ASTM C393/C393M-20
(Test Method)Standard Test Method for Core Shear Properties of Sandwich Constructions by Beam Flexure
Standard Test Method for Core Shear Properties of Sandwich Constructions by 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 core shear strength or core-to-facing shear strength and the stiffness of the sandwich beam, and to obtaining load-deflection data for use in calculating sandwich beam flexural and shear stiffness using Practice D7250/D7250M.
Note 1: Core shear strength and shear modulus are best determined in accordance with Test Method C273, provided bare core material is available.
5.3 Facing strength is best determined in accordance with Test Method D7249/D7249M.
5.4 Practice D7250/D7250M covers the determination of sandwich flexural and shear stiffness and core shear modulus using calculations involving measured deflections of sandwich flexure specimens.
5.5 This test method can be used to produce core shear strength and core-to-facing shear 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.
5.6 Factors that influence the shear strength and shall therefore be reported include the following: facing material, core material, adhesive material, methods of material fabrication, core geometry (cell size), core density, adhesive thickness, specimen geometry, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, speed of testing, and adhesive void content. Further, core-to-facing strength may be different between precured/bonded and co-cured facings in sandwich panels with the same core and facing material.
Note 2: Concentrated loads on beams with thin facings and low density cores can produce results that are difficult to interpret, especial...
SCOPE
1.1 This test method covers determination of the core shear properties of flat sandwich constructions subjected to flexure in such a manner that the applied moments produce curvature of the sandwich facing planes. 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.
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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.
Designation: C393/C393M − 20
Standard Test Method for
Core Shear Properties of Sandwich Constructions by Beam
1
Flexure
This standard is issued under the fixed designation C393/C393M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope C273 Test Method for Shear Properties of Sandwich Core
Materials
1.1 This test method covers determination of the core shear
D883 Terminology Relating to Plastics
propertiesofflatsandwichconstructionssubjectedtoflexurein
D3410 Test Method for Compressive Properties of Polymer
such a manner that the applied moments produce curvature of
Matrix Composite Materials with Unsupported Gage Sec-
the sandwich facing planes. Permissible core material forms
tion by Shear Loading
include those with continuous bonding surfaces (such as balsa
D3878 Terminology for Composite Materials
wood and foams) as well as those with discontinuous bonding
D5229/D5229M Test Method for MoistureAbsorption Prop-
surfaces (such as honeycomb).
erties and Equilibrium Conditioning of Polymer Matrix
1.2 Units—The values stated in either SI units or inch-
Composite Materials
pound units are to be regarded separately as standard. The
D7249/D7249M Test Method for Facesheet Properties of
values stated in each system are not necessarily exact equiva-
Sandwich Constructions by Long Beam Flexure
lents; therefore, to ensure conformance with the standard, each
D7250/D7250M Practice for Determining Sandwich Beam
system shall be used independently of the other, and values
Flexural and Shear Stiffness
from the two systems shall not be combined.
E4 Practices for Force Verification of Testing Machines
1.2.1 Within the text, the inch-pound units are shown in
E6 Terminology Relating to Methods of Mechanical Testing
brackets.
E122 Practice for Calculating Sample Size to Estimate,With
1.3 This standard does not purport to address all of the Specified Precision, the Average for a Characteristic of a
safety concerns, if any, associated with its use. It is the
Lot or Process
responsibility of the user of this standard to establish appro- E177 Practice for Use of the Terms Precision and Bias in
priate safety, health, and environmental practices and deter- ASTM Test Methods
mine the applicability of regulatory limitations prior to use.
E456 Terminology Relating to Quality and Statistics
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- 3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions—Terminology D3878 defines terms relating
Development of International Standards, Guides and Recom-
to high-modulus fibers and their composites, as well as terms
mendations issued by the World Trade Organization Technical
relating to sandwich constructions. Terminology D883 defines
Barriers to Trade (TBT) Committee.
terms relating to plastics. Terminology E6 defines terms
relating to mechanical testing. Terminology E456 and Practice
2. Referenced Documents
E177 define terms relating to statistics. In the event of a
2
conflict between terms, Terminology D3878 shall have prece-
2.1 ASTM Standards:
dence over the other terminologies.
3.2 Symbols:
1
This test method is under the jurisdiction of ASTM Committee D30 on
b = specimen width
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
c = core thickness
Sandwich Construction.
CV = coefficient of variation statistic of a sample population
Current edition approved July 1, 2020. Published August 2020. Originally
for a given property (in percent)
approved in 1957. Last previous edition approved in 2016 as C393/C393M – 16.
DOI: 10.1520/C0393_C0393M-20.
d = sandwich total thickness
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or F,nom
D = effective sandwich flexural stiffness
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
E = effective facing chord modulus
Standards volume information, refer to the standard’s Document Summary page on f
the ASTM website. ε = measuring strain in facing
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C393/C393M − 20
u
F = facing ultimate strength (tensile or compressive) 5.5 This test method can be used to produce core shear
F = co
...
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.
Designation: C393/C393M − 20 C393/C393M − 20
Standard Test Method for
Core Shear Properties of Sandwich Constructions by Beam
1
Flexure
This standard is issued under the fixed designation C393/C393M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers determination of the core shear properties of flat sandwich constructions subjected to flexure in such
a manner that the applied moments produce curvature of the sandwich facing planes. 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.
2. Referenced Documents
2
2.1 ASTM Standards:
C273 Test Method for Shear Properties of Sandwich Core Materials
D883 Terminology Relating to Plastics
D3410 Test Method for Compressive Properties of Polymer Matrix Composite Materials with Unsupported Gage Section by
Shear Loading
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D7249/D7249M Test Method for Facesheet Properties of Sandwich Constructions by Long Beam Flexure
D7250/D7250M Practice for Determining Sandwich Beam Flexural and Shear Stiffness
E4 Practices for Force Verification of Testing Machines
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
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, 2020. Published August 2020. Originally approved in 1957. Last previous edition approved in 2016 as C393/C393M – 16. DOI:
10.1520/C0393_C0393M-20.
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 ----------------------
C393/C393M − 20
3. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to high-modulus fibers and their composites, as well as terms
relating to sandwich constructions. Terminology D883 defines terms relating to plastics. 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
E = effective facing chord modulus
f
ε = measuring strai
...
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