1、Designation: D 3433 99 (Reapproved 2005)Standard Test Method forFracture Strength in Cleavage of Adhesives in Bonded MetalJoints1This standard is issued under the fixed designation D 3433; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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 (1, 2, 5, 6, 9)2covers the determinationof fracture strength in cleavage of adhesi
3、ves when tested onstandard specimens and under specified conditions of prepara-tion and testing (Note 1).1.2 This test method is useful in that it can be used todevelop design parameters for bonded assemblies.NOTE 1While this test method is intended for use in metal-to-metalapplications it may be us
4、ed for measuring fracture properties of adhesivesusing plastic adherends, provided consideration is given to the thicknessand rigidity of the plastic adherends.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standa
5、rd 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 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AST
6、M Standards:3A 167 Specification for Stainless and Heat-ResistingChromium-Nickel Steel Plate, Sheet, and StripA 366/A 366M Specification for Steel, Sheet, Carbon,Cold-Rolled, Commercial QualityB36 Specification for Brass Plate, Sheet, Strip, and RolledBar4B 152 Specification for Copper Sheet, Strip,
7、 Plate, andRolled BarB 209 Specification for Aluminum and Aluminum-AlloySheet and PlateB 265 Specification for Titanium and Titanium Alloy Strip,Sheet, and PlateD 907 Terminology of AdhesivesE4 Practices for Force Verification of Testing MachinesE 399 Test Method for Plane-Strain Fracture Toughness
8、ofMetallic Materials3. Terminology3.1 Definitions: Many of the terms used in this test methodare defined in Terminology D 907.3.2 Definitions of Terms Specific to This Standard:3.2.1 crack-extension force, G,the system isolated (fixedload-displacement) loss of stress field energy for an infinitesi-m
9、al increase, d A, of separational area. In equation form,GdA 52dUT(1)where UT= total elastic energy in the system (component ortest specimen). In the test specimens of this method, the crackfront is nearly straight through the specimen thickness, B, sothat dA=Bda, where da is an infinitesimal forwar
10、d motion ofthe leading edge of the crack. Completely linear-elastic behav-ior is assumed in the calculations (See Annex A1)ofG used inthis method, an allowable assumption when the zone ofnonlinear deformation in the adhesive is small relative tospecimen dimensions and crack size.3.2.1.1 When the she
11、ar stress on the plane of crack andforward to its leading edge is zero, the stress state is termed“opening mode.” The symbol for an opening mode G is GIforplane-strain and G1when the connotation of plane-strain is notwanted.3.2.2 opening mode fracture toughness, G1cthe value of Gjust prior to onset
12、of rapid fracturing when G is increasing withtime.3.2.3 opening mode crack arrest toughness, G1a the valueof G just after arrest of a run-arrest segment of crack extension.3.2.3.1 It is assumed that the dimensions of the part con-taining the crack are large compared to the run-arrest segmentwhich pr
13、ecedes crack arrest and that the quasi-static stress fieldenclosing the crack tip just after crack arrest can be assumed incalculating G1a.1This test method is under the jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.80 on MetalBonding Adhesives.C
14、urrent edition approved April 1, 2005. Published April 2005. Originallyapproved in 1975. Last previous edition approved in 1999 as D 3433 99 .2The boldface numbers in parentheses refer to the references at the end of thistest method.3For referenced ASTM standards, visit the ASTM website, www.astm.or
15、g, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.
16、 Summary of Test Method4.1 This test method involves cleavage testing bondedspecimens such that a crack is made to extend by a tensile forceacting in a direction normal to the crack surface.4.2 Load versus load-displacement across the bondline isrecorded autographically. The G1cand G1avalues are cal
17、cu-lated from this load by equations that have been established onthe basis of elastic stress analysis of specimens of the typedescribed below. The validity of the determination of G1candG1avalues by this test method depends upon the establishmentof a sharp-crack condition in the bondline in a speci
18、men ofadequate size. This test method will measure the fracturestrength of a bonded joint which is influenced by adherendsurface condition, adhesive, adhesive-adherend interactions,primers, adhesive-supporting scrims, etc., and in which of theabove possible areas the crack grows.5. Significance and
19、UseNOTE 2Crack growth in adhesive bond specimens can proceed in twoways: (1) by a slow-stable extension where the crack velocity is dictatedby the crosshead rate or (2) by a run-arrest extension where the stationarycrack abruptly jumps ahead outrunning the crosshead-predicted rate. Thefirst type of
20、crack extension is denoted flat; the second type peakedbecause of the appearance of the autographic record. The flat behavior ischaracteristic of adhesives or test temperatures, or both, for theseadhesives where there is no difference between initiation, G1c, and arrest,G1a. For example, the rubber
21、modified film adhesives testedabove 17.8C (0F) all exhibit flat autographic records. Peaked curvesare exhibited for all modified materials tested below 73C (100F) andin general for unmodified epoxies.It should be noted that both peaked and flat behaviors are determinedfrom a crack-length-independent
22、 specimen. For other specimens orstructures where G increases with a at constant load the onset of crackgrowth would result in rapid complete fracturing whatever the adhesivecharacteristics.5.1 The property G1c(and G1aif relevant) determined bythis test method characterizes the resistance of a mater
23、ial toslow-stable or run-arrest fracturing in a neutral environment inthe presence of a sharp crack under severe tensile constraint,such that the state of stress near the crack front approachestritensile plane strain, and the crack-tip plastic region is smallcompared with the crack size and specimen
24、 dimensions in theconstraint direction. It has not been proven that tough adhesivesystems fully meet this criteria. Therefore, data developedusing equations based on this assumption may not representplane-strain fracture values. Comparison of fracture toughnessbetween adhesive systems widely differe
25、nt in brittleness ortoughness should take this into consideration. In general,systems of similar type toughness (3, 4, 7, 8, 10) can becompared as can the effect of environment on toughness of asingle system. A G1cvalue is believed to represent a lowerlimiting value of fracture toughness for a given
26、 temperature,strain rate, and adhesive condition as defined by manufacturingvariables. This value may be used to estimate the relationbetween failure stress and defect size for a material in servicewherein the conditions of high constraint described abovewould be expected. Background information con
27、cerning thebasis for development of this test method in terms of linearelastic fracture mechanics may be found in Refs (6) and (7).5.1.1 Cyclic loads can cause crack extension at G1valuesless than G1cvalue. Furthermore, progressive stable crackextension under cyclic or sustained load may be promoted
28、 bythe presence of certain environments. Therefore, application ofG1cin the design of service components should be made withawareness of the G increase for a prior crack which may occurin service due to slow-stable crack-extension.5.2 This test method can serve the following purposes:5.2.1 In resear
29、ch and development to establish, in quantita-tive terms, significant to service performance, the effects ofadhesive composition, primers, adherend surface treatments,supporting adhesive carriers (scrim), processing variables, andenvironmental effects.5.2.2 In service evaluation to establish the suit
30、ability of anadhesive system for a specific application for which the stressconditions are prescribed and for which maximum flaw sizescan be established with confidence.5.2.3 For specifications of acceptance and manufacturingquality control, but only when there is a sound basis forspecification of m
31、inimum G1cvalues. The specification of G1cvalues in relation to a particular application should signify thata fracture control study has been conducted on the componentin relation to the expected history of loading and environment,and in relation to the sensitivity and reliability of the crackdetect
32、ion procedures that are to be applied prior to service andsubsequently during the anticipated life.6. Apparatus6.1 Testing Machine, conforming to the requirements ofPractices E4. Select the testing machine such that the crackingload of the specimens falls between 15 and 85 % of thefull-scale capacit
33、y and that is provided with a suitable pair ofself-aligning pinned fixtures to hold the specimen.6.2 Ensure that the pinned fixtures and attachments areconstructed such that they will move into alignment with thetest specimen as soon as the load is applied.6.3 For a discussion of the calculation of
34、separation ratessee Annex A1.7. Test Specimens7.1 Flat Adherend, conforming to the form and dimensionsshown in Fig. 1, cut from test joints as in Fig. 2, prepared asprescribed in Section 8.7.2 Contoured Double-Cantilever Beam (CDCB), conform-ing to the form and dimensions shown in Fig. 3.7.3 The fol
35、lowing grades of metals are suggested for the testspecimens (Note 3):Metal ASTM DesignationBrass B36, Alloy 260 (6), quarter hard temperCopper B 152, cold rolled, Type 110, hard temperAluminum B 209, Alclad 2024, T3 temper, mill finishSteel A 366, regular matte finishCorrosion-resisting steel A 167,
36、 Type 304, No. 2B finishTitanium B 265, Grade 37.4 Test at least twelve specimens, representing at least fourdifferent joints.NOTE 3Since it is unacceptable to exceed the yield point of the metalin flexure during test, the permissible thickness of the specimen will varywith type of metal, and the ge
37、neral level of strength of the adhesive beingD 3433 99 (2005)2investigated. The minimum permissible thickness in a uniform symmetri-cal adherend may be computed from the following relationship:h 56 TaBFty(2)where:h = thickness of metal normal to plane of bonding, mm (or in.),Fty= tensile yield point
38、 of metal (or the stress at proportional limit)MPa (or psi),T = 150 % of the maximum load to start the crack in the adhesivebond, N (or lbf),a = crack length at maximum load, mm (or in.), andB = bond width, mm (or in.).8. Preparation of Test Joints8.1 Cut sheets of the metals or contoured adherends
39、pre-scribed in 7.1-7.3 and to recommended size (Figs. 2 and 3).Alledges of the metal panels and specimens must be flat, free ofburrs, and smooth (4.1-m (160-in.) maximum) before thepanels are surface-treated and bonded. Clean, treat, and dry thesheets or contoured adherends carefully, in accordance
40、with theprocedure prescribed by the manufacturer of the adhesive.Prepare and apply the adhesive in accordance with the recom-mendations of the manufacturer of the adhesive. Apply theadhesive to the faying surface of one or both metal sheets.Thenassemble the sheets, faying surface to faying surface i
41、n pairs,and allow the adhesive to cure under conditions prescribed bythe manufacturer of the adhesive.8.2 It is recommended that each “flat adherend” test joint bemade with sufficient area to provide at least five test specimens.9. Preparation of Test Specimens9.1 For flat adherend test specimens, t
42、rim joint area inaccordance with Fig. 2. Then cut test specimens, as shown inFig. 1, from the joints, Fig. 2 (Note 4). Then cut holes for loadpins as shown in Fig. 1.9.2 Contoured double-cantilever specimens are ready fortest as bonded.NOTE 4Do not use lubricants or oils during the cutting process.
43、Foraluminum it is suggested that the specimens be rough cut 3.2 mm (18 in.)over-size using a four-pitch band saw traveling at approximately 4.2 m/s(800 ft/min) followed by finish dimensioning to a 1-in. wide 3.2-mFIG. 1 Flat Adherend SpecimenFIG. 2 Test JointD 3433 99 (2005)3(125-in.) surface using
44、a five-blade 15-deg carbide fly cutter at 1115 rpmand 0.015 to 0.035-m/s (3 to 7-in./min) feed rate.10. Procedure10.1 Test specimens, prepared as prescribed in Section 8,inan atmosphere maintained at 50 6 4 % relative humidity and23 6 1C (73.4 6 1.8F). Tests at other than ambienttemperature may be r
45、un if desired. It is suggested thatspecimens be conditioned for a minimum of 10 min and amaximum of 30 min at the temperature of test to assureequilibrium. The manufacturer of the adhesive may, however,prescribe a definite period of conditioning under specificconditions before testing.10.2 Determine
46、 the following test specimen dimensions.10.2.1 Distance from center of 6.4-mm (0.25-in.) inside-diameter pin holes to close end of specimen.10.2.2 Width of test specimen, b.10.2.3 Thickness of test specimen 127 mm (5 in.) from pinend and 227 mm (9 in.) from pin end.10.2.4 Bond line thickness 125 mm
47、(5 in.) from pin end and227 mm (9 in.) from pin end.10.3 Load the specimen in the test machine and pin inposition using the 6.4-mm (0.25-in.) inside-diameter pin holes.Balance the recorder or chart, or both. Set the test machine ata crosshead separation rate _ chosen to keep time-to-fracturein the o
48、rder of 1 min, see 6.1 and Annex A1. For example, 2mm/min (0.08 in./min) gives fracture in 1 min for a CDCB12-in. wide m = 90-in.1aluminum adherend specimen havinga 3-in. long starter crack.10.3.1 The chart recording should be such that maximumload occurs on the record and that at least 13 mm (12 in
49、.) ofmotion is represented on the abscissa (_) for each 100 mm (4in.) of ordinate motion (P). For load-time records a chart speedrate should be used such that the slope of the load versus timerecord is similar to that specified for load versus load-displacement (for example, 5 mm/min (0.2 in./mm).10.4 Apply load to specimen until Point A is reached. (SeePoint A, Fig. 4 for flat adherend and Fig. 5, Point A forcontoured double-cantilever specimen.) Point A is the load atwhich the crack begins to grow rapidly. Then stop loading andfollow crack growth curv
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