ASTM D7249/D7249M-16e1
(Test Method)Standard Test Method for Facing Properties of Sandwich Constructions by Long Beam Flexure
Standard Test Method for Facing Properties of Sandwich Constructions by Long Beam Flexure
SIGNIFICANCE AND USE
5.1 Flexure tests on flat sandwich construction may be conducted to determine the sandwich flexural stiffness, the core shear strength, and shear modulus, or the facings’ compressive and tensile strengths. Tests to evaluate core shear strength may also be used to evaluate core-to-facing bonds.
5.2 This test method is limited to obtaining the strength and stiffness of the sandwich panel facings, and to obtaining load-deflection data for use in calculating sandwich beam flexural and shear stiffness using Standard Practice D7250/D7250M. Due to the curvature of the flexural test specimen when loaded, facesheet compression strength from this test may not be equivalent to the facesheet compression strength of sandwich structures subjected to pure edgewise (in-plane) compression.
5.3 Core shear strength and shear modulus are best determined in accordance with Test Method C273 provided bare core material is available. Test Method C393 may also be used to determine core shear strength. Standard Practice D7250/D7250M may be used to calculate the flexural and shear stiffness of sandwich beams.
5.4 This test method can be used to produce facing strength data for structural design allowables, material specifications, and research and development applications; it may also be used as a quality control test for bonded sandwich panels.
5.5 Factors that influence the facing strength and shall therefore be reported include the following: facing material, core material, adhesive material, methods of material fabrication, facing stacking sequence and overall thickness, core geometry (cell size), core density, adhesive thickness, specimen geometry, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, speed of testing, facing void content, adhesive void content, and facing volume percent reinforcement. Further, facing strength may be different between precured/bonded and co-cured facesheets of the same material.
Note 2: ...
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.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: D7249/D7249M − 16
Standard Test Method for
Facing Properties of Sandwich Constructions by Long
1
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.
1
ε NOTE—Equation 4 was corrected editorially in April 2017.
1. Scope 2. Referenced Documents
2
1.1 This test method covers determination of facing prop- 2.1 ASTM Standards:
erties of flat sandwich constructions subjected to flexure in
C393Test Method for Flexural Properties of Sandwich
such a manner that the applied moments produce curvature of Constructions
the sandwich facing planes and result in compressive and
D3878Terminology for Composite Materials
tensile forces in the facings. Permissible core material forms D5229/D5229MTestMethodforMoistureAbsorptionProp-
include those with continuous bonding surfaces (such as balsa
erties and Equilibrium Conditioning of Polymer Matrix
wood and foams) as well as those with discontinuous bonding Composite Materials
surfaces (such as honeycomb).
D5467/D5467MTest Method for Compressive Properties of
Unidirectional Polymer Matrix Composite Materials Us-
1.2 The values stated in either SI units or inch-pound units
ing a Sandwich Beam
are to be regarded separately as standard. The values stated in
D7250/D7250MPractice for Determining Sandwich Beam
each system may not be exact equivalents; therefore, each
Flexural and Shear Stiffness
system shall be used independently of the other. Combining
E6Terminology Relating to Methods of Mechanical Testing
values from the two systems may result in non-conformance
E122PracticeforCalculatingSampleSizetoEstimate,With
with the standard.
Specified Precision, the Average for a Characteristic of a
1.2.1 Within the text, the inch-pound units are shown in
Lot or Process
brackets.
E177Practice for Use of the Terms Precision and Bias in
1.3 This standard does not purport to address all of the ASTM Test Methods
safety concerns, if any, associated with its use. It is the E251Test Methods for Performance Characteristics of Me-
responsibility of the user of this standard to establish appro- tallic Bonded Resistance Strain Gages
priate safety and health practices and determine the applica- E456Terminology Relating to Quality and Statistics
bility of regulatory limitations prior to use.
3. Terminology
NOTE 1—Alternate procedures for determining the compressive
strength of unidirectional polymer matrix composites materials in a
3.1 Definitions—Terminology D3878 defines terms relating
sandwich beam configuration may be found in Test Method D5467/
to high-modulus fibers and their composites. Terminology E6
D5467M.
definestermsrelatingtomechanicaltesting.TerminologyE456
1.4 This international standard was developed in accor-
and Practice E177 define terms relating to statistics. In the
dance with internationally recognized principles on standard-
event of a conflict between terms, Terminology D3878 shall
ization established in the Decision on Principles for the
have precedence over the other terminologies.
Development of International Standards, Guides and Recom-
3.2 Symbols:
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
b = specimen width
c = core thickness
1
This test method is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
2
Sandwich Construction. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJuly1,2016.PublishedJuly2016.Originallyapproved contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in 2006. Last previous edition approved in 2012 as D7249/D7249M–12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7249_D7249M-16E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
´1
D7249/D7249M − 16
CV = coefficient of variation statistic of a sample popu-
lation for a given property (in percent)
1
---------------------- Page: 2 ----------------------
´1
D7249/D7249M − 16
D7250M may be used to calculate the flexural and shear
d = sandwich total thickness
F,nom
stiffness of sandwich beams.
D = effective sandwich flexural stiffness
f
E = effective facing chord modulus
5.4 This test method can be used to produce facing strength
ε = measuring strain in facing
data for structural design allowables, material specifications,
u
F = facing ultimat
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D7249/D7249M − 16 D7249/D7249M − 16
Standard Test Method for
Facing Properties of Sandwich Constructions by Long
1
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.
1
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
2
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
1
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.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
´1
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
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.