1、Designation: D3878 16D3878 18Standard Terminology forComposite Materials1This standard is issued under the fixed designation D3878; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses
2、indicates the year of last reapproval. Asuperscript 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. Scope1.1 These definitions cover generic terms, including terms of commercial im
3、portance, that appear in one or more standards oncomposites containing high-modulus (greater than 20-GPa (3 106 psi) fibers.1.2 The definitions cover, in most cases, special meanings used in the composites industry. No attempt has been made to includecommon meanings of the same terms as used outside
4、 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 standardizationestablished in the Decision on Principles for the Development of International Standa
5、rds, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to Textiles2.2 Industry Standard:3CMH-17 Composite Materials Handbook3. Terminology3.1 Definitions:645 laminatea bala
6、nced symmetric laminate composed of only +45 plies and 45 plies.angleply laminateany balanced laminate consisting of plus and minus theta plies where theta is an acute angle with respect toa reference direction.balanced laminateany laminate that contains one ply of minus theta orientation with respe
7、ct to the laminate principal axis forevery identical ply with a plus theta orientation.bond, nthe act of adhering one surface to another, with or without the use of an adhesive at the interface.co-cure, cocuresee Cure.co-bond, cobond, nthe act of curing (or consolidating) and bonding one semi-solid
8、detail (e.g. uncured thermoset polymer ora thermoplastic polymer) to a solid detail in a single process through principal action of the matrix, possibly with the inclusionof a separate layer of adhesive at the interface.secondary bond, nthe act of bonding two or more already-cured thermoset composit
9、e or other solid details, during which theonly chemical or thermal reaction, or both, occurring is the curing of the adhesive layer at the interface.DISCUSSION1 This terminology is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D3
10、0.01 on Editorial andResource Standards.Current edition approved Aug. 1, 2016April 1, 2018. Published October 2016April 2018. Originally approved in 1981. Last previous edition approved in 20132016 asD3878 07D3878 16.(2013). DOI: 10.1520/D3878-16.10.1520/D3878-18.2 For referencedASTM standards, visi
11、t theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096, http:/www.sae
12、.org.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. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prio
13、r editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1For example, a previously cured composite o
14、r metal doubler bonded via an adhesive to a previously cured skin, or a previously cured face sheet bondedvia an adhesive to a honeycomb core. Also applies to bonding metallic substrates such as aluminum face sheets onto aluminum honeycomb core.braided fabricsee braided fabric under fabric.breather
15、string, na string, composed of a material such as glass, that provides a vacuum path from the laminate to a breather.bundlea general term for a collection of essentially parallel filaments.carbon fiber precursora material from which carbon fiber is made by pyrolysis. Polyacrylonitrile, rayon, or pit
16、ch fibers arecommonly used precursors.catenary:filament catenarythe difference in length of the filaments in a specified length of tow, end, or strand as a result of unequaltension; the tendency of some filaments in a taut horizontal tow, end, or strand to sag lower than others.roving catenarythe di
17、fference in length of the ends, tows, or strands in a specified length of roving as a result of unequaltension; the tendency of some ends, tows, or strands in a taut horizontal roving to sag lower than others.caul, na flat or contoured tool used to distribute pressure and to define a surface for the
18、 top of the laminate during laminateconsolidation or cure.co-fabrication, n(cofabrication) a fabrication process where items such as inserts and other details are bonded into a compositestructural component at the same time that the component is cured or posite:composite materiala substance consisti
19、ng of two or more materials, insoluble in one another, which are combined to form auseful engineering material possessing certain properties not possessed by the constituents.DISCUSSIONaA composite material is inherently inhomogeneous on a microscopic scale but can often be assumed to be homogeneous
20、 on a macroscopic scale forcertain engineering applications. The constituents of a composite retain their identities: they do not dissolve or otherwise merge completely into eachother, although they act in concert.discontinuous fiber-reinforced compositeany composite material consisting of a matrix
21、reinforced by discontinuous fibers. Thefibers may be whiskers or chopped fibers.fabric-reinforced compositeany composite material consisting of a matrix reinforced by fabric (woven, knitted, or braidedassemblages of fibers).fiber-reinforced compositeany composite material consisting of a matrix rein
22、forced by continuous or discontinuous fibers.filamentary compositea composite material reinforced with continuous fibers.unidirectional fiber-reinforced compositeany fiber-reinforced composite with all fibers aligned in a single direction.continuous filament yarn, ntwo or more continuous filaments t
23、wisted into a single fiber bundle.core, nin sandwich construction, an inner layer of a multi-layer adherend assembly.assembly, as shown in Fig. 1.DISCUSSIONThe core is usually of a relatively low density material. material and is often substantially thicker than the other layers. It separates the su
24、rface layers,layers (face sheets), and other possible layers, of a multi-layer sandwich construction, generally stabilizing the face sheets and transmitting shearbetween them.Core can also be used in non-sandwich configurations, such as tubular constructions, where it is usually the innermost materi
25、al.honeycomb core, na core material having a thin-walled cell structure made from a wide range of materials that can be formedinto various cell configurations.DISCUSSIONHoneycomb core materials are formed from sheet materials into configurations resembling honeycomb in appearance. Strictly speaking,
26、 theFIG. 1 Sandwich ConstructionD3878 182honeycomb cell configuration is hexagonal, but in practice, additional configurations are often referred to as “honeycomb,” including, but not limitedto, ox (over-expanded), flex, tube, and dovetail. Honeycomb core materials exhibit anisotropic behavior; ther
27、efore the following notation is used:L = ribbon or longitudinal direction of core, parallel to the material used to construct the core;W = expanded or transverse direction of core; andT = core thickness or cell depth.core shear instability, nthe core-dominated buckling of a sandwich construction dep
28、endent on the transverse shear stiffness ofthe core.DISCUSSIONCore shear instability in a sandwich construction loaded under in-plane compression or shear, occurs through the depth (thickness) of the core, andmay result in failure of the component by causing the face sheets to also fail locally due
29、to reduction in support. This phenomenon is sometimesimprecisely referred to as “shear crimping.”crossply laminatea laminate composed of only 0 and 90 plies. This is not necessarily symmetric.cure, nin thermoset polymer composite materials, the process resulting in the overall transformation of the
30、polymeric matrixphase of the composite from a low molecular weight resin/hardener system to a cross-linked network by chemical reactionco-cure, n(cocure) the act of curing two semi-solid media (i.e. uncured thermoset polymers) in a single process, resulting inthe two media being bonded through princ
31、ipal action of the matrix, possibly with the inclusion of a separate layer of adhesive atthe interface.dam, na solid material (such as silicone rubber, steel, or aluminum), used in processing composites, to contain the matrixmaterial within defined boundaries or to prevent crowning of a processing b
32、ag.damage, nin structures and structural mechanics, a structural anomaly in material or structure created by manufacturing orservice usage.damage resistance, nin structures and structural mechanics, a measure of the relationship between the force, energy, or otherparameter(s) associated with an even
33、t or sequence of events and the resulting damage size and type.DISCUSSIONDamage resistance increases as the force, energy, or other parameter increases for a given size or type of damage. Conversely, damage resistanceincreases as damage decreases, for a given applied force, energy, or other paramete
34、r. Damage resistance and damage tolerance are often confused. Amaterial or structure with high damage resistance will incur less physical damage from a given event. Materials or structures with high damagetolerance may incur varying levels of physical damage but will have high amounts of remaining f
35、unctionality.Adamage-resistant material or structuremay, or may not, be considered damage tolerant.damage tolerance, n1) in structures and structure materials, a measure of the relationship between damage size and type andthe level of a performance parameter, such as stiffness or strength, at which
36、the structure or structural material can operate fora particular loading condition; 2) in structural systems, a measure of the ability of such systems to function at designatedperformance parameters (for example, magnitude, length of time, and type of loading(s) without system failure in the presenc
37、eof a particular or specified level of damage.DISCUSSIONDamage tolerance involves, and can be provided by, a number of factors operating at a number of levels: structural material, structural, and overallsystem. These factors include 1) basic material ability to operate with damage present (often re
38、ferred to as the residual strength aspect), 2) damagegrowth resistance and containment provided by material and structural considerations, and 3) system inspection and maintenance plans which allowthe damage to be detected and corrected and which depend upon material, structural, and operational con
39、siderations.Damage tolerance increases as the damage size increases for a given level of a performance parameter. Damage tolerance increases as the level ofthe performance parameter increases for a given damage size. Damage tolerance depends upon the type of loading which is applied. For example, th
40、edamage tolerance for a compressive load can be, and generally is, different than for the same level of tensile load.Damage resistance is often confused with damage tolerance. Damage tolerance is directly related only to the size and type of damage while beingonly indirectly related to how the damag
41、e was created (see damage resistance). Thus, damage tolerance is distinct from damage resistance.debonda deliberate separation of a bonded joint or interface, usually for repair or rework purposes.debulk, vto decrease voids between lamina before laminate consolidation through use of vacuum or by mec
42、hanical means.DISCUSSIOND3878 183Laminae can be debulked at ambient or elevated temperatures.delaminationseparation of plies in a laminate. This may be local or may cover a large area in the laminate.denier, na direct numbering system for expressing linear density, equal to the mass in grams per 900
43、0 metres of yarn, filament,fiber, or other textile strand.disbondan area within a bonded interface between two adherents in which an adhesive or cohesive failure has occurred. It mayoccur at any time during the life of the structure and may arise from a wide variety of causes. It is sometimes used t
44、o describean area of separation between two laminae in the finished laminate (the term “delamination” is preferred).discontinuous fibera polycrystalline or amorphous fiber that is discontinuous within the sample or component or that has oneor both ends inside of the stress field under consideration.
45、 The minimum diameter of a discontinuous fiber is not limited, butthe maximum diameter may not exceed 0.25 mm (0.010 in.).end, nin fibrous composites, a general term for a continuous, ordered assembly of essentially parallel, collimated filaments, withor without twist.DISCUSSIONThis term covers tow,
46、 strand, sliver, yarn, and roving. The relationship between fiber form terms is shown in Table X1.1.fabrica planar textile (Synonym: cdth)braided fabric, na cloth constructed by a braiding process.knitted fabric, na cloth constructed by a knitting process.nonwoven fabric, na cloth constructed by bon
47、ding or interlocking, or both (but not interlacing) fiber by any combination ofmechanical, chemical, thermal, or solvent means.plied yarn, na yarn formed by twisting together two or more single yarns in one operation.DISCUSSIONPlying, which is done in the opposite direction from the twist of each of
48、 the simple yarns, serves to counter the tendency of simple yarns to untwist.woven fabric, na cloth constructed by a weaving process.face sheets, facesheets, nin sandwich construction, the outer structural layers on each face of the core. (Synonyms: face, skin,facing.)DISCUSSIONThe face sheets are g
49、enerally thin and of higher density relative to the core. The face sheets provide the primary ability to equilibrate the in-planenormal and shear forces from bending and torsion applied to the construction. If the face sheets are composite, then the entire composite laminatebonded to one side of the core constitutes a face sheet, as shown in Fig. 1.face sheet dimpling, nin sandwich construction, (1) the buckling of a face sheet into or out of the individual cells of ahoneycomb core discontinuou
