1、Designation: D3878 16Standard 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 indicate
2、s 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 termsof commercial importance,
3、 that appear in one or more stan-dards on composites containing high-modulus (greater than20-GPa (3 106psi) fibers.1.2 The definitions cover, in most cases, special meaningsused in the composites industry. No attempt has been made toinclude common meanings of the same terms as used outsidethe compos
4、ites industry.1.3 Definitions included have, in general, been approved asstandard.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to Textiles2.2 Industry Standard:3CMH-17 Composite Materials Handbook3. Terminology3.1 Definitions:645 laminatea balanced symmetric laminate composed
5、 ofonly +45 plies and 45 plies.angleply laminateany balanced laminate consisting of plusand minus theta plies where theta is an acute angle withrespect to a reference direction.balanced laminateany laminate that contains one ply ofminus theta orientation with respect to the laminate principalaxis fo
6、r every identical ply with a plus theta orientation.bond, nthe act of adhering one surface to another, with orwithout the use of an adhesive at the interface.co-cure, cocuresee Cure.co-bond, cobond, nthe act of curing (or consolidating) andbonding one semi-solid detail (e.g. uncured thermoset polyme
7、ror a thermoplastic polymer) to a solid detail in a single processthrough principal action of the matrix, possibly with theinclusion of a separate layer of adhesive at the interface.secondary bond, nthe act of bonding two or more already-cured thermoset composite or other solid details, during which
8、the only chemical or thermal reaction, or both, occurring is thecuring of the adhesive layer at the interface.DISCUSSIONFor example, a previously cured composite or metaldoubler bonded via an adhesive to a previously cured skin, or apreviously cured face sheet bonded via an adhesive to a honeycombco
9、re.Also applies to bonding metallic substrates such as aluminum facesheets onto aluminum honeycomb core.braided fabricsee braided fabric under fabric.breather string, na string, composed of a material such asglass, that provides a vacuum path from the laminate to abreather.bundlea general term for a
10、 collection of essentially parallelfilaments.carbon fiber precursora material from which carbon fiberis made by pyrolysis. Polyacrylonitrile, rayon, or pitch fibersare commonly used precursors.catenary:filament catenarythe difference in length of the filamentsin a specified length of tow, end, or st
11、rand as a result of unequaltension; the tendency of some filaments in a taut horizontaltow, end, or strand to sag lower than others.roving catenarythe difference 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
12、strands in a tauthorizontal roving to sag lower than others.caul, na flat or contoured tool used to distribute pressure andto define a surface for the top of the laminate during laminateconsolidation or cure.1This terminology is under the jurisdiction of ASTM Committee D30 onComposite Materials and
13、is the direct responsibility of Subcommittee D30.01 onEditorial and Resource Standards.Current edition approved Aug. 1, 2016. Published October 2016. Originallyapproved in 1981. Last previous edition approved in 2013 as D3878 07(2013).DOI: 10.1520/D3878-16.2For referenced ASTM standards, visit the A
14、STM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096, http:/www.sae.org.Co
15、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1co-fabrication, n(cofabrication) a fabrication process whereitems such as inserts and other details are bonded into acomposite structural component at the same time that thecomponent is cu
16、red or posite:composite materiala substance consisting of two or morematerials, insoluble in one another, which are combined toform a useful engineering material possessing certain proper-ties not possessed by the constituents.DISCUSSIONa composite material is inherently inhomogeneous on amicroscopi
17、c scale but can often be assumed to be homogeneous on amacroscopic scale for certain engineering applications. The constitu-ents of a composite retain their identities: they do not dissolve orotherwise merge completely into each other, although they act inconcert.discontinuous fiber-reinforced compo
18、site any compositematerial consisting of a matrix reinforced by discontinuousfibers. The fibers may be whiskers or chopped fibers.fabric-reinforced compositeany composite material con-sisting of a matrix reinforced by fabric (woven, knitted, orbraided assemblages of fibers).fiber-reinforced composit
19、eany composite material consist-ing of a matrix reinforced by continuous or discontinuousfibers.filamentary compositea composite material reinforcedwith continuous fibers.unidirectional fiber-reinforced compositeany fiber-reinforced composite with all fibers aligned in a single direc-tion.continuous
20、 filament yarn, ntwo or more continuous fila-ments twisted into a single fiber bundle.core, nan inner layer of a multi-layer adherend assembly.DISCUSSIONThe core is usually of a relatively low density material.It separates the surface layers, and other possible layers, of a multi-layer construction,
21、 generally stabilizing and transmitting shear betweenthem.honeycomb core, na core material having a thin-walledcell structure made from a wide range of materials that can beformed into various cell configurations.DISCUSSIONHoneycomb core materials are formed from sheetmaterials into configurations r
22、esembling honeycomb in appearance.Strictly speaking, the honeycomb cell configuration is hexagonal, but inpractice, additional configurations are often referred to as“honeycomb,” including, but not limited to, ox (over-expanded), flex,tube, and dovetail. Honeycomb core materials exhibit anisotropicb
23、ehavior; therefore the following notation is used:L = ribbon or longitudinal direction of core, parallel to the material usedto construct the core;W = expanded or transverse direction of core; andT = core thickness or cell depth.core shear instability, nthe core-dominated buckling of asandwich const
24、ruction dependent on the transverse shearstiffness of the core.DISCUSSIONCore shear instability in a sandwich construction loadedunder in-plane compression or shear, occurs through the depth (thick-ness) of the core, and may result in failure of the component by causingthe face sheets to also fail l
25、ocally due to reduction in support. Thisphenomenon is sometimes imprecisely referred to as “shear crimping.”crossply laminatea laminate composed of only 0 and 90plies. This is not necessarily symmetric.cure, nin thermoset polymer composite materials, the pro-cess resulting in the overall transformat
26、ion of the polymericmatrix phase of the composite from a low molecular weightresin/hardener system to a cross-linked network by chemicalreactionco-cure, n(cocure) the act of curing two semi-solid media(i.e. uncured thermoset polymers) in a single process, resultingin the two media being bonded throu
27、gh principal action of thematrix, possibly with the inclusion of a separate layer ofadhesive at the interface.dam, na solid material (such as silicone rubber, steel, oraluminum), used in processing composites, to contain thematrix material within defined boundaries or to preventcrowning of a process
28、ing bag.damage, nin structures and structural mechanics, a struc-tural anomaly in material or structure created by manufac-turing or service usage.damage resistance, n in structures and structuralmechanics, a measure of the relationship between the force,energy, or other parameter(s) associated with
29、 an event orsequence of events and the resulting damage size and type.DISCUSSIONDamage resistance increases as the force, energy, orother parameter increases for a given size or type of damage.Conversely, damage resistance increases as damage decreases, for agiven applied force, energy, or other par
30、ameter. Damage resistance anddamage tolerance are often confused. A material or structure with highdamage resistance will incur less physical damage from a given event.Materials or structures with high damage tolerance may incur varyinglevels of physical damage but will have high amounts of remainin
31、gfunctionality.Adamage-resistant material or structure may, or may not,be considered damage tolerant.damage tolerance, n1) in structures and structure materials,a measure of the relationship between damage size and typeand the level of a performance parameter, such as stiffness orstrength, at which
32、the structure or structural material canoperate for a particular loading condition; 2) in structuralsystems, a measure of the ability of such systems to functionat designated performance parameters (for example,magnitude, length of time, and type of loading(s) withoutsystem failure in the presence o
33、f a particular or specifiedlevel of damage.DISCUSSIONDamage tolerance involves, and can be provided by, anumber of factors operating at a number of levels: structural material,structural, and overall system. These factors include 1) basic materialability to operate with damage present (often referre
34、d to as the residualstrength aspect), 2) damage growth resistance and containment pro-vided by material and structural considerations, and 3) system inspec-tion and maintenance plans which allow the damage to be detected andcorrected and which depend upon material, structural, and operationalconside
35、rations.Damage tolerance increases as the damage size increases for a givenlevel of a performance parameter. Damage tolerance increases as thelevel of the performance parameter increases for a given damage size.Damage tolerance depends upon the type of loading which is applied.For example, the damag
36、e tolerance for a compressive load can be, andgenerally is, different than for the same level of tensile load.D3878 162Damage resistance is often confused with damage tolerance. Dam-age tolerance is directly related only to the size and type of damagewhile being only indirectly related to how the da
37、mage was created (seedamage resistance). Thus, damage tolerance is distinct from damageresistance.debonda deliberate separation of a bonded joint or interface,usually for repair or rework purposes.debulk, vto decrease voids between lamina before laminateconsolidation through use of vacuum or by mech
38、anicalmeans.DISCUSSIONLaminae can be debulked at ambient or elevatedtemperatures.delaminationseparation of plies in a laminate. This may belocal or may cover a large area in the laminate.denier, na direct numbering system for expressing lineardensity, equal to the mass in grams per 9000 metres of ya
39、rn,filament, fiber, or other textile strand.disbondan area within a bonded interface between twoadherents in which an adhesive or cohesive failure hasoccurred. It may occur at any time during the life of thestructure and may arise from a wide variety of causes. It issometimes used to describe an are
40、a of separation betweentwo laminae in the finished laminate (the term “delamina-tion” is preferred).discontinuous fibera polycrystalline or amorphous fiberthat is discontinuous within the sample or component or thathas one or both ends inside of the stress field underconsideration. The minimum diame
41、ter of a discontinuousfiber is not limited, but the maximum diameter may notexceed 0.25 mm (0.010 in.).end, nin fibrous composites, a general term for a continuous,ordered assembly of essentially parallel, collimatedfilaments, with or without twist.DISCUSSIONThis term covers tow, strand, sliver, yar
42、n, 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 bonding orinterlocking,
43、or both (but not interlacing) fiber by any combi-nation of mechanical, chemical, thermal, or solvent means.plied yarn, na yarn formed by twisting together two ormore single yarns in one operation.DISCUSSIONPlying, which is done in the opposite direction from thetwist of each of the simple yarns, ser
44、ves to counter the tendency ofsimple yarns to untwist.woven fabric, na cloth constructed by a weaving process.face sheets, facesheets, nin sandwich construction, the outerstructural layers on each face of the core. (Synonyms: face,skin, facing.)DISCUSSIONThe face sheets are generally thin and of hig
45、her densityrelative to the core. The face sheets provide the primary ability toequilibrate the in-plane normal and shear forces from bending andtorsion applied to the construction. If the face sheets are composite,then the entire composite laminate bonded to one side of the coreconstitutes a face sh
46、eet, as shown in Fig. 1.face sheet dimpling, nin sandwich construction,(1) thebuckling of a face sheet into or out of the individual cells ofa honeycomb core due to localized compressive or shearstresses, or both, or (2) the sagging of the face sheet into theindividual honeycomb cells during curing
47、of composite facesheets onto the core.DISCUSSIONAlthough described by the same phrase, these twophenomena are different in nature and in subsequent effects.face sheet wrinkle, nin sandwich construction, the localizedelastic instability (buckling) of a face sheet into or awayfrom the core as a result
48、 of in-plane compression forces.DISCUSSIONThis stress-induced phenomenon generally progressesacross the width of a sandwich panel and may result in panel failure.Not to be confused with fabrication-induced face sheet wrinkling,which is a distinctly different phenomenon.fabrication, nthe process of m
49、anufacturing, forming,constructing, or assembling a product or component.fiber, none or more filaments in an ordered assemblage.DISCUSSIONThere are a number of general and specific terms thatdefine specific types of fiber forms. The relationship between fiber formterms is shown in Table 1.fiber contentthe amount of fiber present in a compositeexpressed either as percent by weight or percent by volume.This is sometimes stated as a fraction, that is, fiber volumefraction.fiber volume fractionse
