ASTM D3878-20

Standard Terminology for Composite Materials

SCOPE
1.1 These definitions cover generic terms, including terms of commercial importance, that appear in one or more standards on composites containing high-modulus (greater than 20 GPa (3 × 10 6 psi)) fibers.  
1.2 The definitions cover, in most cases, special meanings used in the composites industry. No attempt has been made to include common meanings of the same terms as used outside the composites industry.  
1.3 Definitions included have, in general, been approved as standard.  
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.

General Information

• Status: Historical
• Publication Date: 14-Apr-2020
• ICS: 01.040.49 - Aircraft and space vehicle engineering (Vocabularies)
• ICS: 49.025.60 - Textiles
• Technical Committee: D30 - Composite Materials
• Drafting Committee: D30.01 - Editorial and Resource Standards

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D3878 − 20
Standard Terminology for
1
Composite Materials
This standard is issued under the fixed designation D3878; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope angleply laminate—any balanced laminate consisting of plus
and minus theta plies where theta is an acute angle with
1.1 These definitions cover generic terms, including terms
respect to a reference direction.
of commercial importance, that appear in one or more stan-
dards on composites containing high-modulus (greater than
balanced laminate—any laminate that contains one ply of
6
20GPa (3×10 psi)) fibers.
minusthetaorientationwithrespecttothelaminateprincipal
axis for every identical ply with a plus theta orientation.
1.2 The definitions cover, in most cases, special meanings
used in the composites industry. No attempt has been made to
bond, n—the act of adhering one surface to another, with or
include common meanings of the same terms as used outside
without the use of an adhesive at the interface.
the composites industry.
co-cure, cocure—see Cure.
1.3 Definitions included have, in general, been approved as
co-bond, cobond, n—theactofcuring(orconsolidating)and
standard.
bondingonesemi-soliddetail(forexample,uncuredthermoset
1.4 This international standard was developed in accor- polymerorathermoplasticpolymer)toasoliddetailinasingle
dance with internationally recognized principles on standard- process through principal action of the matrix, possibly with
ization established in the Decision on Principles for the the inclusion of a separate layer of adhesive at the interface.
Development of International Standards, Guides and Recom-
secondary bond, n—the act of bonding two or more already-
mendations issued by the World Trade Organization Technical
cured thermoset composite or other solid details, during which
Barriers to Trade (TBT) Committee.
the only chemical or thermal reaction, or both, occurring is the
curing of the adhesive layer at the interface.
2. Referenced Documents
DISCUSSION—For example, a previously cured composite or metal
2
2.1 ASTM Standards:
doubler bonded via an adhesive to a previously cured skin, or a
D123Terminology Relating to Textiles
previously cured face sheet bonded via an adhesive to a honeycomb
3 core.Alsoappliestobondingmetallicsubstratessuchasaluminumface
2.2 Industry Standard:
sheets onto aluminum honeycomb core.
CMH-17Composite Materials Handbook
braided fabric—see braided fabric under fabric.
3. Terminology
breather string, n—a string, composed of a material such as
3.1 Definitions:
glass, that provides a vacuum path from the laminate to a
645° laminate—a balanced symmetric laminate composed of
breather.
only +45° plies and −45° plies.
bundle, n—a general term for a collection of essentially
parallel filaments.
1
This terminology is under the jurisdiction of ASTM Committee D30 on
carbon fiber precursor, n—amaterialfromwhichcarbonfiber
Composite Materials and is the direct responsibility of Subcommittee D30.01 on
is made by pyrolysis.
Editorial and Resource Standards.
DISCUSSION—Polyacrylonitrile, rayon, or pitch fibers are commonly
Current edition approved April 15, 2020. Published April 2020. Originally
used precursors.
approved in 1981. Last previous edition approved in 2019 as D3878–19a. DOI:
10.1520/D3878-20.
2 catenary:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
filament catenary, n—the difference in length of the fila-
Standards volume information, refer to the standard’s Document Summary page on
ments in a specified length of tow, end, or strand as a result of
the ASTM website.
3
unequal tension; the tendency of some filaments in a taut
AvailablefromSAEInternational(SAE),400CommonwealthDr.,Warrendale,
PA 15096, http://www.sae.org. horizontal tow, end, or strand to sag lower than others.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D3878 − 20
DISCUSSION—Honeycomb core materials are formed from sheet
roving catenary, n—the difference in length of the ends,
materials into configurations resembling honeycomb in appearance.
tows, or strands in a specified length of roving as a result of
Strictlyspeaking,thehoneycombcellconfigurationishexagonal,butin
unequaltension;thetendencyofsomeends,tows,orstrandsin
practice, additional configurations are often referred to as
a taut horizontal ro
...

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: D3878 − 19a D3878 − 20
Standard Terminology for
1
Composite Materials
This standard is issued under the fixed designation D3878; 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 These definitions cover generic terms, including terms of commercial importance, that appear in one or more standards on
6
composites containing high-modulus (greater than 20 GPa (3 × 10 psi)) fibers.
1.2 The definitions cover, in most cases, special meanings used in the composites industry. No attempt has been made to include
common meanings of the same terms as used outside the composites industry.
1.3 Definitions included have, in general, been approved as standard.
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:
D123 Terminology Relating to Textiles
3
2.2 Industry Standard:
CMH-17 Composite Materials Handbook
3. Terminology
3.1 Definitions:
645° laminate—a balanced symmetric laminate composed of only +45° plies and −45° plies.
angleply laminate—any balanced laminate consisting of plus and minus theta plies where theta is an acute angle with respect to
a reference direction.
balanced laminate—any laminate that contains one ply of minus theta orientation with respect to the laminate principal axis for
every identical ply with a plus theta orientation.
bond, n—the act of adhering one surface to another, with or without the use of an adhesive at the interface.
co-cure, cocure—see Cure.
co-bond, cobond, n—the act of curing (or consolidating) and bonding one semi-solid detail (for example, uncured thermoset
polymer or a thermoplastic polymer) to a solid detail in a single process through principal action of the matrix, possibly with the
inclusion of a separate layer of adhesive at the interface.
secondary bond, n—the act of bonding two or more already-cured thermoset composite or other solid details, during which the
only chemical or thermal reaction, or both, occurring is the curing of the adhesive layer at the interface.
DISCUSSION—
1
This terminology is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.01 on Editorial and
Resource Standards.
Current edition approved Oct. 15, 2019April 15, 2020. Published October 2019April 2020. Originally approved in 1981. Last previous edition approved in 2019 as
D3878 – 19.D3878 – 19a. DOI: 10.1520/D3878-19A.10.1520/D3878-20.
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.
3
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D3878 − 20
For example, a previously cured composite or metal doubler bonded via an adhesive to a previously cured skin, or a previously cured face sheet bonded
via an adhesive to a honeycomb core. Also applies to bonding metallic substrates such as aluminum face sheets onto aluminum honeycomb core.
braided fabric—see braided fabric under fabric.
breather string, n—a string, composed of a material such as glass, that provides a vacuum path from the laminate to a breather.
bundle—bundle, n—a general term for a collection of essentially parallel filaments.
carbon fiber precursor—precursor, n—a material from which carbon fiber is made by pyrolysis. Polyacrylonitrile, rayon, or pitch
fibers are commonly used precursors.
DISCUSSION—
Polyacrylonitrile, rayon, or pitch fibers are commonly used precursors.
catenary:
filament catenary—catenary, n—the difference in length of the filaments in a specified length of tow, end, or strand as a result
of unequal tension; the tendency of some filaments in a taut
...