ASTM D7249/D7249M-16e1

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of the standard as published by ASTM is to be considered the official document.
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Designation: D7249/D7249M − 16 D7249/D7249M − 16
Standard Test Method for
Facing Properties of Sandwich Constructions by Long
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Beam Flexure
This standard is issued under the fixed designation D7249/D7249M; 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.
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ε NOTE—Equation 4 was corrected editorially in April 2017.
1. Scope
1.1 This test method covers determination of facing properties of flat sandwich constructions subjected to flexure in such a
manner that the applied moments produce curvature of the sandwich facing planes and result in compressive and tensile forces in
the facings. 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 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—Alternate procedures for determining the compressive strength of unidirectional polymer matrix composites materials in a sandwich beam
configuration may be found in Test Method D5467/D5467M.
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.
2. Referenced Documents
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2.1 ASTM Standards:
C393 Test Method for Flexural Properties of Sandwich Constructions
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D5467/D5467M Test Method for Compressive Properties of Unidirectional Polymer Matrix Composite Materials Using a
Sandwich Beam
D7250/D7250M Practice for Determining Sandwich Beam Flexural and Shear Stiffness
E6 Terminology Relating to Methods of Mechanical Testing
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E251 Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
E456 Terminology Relating to Quality and Statistics
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This test method is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.09 on Sandwich
Construction.
Current edition approved July 1, 2016. Published July 2016. Originally approved in 2006. Last previous edition approved in 2012 as D7249/D7249M – 12. DOI:
10.1520/D7249_D7249M-16.10.1520/D7249_D7249M-16E01.
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volume information, refer to the standard’s Document Summary page on the ASTM website.
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D7249/D7249M − 16
3. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to high-modulus fibers and their composites. Terminology E6
defines terms relating to mechanical testing. Terminology E456 and Practice E177 define terms relating to statistics. In the event
of a conflict between terms, Terminology D3878 shall have precedence over the other terminologies.
3.2 Symbols:
b = specimen width
c = core thickness
CV = coefficient of variation statistic of a sample population for a given property (in percent)
d = sandwich total thickness
F,nom
D = effective sandwich flexural stiffness
f
E = effective facing chord modul
...