ASTM C271/C271M-16(2022)e1
(Test Method)Standard Test Method for Density of Sandwich Core Materials
Standard Test Method for Density of Sandwich Core Materials
SIGNIFICANCE AND USE
5.1 Density is a fundamental physical property that can be used in conjunction with other properties to characterize the sandwich core. Most sandwich core structural properties, such as strength and stiffness, are proportional to the density.
5.2 This test method provides a standard method of obtaining sandwich core density data for design properties, material specifications, research and development applications, and quality assurance.
5.3 Factors that influence the density and shall therefore be reported include the following: core material, methods of material fabrication, core geometry (nominal cell size), specimen geometry, specimen preparation, methods of weight and dimensional measurement, specimen conditioning, and moisture content during weight and dimensional measurements.
SCOPE
1.1 This test method covers the determination of the density of sandwich construction core materials. Permissible core material forms include those with continuous bonding surfaces (such as balsa wood and foams) as well as those with discontinuous bonding surfaces (such as honeycomb).
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.2.1 Within the text, the inch-pound units are shown in brackets.
1.3 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.
1.4 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
Relations
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.
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Designation: C271/C271M − 16 (Reapproved 2022)
Standard Test Method for
Density of Sandwich Core Materials
This standard is issued under the fixed designation C271/C271M; 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.
ε NOTE—Editorial corrections were made in Section 1 in May 2022.
1. Scope Composite Materials
E122 Practice for Calculating Sample Size to Estimate,With
1.1 This test method covers the determination of the density
Specified Precision, the Average for a Characteristic of a
of sandwich construction core materials. Permissible core
Lot or Process
material forms include those with continuous bonding surfaces
E171 Practice for Conditioning and Testing Flexible Barrier
(such as balsa wood and foams) as well as those with
Packaging
discontinuous bonding surfaces (such as honeycomb).
E177 Practice for Use of the Terms Precision and Bias in
1.2 Units—The values stated in either SI units or inch-
ASTM Test Methods
pound units are to be regarded separately as standard. The
E456 Terminology Relating to Quality and Statistics
values stated in each system are not necessarily exact equiva-
lents; therefore, to ensure conformance with the standard, each
3. Terminology
system shall be used independently of the other, and values
3.1 Definitions—Terminology D3878 defines terms relating
from the two systems shall not be combined.
to high-modulus fibers and their composites, as well as terms
1.2.1 Within the text, the inch-pound units are shown in
relating to sandwich constructions. Terminology D883 defines
brackets.
terms relating to plastics.Terminology E456 and Practice E177
1.3 This standard does not purport to address all of the
define terms relating to statistics. In the event of a conflict
safety concerns, if any, associated with its use. It is the
between terms, Terminology D3878 shall have precedence
responsibility of the user of this standard to establish appro-
over the other terminologies.
priate safety, health, and environmental practices and deter-
3.2 Symbols:
mine the applicability of regulatory limitations prior to use.
3.2.1 CV—coefficient of variation statistic of a sample
1.4 This international standard was developed in accor-
population for a given property (in percent)
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.2.2 d —density of a test specimen in inch-pound units
IP
Development of International Standards, Guides and Recom-
3.2.3 d —density of a test specimen in SI units
SI
mendations issued by the World Trade Organization Technical
3.2.4 l—length of a test specimen
Barriers to Trade (TBT) Committee.
3.2.5 S —standard deviation statistic of a sample popula-
n–1
2. Referenced Documents
tion for a given property
2.1 ASTM Standards: 3.2.6 t—thickness of a test specimen
D883 Terminology Relating to Plastics
3.2.7 x —test result for an individual specimen from the
i
D3878 Terminology for Composite Materials
sample population for a given property
D5229/D5229M Test Method for MoistureAbsorption Prop-
3.2.8 x¯—mean or average (estimate of mean) of a sample
erties and Equilibrium Conditioning of Polymer Matrix
population for a given property
3.2.9 w—width of a test specimen
This test method is under the jurisdiction of ASTM Committee D30 on
3.2.10 W—mass of a test specimen
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
Sandwich Construction.
Current edition approved May 1, 2022. Published May 2022. Originally
4. Summary of Test Method
approved in 1951. Last previous edition approved in 2016 as C271/C271M – 16.
DOI: 10.1520/C0271_C0271M-16R22E01.
4.1 This test method consists of environmentally condition-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ing a sandwich core specimen, weighing the specimen, mea-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
suring the length, width and thickness of the specimen, and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. calculating the density.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C271/C271M − 16 (2022)
5. Significance and Use 7.5 Gloves—Clean, non-linting gloves for use when han-
dling specimens.
5.1 Density is a fundamental physical property that can be
used in conjunction with other properties to characterize the
8. Sampling and Test Specimens
sandwich core. Most sandwich core structural properties, such
8.1 Sampling—Test at least five specimens per test condi-
as strength and stiffness, are proportional to the density.
tion unless valid results can be gained through the use of fewer
5.2 This test method provides a standard method of obtain-
specimens, as in the case of a designed experiment. For
ing sandwich core density data for design properties, material
statistically significant data, consult the procedures outlined in
specifications, research and development applications, and
Practice E122. Report the method of sampling.
quality assurance.
8.2 Geometry—Test specimens shall have a square or rect-
5.3 Factors that influence the density and shall therefore be
angular cross-section. The recommended minimum specimen
reported include the following: core material, methods of
size is 300 mm [12.0 in.] in length by 300 mm [12.0 in.] in
material fabrication, core geometry (nominal cell size), speci-
width, with the thickness equal to the sandwich core thickness.
men geometry, specimen preparation, methods of weight and
NOTE 1—The specimen’s cross-sectional area (length times width) is
dimensional measurement, specimen conditioning, and mois-
defined in the facing plane, in regard to the orientation that the core would
be placed in a structural sandwich construction. For example, for a
ture content during weight and dimensional measurements.
honeycomb core the cross-sectional area is defined in the plane of the
cells, which is perpendicular to the orientation of the cell walls.
6. Interferences
8.3 Specimen Preparation and Machining—Prepare the test
6.1 Material and Specimen Preparation—Poormaterialfab-
specimens so that the facing plane surfaces are parallel to each
rication practices and damage induced by improper specimen
other and perpendicular to the sides of the specimen. Take
machining are known causes of high data scatter in composites
precautions when cutting specimens from large sheets of core
and sandwich structures in general. Important aspects of
to avoid notches, undercuts, rough or uneven surfaces due to
sandwich core specimen preparation that contribute to data
inappropriate machining methods. Obtain final dimensions by
scatter include the existence of joints, voids or other core
lubricated precision sawing, milling, or grinding. The use of
discontinuities, out-of-plane curvature, and surface roughness.
diamond tooling has been found to be extremely effective for
manymaterialsystems.Recordandreportthespecimencutting
6.2 Geometry—Specific geometric factors that affect sand-
preparation method.
wich density measurement include uniformity of core cell
geometry and core thickness.
8.4 Labeling—Label the test specimens so that they will be
distinct from each other and traceable back to the sheet of
6.3 Environment—Resultsareaffectedbytheenvironmental
origin, and will neither influence the test nor be affected by it.
conditions under which specimens are conditioned, as well as
the conditions under which the tests are conducted. Specimens
9. Calibration
testedinvariousenvironments,withdifferentambientmoisture
contents, can exhibit significant differences in measured den-
9.1 The accuracy of all measuring equipment shall have
sity.
certified calibrations that are current at the time of use of the
equipment.
7. Apparatus
10. Conditioning
7.1 Oven or Vacuum Drying Chamber—An air-circulating
oven is required that shall be capable of maintaining the 10.1 The recommended pre-test condition is effective mois-
required uniform temperatures to within 63°C [65 °F]. A ture equilibrium as established by Test Method D5229/
vacuum drying chamber or a vacuum oven may also be used.
D5229M; however, if the test requestor does not explicitly
specify a pre-test conditioning environment, no conditioning is
7.2 Desiccator—Aclean, dry desiccator in which specimens
required and the test specimens may be tested as prepared.
being oven-dried shall be brought to laboratory tempera
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