ASTM D3878-23

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: Published
• Publication Date: 30-Apr-2023
• 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)

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: D3878 − 23
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 angleply, adj—describing a laminate that is balanced, and that
consists only of plies with ply orientations of plus theta and
1.1 These definitions cover generic terms, including terms
minus theta.
of commercial importance, that appear in one or more stan-
DISCUSSION—An angleply laminate is not necessarily symmetric.
dards on composites containing high-modulus (greater than
6
20 GPa (3 × 10 psi)) fibers.
balanced, adj—describing a laminate that contains one ply
with a ply orientation of minus theta for every ply of the
1.2 The definitions cover, in most cases, special meanings
same material and thickness with a ply orientation of plus
used in the composites industry. No attempt has been made to
theta, and any number of plies with a ply orientation of 0° or
include common meanings of the same terms as used outside
90°.
the composites industry.
DISCUSSION—A ply with an orientation of 0° or 90° is balanced unto
1.3 Definitions included have, in general, been approved as
itself, and thus does not require another ply to balance it within a
standard.
laminate.
1.4 This international standard was developed in accor-
bond, n—the act of adhering one surface to another, with or
dance with internationally recognized principles on standard-
without the use of an adhesive at the interface.
ization established in the Decision on Principles for the
DISCUSSION—See co-cure (cocure), co-bond (cobond) and second-
Development of International Standards, Guides and Recom-
ary bond for associated terms.
mendations issued by the World Trade Organization Technical
braid, n—a textile process that interlaces, in a specific pattern,
Barriers to Trade (TBT) Committee.
three or more yarns such that no two yarns are twisted
around each other.
2. Referenced Documents
2
breather string, n—a string, composed of a material such as
2.1 ASTM Standards:
glass, that provides a vacuum path from the laminate to a
D123 Terminology Relating to Textiles
breather.
3
2.2 Industry Standard:
CMH-17 Composite Materials Handbook
bundle, n—a general term for a collection of essentially
parallel filaments.
3. Terminology
carbon fiber precursor, n—a material from which carbon fiber
3.1 Definitions:
is made by pyrolysis.
645°, adj—describing a laminate that is balanced, and that
DISCUSSION—Polyacrylonitrile, rayon, and pitch fibers are commonly
consists only of plies with ply orientations of +45° and −45°.
used precursors.
DISCUSSION—A 645° laminate is not necessarily symmetric.
caul, n—a flat or contoured tool used to distribute pressure and
to define a surface for the top of the laminate during laminate
consolidation or cure.
1
This terminology is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.01 on
co-bond, cobond, n—the act of curing (or consolidating) and
Editorial and Resource Standards.
bonding one semi-solid detail (for example, uncured ther-
Current edition approved May 1, 2023. Published June 2023. Originally
moset polymer or a thermoplastic polymer) to a solid detail
approved in 1981. Last previous edition approved in 2020 as D3878 – 20b. DOI:
10.1520/D3878-23.
in a single process through principal action of the matrix,
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
possibly with the inclusion of a separate layer of adhesive at
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the interface.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3
co-cure, cocure, n—the act of curing two semi-solid details
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,
PA 15096, http://www.sae.org. (that is, uncured thermoset polymers) in a single process,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D3878 − 23
resulting in the two details being bonded through principal matrix material within defined boundaries or to prevent
action of the matrix, possibly with the inclusion of a separate crowning of a processing bag.
layer of
...

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 − 20b D3878 − 23
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, 645°, n—adj—a balanced and symmetric laminate consistingdescribing a laminate that is balanced, and that
consists only of plies with ply orientations of only +45° and −45°.
DISCUSSION—
A 645° laminate is not necessarily symmetric.
angleply laminate, angleply, n—adj—describing a balanced laminate consisting laminate that is balanced, and that consists only
of plies with ply orientations of only plus theta and minus theta.
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. 1, 2020May 1, 2023. Published October 2020June 2023. Originally approved in 1981. Last previous edition approved in 2020 as
D3878 – 20a.D3878 – 20b. DOI: 10.1520/D3878-20B.10.1520/D3878-23.
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 − 23
DISCUSSION—
An angleply laminate is not necessarily symmetric.
balanced laminate, balanced, n—adj—describing a laminate that contains one ply with a ply orientation of minus theta for
every ply of the same material and thickness with a ply orientation of plus theta.theta, and any number of plies with a ply
orientation of 0° or 90°.
DISCUSSION—
A ply with an orientation of 0° or 90° is balanced unto itself, and thus does not require another ply to balance it within a laminate.
bond, n—the act of adhering one surface to another, with or without the use of an adhesive at the interface.
DISCUSSION—
See co-cure (cocure),co-bond (cobond) and secondary bond for associated terms.
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—
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.
braidedbraid, fabric—n—seea braided fabrictextile process underthat fabric.interlaces, in a specific pattern,
...