ASTM_D_6856_-_D_6856M_-_03_2008e1.pdf

Designation:D6856/D6856M03(Reapproved 2008)1Standard Guide forTesting Fabric-Reinforced“Textile”Composite Materials1This standard is issued under the fixed designation D6856/D6856M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEEditorially changed to a combined standard in September 2010.INTRODUCTIONA variety of fabric-reinforced composite materials have been developed for use in aerospace,automotive,and other applications.These composite materials are reinforced with continuous fiberyarns that are formed into two-dimensional or three-dimensional fabrics.Various fabric constructions,such as woven,braided,stitched,and so forth,can be used to form the fabric reinforcement.Due tothe nature of the reinforcement,these materials are often referred to as“textile”composites.Textile composites can be fabricated from 2-dimensional(2-D)or 3-dimensional(3-D)fabrics.Stitched preforms and 3-D fabrics contain through-thickness yarns,which can lead to greaterdelamination resistance.Textile composites are also amenable to automated fabrication.However,themicrostructure(or fiber architecture)of a textile composite,which consists of interlacing yarns,canlead to increased inhomogeneity of the local displacement fields in the laminate.Depending upon thesize of the yarns and the pattern of the weave or braid,the inhomogeneity within a textile compositecan be large compared to traditional tape laminates.Thus,special care should be exercised in the use of the currentASTM standards developed for highperformance composites.In many cases,the current ASTM standards are quite adequate if properattention is given to the special testing considerations for textile composites covered in this guide.However,in some cases,current standards do not meet the needs for testing of the required properties.This guide is intended to increase the users awareness of the special considerations necessary for thetesting of these materials.It also provides the user with recommended ASTM standards that areapplicable for evaluating textile composites.The specific properties for which current ASTMstandards might not apply are also highlighted in this guide.1.Scope1.1 This guide is applicable to the testing of textile com-posites fabricated using fabric preforms,such as weaves,braids,stitched preforms,and so forth,as the reinforcement.The purpose of this guide is to:1.1.1 Ensure that proper consideration is given to the uniquecharacteristics of these materials in testing.1.1.2 Assist the user in selecting the best currently availableASTM test method for the measurement of commonly evalu-ated material properties for this class of materials.1.2 Areas where current ASTM test methods do not meetthe needs for testing of textile composites are indicated.1.3 It is not the intent of this guide to cover all test methodswhich could possibly be used for textile composites.Only themost commonly used and most applicable standards areincluded.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,each1This guide is under the jurisdiction of ASTM Committee D30 on CompositeMaterials and is the direct responsibility of Subcommittee D30.04 on Lamina andLaminate Test Methods.Current edition approved Sept.1,2008.Published December 2008.Originallyapproved in 2003.Last previous edition approved in 2003 as D6856-03.DOI:10.1520/D6856_D6856M-03R08E01.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 system shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2D790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-alsD792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD883 Terminology Relating to PlasticsD2344/D2344M Test Method for Short-Beam Strength ofPolymer Matrix Composite Materials and Their LaminatesD3039/D3039M Test Method for Tensile Properties of Poly-mer Matrix Composite MaterialsD3171 Test Methods for Constituent Content of CompositeMaterialsD3410/D3410M Test Method for Compressive Properties ofPolymer Matrix Composite Materials with UnsupportedGage Section by Shear LoadingD3479/D3479M Test Method for Tension-Tension Fatigueof Polymer Matrix Composite MaterialsD3