, and stainless steels. In the case of COPVs, the composites through which the NDT interrogation must be made after overwrapping include, but are not limited to, various polymer matrix resins (for example...
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Designation: E2982 − 14
Standard Guide for
Nondestructive Testing of Thin-Walled Metallic Liners in
Filament-Wound Pressure Vessels Used in Aerospace
1
Applications
This standard is issued under the fixed designation E2982; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope must be made after overwrapping include, but are not limited
to, various polymer matrix resins (for example, epoxies,
1.1 This guide discusses current and potential nondestruc-
cyanate esters, polyurethanes, phenolic resins, polyimides
tive testing (NDT) procedures for finding indications of dis-
(including bismaleimides), polyamides) with continuous fiber
continuities in thin-walled metallic liners in filament-wound
reinforcement (for example, carbon, aramid, glass, or poly-
pressure vessels, also known as composite overwrapped pres-
(phenylenebenzobisoxazole) (PBO)).
sure vessels (COPVs). In general, these vessels have metallic
liner thicknesses less than 2.3 mm (0.090 in.), and fiber
1.6 ThisguidedescribestheapplicationofestablishedNDT
loadings in the composite overwrap greater than 60 percent by
procedures; namely,Acoustic Emission (AE, Section 7), Eddy
weight. In COPVs, the composite overwrap thickness will be
Current Testing (ECT, Section 8), Laser Profilometry (LP,
of the order of 2.0 mm (0.080 in.) for smaller vessels, and up
Section 9), Leak Testing (LT, Section 10), Penetrant Testing
to 20 mm (0.80 in.) for larger ones.
(PT, Section 11), and Radiologic Testing (RT, Section 12).
These procedures can be used by cognizant engineering
1.2 This guide focuses on COPVs with nonload sharing
organizations for detecting and evaluating flaws, defects, and
metallic liners used at ambient temperature, which most
accumulateddamageinmetallicPVs,thebaremetalliclinerof
closely represents a Compressed GasAssociation (CGA) Type
COPVsbeforeoverwrapping,andthemetalliclinerofnewand
III metal-lined COPV. However, it also has relevance to (1)
in-service COPVs.
monolithic metallic pressure vessels (PVs) (CGAType I), and
(2) metal-lined hoop-wrapped COPVs (CGAType II).
1.7 Due to difficulties associated with inspecting thin-
1.3 The vessels covered by this guide are used in aerospace walled metallic COPV liners through composite overwraps,
applications; therefore, the examination requirements for dis- andtheavailabilityoftheNDEmethodslistedinSection1.6to
continuities and inspection points will in general be different inspect COPV liners before overwrapping and metal PVs,
and more stringent than for vessels used in non-aerospace ultrasonic testing (UT) is not addressed in this standard. UT
applications. may still be performed as agreed upon between the supplier
and customer. Ultrasonic requirements may utilize Practice
1.4 This guide applies to (1) low pressure COPVs and PVs
E2375 as applicable based upon the specific liner application
used for storing aerospace media at maximum allowable
and metal thickness. Alternate ultrasonic inspection methods
working pressures (MAWPs) up to 3.5 MPa (500 psia) and
3 3 such as Lamb wave, surface wave, shear wave, reflector plate,
volumesupto2m (70ft ),and (2)highpressureCOPVsused
etc. may be established and documented per agreed upon
forstoringcompressedgasesatMAWPsupto70MPa(10,000
3 3 contractual requirements. The test requirements should be
psia) and volumes down to 8000 cm (500 in. ). Internal
developed in conjunction with the specific criteria defined by
vacuum storage or exposure is not considered appropriate for
engineering analysis.
any vessel size.
1.8 In general, AE and PT are performed on the PV or the
1.5 The metallic liners under consideration include but are
baremetalliclinerofaCOPVbeforeoverwrapping(inthecase
not limited to ones made from aluminum alloys, titanium
of COPVs, AE is done before overwrapping to minimize
alloys, nickel-based alloys, and stainless steels. In the case of
interferencefromthecompositeoverwrap).ET,LT,andRTare
COPVs, the composites through which the NDT interrogation
performed on the PV, bare metallic liner of a COPV before
overwrapping, or on the as-manufactured COPV. LP is per-
1
This test method is under the jurisdiction of ASTM Committee E07 on
formed on the inner and outer surfaces of the PV, or on the
Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on
inner surface of the COPV liner both before and after over-
Specialized NDT Methods.
wrapping. Furthermore, AE and RT are well suited for evalu-
Current edition approved Oct. 1, 2014. Published November 2014. DOI:
10.1520/E2982-14. ating the weld integrity of welded PVs and COPV liners.
Copyrigh
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