1、Designation: E 1922 04Standard Test Method forTranslaminar Fracture Toughness of Laminated andPultruded Polymer Matrix Composite Materials1This standard is issued under the fixed designation E 1922; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of translami-nar fracture toughness, KTL, for l
3、aminated 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 testmethod are not
4、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 of glass fiber
5、 epoxy matrix, glass fiber-polyestermatrix pultrusions and carbon fiber bismaleimide matrixlaminates (1-4, 6, 7).21.4 A range of eccentrically loaded, single-edge-notch ten-sion, ESE(T), specimen sizes with proportional planar dimen-sions is provided, but planar size may be variable and adjusted,wit
6、h associated changes in the applied test load. Specimenthickness 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 therequirements of
7、 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 Values stated in SI units are to be regarded as thestandard.1.7 This standard does not purport to address all of
8、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 use.2. Referenced Documents2.1 ASTM Standards:3D 883 Terminology Relati
9、ng to PlasticsD 3039 Test Method for Tensile Properties of PolymerMatrix Composite MaterialsD 3878 Terminology of High-Modulus Reinforcing Fibersand their CompositesD 5229 Test Method for Moisture Adsorption Propertiesand Equilibrium Conditioning of Polymer Matrix Com-posite MaterialsD 5528 Test Met
10、hod for Mode I Interlaminar FractureToughness of Unidirectional Fiber-Reinforced PolymerMatrix CompositesE 4 Practices for Force Verification of Testing MachinesE 6 Terminology Relating to Methods of Mechanical Test-ingE 83 Practice for Verification and Classification of Exten-sometersE 399 Test Met
11、hod for Plane-Strain Fracture Toughness ofMetallic MaterialsE 1823 Terminology Relating to Fatigue and Fracture Test-ing3. Terminology3.1 Definitions:3.1.1 Terminology E 6, E 1823, and D 3878 are applicableto this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 notch-mouth displ
12、acement, 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 surface (see Fig. 1).3.2.2 notch length, anLthe distance from a referenceplane to the front
13、of the machined notch. The reference planedepends on the specimen form, and normally is taken to beeither the boundary, or a plane containing either the load line or1This test method is under the jurisdiction of ASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommitt
14、ee E08.05 on CyclicDeformation and Fatigue Crack Formation.Current edition approved May 1, 2004. Published June 2004. Originallyapproved in 1997. Last previous edition apporved in 1997 as E192297.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For ref
15、erenced 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, We
16、st Conshohocken, PA 19428-2959, United States.the 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 of notchlength, an, to specimen width, W.3.2.4 For additional information, see Terminology D 883
17、and Test Methods D 3039, D 5229, and D 5528.4. Summary of Test Method4.1 This test method involves tension testing of eccentri-cally loaded, single-edge-notch, ESE(T), specimens in openingmode loading. Load versus displacement across the notch atthe specimen edge, Vn, is recorded. The load correspon
18、ding toa prescribed increase in normalized notch length is determined,using the load-displacement record. The translaminar fracturetoughness, KTL, is calculated from this load using equationsthat have been established on the basis of elastic stress analysisof the modified single-edge notched specime
19、n.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 notch-tip condition, the allowed increasein notch-mouth displacement near the maximum load point ofthe test
20、s 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 fibers aligned parallel to the directionof the notch.5. Significance and Use5.1 The parameter KTLdetermin
21、ed 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 valid onlyfor conditions in which the damage zone at the notch tip issmall compared with the notch length an
22、d 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 variables and stackingsequence of the laminate on the translaminar fracture resistanceof composite laminates. I
23、n acceptance and quality controlspecifications, KTLdata can be used to establish criteria formaterial processing and component inspection.5.3 The translaminar fracture toughness, KTL, determined bythis test method may be a function of the testing speed andtemperature. This test method is intended fo
24、r 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 componentsshould be made with awareness that the test parametersspecified by this test may differ from service cond
25、itions,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 in this testmethod. For example, the notch-tip damage may b
26、e moreextensive and may not be accompanied by any significantamount of effective translaminar crack growth. Typically,lower strength composite materials and those with a significantFIG. 1 Test Arrangement for Translaminar Fracture Toughness TestsNOTE 1All dimensions +/ 0.01 W, except as noted.NOTE 2
27、A surfaces perpendicular and parallel as applicable within 0.01 W.FIG. 2 Translaminar Fracture Toughness Test SpecimenE1922042proportion of reinforcing fibers aligned in a direction perpen-dicular to the notch axis may not experience the containednotch-tip damage required for a valid test.6. Apparat
28、us6.1 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. A typical arrangement is shown in Fig. 1. Pin-loading clevises of the type used in Test Method E 399 are usedto a
29、pply 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 Practices E 4).6.2 Displacement GageA displacement gage shall be usedto measure the displacement at the notch mo
30、uth during loading.An electronic displacement gage of the type described in TestMethod E 399 can provide a highly sensitive indicator ofnotch-mouth displacement for this purpose. The gage is at-tached to the specimen using knife edges affixed to thespecimen or integral knife edges machined into the
31、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 thesame result. The accuracies of the displacement measuring andrecording devices should be such that the displa
32、cement can bedetermined with an accuracy of 61 %. (For additional infor-mation see Practice E 83).7. Specimen Configuration and Preparation7.1 Specimen ConfigurationThe required test and speci-men configurations are shown in Fig. 1 and Fig. 2. The notchlength, an, shall be between 0.5 and 0.6 times
33、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 2 mmhas been found to work well. However, too small a thicknesscan cause out-of-plane buckling, which invalid
34、ates 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 OrientationThe load axis of the specimenbefore testing shall be aligned to within 2 with the intendedlaminate test
35、 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 Specimen PreparationThe dimensional tolerancesshown in Fig. 2 shall be followed in the specimen preparation.T
36、he 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 profile. A diamond impregnated copper slitting saw or ajewelers saw have been found to work well. Use caution to
37、prevent 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 results for eachmaterial condition. If material variations are expected, fivetests are required.8.2 Specimen Meas
38、urementThree 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 test, so it isrequired that the specimen measurements be done prior totesting. Also, exercise care to preven
39、t injury to test personnel.8.2.1 Measure the notch length, an, to the nearest 0.1 mmon each side of the specimen. Use the average of the two notchlength measurements in the calculations of applied K.8.2.2 Measure the thickness, B, to the nearest 0.002 W,atnofewer than three equally spaced positions
40、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 fraction ofmatrix material. Therefore, the nominal average thicknesscalculated from the individual thickness of a
41、ll 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 thatthe time from zero to peak load is between 30 and 100 s.8.4 Test Record Make a plot of load versus the o
42、utput 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 and droppedto 50 % of the peak value.9. Calculation or Interpretation of Results9.1 Calculation of Applied Str
43、ess Intensity Factor,KCalculate the applied K for the ESE(T) specimen from thefollowing expression (4, 5);K 5 P/BW1/2# a1/21.41a 3.97 10.88 a126.25 a238.9 a3130.15 a49.27 a5# / 1a3/2(1)where:K = applied stress intensity factor, MPa m1/2,P = applied load, MN,a = a/W (dimensionless),an= notch length a
44、s 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,and the expression is valid for 0 # a # 1, for isotropicmaterials and for a wide range of laminates (1).9.2 Validity Criteria for KTLTranslaminar fracture testsof carbon fiber/ poly
45、mer matrix laminates (1-4) have shownthat materials with a relatively small damage zone, required forconsistent KTLmeasurements, also display relatively smallamounts of additional notch-mouth displacement, DVn, duringfracture. A typical load versus notch-mouth displacement plotfor a laminate is show
46、n 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 the notch-mouth displacement valuesat maximum load are within the following criterion (4):E1922043DVn/Vn2o# 0.3 (2)
47、where:Vn-o= Vnat P=Pmaxon the extension of the initial linearportion of the plot (see Fig. 3), andDVn= the additional notch-mouth displacement up to thePmaxpoint.9.3 Determination of KTLTo determine the translaminarfracture toughness, use the following procedure.9.3.1 Determine the maximum applied K
48、 value, Kmax, cor-responding to the maximum load during the test, Pmax, usingthe equation in 9.1.9.3.2 Determine the values of D Vnand Vn-ofrom the loadversus notch-mouth displacement plot, using the procedureshown in Fig. 3.9.3.3If: DVn/Vn-o# 0.3, then Kmax= KTL.If: DVn/Vn-o 0.3, the extent of dama
49、ge 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 typeof fiber and matrix and the ply sequence of the laminate,10.1.4 The temperature and relative humidity at the ti
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