Standard Test Method for Flatwise Compressive Properties of Sandwich Cores

SIGNIFICANCE AND USE
Flatwise compressive strength and modulus are fundamental mechanical properties of sandwich cores that are used in designing sandwich panels. Deformation data can be obtained, and from a complete force versus deformation curve, it is possible to compute the compressive stress at any applied force (such as compressive stress at proportional limit force or compressive strength at the maximum force) and to compute the effective modulus of the core.
This test method provides a standard method of obtaining the flatwise compressive strength and modulus for sandwich core structural design properties, material specifications, research and development applications, and quality assurance.
In order to prevent local crushing at the edges of some honeycomb cores, it is often desirable to stabilize the edges with a suitable material, such as a thin layer of resin or thin facings. Flatwise compressive strength data may be generated using either stabilized specimens (reported as stabilized compression strength) or non-stabilized specimens (reported as bare compression strength). It is customary aerospace industry practice to determine compression modulus only when using stabilized specimens.
Factors that influence the flatwise compressive strength and shall therefore be reported include the following: core material, methods of material fabrication, core geometry (cell size), core density, specimen geometry, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, and speed of testing.
SCOPE
1.1 This test method covers the determination of compressive strength and modulus of sandwich cores. These properties are usually determined for design purposes in a direction normal to the plane of facings as the core would be placed in a structural sandwich construction. The test procedures pertain to compression in this direction in particular, but also can be applied with possible minor variations to determining compressive properties in other directions. 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 This test method does not cover the determination of compressive core crush properties. Reference Test Method D7336/D7336M for determination of static energy absorption properties of honeycomb sandwich core materials.
1.3 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.
1.3.1 Within the text the inch-pound units are shown in brackets.
1.4 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.

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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:C365/C365M–11
Standard Test Method for
1
Flatwise Compressive Properties of Sandwich Cores
This standard is issued under the fixed designation C365/C365M; 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 Department of Defense.
1. Scope C271/C271M Test Method for Density of Sandwich Core
Materials
1.1 This test method covers the determination of compres-
C274 Terminology of Structural Sandwich Constructions
sive strength and modulus of sandwich cores. These properties
D883 Terminology Relating to Plastics
are usually determined for design purposes in a direction
D3878 Terminology for Composite Materials
normal to the plane of facings as the core would be placed in
D5229/D5229M Test Method for Moisture Absorption
a structural sandwich construction. The test procedures pertain
Properties and Equilibrium Conditioning of Polymer Ma-
to compression in this direction in particular, but also can be
trix Composite Materials
appliedwithpossibleminorvariationstodeterminingcompres-
D7336/D7336M Test Method for Static Energy Absorption
sive properties in other directions. Permissible core material
Properties of Honeycomb Sandwich Core Materials
forms include those with continuous bonding surfaces (such as
E4 Practices for Force Verification of Testing Machines
balsa wood and foams) as well as those with discontinuous
E6 TerminologyRelatingtoMethodsofMechanicalTesting
bonding surfaces (such as honeycomb).
E122 Practice for Calculating Sample Size to Estimate,
1.2 This test method does not cover the determination of
With Specified Precision, the Average for a Characteristic
compressive core crush properties. Reference Test Method
of a Lot or Process
D7336/D7336M for determination of static energy absorption
E177 Practice for Use of the Terms Precision and Bias in
properties of honeycomb sandwich core materials.
ASTM Test Methods
1.3 The values stated in either SI units or inch-pound units
E456 Terminology Relating to Quality and Statistics
are to be regarded separately as standard. The values stated in
E1309 Guide for Identification of Fiber-Reinforced
each system may not be exact equivalents; therefore, each
Polymer-Matrix Composite Materials in Databases
system shall be used independently of the other. Combining
E1434 Guide for Recording Mechanical Test Data of Fiber-
values from the two systems may result in non-conformance
Reinforced Composite Materials in Databases
with the standard.
E1471 Guide for Identification of Fibers, Fillers, and Core
1.3.1 Within the text the inch-pound units are shown in
Materials in Computerized Material Property Databases
brackets.
1.4 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Definitions—Terminology D3878 defines terms relating
responsibility of the user of this standard to establish appro-
to high-modulus fibers and their composites. Terminology
priate safety and health practices and determine the applica-
C274 defines terms relating to structural sandwich construc-
bility of regulatory limitations prior to use.
tions. Terminology D883 defines terms relating to plastics.
2. Referenced Documents Terminology E6 defines terms relating to mechanical testing.
2
Terminology E456 and Practice E177 define terms relating to
2.1 ASTM Standards:
statistics.Intheeventofaconflictbetweenterms,Terminology
D3878 shall have precedence over the other terminologies.
1
This test method is under the jurisdiction of ASTM Committee D30 on
3.2 Symbols:
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
3.2.1 A—cross-sectional area of a test specimen
Sandwich Construction.
3.2.2 CV—coefficient of variation statistic of a sample
Current edition approved April 1, 2011. Published May 2011. Originally
population for a given property (in percent)
approved in 1955. Last previous edition approved in 2005 as C365/C365M – 05.
fc
DOI: 10.1520/C0365_C0365M-11.
3.2.3 E —flatwise compressive modulus
z
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or fcu
3.2.4 F —ultimate flatwise compressive strength
z
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
fc0.02
3.2.5 F —flatwise compressive strength at 2 % LVDT/
Standards volume information, refer to the standard’s Document Summary page on z
the ASTM website. compressometer deflection
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ---------------
...

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:C365/C365M–05 Designation:C365/C365M–11
Standard Test Method for
1
Flatwise Compressive Properties of Sandwich Cores
This standard is issued under the fixed designation C365/C365M; 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 Department of Defense.
1. Scope
1.1 This test method covers the determination of compressive strength and modulus of sandwich cores. These properties are
usually determined for design purposes in a direction normal to the plane of facings as the core would be placed in a structural
sandwich construction. The test procedures pertain to compression in this direction in particular, but also can be applied with
possible minor variations to determining compressive properties in other directions. 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).
1.2The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text the
inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must
be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.3
1.2 This test method does not cover the determination of compressive core crush properties. Reference Test Method
D7336/D7336M for determination of static energy absorption properties of honeycomb sandwich core materials.
1.3 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.
1.3.1 Within the text the inch-pound units are shown in brackets.
1.4 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:
C271/C271M Test Method for Density of Sandwich Core Materials
C274 Terminology of Structural Sandwich Constructions
D883 Terminology Relating to Plastics
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for MoistureAbsorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D7336/D7336M Test Method for Static Energy Absorption Properties of Honeycomb Sandwich Core Materials
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
E1309 Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Databases
E1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in Databases
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.April 1, 2005.2011. Published October 2005.May 2011. Originally approved in 1955. Last previous edition approved in 20032005 as
C365/C365M – 035. DOI: 10.1520/C0365_C0365M-0511.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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 ----------------------
C365/C365M–11
E1471 Guide for Identification of Fibers, Fillers, and Core Materials in Computerized Material Property Databases
3. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to high-modulus fib
...

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