Standard Practice for Damage Resistance Testing of Sandwich Constructions

SIGNIFICANCE AND USE
5.1 This practice provides supplemental instructions that allow Test Methods D6264/D6264M (for quasi-static indentation testing) and D7136/D7136M (for drop-weight impact testing) to determine damage resistance properties of sandwich constructions. Susceptibility to damage from concentrated out-of-plane forces is one of the major design concerns of many structures made using sandwich constructions. Knowledge of the damage resistance properties of a sandwich panel is useful for product development and material selection.  
5.2 Sandwich damage resistance testing can serve the following purposes:  
5.2.1 To establish quantitatively the effects of facing geometry, facing stacking sequence, facing-to-core interface, core geometry (cell size, cell wall thickness, core thickness, etc.), core density, core strength, processing and environmental variables on the damage resistance of a particular sandwich panel to a concentrated quasi-static indentation force, drop-weight impact force, or impact energy.  
5.2.2 To compare quantitatively the relative values of the damage resistance parameters for sandwich constructions with different facing, core or adhesive materials. The damage response parameters can include dent depth, damage dimensions and location(s), indentation or impact force magnitudes, impact energy magnitudes, as well as the force versus time curve.  
5.2.3 To impart damage in a specimen for subsequent damage tolerance tests, such as Test Method D8287/D8287M and Practice D8388/D8388M.  
5.2.4 Quasi-static indentation tests can also be used to identify a specific sequence of damage events (only the final damage state is identifiable after a drop-weight impact test).  
5.3 The properties obtained using these practices can provide guidance in regard to the anticipated damage resistance capability of sandwich structures with similar materials, geometry, stacking sequence, and so forth. However, it must be understood that the damage resistance of a sandwich structu...
SCOPE
1.1 This practice provides instructions for modifying laminate quasi-static indentation and drop-weight impact test methods to determine damage resistance properties of sandwich constructions. 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, truss cores and fiber-reinforced cores).  
1.2 This practice supplements Test Methods D6264/D6264M (for quasi-static indentation testing) and D7136/D7136M (for drop-weight impact testing) with provisions for testing sandwich specimens. Several important test specimen parameters (for example, facing thickness, core thickness and core density) are not mandated by this practice; however, repeatable results require that these parameters be specified and reported.  
1.3 Three test procedures are provided. Procedures A and B correspond to D6264/D6264M test procedures for rigidlybacked and edge-supported test conditions, respectively. Procedure C corresponds to D7136/D7136M test procedures. All three procedures are suitable for imparting damage to a sandwich specimen in preparation for subsequent damage tolerance testing in accordance with Test Method D8287/D8287M (compressive loading) and Practice D8388/D8388M (flexural loading).  
1.4 In general, Procedure A is considered to be the most suitable procedure for comparative damage resistance assessments, due to reduced influence of flexural stiffness and support fixture characteristics upon damage formation. However, the selection of a test procedure and associated support conditions should be done in consideration of the intended structural application, and as such Procedures B and C may be more appropriate for comparative purposes for some applications.  
1.5 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 ...

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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: D7766/D7766M − 23
Standard Practice for
1
Damage Resistance Testing of Sandwich Constructions
This standard is issued under the fixed designation D7766/D7766M; 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. Scope values stated in each system are not necessarily exact equiva-
lents; therefore, to ensure conformance with the standard, each
1.1 This practice provides instructions for modifying lami-
system shall be used independently of the other, and values
nate quasi-static indentation and drop-weight impact test meth-
from the two systems shall not be combined.
ods to determine damage resistance properties of sandwich
1.5.1 Within the text the inch-pound units are shown in
constructions. Permissible core material forms include those
brackets.
with continuous bonding surfaces (such as balsa wood and
1.6 This standard does not purport to address all of the
foams) as well as those with discontinuous bonding surfaces
safety concerns, if any, associated with its use. It is the
(such as honeycomb, truss cores and fiber-reinforced cores).
responsibility of the user of this standard to establish appro-
1.2 This practice supplements Test Methods D6264/
priate safety, health, and environmental practices and deter-
D6264M (for quasi-static indentation testing) and D7136/
mine the applicability of regulatory limitations prior to use.
D7136M (for drop-weight impact testing) with provisions for
1.7 This international standard was developed in accor-
testing sandwich specimens. Several important test specimen
dance with internationally recognized principles on standard-
parameters (for example, facing thickness, core thickness and
ization established in the Decision on Principles for the
core density) are not mandated by this practice; however,
Development of International Standards, Guides and Recom-
repeatable results require that these parameters be specified and
mendations issued by the World Trade Organization Technical
reported.
Barriers to Trade (TBT) Committee.
1.3 Three test procedures are provided. Procedures A and B
correspond to D6264/D6264M test procedures for rigidly-
2. Referenced Documents
backed and edge-supported test conditions, respectively. Pro-
2
2.1 ASTM Standards:
cedure C corresponds to D7136/D7136M test procedures. All
D792 Test Methods for Density and Specific Gravity (Rela-
three procedures are suitable for imparting damage to a
tive Density) of Plastics by Displacement
sandwich specimen in preparation for subsequent damage
D883 Terminology Relating to Plastics
tolerance testing in accordance with Test Method D8287/
D3171 Test Methods for Constituent Content of Composite
D8287M (compressive loading) and Practice D8388/D8388M
Materials
(flexural loading).
D3878 Terminology for Composite Materials
1.4 In general, Procedure A is considered to be the most
D5229/D5229M Test Method for Moisture Absorption Prop-
suitable procedure for comparative damage resistance
erties and Equilibrium Conditioning of Polymer Matrix
assessments, due to reduced influence of flexural stiffness and
Composite Materials
support fixture characteristics upon damage formation.
D5687/D5687M Guide for Preparation of Flat Composite
However, the selection of a test procedure and associated
Panels with Processing Guidelines for Specimen Prepara-
support conditions should be done in consideration of the
tion
intended structural application, and as such Procedures B and
D6264/D6264M Test Method for Measuring the Damage
C may be more appropriate for comparative purposes for some
Resistance of a Fiber-Reinforced Polymer-Matrix Com-
applications.
posite to a Concentrated Quasi-Static Indentation Force
D7136/D7136M Test Method for Measuring the Damage
1.5 Units—The values stated in either SI units or inch-
Resistance of a Fiber-Reinforced Polymer Matrix Com-
pound units are to be regarded separately as standard. The
posite to a Drop-Weight Impact Event
1
This practice is under the jurisdiction of ASTM Committee D30 on Composite
Materials and is the direct responsibility of Subcommittee D30.09 on Sandwich
2
Construction. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2023. Published June 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2011. Last previous edition approved in 2016 as D7766/D7766M – 16. Standards volume information, refer to the standard’s
...

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: D7766/D7766M − 16 D7766/D7766M − 23
Standard Practice for
1
Damage Resistance Testing of Sandwich Constructions
This standard is issued under the fixed designation D7766/D7766M; 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. Scope
1.1 This practice provides instructions for modifying laminate quasi-static indentation and drop-weight impact test methods to
determine damage resistance properties of sandwich constructions. 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, truss
cores and fiber-reinforced cores).
1.2 This practice supplements Test Methods D6264/D6264M (for quasi-static indentation testing) and D7136/D7136M (for
drop-weight impact testing) with provisions for testing sandwich specimens. Several important test specimen parameters (for
example, facing thickness, core thickness and core density) are not mandated by this practice; however, repeatable results require
that these parameters be specified and reported.
1.3 Three test procedures are provided. Procedures A and B correspond to D6264/D6264M test procedures for rigidlybacked and
edge-supported test conditions, respectively. Procedure C corresponds to D7136/D7136M test procedures. All three procedures are
suitable for imparting damage to a sandwich specimen in preparation for subsequent damage tolerance testing.testing in accordance
with Test Method D8287/D8287M (compressive loading) and Practice D8388/D8388M (flexural loading).
1.4 In general, Procedure A is considered to be the most suitable procedure for comparative damage resistance assessments, due
to reduced influence of flexural stiffness and support fixture characteristics upon damage formation. However, the selection of a
test procedure and associated support conditions should be done in consideration of the intended structural application, and as such
Procedures B and C may be more appropriate for comparative purposes for some applications.
1.5 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, each system mustto ensure conformance with the standard, each
system shall be used independently of the other. Combiningother, and values from the two systems may result in non-conformance
with the standard.shall not be combined.
1.5.1 Within the text the inch-pound units are shown in brackets.
1.6 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.7 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.
1
This practice 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 May 15, 2016May 1, 2023. Published June 2016June 2023. Originally approved in 2011. Last previous edition approved in 20112016 as
D7766/D7766MD7766/D7766M – 16.–11. DOI: 10.1520/D7766_D7766M-16.10.1520/D7766_D7766M-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7766/D7766M − 23
2. Referenced Documents
2
2.1 ASTM Standards:
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D3171 Test Methods for Constituent Content of Composite Materials
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D5687/D5687M Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparati
...

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