ASTM C480/C480M-08
(Test Method)Standard Test Method for Flexure Creep of Sandwich Constructions
Standard Test Method for Flexure Creep of Sandwich Constructions
SIGNIFICANCE AND USE
The determination of the creep rate provides information on the behavior of sandwich constructions under constant applied force. Creep is defined as deflection under constant force over a period of time beyond the initial deformation as a result of the application of the force. Deflection data obtained from this test method can be plotted against time, and a creep rate determined. By using standard specimen constructions and constant loading, the test method may also be used to evaluate creep behavior of sandwich panel core-to-facing adhesives.
This test method provides a standard method of obtaining flexure creep of sandwich constructions for quality control, acceptance specification testing, and research and development.
Factors that influence the sandwich construction creep response 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, core thickness, 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 and core-to-facing strength and creep response may be different between precured/bonded and co-cured facesheets of the same material.
SCOPE
1.1 This test method covers the determination of the creep characteristics and creep rate of flat sandwich constructions loaded in flexure, at any desired temperature. 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. Within the text the inch-pound units are shown in brackets. 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 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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Designation: C480/C480M − 08
StandardTest Method for
1
Flexure Creep of Sandwich Constructions
This standard is issued under the fixed designation C480/C480M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E6Terminology Relating to Methods of MechanicalTesting
E122PracticeforCalculatingSampleSizetoEstimate,With
1.1 This test method covers the determination of the creep
Specified Precision, the Average for a Characteristic of a
characteristics and creep rate of flat sandwich constructions
Lot or Process
loaded in flexure, at any desired temperature. Permissible core
E177Practice for Use of the Terms Precision and Bias in
materialformsincludethosewithcontinuousbondingsurfaces
ASTM Test Methods
(such as balsa wood and foams) as well as those with
E456Terminology Relating to Quality and Statistics
discontinuous bonding surfaces (such as honeycomb).
E1309 Guide for Identification of Fiber-Reinforced
1.2 The values stated in either SI units or inch-pound units
Polymer-Matrix Composite Materials in Databases
are to be regarded separately as standard. Within the text the
E1434Guide for Recording Mechanical Test Data of Fiber-
inch-pound units are shown in brackets. The values stated in
Reinforced Composite Materials in Databases
eitherSIunitsorinch-poundunitsaretoberegardedseparately
asstandard.Thevaluesstatedineachsystemmaynotbeexact
3. Terminology
equivalents;therefore,eachsystemshallbeusedindependently
3.1 Definitions—Terminology D3878 defines terms relating
of the other. Combining values from the two systems may
to high-modulus fibers and their composites. Terminology
result in non-conformance with the standard.
C274 defines terms relating to structural sandwich construc-
1.3 This standard does not purport to address all of the
tions. Terminology D883 defines terms relating to plastics.
safety concerns, if any, associated with its use. It is the
Terminology E6 defines terms relating to mechanical testing.
responsibility of the user of this standard to establish appro-
Terminology E456 and Practice E177 define terms relating to
priate safety and health practices and determine the applica-
statistics.Intheeventofaconflictbetweenterms,Terminology
bility of regulatory limitations prior to use.
D3878 shall have precedence over the other terminology
documents.
2. Referenced Documents
3.2 Symbols:
2
2.1 ASTM Standards:
3.2.1 A—distance between pivot point and point of applied
C274Terminology of Structural Sandwich Constructions
force on the specimen
C393/C393MTest Method for Core Shear Properties of
3.2.2 b—specimen width
Sandwich Constructions by Beam Flexure
D883Terminology Relating to Plastics 3.2.3 B—distancefrompivotpointtocenterofgravityofthe
D3878Terminology for Composite Materials
loading arm
D5229/D5229MTestMethodforMoistureAbsorptionProp-
3.2.4 c—core thickness
erties and Equilibrium Conditioning of Polymer Matrix
3.2.5 CR —creep rate at time, i
I i
Composite Materials
3.2.6 d—sandwich total thickness
D7249/D7249MTestMethodforFacingPropertiesofSand-
wich Constructions by Long Beam Flexure
3.2.7 d—initial static deflection under the same load and at
the same temperature
3.2.8 D—total deflection at time, t
1
This specification is under the jurisdiction of ASTM Committee D30 on
3.2.9 F—applied facing stress
Composite Materials and is the direct responsibility of Subcommittee D30.09 on
f
Sandwich Construction.
3.2.10 F —applied core shear stress
s
Current edition approved Sept. 1, 2008. Published October 2008. Originally
approvedin1961.Lastpreviouseditionapprovedin2005asC480–99(2005).DOI:
3.2.11 M—distance between point and weight point
10.1520/C0480_C0480M-08.
2 3.2.12 n—number of specimens
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
3.2.13 p—mass of loading plate and rod
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.2.14 P—applied force
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C480/C480M − 08
3.2.15 S—length of support span 7. Apparatus
3.2.16 w—mass of lever arm
7.1 Micrometers and Calipers—Amicrometer having a flat
anvil interface, or a caliper of suitable size, shall be used. The
3.2.17 W—mass of weight (including tray mass)
instruments(s) shall have an accuracy of 625 µm [60.001 in.]
for thickness measurement, and an accuracy of 6250 µm
4. Summary of Test Method
[60.010 in.] for length and width measurements.
4.1 This t
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C480–99 (Reapproved 2005) Designation: C 480/C 480M – 08
Standard Test Method for
1
Flexure Creep of Sandwich Constructions
ThisstandardisissuedunderthefixeddesignationC480/C480M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1This test method covers the determination of the creep characteristics and creep rate of sandwich constructions loaded in
flexure, at any desired temperature.
1.2The values stated in SI units are to be regarded as the standard. The inch-pound units given may be approximate.
1.1 This test method covers the determination of the creep characteristics and creep rate of flat sandwich constructions loaded
in flexure, at any desired temperature. 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. Within the text the
inch-pound units are shown in brackets. 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 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: ASTM Standards:
C274 Terminology of Structural Sandwich Constructions
C393Test Method for Flexural Properties of Sandwich Constructions 393/C393M Test Method for Core Shear Properties of
Sandwich Constructions by Beam Flexure
D883 Terminology Relating to Plastics
D3878 Terminology for Composite Materials
D5229/D5229M TestMethodforMoistureAbsorptionPropertiesandEquilibriumConditioningofPolymerMatrixComposite
Materials
D7249/D7249M Test Method for Facing Properties of Sandwich Constructions by Long Beam Flexure
E6 Terminology Relating to Methods of Mechanical Testing
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, theAverage 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
3. Significance and Use
3.1The determination of the creep rate provides information on the behavior of sandwich constructions under constant load.
Creepisdefinedasdeflectionunderconstantloadoveraperiodoftimebeyondtheinitialdeformationasaresultoftheapplication
of the load. Deflection data obtained from this test method can be plotted against time, and a creep rate determined. By using
standard specimen constructions and constant loading, the test method may also be used to evaluate creep behavior of sandwich
panel core-to-facing adhesives.
3.2This test method provides a standard method of obtaining flexure creep of sandwich constructions for quality control,
1
This specification 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 Mar.Sept. 1, 2005.2008. Published March 2005.October 2008. Originally approved in 1961. Last previous edition approved in 19992005 as
C480–99(2005).
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@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 ----------------------
C 480/C 480M – 08
acceptance specification testing, and research and development. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to high-modulus fibers and their compos
...
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