ASTM D6115-97(2011)
(Test Method)Standard Test Method for Mode I Fatigue Delamination Growth Onset of Unidirectional Fiber-Reinforced Polymer Matrix Composites
Standard Test Method for Mode I Fatigue Delamination Growth Onset of Unidirectional Fiber-Reinforced Polymer Matrix Composites
SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material’resistance to interlaminar fracture under fatigue loads is useful for product development and material selection. Furthermore, a measurement of the relationship of the mode I cyclic strain energy release rate and the number of cycles to delamination growth onset, G–N, that is independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on G–N of a particular composite material.
5.2.2 To compare quantitatively the relative values of G–N for composite materials with different constituents.
5.2.3 To develop criteria for avoiding the onset of delamination growth under fatigue loading for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method determines the number of cycles (N) for the onset of delamination growth based on the opening mode I cyclic strain energy release rate (G), using the Double Cantilever Beam (DCB) specimen shown in . This test method applies to constant amplitude, tension-tension fatigue loading of continuous fiber-reinforced composite materials. When this test method is applied to multiple specimens at various G-levels, the results may be shown as a G-N curve, as illustrated in Fig 2.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with single-phase polymer matrices. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials, however, certain interferences have been noted (see Section 6.5 of Test Method D 5528).
1.3 The values stated in SI units are to be regarded as standard. The values provided in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6115 − 97 (Reapproved 2011)
Standard Test Method for
Mode I Fatigue Delamination Growth Onset of Unidirectional
1
Fiber-Reinforced Polymer Matrix Composites
This standard is issued under the fixed designation D6115; 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 D2584 Test Method for Ignition Loss of Cured Reinforced
Resins
1.1 This test method determines the number of cycles (N)
D2651 GuideforPreparationofMetalSurfacesforAdhesive
for the onset of delamination growth based on the opening
Bonding
mode I cyclic strain energy release rate (G), using the Double
D2734 TestMethodsforVoidContentofReinforcedPlastics
Cantilever Beam (DCB) specimen shown in Fig. 1. This test
D3171 Test Methods for Constituent Content of Composite
method applies to constant amplitude, tension-tension fatigue
Materials
loading of continuous fiber-reinforced composite materials.
D3878 Terminology for Composite Materials
When this test method is applied to multiple specimens at
D5229/D5229M TestMethodforMoistureAbsorptionProp-
various G-levels, the results may be shown as a G–N curve, as
erties and Equilibrium Conditioning of Polymer Matrix
illustrated in Fig. 2.
Composite Materials
1.2 This test method is limited to use with composites
D5528 TestMethodforModeIInterlaminarFractureTough-
consisting of unidirectional carbon fiber tape laminates with
ness of Unidirectional Fiber-Reinforced Polymer Matrix
single-phase polymer matrices. This limited scope reflects the
Composites
experience gained in round robin testing.This test method may
E4 Practices for Force Verification of Testing Machines
proveusefulforothertypesandclassesofcompositematerials,
E6 Terminology Relating to Methods of Mechanical Testing
however,certaininterferenceshavebeennoted(seeSection6.5
E122 Practice for Calculating Sample Size to Estimate,With
of Test Method D5528).
Specified Precision, the Average for a Characteristic of a
1.3 The values stated in SI units are to be regarded as Lot or Process
E177 Practice for Use of the Terms Precision and Bias in
standard. No other units of measurement are included in this
standard. ASTM Test Methods
1.3.1 Exception—Thevaluesprovidedinparenthesesarefor E456 Terminology Relating to Quality and Statistics
E467 Practice for Verification of Constant Amplitude Dy-
information only.
namic Forces in an Axial Fatigue Testing System
1.4 This standard does not purport to address all of the
E691 Practice for Conducting an Interlaboratory Study to
safety concerns, if any, associated with its use. It is the
Determine the Precision of a Test Method
responsibility of the user of this standard to establish appro-
E739 PracticeforStatisticalAnalysisofLinearorLinearized
priate safety and health practices and determine the applica-
Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data
bility of regulatory limitations prior to use.
E1049 Practices for Cycle Counting in Fatigue Analysis
E1150 Definitions of Terms Relating to Fatigue (Withdrawn
2. Referenced Documents
3
1996)
2
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
3. Terminology
3.1 Terminology D3878 defines terms relating to high-
modulus fibers and their composites. Terminology D883 de-
1
This specification is under the jurisdiction of ASTM Committee D30 on
fines terms relating to plastics. Terminology E6 defines terms
Composite Materials and is the direct responsibility of Subcommittee D30.06 on
relating to mechanical testing. Terminology E456 and Practice
Interlaminar Properties.
Current edition approved Aug. 1, 2011. Published December 2011. Originally E177 define terms relating to statistics. Definitions E1150
approved in 1997. Last previous edition approved in 2004 as D6115 – 97 (2004).
defines terms relating to fatigue. In the event of conflict
DOI: 10.1520/D6115-97R11.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
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D6115 − 97 (2011)
3.3.10 G —opening mode I interlaminar fracture tough-
Ic
ness.
3.3.11 [G ] —average values of G from the quasi-static
Ic av Ic
tests.
3.3.12 G —maximum or peak cyclic mode I strain en-
Imax
ergy release rate.
3.3.13 G–N—relationship between the cyclic strain energy
release rat
...
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