1、Designation: E1922 04 (Reapproved 2015)Standard Test Method forTranslaminar Fracture Toughness of Laminated andPultruded Polymer Matrix Composite Materials1This standard is issued under the fixed designation E1922; the number immediately following the designation indicates the year oforiginal adopti
2、on 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.1. Scope1.1 This test method covers the determination of translami-nar fracture toughn
3、ess, KTL, for laminated and pultrudedpolymer matrix composite materials of various ply orientationsusing test results from monotonically loaded notched speci-mens.1.2 This test method is applicable to room temperaturelaboratory air environments.1.3 Composite materials that can be tested by this test
4、method are not limited by thickness or by type of polymermatrix or fiber, provided that the specimen sizes and the testresults meet the requirements of this test method. This testmethod was developed primarily from test results of variouscarbon fiber epoxy matrix laminates and from additionalresults
5、 of glass fiber epoxy matrix, glass fiber-polyestermatrix pultrusions and carbon fiber bismaleimide matrixlaminates (1-4, 5, 6).21.4 A range of eccentrically loaded, single-edge-notchtension, ESE(T), specimen sizes with proportional planardimensions is provided, but planar size may be variable andad
6、justed, with associated changes in the applied test load.Specimen thickness is a variable, independent of planar size.1.5 Specimen configurations other than those contained inthis test method may be used, provided that stress intensitycalibrations are available and that the test results meet therequ
7、irements of this test method. It is particularly importantthat the requirements discussed in 5.1 and 5.4 regardingcontained notch-tip damage be met when using alternativespecimen configurations.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are include
8、d in thisstandard.1.7 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 to determine theapplicability of regulatory limitations prior to
9、use.2. Referenced Documents2.1 ASTM Standards:3D883 Terminology Relating to PlasticsD3039/D3039M Test Method for Tensile Properties of Poly-mer Matrix Composite MaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning
10、of Polymer MatrixComposite MaterialsD5528 Test Method for Mode I Interlaminar Fracture Tough-ness of Unidirectional Fiber-Reinforced Polymer MatrixCompositesE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE83 Practice for Verification an
11、d Classification of Exten-someter SystemsE399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE1823 Terminology Relating to Fatigue and Fracture Testing3. Terminology3.1 Definitions:3.1.1 Terminology E6, E1823, and D3878 are applicable tothis test method.3.2 Def
12、initions of Terms Specific to This Standard:3.2.1 notch-mouth displacement, VnLthe Mode I (alsocalled opening mode) component of crack or notch displace-ment due to elastic and permanent deformation. The displace-ment is measured across the mouth of the notch on thespecimen edge (see Fig. 1).3.2.2 n
13、otch length, anLthe distance from a referenceplane to the front of the machined notch. The reference plane1This test method is under the jurisdiction of ASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommittee E08.05 on CyclicDeformation and Fatigue Crack Formation.
14、Current edition approved May 1, 2015. Published August 2015. Originallyapproved in 1997. Last previous edition approved in 2010 as E192204(2010)1.DOI: 10.1520/E1922-04R15.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, v
15、isit 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-
16、2959. United States1depends on the specimen form, and normally is taken to beeither the boundary, or a plane containing either the load line orthe centerline of a specimen or plate. The reference plane isdefined prior to specimen deformation (see Fig. 2).3.2.3 normalized notch size, an/W ndthe ratio
17、 of notchlength, an, to specimen width, W.3.2.4 For additional information, see Terminology D883and Test Methods D3039/D3039M, D5229/D5229M, andD5528.4. Summary of Test Method4.1 This test method involves tension testing of eccentri-cally loaded, single-edge-notch, ESE(T), specimens in openingmode l
18、oading. Load versus displacement across the notch atthe specimen edge, Vn, is recorded. The load corresponding toa prescribed increase in normalized notch length is determined,using the load-displacement record. The translaminar fracturetoughness, KTL, is calculated from this load using equationstha
19、t have been established on the basis of elastic stress analysisof the modified single-edge notched specimen.4.2 The validity of translaminar fracture toughness, KTL,determined by this test method depends on maintaining arelatively contained area of damage at the notch tip. Tomaintain this suitable n
20、otch-tip condition, the allowed increasein notch-mouth displacement near the maximum load point ofthe tests is limited to a small value. Small increases innotch-mouth displacement are more likely for relatively thicksamples and for samples with a significant proportion of thenear surface reinforcing
21、 fibers aligned parallel to the directionof the notch.5. Significance and Use5.1 The parameter KTLdetermined by this test method is ameasure of the resistance of a polymer matrix compositelaminate to notch-tip damage and effective translaminar crackgrowth under opening mode loading. The result is va
22、lid onlyfor conditions in which the damage zone at the notch tip issmall compared with the notch length and the in-plane speci-men dimensions.5.2 This test method can serve the following purposes. Inresearch and development, KTLdata can quantitatively estab-lish the effects of fiber and matrix varia
23、bles and stackingsequence of the laminate on the translaminar fracture resistanceof composite laminates. In acceptance and quality controlspecifications, KTLdata can be used to establish criteria formaterial processing and component inspection.5.3 The translaminar fracture toughness, KTL, determined
24、 bythis test method may be a function of the testing speed andtemperature. This test method is intended for room temperatureand quasi-static conditions, but it can apply to other testconditions provided that the requirements of 9.2 and 9.3 aremet. Application of KTLin the design of service component
25、sshould be made with awareness that the test parametersFIG. 1 Test Arrangement for Translaminar Fracture Toughness TestsNOTE 1All dimensions +/ 0.01 W, except as noted.NOTE 2A surfaces perpendicular and parallel as applicable within 0.01 W.FIG. 2 Translaminar Fracture Toughness Test SpecimenE1922 04
26、 (2015)2specified by this test may differ from service conditions,possibly resulting in a different material response than that seenin service.5.4 Not all types of laminated polymer matrix compositematerials experience the contained notch-tip damage andeffective translaminar crack growth of concern
27、in this testmethod. For example, the notch-tip damage may be moreextensive and may not be accompanied by any significantamount of effective translaminar crack growth. Typically,lower strength composite materials and those with a significantproportion of reinforcing fibers aligned in a direction perp
28、en-dicular to the notch axis may not experience the containednotch-tip damage required for a valid test.6. Apparatus6.1 LoadingSpecimens shall be loaded in a testing ma-chine that has provision for simultaneous recording of the loadapplied to the specimen and the resulting notch-mouth dis-placement.
29、 A typical arrangement is shown in Fig. 1. Pin-loading clevises of the type used in Test Method E399 are usedto apply the load to the specimen. The accuracies of the loadmeasuring and recording devices should be such that load canbe determined with an accuracy of 61 %. (For additionalinformation see
30、 Practices E4).6.2 Displacement GageAdisplacement gage shall be usedto measure the displacement at the notch mouth during loading.An electronic displacement gage of the type described in TestMethod E399 can provide a highly sensitive indicator ofnotch-mouth displacement for this purpose. The gage is
31、 at-tached to the specimen using knife edges affixed to thespecimen or integral knife edges machined into the specimen.Integral knife edges may not be suitable for relatively lowstrength materials. Other types of gages and attachments maybe used if it can be demonstrated that they will accomplish th
32、esame result. The accuracies of the displacement measuring andrecording devices should be such that the displacement can bedetermined with an accuracy of 61 %. (For additional infor-mation see Practice E83).7. Specimen Configuration and Preparation7.1 Specimen ConfigurationThe required test and spec
33、i-men configurations are shown in Fig. 1 and Fig. 2. The notchlength, an, shall be between 0.5 and 0.6 times the specimenwidth, W. The notch width shall be 0.015 W or thinner (see Fig.2). The specimen thickness, B, is the full thickness of thecomposite material to be tested. A thickness as small as
34、2 mmhas been found to work well. However, too small a thicknesscan cause out-of-plane buckling, which invalidates the test.The specimen width is selected by the user. A value of Wbetween 25 and 50 mm has been found to work well. Otherspecimen dimensions are based on specimen width.7.2 Specimen Orien
35、tationThe load axis of the specimenbefore testing shall be aligned to within 2 with the intendedlaminate test direction. For example, a KTLtest of a 0/905Slaminate would involve the testing of a twenty ply specimenwith the fibers in the 0 plies aligned within 2 with the loadaxis of the specimen.7.3
36、Specimen PreparationThe dimensional tolerancesshown in Fig. 2 shall be followed in the specimen preparation.The notch can be prepared using any process that produces therequired narrow slit. Prior tests (12) show that a notch widthless than 0.015 W gives consistent results regardless of notchtip pro
37、file. A diamond impregnated copper slitting saw or ajewelers saw have been found to work well. Use caution toprevent splitting or delamination of the surface plies near thenotch tip.8. Procedure8.1 Number of Tests It is required that enough tests beperformed to obtain three valid replicate test resu
38、lts for eachmaterial condition. If material variations are expected, fivetests are required.8.2 Specimen MeasurementThree specimen measure-ments are necessary to calculate applied K: notch length, an;thickness, B; and width, W. Complete separation of thespecimen into two pieces often occurs during a
39、 test, so it isrequired that the specimen measurements be done prior totesting. Also, exercise care to prevent injury to test personnel.8.2.1 Measure the notch length, an, to the nearest 0.1 mm oneach side of the specimen. Use the average of the two notchlength measurements in the calculations of ap
40、plied K.8.2.2 Measure the thickness, B, to the nearest 0.002 W,atnofewer than three equally spaced positions around the notch.Record the average of the three measurements as B for thatspecimen. Composite fabrication methods result in variationsin specimen thickness, due to differences in volume frac
41、tion ofmatrix material. Therefore, the nominal average thicknesscalculated from the individual thickness of all the specimenstested from a given component shall be used in the calculationof applied K.8.2.3 Measure the width, W, to the nearest 0.05 mm.8.3 Loading Rate Load the specimen at a rate such
42、 thatthe time from zero to peak load is between 30 and 100 s.8.4 Test Record Make a plot of load versus the output ofthe displacement gage. Choose plotting scales so that the slopeof the initial linear portion of the record is between 0.7 and 1.5.Continue the test until the load has reached a peak a
43、nd droppedto 50 % of the peak value.9. Calculation or Interpretation of Results9.1 Calculation of Applied Stress Intensity Factor,KCalculate the applied K for the ESE(T) specimen from thefollowing expression (4, 7);K 5 P/BW1/2# 1/21.41#3.97 2 10.88 126.25 22 38.9 3130.15 42 9.27 5#/1 2 #3/2(1)where:
44、K = applied stress intensity factor, MPa m1/2,P = applied load, MN, = a/W (dimensionless),an= notch length as determined in 8.2.1,m,B = specimen thickness as determined in 8.2.2,m,W = specimen width as determined in 8.2.3,m,E1922 04 (2015)3and the expression is valid for 0 1, for isotropicmaterials
45、and for a wide range of laminates (1).9.2 Validity Criteria for KTLTranslaminar fracture tests ofcarbon fiber/ polymer matrix laminates (1-4) have shown thatmaterials with a relatively small damage zone, required forconsistent KTLmeasurements, also display relatively smallamounts of additional notch
46、-mouth displacement, Vn, duringfracture. A typical load versus notch-mouth displacement plotfor a laminate is shown in Fig. 3. For a variety of materials, themaximum applied K value determined from the maximum loadduring the test provides a consistent measure of translaminarfracture toughness when t
47、he notch-mouth displacement valuesat maximum load are within the following criterion (4):Vn/Vn2o#0.3 (2)where:Vn-o= Vnat P=Pmaxon the extension of the initial linearportion of the plot (see Fig. 3), andVn= the additional notch-mouth displacement up to thePmaxpoint.9.3 Determination of KTLTo determin
48、e the translaminarfracture toughness, use the following procedure.9.3.1 Determine the maximum applied K value, Kmax, cor-responding to the maximum load during the test, Pmax, usingthe equation in 9.1.9.3.2 Determine the values of Vnand Vn-ofrom the loadversus notch-mouth displacement plot, using the
49、 procedureshown in Fig. 3.9.3.3If: Vn/Vn-o# 0.3, then Kmax= KTL.If: Vn/Vn-o 0.3, the extent of damage around the notch maybe too large and it is not possible to obtain ameasure of KTL.10. Report10.1 Report the following information for each specimentested:10.1.1 The principal dimensions of the specimen, includingthickness, width, and notch depth,10.1.2 Descriptions of the test equipment and procedures,including testing machine, rate of loading, and displacementgages,10.1.3 Description of the tested material, including the
