ASTM_D_3846_-_08_2015.pdf

Designation:D384608(Reapproved 2015)Standard Test Method forIn-Plane Shear Strength of Reinforced Plastics1This standard is issued under the fixed designation D3846;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 This test method covers the determination of the in-plane shear strength of reinforced thermosetting plastics in flatsheet form in thicknesses ranging from 2.54 to 6.60 mm(0.100to 0.260 in.).This protocol in not for reinforced pultrudedthermoset products,which may use Test Method D2344/D2344M.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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 limitations prior to use.NOTE1There is no known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD695 Test Method for Compressive Properties of RigidPlasticsD2344/D2344M Test Method for Short-Beam Strength ofPolymer Matrix Composite Materials and Their LaminatesE4 Practices for Force Verification of Testing MachinesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 in-plane shear strengththe shear strength at rupturein which the plane of fracture is located along the longitudinalaxis of the specimen between two centrally located notchesmachined halfway through its thickness on opposing faces.4.Summary of Test Method4.1 In-plane shear strength,as determined by this testmethod,is measured by applying a compressive load to anotched specimen of uniform width.The specimen is loadededgewise in a supporting jig of the same description as thatreferenced in Test Method D695 for testing thin specimens.Aschematic of the specimen used for this test and the supportingjig is shown in Fig.1.Failure of the specimen occurs in shearbetween two centrally located notches machined halfwaythrough its thickness and spaced a fixed distance apart onopposing faces.5.Significance and Use5.1 Shear tests of various kinds are widely used in thereinforced plastics industry to assess the strength of thereinforcement-to-resin bond in polyester-,vinyl ester-,andepoxy-resin composites.In addition to their importance for thegeneration of data for research and development,qualitycontrol,and specification purposes,such tests are of fundamen-tal value to the fibrous reinforcement industry,since they canbe used to assess the potential of new sizing systems for thesurface treatment of glass fibers.5.2 This test method is useful for establishing the shearstrength of laminates or other reinforced plastics havingrandomly dispersed fiber reinforcement.While the test alsolends itself to parallel-fiber reinforced plastics,it has beendesigned to accommodate nonparallel-fiber reinforced materi-als that cannot be tested satisfactorily by the short-beamprocedure described in Test Method D2344/D2344M.6.Apparatus6.1 Testing MachineAny suitable testing machine capableof control of constant-rate-of-crosshead movement and com-prising essentially the following:6.1.1 Drive MechanismA drive mechanism for impartingto the movable member a uniform,controlled velocity withrespect to the stationary member,as required in 10.3.6.1.2 Load IndicatorA load-indicating mechanism ca-pable of showing the total compressive load carried by the test1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset-ting Plastics.Current edition approved Sept.1,2015.Published September 2015.Originallyapproved in 1979.Last previous edition approved in 2008 as D3846-08.DOI:10.1520/D3846-08R15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 specimen.The mechanism shall be essentially free of inertiallag at the specified rate of testing and shall indicate the loadwith an accuracy of 61%of the maximum indicated value ofthe test(load).The accuracy of the testing machine shall beverified at least once a year in accordance with Practices E4.6.1.3 Compression ToolA compression tool for applyingthe load to the test specimen,such as those shown in Figs.1and