1、Designation: D4255/D4255M 01 (Reapproved 2007)D4255/D4255M 15Standard Test Method forIn-Plane Shear Properties of Polymer Matrix CompositeMaterials by the Rail Shear Method1This standard is issued under the fixed designation D4255/D4255M; the number immediately following the designation indicates th
2、eyear 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.This standard has been approved for use by agencies of the U.S
3、. Department of Defense.1. Scope1.1 This test method determines the in-plane shear properties of high-modulus fiber-reinforced composite materials by eitherof two procedures. In Procedure A, laminates clamped between two pairs of loading rails are tested. When loaded in tension therails introduce sh
4、ear forces in the specimen. In Procedure B, laminates clamped on opposite edges with a tensile or compressiveload applied to a third pair of rails in the center are tested.1.2 Application of this test method is limited to continuous-fiber or discontinuous-fiber-reinforced polymer matrix compositesin
5、 the following material forms:1.2.1 Laminates composed only of unidirectional fibrous laminae, with the fiber direction oriented either parallel orperpendicular to the fixture rails.1.2.2 Laminates composed only of woven fabric filamentary laminae with the warp direction oriented either parallel orp
6、erpendicular to the fixture rails.1.2.3 Laminates of balanced and symmetric construction, with the 0 direction oriented either parallel or perpendicular to thefixture rails.1.2.4 Short-fiber-reinforced composites with a majority of the fibers being randomly distributed.NOTE 1Additional test methods
7、for determining in-plane shear properties of polymer matrix composites may be found in Test MethodsD5379/D5379M and D5448/D5448M, and Practice D3518/D3518M.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user o
8、f this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text theinch-pounds units are shown in bracket
9、s. The values stated in each system are not exact equivalents; therefore, each system mustbe used independently of the other. Combining values from the two systems may result in nonconformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associa
10、ted with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity (Relative De
11、nsity) of Plastics by DisplacementD883 Terminology Relating to PlasticsD2584 Test Method for Ignition Loss of Cured Reinforced ResinsD2734 Test Methods for Void Content of Reinforced PlasticsD3171 Test Methods for Constituent Content of Composite Materials1 This test method is under the jurisdiction
12、 of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.04 on Lamina andLaminate Test Methods.Current edition approved May 1, 2007April 1, 2015. Published June 2007April 2015. Originally approved in 1983. Last previous edition approved in 20012007 asD4255/D
13、4255M 01.D4255/D4255M 01(2007). DOI: 10.1520/D4255_D4255M-01R07.10.1520/D4255_D4255M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summar
14、y page on the ASTM website.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 t
15、hat users consult prior 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 States1D3518/D3518M Test Met
16、hod for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test of a 645LaminateD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix CompositeMaterialsD5379/D5379M Test Method for She
17、ar Properties of Composite Materials by the V-Notched Beam MethodD5448/D5448M Test Method for Inplane Shear Properties of Hoop Wound Polymer Matrix Composite CylindersE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE111 Test Method for Y
18、oungs Modulus, Tangent Modulus, and Chord ModulusE122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcessE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE251 Test Methods for Performance Characteris
19、tics of Metallic Bonded Resistance Strain GagesE456 Terminology Relating to Quality and StatisticsE1237 Guide for Installing Bonded Resistance Strain GagesE1309 Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in DatabasesE1434 Guide for Recording Mechanical Test Data
20、of Fiber-Reinforced Composite Materials in DatabasesE1471 Guide for Identification of Fibers, Fillers, and Core Materials in Computerized Material Property Databases2.2 ASTM Adjunct:Adjunct No. ADJD4255, Rail Shear Fixtures Machining Drawings33. Terminology3.1 Terminology D3878 defines terms relatin
21、g to high-modulus fibers and their composites. Terminology D883 defines termsrelating to plastics. Terminology E6 defines terms relating to mechanical testing. Terminology E456 and Practice E177 define termsrelating to statistics. In the event of a conflict between terms, Terminology D3878 shall hav
22、e precedence over the other terminologystandards.3 A copy of the detailed drawing for the construction of the fixtures shown in Figs. 1 and 2 is available at a nominal cost from ASTM Headquarters. Request Adjunct No.ADJD4255.FIG. 1 Procedure A Assembly Rail Shear ApparatusD4255/D4255M 152NOTE 2If th
23、e term represents a physical quantity, its analytical dimensions are stated immediately following the term (or letter symbol) infundamental dimension form, using the following ASTM standard symbology for fundamental dimensions, shown within square brackets: M for mass,L for length, T for time, for t
24、hermodynamic temperature, and nd for nondimensional quantities. Use of these symbols is restricted to analyticaldimensions when used with square brackets, as the symbols may have other definitions when used without the brackets.3.2 Definitions of Terms Specific to This Standard:3.2.1 in-plane shear,
25、 nshear associated with shear forces applied to the edges of the laminate so that the resulting sheardeformations occur in the plane of the laminate rather than through the thickness.3.2.2 offset shear stress M/(LT2), , nthe shear stress associated with an offset of the shear chord modulus of elasti
26、city linealong the strain axis (see 12.4).3.2.3 shear strength M/(LT2),nthe shear stress carried by a material at failure under a pure shear condition.3.2.4 transition region, na strain region of a stress-strain or strain-strain curve over which a significant change in the slopeof the curve occurs w
27、ithin a small strain range.3.2.4.1 DiscussionMany filamentary composite materials exhibit a nonlinear response during loading, such as seen in plots of either longitudinalstress versus longitudinal strain or transverse strain versus longitudinal strain. In certain cases, the nonlinear response may b
28、econveniently approximated by a bilinear fit. There are several physical reasons for the existence of a transition region. Commonexamples include matrix cracking under tensile loading and ply delamination.3.2.5 traveler, na small piece of the same material as, and processed similarly to, the test sp
29、ecimen, used for example tomeasure moisture content as a result of conditioning. This is also sometimes termed as a reference sample.3.3 Symbols:A = cross-sectional area of test specimenBy = percent bending of specimenCV = coefficient of variation statistic of a sample population for a given propert
30、y, %F12o = offset shear stress, the value of the shear stress at the intersection of the stress-strain plot with a line passing through theoffset strain value at zero stress and with a slope equal to the shear chord modulus of elasticityFu = ultimate shear stressG = shear modulus of elasticityh = sp
31、ecimen thicknessl = specimen length, the dimension parallel to the rails in the gage sectionn = number of specimensPi = load carried by test specimen at ith data pointPmax = load carried by a test specimen that is the lesser of (1) the maximum load before failure, (2) the load at 5 % shear strain,or
32、 (3) the load at the bending limit (see 11.8.1)sSn1 = sample standard deviationxi = measured or derived property for an individual specimen from the sample populationFIG. 2 Procedure A Partially Assembled Typical Test FixtureD4255/D4255M 153 = sample mean (average) = shear strain = indicated normal
33、strain from strain transducer = 10-6 m/m (10-6 in./in.)i = shear stress at ith data point4. Summary of Test Method4.1 Procedure A: Two-Rail Shear TestA flat panel with holes along opposing edges is clamped, usually by through bolts,between two pairs of parallel steel loading rails, see Figs. 1 and 2
34、. When loaded in tension, this fixture introduces shear forces inthe specimen that produce failures across the panel. This test method is typical but not the only configuration usable. The two-railshear fixtures can also be compression loaded. The load may be applied to failure.4.1.1 If load-strain
35、data are required, the specimen may be instrumented with strain gages. Two three-element strain gagerosettes are installed at corresponding locations on both faces of the specimen.4.2 Procedure B: Three-Rail Shear TestA flat panel, clamped securely between pairs of rails on opposite edges and in its
36、center, is loaded by supporting the side rails while loading the center rails. See Figs. 3-5.Aload on the center rail of either tensionor compression produces a shear load in each section of the specimen. The load may be applied to failure.4.2.1 The test fixture consists of three pairs of parallel r
37、ails usually bolted to the test specimen by through bolts. The two outsidepairs of rails are attached to a base plate which rests on the test machine. A third pair (middle rails) is guided through a slot inthe top of the base fixture. The unit is normally loaded in compression. It is also permissibl
38、e to load the middle rails in tension,but this requires attaching the base fixture to the test machine.4.2.2 If load-strain data are required, the specimen may be instrumented with strain gages. Three-element strain gage rosettesare to be installed at corresponding locations on opposite faces of the
39、 specimen.4.3 Detailed fixture drawings are available as ASTM Adjunct No. ADJD4255.5. Significance and Use5.1 These shear tests are designed to produce in-plane shear property data for material specifications, research and development,and design. Factors that influence the shear response and should
40、therefore be reported include: material, methods of materialpreparation and lay-up, specimen stacking sequence, specimen preparation, specimen conditioning, environment of testing,FIG. 3 Procedure B Assembly Rail Shear FixtureD4255/D4255M 154specimen alignment and gripping, speed of testing, time at
41、 temperature, void content, and fiber volume reinforcement content.Properties that may be measured by this test method include:5.1.1 In-plane shear stress versus shear strain response,5.1.2 In-plane shear chord modulus of elasticity,5.1.3 Offset shear stress, and5.1.4 Maximum in-plane shear stress.
42、In cases in which the strain at failure is greater than 5 %, the shear stress correspondingto 5 % shear strain should be reported.6. Interferences6.1 There are no standard test methods capable of producing a perfectly pure and uniform shear stress condition to failure forevery material, although som
43、e test methods can come acceptably close for a specific material for a given engineering purpose. Theoff-axis load of the two-rail method introduces a comparatively small tensile load in the panel.6.2 Material and Specimen PreparationPoor material fabrication practices, lack of control of fiber alig
44、nment, and damageinduced by improper specimen machining are known causes of high material data scatter in composites.6.3 Determination of FailureRail shear specimens, especially thin ones, can buckle during load application. Buckling can bedetected by measuring surface strains on opposite faces of t
45、he specimens with three-element strain gage rosettes. Data measuredwith the specimen in a buckled state are not representative of the material shear properties. Modulus data must be checked toconfirm that buckling has not occurred in the modulus measurement range. Strength measurements must be check
46、ed to confirmthat shear strength has not been influenced by specimen buckling. Failure by buckling should not be interpreted as indicating themaximum shear strength.FIG. 4 Procedure B Assembled Typical Test FixtureD4255/D4255M 1556.3.1 Ply delamination is another possible failure mode for laminates
47、containing a large number of 45 plies. This failure reflectsinstability of 45 plies loaded in compression as contrasted to the overall buckling failure previously described. Differences instrain gage readings will not be noticeable, but the failure can be identified by delaminated plies in contrast
48、to fiber breakage.46.4 GrippingFailure through bolt holes indicates inadequate gripping. Alternate gripping methods are discussed in 7.2.3.6.5 End EffectsThis test method assumes a state of pure shear throughout the length of the specimen gage section. However,the gage section ends have zero shear s
49、tress because no traction and no constraints are applied there.Astress transition region existsbetween the ends and interior portions of the gage section. The length of this transition region determines the error induced in thematerial shear data.7. Apparatus7.1 MicrometersMicrometers and CalipersThe micrometer(s) shall use a suitable sizeAmicrometer with a 4 to 7 mm 0.16to 0.28 in. nominal diameter ball interface on irregular surfaces such as the bag-side of a laminate and or a flat anvil interface shallbe used to measure t
