1、Designation: E1922 04 (Reapproved 2010)1Standard 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 adopt
2、ion 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.1NOTE1.6 and 3.2.1 were editorially updated in January 2011.1. Scope1.1 This test met
3、hod covers the determination of translami-nar fracture toughness, 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 environ
4、ments.1.3 Composite materials that can be tested by this testmethod 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 variousc
5、arbon fiber epoxy matrix laminates and from additionalresults of glass fiber 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 plan
6、ar dimen-sions is provided, but planar size may be variable and adjusted,with 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 intensity
7、calibrations are available and that the test results meet therequirements 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
8、be regarded asstandard. No other units of measurement are included 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
9、to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D883 Terminology Relating to PlasticsD3039/D3039M Test Method for Tensile Properties ofPolymer Matrix Composite MaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method f
10、or Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composite MaterialsD5528 Test Method for Mode I Interlaminar FractureToughness of Unidirectional Fiber-Reinforced PolymerMatrix CompositesE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to
11、 Methods of Mechanical TestingE83 Practice for Verification and Classification of Exten-someter SystemsE399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE1823 Terminology Relating to Fatigue and Fracture Test-ing3. Terminology3.1 Definitions:3.1.1 Terminology
12、 E6, E1823, and D3878 are applicable tothis test method.3.2 Definitions of Terms Specific to This Standard:1This 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
13、.Current edition approved Oct. 1, 2010. Published January 2011. Originallyapproved in 1997. Last previous edition approved in 2004 as E192204. DOI:10.1520/E1922-04R10E01.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, vi
14、sit 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, West Conshohocken, PA 19428-
15、2959, United States.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 notch length, anLthe dist
16、ance from a referenceplane to the front 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 orthe centerline of a specimen or plate. The reference plane isdefined prior to specimen deformat
17、ion (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 D883and Test Methods D3039/D3039M, D5229/D5229M, andD5528.4. Summary of Test Method4.1 This test method involves tension testing of eccentri-cally
18、 loaded, single-edge-notch, ESE(T), specimens in openingmode loading. 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 fracturet
19、oughness, KTL, is calculated from this load using equationsthat 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 contain
20、ed 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 tests is limited to a small value. Small increases innotch-mouth displacement are more likely for relatively thicksamples and for sample
21、s with a significant proportion of thenear surface reinforcing 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 transla
22、minar 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 and the in-plane speci-men dimensions.5.2 This test method can serve the following purposes. Inresearch and development, KTLdata can q
23、uantitatively estab-lish the effects of fiber and matrix variables 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 inspe
24、ction.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 for room temperatureand quasi-static conditions, but it can apply to other testconditions provided that the requirements of 9.2 and 9.
25、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 conditions,possibly resulting in a different material response than that seenin service.5.4 Not all types of laminated polymer matrix co
26、mpositematerials experience the contained notch-tip damage andeffective translaminar crack growth of concern 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
27、 composite materials and those with a significantproportion 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. Apparatus6.1 LoadingSpecimens shall be loaded in a testing ma-chine that has provisi
28、on 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 E399 are usedto apply the load to the specimen. The accuracies of the loadmeasuring and recordi
29、ng devices should be such that load canbe determined with an accuracy of 61 %. (For additionalinformation see Practices E4).6.2 Displacement GageAdisplacement gage shall be usedto measure the displacement at the notch mouth during loading.FIG. 1 Test Arrangement for Translaminar Fracture Toughness T
30、estsE1922 04 (2010)12An 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 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 displ
32、acement 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 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/ polymer
45、 matrix laminates (1-4) have shownthat materials with a relatively small damage zone, required forNOTE 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 (2010)13consistent KT
46、Lmeasurements, also display relatively smallamounts of additional notch-mouth displacement, DVn, 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 tes
47、t provides a consistent measure of translaminarfracture toughness when the notch-mouth displacement valuesat maximum load are within the following criterion (4):DVn/Vn2o#0.3 (2)where:Vn-o= Vnat P=Pmaxon the extension of the initial linearportion of the plot (see Fig. 3), andDVn= the additional notch
48、-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 value, Kmax, cor-responding to the maximum load during the test, Pmax, usingthe equation in 9.1.9.3.2 Determine the values
49、 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 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 displ
