ASTM C393/C393M-16

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, especiall...
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 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.

General Information

• Status: Historical
• Publication Date: 31-Mar-2016
• ICS: 83.120 - Reinforced plastics
• Technical Committee: D30 - Composite Materials
• Drafting Committee: D30.09 - Sandwich Construction

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
Designation: C393/C393M − 16
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 D7249/D7249M Test Method for Facing Properties of Sand-
wich Constructions by Long Beam Flexure
1.1 This test method covers determination of the core shear
D7250/D7250M Practice for Determining Sandwich Beam
propertiesofflatsandwichconstructionssubjectedtoflexurein
Flexural and Shear Stiffness
such a manner that the applied moments produce curvature of
E4 Practices for Force Verification of Testing Machines
the sandwich facing planes. Permissible core material forms
E6 Terminology Relating to Methods of Mechanical Testing
include those with continuous bonding surfaces (such as balsa
E122 Practice for Calculating Sample Size to Estimate,With
wood and foams) as well as those with discontinuous bonding
Specified Precision, the Average for a Characteristic of a
surfaces (such as honeycomb).
Lot or Process
1.2 The values stated in either SI units or inch-pound units
E177 Practice for Use of the Terms Precision and Bias in
are to be regarded separately as standard. The values stated in
ASTM Test Methods
each system may not be exact equivalents; therefore, each
E456 Terminology Relating to Quality and Statistics
system shall be used independently of the other. Combining
values from the two systems may result in non-conformance
3. Terminology
with the standard.
3.1 Definitions—Terminology D3878 defines terms relating
1.2.1 Within the text the inch-pound units are shown in
to high-modulus fibers and their composites, as well as terms
brackets.
relating to sandwich constructions. Terminology D883 defines
1.3 This standard does not purport to address all of the
terms relating to plastics. Terminology E6 defines terms
safety concerns, if any, associated with its use. It is the
relating to mechanical testing. Terminology E456 and Practice
responsibility of the user of this standard to establish appro-
E177 define terms relating to statistics. In the event of a
priate safety and health practices and determine the applica-
conflict between terms, Terminology D3878 shall have prece-
bility of regulatory limitations prior to use.
dence over the other terminologies.
3.2 Symbols: b = specimen width
2. Referenced Documents
c = core thickness
2
2.1 ASTM Standards:
CV = coefficient of variation statistic of a sample population
C273 Test Method for Shear Properties of Sandwich Core
for a given property (in percent)
Materials
d = sandwich total thickness
D883 Terminology Relating to Plastics
F,nom
D = effective sandwich flexural stiffness
D3878 Terminology for Composite Materials
E = effective facing chord modulus
f
D5229/D5229M Test Method for MoistureAbsorption Prop-
ε = measuring strain in facing
erties and Equilibrium Conditioning of Polymer Matrix
u
F = facing ultimate strength (tensile or compressive)
Composite Materials
F = core compression allowable strength
c
F = core shear allowable strength
s
ult
1
This test method is under the jurisdiction of ASTM Committee D30 on
F = core shear ultimate strength
s
yield
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
F = core shear yield strength
s
Sandwich Construction.
k = core shear strength factor to ensure core failure
Current edition approved April 1, 2016. Published April 2016. Originally
ɛ1
L = length of loading span
approved in 1957. Last previous edition approved in 2011 as C393 – 11 . DOI:
10.1520/C0393_C0393M-16.
S = length of support span
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
l = length of loading pad
pad
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
n = number of specimens
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. P = applied force
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C393/C393M − 16
P = maximum force carried by test specimen before Further, core-to-facing strength may be different between
max
failure precured/bonded and co-cured facings in sandwich panels with
ftu
F = ultimate flatwise tensile strength the same core and facing material.
Z
NOTE 2—Concentrated loads on beams with thin facings and low
P = maximum force carried by test specimen before
max
density cores ca
...

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: C393/C393M − 11 C393/C393M − 16
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
ε NOTE—Sections 7 and 11 were editorially corrected in February 2012.
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 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.
2. Referenced Documents
2
2.1 ASTM Standards:
C273 Test Method for Shear Properties of Sandwich Core Materials
3
C274 Terminology of Structural Sandwich Constructions (Withdrawn 2016)
D883 Terminology Relating to Plastics
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 Facing 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
3
E1309 Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Databases (Withdrawn 2015)
3
E1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in Databases (Withdrawn 2015)
3. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to high-modulus fibers and their composites.
Terminologycomposites, as C274 defineswell as terms relating to structural sandwich constructions. Terminology D883 defines
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 Oct. 1, 2011April 1, 2016. Published November 2011April 2016. Originally approved in 1957. Last previous edition approved in 20062011 as
ɛ1
C393 – 06.C393 – 11 . DOI: 10.1520/C0393_C0393M-11.10.1520/C0393_C0393M-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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 − 16
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 strain in fa
...