ASTM_D_3878_-_16.pdf

Designation:D387816Standard 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 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 termsof commercial importance,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 composites 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 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 for 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 polymeror 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 whichthe 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 honeycombcore.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 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 strand 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 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 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 ASTM 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 co-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 cured 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 amicroscopic 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