ASTM D6264-98
(Test Method)Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer-Matrix Composite to a Concentrated Quasi-Static Indentation Force
Standard Test Method for Measuring the Damage Resistance of a Fiber-Reinforced Polymer-Matrix Composite to a Concentrated Quasi-Static Indentation Force
SCOPE
1.1 A quasi-static indentation (QSI) test method is used to obtain quantitative measurements of the damage resistance of a continuous-fiber-reinforced composite material to a concentrated indentation force (Fig. 1). The indentation force is applied to the specimen by slowly pressing a hemispherical indenter into the surface. Procedures are specified for determining the damage resistance for a simply supported test specimen and for a rigidly backed test specimen. The damage resistance is quantified in terms of a critical contact force associated with a single event or sequence of events to cause a specific size and type fo damage in the specimen. These tests may be used to screen materials for damage resistance or to inflict damage into a specimen for subsequent damage tolerance testing. This test method is limited to use with composites consisting of layers of unidirectional fibers or layers of fabric. This test method may prove useful for other types and classes of composite materials. Certain interferences, however, have been noted (see 6.7).
1.2 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.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information purposes only.
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Designation: D 6264 – 98
Standard Test Method for
Measuring the Damage Resistance of a Fiber-Reinforced
Polymer-Matrix Composite to a Concentrated Quasi-Static
Indentation Force
This standard is issued under the fixed designation D 6264; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 A quasi-static indentation (QSI) test method is used to
obtain quantitative measurements of the damage resistance of
a continuous-fiber-reinforced composite material to a concen-
trated indentation force (Fig. 1). The indentation force is
applied to the specimen by slowly pressing a hemispherical
indenter into the surface. Procedures are specified for deter-
mining the damage resistance for a simply supported test
specimen and for a rigidly backed test specimen. The damage
resistance is quantified in terms of a critical contact force
associated with a single event or sequence of events to cause a
specific size and type of damage in the specimen. These tests
may be used to screen materials for damage resistance or to
inflict damage into a specimen for subsequent damage toler-
FIG. 1 Quasi-Static Indentation Test
ance testing. This test method is limited to use with composites
consisting of layers of unidirectional fibers or layers of fabric.
This test method may prove useful for other types and classes
posites by Matrix Digestion
of composite materials. Certain interferences, however, have
D 3878 Terminology of High-Modulus Reinforcing Fibers
been noted (see 6.7).
and Their Composites
1.2 This standard does not purport to address all of the
D 5229/D5229M Test Method for Moisture Absorption
safety concerns, if any, associated with its use. It is the
Properties and Equilibrium Conditioning of Polymer Ma-
responsibility of the user of this standard to establish appro-
trix Composite Materials
priate safety and health practices and determine the applica-
D 5687/D5687M Guide for Preparation of Flat Composite
bility of regulatory limitations prior to use.
Panels With Processing Guidelines for Specimen Prepara-
1.3 The values stated in SI units are to be regarded as
tion
standard. The values given in parentheses are provided for
E 4 Practices for Force Verification of Testing Machines
information purposes only.
E 6 Terminology Relating to Methods of Mechanical Test-
ing
2. Referenced Documents
E 18 Test Methods for Rockwell Hardness and Rockwell
2.1 ASTM Standards:
Superficial Hardness of Metallic Materials
D 883 Terminology Relating to Plastics
E 122 Practice for Choice of Sample Size to Estimate a
D 2734 Test Methods for Void Content of Reinforced Plas-
Measure of Quality for a Lot or Process
tics
3. Terminology
D 3171 Practice for Fiber Content of Resin Matrix Com-
3.1 Definitions—Terminology D 3878 defines terms relating
to high-modulus fibers and their composites. Terminology
This standard is under the jurisdiction of ASTM Committee D-30 on Composite
Materials and is the direct responsibility of Subcommittee D30.05 on Structural Test
Methods.
Current edition approved June 10, 1998. Published July 1998. Annual Book of ASTM Standards, Vol 15.03.
2 5
Annual Book of ASTM Standards, Vol 08.01. Annual Book of ASTM Standards, Vol 03.01.
3 6
Annual Book of ASTM Standards, Vol 08.02. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6264–98
D 883 defines terms relating to plastics. Terminology E 6 test specimen and for a rigidly backed test specimen. The
defines terms relating to mechanical testing. In the event of a damage response is a function of the test configuration.
conflict between terms, Terminology D 3878 shall have prece-
4.2 A record of the applied contact force/indenter displace-
dence over the other standards.
ment (F/d) is recorded on either an X-Y recorder, an equivalent
3.2 Definitions of Terms Specific to This Standard—The
real-time plotting device, or stored digitally and postprocessed.
terms in this test method may conflict with general usage.
There is not yet an established consensus concerning the use of
5. Significance and Use
these terms. The following descriptions are intended only for
5.1 Susceptibility to damage from concentrated indentation
use in this test method.
forces is one of the major weaknesses of many structures made
NOTE 1—If the term represents a physical quantity, its analytical of advanced laminated composites. Knowledge of the damage
dimensions are stated immediately following the term (or letter symbol) in
resistance of a laminated composite material subjected to a
fundamental dimension form, using the following ASTM standard sym-
concentrated indentation force is useful for product develop-
bology for fundamental dimensions shown within square brackets: [M] for
ment and material selection.
mass, [L] for length, [T] for time, [u] for thermodynamic temperature, and
5.2 The QSI test method can serve the following purposes:
[nd] for nondimensional quantities. Use of these symbols is restricted to
analytical dimensions when used with square brackets, as the symbols 5.2.1 To establish quantitatively the effects of stacking
may have other definitions when used without the brackets.
sequence, fiber surface treatment, variations in fiber volume
−2
fraction, and processing and environmental variables on the
3.2.1 contact force, F [MLT ],n—the total force applied
damage resistance of a particular composite laminate to a
normal to the face of the specimen by the indenter.
concentrated quasi-static indentation force.
3.2.2 damage, n—in structures and structural materials,a
structural anomaly in a material or structure created by 5.2.2 To compare quantitatively the relative values of the
manufacturing or service usage. damage resistance parameters for composite materials with
3.2.3 damage resistance, n— in structures and structural different constituents. The damage response parameters include
materials, a measure of the relationship between the force, d, F , and F , as well as the F/d curve.
1 max
energy, or other parameter(s) associated with an event or
5.2.3 To place a controlled amount of damage in a specimen
sequence of events and the resulting damage size and type.
for subsequent damage tolerance tests.
3.2.4 dent depth, d [L],n—residual depth of the depression
5.2.4 To isolate and measure the indentation response of the
formed by an indenter after removal of load. The dent depth
specimen without bending (rigidly backed configuration).
shall be defined as the maximum distance in a direction normal
to the face of the specimen from the lowest point in the dent to
6. Interferences
the plane of the indented surface that is undisturbed by the
6.1 The QSI test simulates the force/displacement relation-
dent.
ships of many impacts governed by boundary conditions (1-7).
−2
3.2.5 F force, F [ MLT ],n—contact force at which the
1 1
These are typically relatively large-mass low-velocity hard-
force/indenter displacement curve has a discontinuity in force
body impacts on plates with a relatively small unsupported
or slope.
region. This test method does not address wave propagation
3.2.6 indenter displacement, d [L],n— the displacement of
and vibrations in the specimen, time-dependent material be-
the indenter relative to the specimen support.
havior, or inertia-dominated impact events.
−2
3.2.7 maximum force, F [MLT ],n—the maximum
max
6.2 The damage response of a specimen is dependent on
contact force a laminate will resist. This force is obtained from
many factors, including the indenter geometry and specimen
the F/d curve after a point is reached where the contact force
support conditions. Consequently, comparisons cannot be
does not increase with increasing indenter displacement.
made between materials unless identical test configurations,
3.3 Symbols:
identical test conditions, and identical laminates are used.
Therefore, all deviations from the standard test configuration
d = dent depth (see 3.2.4). should be reported in the results.
F = contact force (see 3.2.1).
6.3 Force F does not represent the initiation of damage, but
F = F force (see 3.2.5).
1 1 generally represents when the displacement of the indenter is
F = maximum force (see 3.2.7).
max
affected by large-scale damage formation. Typically, matrix
N = number of ply groups in a laminate’s stacking
cracks and small delaminations form before this force.
sequence.
6.4 The dent depth may “relax” or reduce with time or upon
d = indenter displacement (see 3.2.6).
exposure to different environmental conditions.
4. Summary of Test Method
6.5 Treatment and interpretation of delamination growth are
beyond the scope of this test method.
4.1 The quasi-static indentation (QSI) test is used to mea-
6.6 Material and Specimen Preparation— Poor material
sure the damage resistance of a uniform-thickness laminated
fabrication practices, lack of control of fiber alignment, and
composite specimen. An indentation force is applied slowly by
damage induced by improper coupon machining are known
pressing a displacement-controlled hemispherical indenter into
causes of high material data scatter in composites.
the face of the specimen. The displacement is increased until
the desired damage state is reached. Procedures are specified 6.7 Application to Other Materials, Lay-Ups, and Architec-
for determining the damage resistance for a simply supported tures:
D6264–98
6.7.1 The QSI test primarily has been used for testing 7.5 Load Versus Indenter Displacement (F Versus d)
carbon-fiber-reinforced tape and fabric laminates with polymer Record—An X-Y plotter, or similar device, shall be used to
matrices. For other materials, a quite different response may make a permanent record during the test of load versus indenter
occur. displacement. Alternatively, the data may be stored digitally
and postprocessed.
6.7.2 Nonlaminated, 3D fiber-reinforced, or textile compos-
ites may fail by different mechanisms than laminates. The most 7.6 Specimen Support—The damage resistance may be
determined for a specimen that is simply supported or rigidly
critical damage may be in the form of matrix cracking or fiber
failure, or both, rather than delaminations. backed. For both configurations, the specimen’s face shall be
held normal to the axis of the indenter.
7.6.1 Simply Supported Configuration— The fixture shall
7. Apparatus
consist of a single plate with a 127.0 6 2.5 mm (5.006 0.10
7.1 Testing Machine—The testing machine shall be in
in.) diameter opening made from a structural metal such as
conformance with Practices E 4 and shall satisfy the following
aluminum or steel. The top rim of the opening shall be rounded
requirements:
with a radius of 0.756 0.25 mm (0.03 6 0.01 in.). The plate
7.1.1 Testing Machine Heads—The testing machine shall
shall be sufficiently large to support the entire lower surface of
have both an essentially stationary head and a movable head.
the specimen, excluding the circular opening. The thickness of
7.1.2 Drive Mechanism—The testing machine drive mecha-
the plate shall be a minimum of 25 mm (1.0 in.) and greater
nism shall be capable of imparting to the movable head a
than the expected maximum indenter displacement. A typical
controlled velocity with respect to the stationary head. The
support fixture is shown in Fig. 2.
velocity of the movable head shall be capable of being
7.6.2 Rigidly Backed Configuration—The specimen shall be
regulated as specified in 11.6.
placed directly on the flat rigid support that is mounted in the
7.1.3 Load Indicator—The testing machine load-sensing
lower head of the testing machine. For this configuration, the
device shall be capable of indicating the total load being
support shall be made from steel with a minimum thickness of
carried by the test specimen. This device essentially shall be
12.7 mm (0.5 in.).
free from inertia lag at the specified rate of testing and shall
7.7 Micrometers—The micrometer(s) shall use a suitable
indicate the load with an accuracy over the load range(s) of
size diameter ball-interface on irregular surfaces such as the
interest of within 61 % of the indicated value.
bag-side of a laminate, and a flat anvil interface on machined
7.1.4 Grips—The top head of the testing machine shall
or very smooth tooled surfaces. The accuracy of the instru-
carry a grip to hold the indenter such that the direction of load
ments shall be suitable for reading to within 1 % of the sample
applied to the specimen is coincident with the axis of travel.
width and thickness. For typical specimen geometries, an
The grip shall apply sufficient pressure to prevent slippage of
instrument with an accuracy of 62.5 μm [60.0001 in.] is
the indenter. The lower head shall have a means of attaching a
desirable for thickness measurement, while an instrument with
flat rigid support.
an accuracy of 625 μm [60.001 in.] is desirable for width
7.2 Flat Rigid Support—A flat rigid surface shall be at-
measurement.
tached to the lower head and used to support the specimen or
7.8 Dent Depth Indicator—The dent depth can be measured
test fixture. The support surface shall be normal to the axis of
using a dial depth gage, a depth gage micrometer, or a properly
travel of the testing machine head and have a large enough
calibrated displacement transducer. The measuring probe shall
surface to support completely the specimen or test fixture. A
have a hemispherical tip with a diameter between 1.5 and 5.0
convenient means of providing this surface is through the use
mm (0.06–0.20 in.). An instrument with an accuracy of 625
of a metal “T” in which the lower part of the“ T” is clamped in
μm [60.001 in.] is desirable for depth measurement.
the lower grips and the top part of the “T” provides the support
8. Sampling and Test Specimens
surface. If the rigidly backed configuration is to be used, this
support shall be made from steel with a minimum thickness of
8.1 Sampling—Test at least five specimens per condition,
12.7 mm (0.5 in.).
unless valid results can be gained through the use of fewer
7.3 Indenter—The indenter shall have a smooth hemispheri-
specimens, such as in the case of a designed experiment. For
cal tip with a diameter of 12.7 6 0.1 mm (0.5006 0.003 in.)
statistically significant data, the procedures outlined in Practice
and a hardness of 60 to 62 HRC as specified in Test Methods E 122 should be consulted. Report the method of sampling.
E 18. If a different indenter is used as part of the testing, the
8.2 Specimen Lay-Up—The laminate
...
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