1、Designation: D5379/D5379M 05D5379/D5379M 12Standard Test Method forShear Properties of Composite Materials by the V-NotchedBeam Method1This standard is issued under the fixed designation D5379/D5379M; the number immediately following the designation indicates theyear of original adoption or, in the
2、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.1. Scope1.1 This test method covers the shear properties of composite materials reinforced by high-m
3、odulus fibers. The compositematerials are limited to continuous-fiber or discontinuous-fiber-reinforced composites in the following material forms:1.1.1 Laminates composed only of unidirectional fibrous laminae, with the fiber direction oriented either parallel orperpendicular to the loading axis.1.
4、1.2 Laminates composed only of woven fabric filamentary laminae with the warp direction oriented either parallel orperpendicular to the loading axis.1.1.3 Laminates composed only of unidirectional fibrous laminae, containing equal numbers of plies oriented at 0 and 90 ina balanced and symmetric stac
5、king sequence, with the 0 direction oriented either parallel or perpendicular to the loading axis.1.1.4 Short-fiber-reinforced composites with a majority of the fibers being randomly distributed.NOTE 1This shear test concept was originally developed without reference to fiber direction for use on is
6、otropic materials such as metals or ceramics.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text theinch-pound units are shown in brackets. The values stated in each system aremay not be exact equivalents; therefore, each systemmust
7、shall be used independently of the other. Combining values from the two systems may result in nonconformancenon-conformance with the standard.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 of this standar
8、d 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 Density) of Plastics by DisplacementD883 Terminology Relating to Plasti
9、csD2584 Test Method for Ignition Loss of Cured Reinforced ResinsD2734 Test Methods for Void Content of Reinforced PlasticsD3171 Test Methods for Constituent Content of Composite MaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for Moisture Absorption Properties and Equilibr
10、ium Conditioning of Polymer Matrix CompositeMaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE111 Test Method for Youngs Modulus, Tangent Modulus, and Chord ModulusE122 Practice for Calculating Sample Size to Estimate, With Speci
11、fied 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 Characteristics of Metallic Bonded Resistance Strain Gauges1 This test method is under the jurisdiction of ASTM Committee D30
12、 on Composite Materialsand is the direct responsibility of Subcommittee D30.04 on Lamina andLaminate Test Methods.Current edition approved March 1, 2005July 15, 2012. Published March 2005February 2013. Originally approved in 1993. Last previous edition approved in 19982005as D5379/D5379M - 98.D5379/
13、D5379M 05. DOI: 10.1520/D5379_D5379M-05.10.1520/D5379_D5379M-12.2 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 Summary page on the ASTM websi
14、te.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 that users consult prior
15、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 States1E456 Terminology Relating to Quality and Stat
16、isticsE1237 Guide for Installing Bonded Resistance Strain Gages2.2 Other Documents:ANSI Y14.5M-1982 Geometric Dimensioning and Tolerancing3ANSI/ASME B 46.1-1985 Surface Texture (Surface Roughness, Waviness, and Lay)32.3 ASTM Adjuncts:V-Notched Beam Shear Fixture Machining Drawings43. Terminology3.1
17、DefinitionsTerminology D3878 defines terms relating to high-modulus fibers and their composites. Terminology D883defines terms relating to plastics. Terminology E6 defines terms relating to mechanical testing. Terminology E456 and PracticeE177 define terms relating to statistics. In the event of a c
18、onflict between terms, Terminology D3878 shall have precedence overthe other standards.3.2 Definitions of Terms Specific to This Standard:NOTE 2If the term represents a physical quantity, its analytical dimensions are stated immediately following the term (or letter symbol) infundamental dimension f
19、orm, using the following ASTM standard symbology for fundamental dimensions, shown within square brackets: M for mass,L for length, T for time, for thermodynamic temperature, and nd for nondimensional quantities. Use of these symbols is restricted to analyticaldimensions when used with square bracke
20、ts, as the symbols may have other definitions when used without the brackets.3.2.1 in-plane shear, nany of the shear properties describing the response resulting from a shear loadforce or deformationapplied to the 1-2 material plane. (See also material coordinate system.)3.2.2 interlaminar shear, na
21、ny of the shear properties describing the response resulting from a shear loadforce or deformationapplied to the 1-3 or 2-3 material planes. (See also material coordinate system.)3.2.3 material coordinate system, na Cartesian coordinate system describing the principal material coordinate system, usi
22、ng1, 2, and 3 for the axes, as shown in Fig. 1.3.2.4 nominal value, na value, existing in name only, assigned to a measurable property for the purpose of convenientdesignation. Tolerances may be applied to a nominal value to define an acceptable range for the property.3.2.5 shear strength, nthe shea
23、r stress carried by a material at failure under a pure shear condition.3.2.5.1 DiscussionThere are no standard test methods that are capable of producing a perfectly pure shear stress condition tofailure for every material, although some test methods can come acceptably close for a specific material
24、 for a given engineeringpurpose.3.3 Symbols:3.3.1 Aminimum cross-sectional area of a coupon.3.3.2 CVcoefficient of variation statistic of a sample population for a given property (in percent).3.3.3 Fsuultimate shear strength in the test direction.3.3.4 Fuultimate strength in the test direction.3.3.5
25、 F (offset)the value of the shear stress at the intersection of the shear chord modulus of elasticity and the stress straincurve when the modulus is offset along the engineering shear strain axis from the origin by the reported strain offset value.3 Available from American National Standards Institu
26、te (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.4 Available from ASTM International Headquarters. Order Adjunct No. ADJD5379.FIG. 1 Material Coordinate SystemD5379/D5379M 1223.3.6 Gshear modulus of elasticity in the test direction.3.3.7 hcoupon thickness.3.3.8 nnumber of coupons per sample
27、population.3.3.9 Ploadforce carried by test coupon.3.3.10 Pf load force carried by test coupon at failure.3.3.11 Pmaxmaximum loadforce carried by test coupon before failure.3.3.12 sn1standard deviation statistic of a sample population for a given property.3.3.13 wcoupon width.3.3.14 xitest result fo
28、r an individual coupon from the sample population for a given property.3.3.15 xmean or average (estimate of mean) of a sample population for a given property.3.3.16 shear engineering shear strain.3.3.17 general symbol for strain, whether normal strain or shear strain.3.3.18 indicated normal strain f
29、rom strain transducer or extensometer.3.3.19 normal stress.3.3.20 shear stress.3.3.21 ply orientation angle.4. Summary of Test Method4.1 A material coupon in the form of a rectangular flat strip with symmetrical centrally located v-notches, shown schematicallyin Fig. 2, is loaded in a mechanical tes
30、ting machine by a special fixture (shown schematically in Fig. 3 and in more detail in themachining drawings of ASTM Adjunct ADJD5379.54.2 The specimen is inserted into the fixture with the notch located along the line of action of loading by means of an alignmenttool that references the fixture. Th
31、e two halves of the fixture are compressed by a testing machine while monitoring load.force.The relative displacement between the two fixture halves loads the notched specimen. By placing two strain gagegauge elements,oriented at 645 to the loading axis, in the middle of the specimen (away from the
32、notches) and along the loading axis, the shearresponse of the material can be measured.5 The specimen and fixture are based upon work at the University of Wyoming Composite Materials Research Group (1, 2), and were subsequently modified by the group(3, 4) into the configuration used by this test met
33、hod. The Wyoming investigations referred to the earlier work of Arcan (5-7) and Iosipescu (8-10), and the later work of anumber of other researchers, including Refs (11-16) (early historical perspectives are given in Refs (1, 17). The boldface numbers in parentheses refer to the list of referencesat
34、 the end of this standard.Nominal Specimen Dimensionsd1 = 20.0 mm 0.75 in.d1 = 19 mm 0.75 in.d2 = 4.0 mm 0.15 in.d2 = 3.8 mm 0.15 in.h = as requiredL = 76.0 mm 3.0 in.L = 76 mm 3.0 in.r = 1.3 mm 0.05 in.w = 12.0 mm 0.45 in.w = 11.4 mm 0.45 in.FIG. 2 V-Notched Beam Test Coupon SchematicD5379/D5379M 1
35、234.3 The loading can be idealized as asymmetric flexure, as shown by the shear and bending moment diagrams of Fig. 4.6 Thenotches influence the shear strain along the loading direction, making the distribution more uniform than would be seen withoutthe notches. While the degree of uniformity is a f
36、unction of material orthotropy, the best overall results, when testing in the 1-2plane, have been obtained on 0/90nsns-type laminates.5. Significance and Use5.1 This test method is designed to produce shear property data for material specifications, research and development, qualityassurance, and st
37、ructural design and analysis. Either in-plane or interlaminar shear properties may be evaluated, depending uponthe orientation of the material coordinate system relative to the loading axis. Factors that influence the shear response and shouldtherefore be reported include the following: material, me
38、thods of material preparation and lay-up, specimen stacking sequence,specimen preparation, specimen conditioning, environment of testing, specimen alignment and gripping, speed of testing, time attemperature, void content, and volume percent reinforcement.5.2 In anisotropic materials, properties may
39、 be obtained in any of the six possible shear planes by orienting the testing planeof the specimen with the desired material plane (1-2 or 2-1, 1-3 or 3-1, 2-3 or 3-2). Only a single shear plane may be evaluatedfor any given specimen. Properties, in the test direction, which may be obtained from thi
40、s test method, include the following:5.2.1 Shear stress/strain response,5.2.2 Ultimate strength,5.2.3 Ultimate strain, and5.2.4 Shear chord modulus of elasticity, andelasticity.5.2.5 Transition strain.6. Interferences6.1 Material and Specimen PreparationPoor material fabrication practices, lack of c
41、ontrol of fiber alignment, and damageinduced by improper coupon machining are known causes of high material data scatter in composites.6.2 Materials and Coarse StructureOne of the fundamental assumptions of this test method is that the material must berelatively homogeneous with respect to the size
42、of the test section. Materials that have relatively coarse features with respect tothe test section dimensions, such as fabrics using large filament count tows (such as tows of 12 000 filaments or more) or certainbraided structures, should not be tested with this specimen size. Scale-up of the speci
43、men and the fixturing to accommodate suchmaterials is possible, but is beyond the scope of this test method.6 While the idealization indicates constant shear loading and zero bending moment in the specimen at the notches, the actual load application is distributed and imperfect,which contributes to
44、asymmetry in the shear strain distribution and to a component of normal stress that is particularly deleterious to 90nn specimens (16).FIG. 3 V-Notched Beam Test Fixture SchematicD5379/D5379M 1246.3 Elastic Modulus MeasurementThe calculations in this test method assume a uniform shear stress state b
45、etween thenotches. The actual degree of uniformity varies with the level of material orthotropy and the direction of loading. Both analysisand full-field experimental strain measurement have shown that when testing in the 1-2 plane, 0nn specimens result in an elasticmodulus estimate that is too high
46、 (about 10 % too high for carbon/epoxy), while 90nn specimens of the same material result ina value that is about 20 % too low. The most accurate measurements of in-plane shear modulus for unidirectional materials havebeen shown to result from the 0/90nsns specimen. The use of specialized shear stra
47、in gauges, which span the length of the testsection between the notch roots, allows the average shear strain to be measured even with a nonuniform shear stress state present,and thus are recommended.6.4 LoadForce EccentricityTwisting of the specimen during loading can occur, affecting strength resul
48、ts, and especially,elastic modulus measurement.Twisting may occur due to an out-of-tolerance fixture, or from specimens that are too thin (unstable),improperly installed in the fixture, out-of-tolerance because of poor specimen preparation, or of a material configuration with anextremely low toleran
49、ce to twist. It is recommended that at least one specimen of each sample be tested with back-to-back rosettesto evaluate the degree of twist. Evaluate the percent twist for the specimen by substituting the shear modulus from each side, Gaand Gb, into |(G a Gb)/(G a + G b)| 100, evaluated at 0.004 absolute strain. If the amount of twist is greater than 3 %, then thespecimens should be examined for cause of the twisting, and corrected, if possible. If no cause is apparent or correction
