ASTM D3433-99(2005)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3433 − 99 (Reapproved2005)
Standard Test Method for
Fracture Strength in Cleavage of Adhesives in Bonded Metal
Joints
This standard is issued under the fixed designation D3433; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope B152/B152MSpecification for Copper Sheet, Strip, Plate,
2 and Rolled Bar
1.1 This test method(1, 2, 5, 6, 9) covers the determination
B209 Specification for Aluminum and Aluminum-Alloy
of fracture strength in cleavage of adhesives when tested on
Sheet and Plate
standard specimens and under specified conditions of prepara-
B265Specification for Titanium and Titanium Alloy Strip,
tion and testing (Note 1).
Sheet, and Plate
1.2 This test method is useful in that it can be used to
D907Terminology of Adhesives
develop design parameters for bonded assemblies.
E4Practices for Force Verification of Testing Machines
E399Test Method for Linear-Elastic Plane-Strain Fracture
NOTE 1—While this test method is intended for use in metal-to-metal
applications it may be used for measuring fracture properties of adhesives Toughness K of Metallic Materials
Ic
using plastic adherends, provided consideration is given to the thickness
and rigidity of the plastic adherends.
3. Terminology
1.3 The values stated in SI units are to be regarded as the
3.1 Definitions: Many of the terms used in this test method
standard. The values given in parentheses are for information
are defined in Terminology D907.
only.
3.2 Definitions of Terms Specific to This Standard:
1.4 This standard does not purport to address all of the
3.2.1 crack-extension force, G,—the system isolated (fixed
safety concerns, if any, associated with its use. It is the
load-displacement) loss of stress field energy for an infinitesi-
responsibility of the user of this standard to establish appro-
mal increase, d A, of separational area. In equation form,
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
GdA52dU (1)
T
2. Referenced Documents
where U =total elastic energy in the system (component or
T
test specimen). In the test specimens of this method, the crack
2.1 ASTM Standards:
front is nearly straight through the specimen thickness, B, so
A167 Specification for Stainless and Heat-Resisting
that dA=B da, where da is an infinitesimal forward motion of
Chromium-Nickel Steel Plate, Sheet, and Strip
the leading edge of the crack. Completely linear-elastic behav-
A366/A366M Specification for Commercial Steel (CS)
ior is assumed in the calculations (See AnnexA1)of G used in
Sheet, Carbon, (0.15 Maximum Percent) Cold-Rolled
this method, an allowable assumption when the zone of
(Withdrawn 2000)
nonlinear deformation in the adhesive is small relative to
B36/B36MSpecification for Brass Plate, Sheet, Strip, And
specimen dimensions and crack size.
Rolled Bar
3.2.1.1 When the shear stress on the plane of crack and
forward to its leading edge is zero, the stress state is termed
This test method is under the jurisdiction of ASTM Committee D14 on
“opening mode.” The symbol for an opening mode G is G for
I
Adhesives and is the direct responsibility of Subcommittee D14.80 on Metal
plane-strain and G when the connotation of plane-strain is not
Bonding Adhesives. 1
Current edition approved April 1, 2005. Published April 2005. Originally
wanted.
approved in 1975. Last previous edition approved in 1999 as D3433–99. DOI:
3.2.2 opening mode fracture toughness, G —thevalueof G
1c
10.1520/D3433-99R05.
2 justpriortoonsetofrapidfracturingwhen Gisincreasingwith
The boldface numbers in parentheses refer to the references at the end of this
test method.
time.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 3.2.3 opening mode crack arrest toughness, G —the value
1a
Standards volume information, refer to the standard’s Document Summary page on
of Gjustafterarrestofarun-arrestsegmentofcrackextension.
the ASTM website.
3.2.3.1 It is assumed that the dimensions of the part con-
The last approved version of this historical standard is referenced on
www.astm.org. taining the crack are large compared to the run-arrest segment
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3433 − 99 (2005)
whichprecedescrackarrestandthatthequasi-staticstressfield basis for development of this test method in terms of linear
enclosingthecracktipjustaftercrackarrestcanbeassumedin elastic fracture mechanics may be found in Refs (6) and (7).
calculating G . 5.1.1 Cyclic loads can cause crack extension at G values
1 a 1
less than G value. Furthermore, progressive stable crack
1c
4. Summary of Test Method
extension under cyclic or sustained load may be promoted by
the presence of certain environments.Therefore, application of
4.1 This test method involves cleavage testing bonded
G in the design of service components should be made with
1c
specimenssuchthatacrackismadetoextendbyatensileforce
awareness of the G increase for a prior crack which may occur
acting in a direction normal to the crack surface.
in service due to slow-stable crack-extension.
4.2 Load versus load-displacement across the bondline is
5.2 This test method can serve the following purposes:
recorded autographically. The G and G values are calcu-
1c 1a
5.2.1 In research and development to establish, in quantita-
lated from this load by equations that have been established on
tive terms, significant to service performance, the effects of
the basis of elastic stress analysis of specimens of the type
adhesive composition, primers, adherend surface treatments,
described below. The validity of the determination of G and
1c
supporting adhesive carriers (scrim), processing variables, and
G values by this test method depends upon the establishment
1a
environmental effects.
of a sharp-crack condition in the bondline in a specimen of
5.2.2 In service evaluation to establish the suitability of an
adequate size. This test method will measure the fracture
adhesive system for a specific application for which the stress
strength of a bonded joint which is influenced by adherend
conditions are prescribed and for which maximum flaw sizes
surface condition, adhesive, adhesive-adherend interactions,
can be established with confidence.
primers, adhesive-supporting scrims, etc., and in which of the
5.2.3 For specifications of acceptance and manufacturing
above possible areas the crack grows.
quality control, but only when there is a sound basis for
specification of minimum G values.The specification of G
5. Significance and Use
1 c 1c
NOTE2—Crackgrowthinadhesivebondspecimenscanproceedintwo values in relation to a particular application should signify that
ways: (1) by a slow-stable extension where the crack velocity is dictated
a fracture control study has been conducted on the component
by the crosshead rate or (2) by a run-arrest extension where the stationary
in relation to the expected history of loading and environment,
crack abruptly jumps ahead outrunning the crosshead-predicted rate. The
and in relation to the sensitivity and reliability of the crack
first type of crack extension is denoted flat; the second type peaked
detection procedures that are to be applied prior to service and
because of the appearance of the autographic record. The flat behavior is
characteristic of adhesives or test temperatures, or both, for these subsequently during the anticipated life.
adhesives where there is no difference between initiation, G , and arrest,
1c
G . For example, the rubber modified film adhesives tested
1a
6. Apparatus
above−17.8°C (0°F) all exhibit flat autographic records. Peaked curves
are exhibited for all modified materials tested below −73°C (−100°F) and
6.1 Testing Machine, conforming to the requirements of
in general for unmodified epoxies.
Practices E4. Select the testing machine such that the cracking
It should be noted that both peaked and flat behaviors are determined
load of the specimens falls between 15 and 85% of the
from a crack-length-independent specimen. For other specimens or
full-scale capacity and that is provided with a suitable pair of
structures where G increases with a at constant load the onset of crack
growth would result in rapid complete fracturing whatever the adhesive self-aligning pinned fixtures to hold the specimen.
characteristics.
6.2 Ensure that the pinned fixtures and attachments are
5.1 The property G (and G if relevant) determined by
1c 1a constructed such that they will move into alignment with the
this test method characterizes the resistance of a material to
test specimen as soon as the load is applied.
slow-stable or run-arrest fracturing in a neutral environment in
6.3 For a discussion of the calculation of separation rates
the presence of a sharp crack under severe tensile constraint,
see Annex A1.
such that the state of stress near the crack front approaches
tritensile plane strain, and the crack-tip plastic region is small
7. Test Specimens
compared with the crack size and specimen dimensions in the
7.1 Flat Adherend, conforming to the form and dimensions
constraint direction. It has not been proven that tough adhesive
shown in Fig. 1, cut from test joints as in Fig. 2, prepared as
systems fully meet this criteria. Therefore, data developed
prescribed in Section 8.
using equations based on this assumption may not represent
plane-strain fracture values. Comparison of fracture toughness
7.2 Contoured Double-Cantilever Beam (CDCB), conform-
between adhesive systems widely different in brittleness or
ing to the form and dimensions shown in Fig. 3.
toughness should take this into consideration. In general,
7.3 Thefollowinggradesofmetalsaresuggestedforthetest
systems of similar type toughness (3, 4, 7, 8, 10) can be
specimens (Note 3):
compared as can the effect of environment on toughness of a
Metal ASTM Designation
single system. A G value is believed to represent a lower
1c
Brass B36/B36M, Alloy 260 (6), quarter hard tem-
limiting value of fracture toughness for a given temperature,
per
strainrate,andadhesiveconditionasdefinedbymanufacturing Copper B152/B152M, cold rolled, Type 110, hard
temper
variables. This value may be used to estimate the relation
Aluminum B209, Alclad 2024, T3 temper, mill finish
between failure stress and defect size for a material in service
Steel A366/A366M, regular matte finish
wherein the conditions of high constraint described above Corrosion-resisting steel A167, Type 304, No. 2B finish
Titanium B265, Grade 3
would be expected. Background information concerning the
D3433 − 99 (2005)
FIG. 1 Flat Adherend Specimen
FIG. 2 Test Joint
7.4 Test at least twelve specimens, representing at least four edges of the metal panels and specimens must be flat, free of
different joints. burrs, and smooth (4.1-µm (160-µin.) maximum) before the
panelsaresurface-treatedandbonded.Clean,treat,anddrythe
NOTE 3—Since it is unacceptable to exceed the yield point of the metal
sheetsorcontouredadherendscarefully,inaccordancewiththe
in flexure during test, the permissible thickness of the specimen will vary
with type of metal, and the general level of strength of the adhesive being procedure prescribed by the manufacturer of the adhesive.
investigated. The minimum permissible thickness in a uniform symmetri-
Prepare and apply the adhesive in accordance with the recom-
cal adherend may be computed from the following relationship:
mendations of the manufacturer of the adhesive. Apply the
adhesivetothefayingsurfaceofoneorbothmetalsheets.Then
6 Ta
h 5 (2)
Œ
assemble the sheets, faying surface to faying surface in pairs,
BF
ty
and allow the adhesive to cure under conditions prescribed by
where:
the manufacturer of the adhesive.
h = thickness of metal normal to plane of bonding, mm (or
8.2 Itisrecommendedthateach“flatadherend”testjointbe
in.),
madewithsufficientareatoprovideatleastfivetestspecimens.
F = tensileyieldpointofmetal(orthestressatproportional
ty
limit) MPa (or psi),
9. Preparation of Test Specimens
T = 150% of the maximum load to start the crack in the
adhesive bond, N (or lbf),
9.1 For flat adherend test specimens, trim joint area in
a = crack length at maximum load, mm (or in.), and
accordance with Fig. 2. Then cut test specimens, as shown in
B = bond width, mm (or in.).
Fig. 1, from the joints, Fig. 2 (Note 4). Then cut holes for load
pins as shown in Fig. 1.
8. Preparation of Test Joints
9.2 Contoured double-cantilever specimens are ready for
8.1 Cut sheets of the metals or contoured adherends pre-
scribedin7.1-7.3andtorecommendedsize(Figs.2and3).All test as bonded.
D3433 − 99 (2005)
FIG. 3 Contoured Double-Cantilever Beam Specimen
NOTE 4—Do not use lubricants or oils during the cutting process. For
mm/min (0.08 in./min) gives fracture in 1 min for a CDCB
−1
aluminum it is suggested that the specimens be rough cut 3.2 mm ( ⁄8 in.)
⁄2-in. wide m=90-in. aluminum adherend specimen having
over-size using a four-pitch band saw traveling at approximately 4.2 m/s
a 3-in. long starter crack.
(800 ft/min) followed by finish dimensioning to a 1-in. wide 3.2-µm
10.3.1 The chart recording should be such that maximum
(125-µin.) surface using a five-blade 15-deg carbide fly cutter at 1115 rpm
and 0.015 to 0.035-m/s (3 to 7-in./min) feed rate. load occurs on the record and that at least 13 mm ( ⁄2 in.) of
motion is represented on the abscissa (n) for each 100 mm (4
10. Procedure
in.)ofordinatemotion(P).Forload-timerecordsachart speed
10.1 Test specimens, prepared as prescribed in Section 8,in rate should be used such that the slope of the load versus time
an atmosphere maintained at 50 6 4% relative humidity and record is similar to that specified for load versus load-
23 6 1°C (73.4 6 1.8°F). Tests at other than ambient displacement (for example, 5 mm/min (0.2 in./mm)).
temperature may be run if desired. It is suggested that
10.4 Apply load to specimen until Point A is reached. (See
specimens be conditioned for a minimum of 10 min and a
Point A, Fig. 4 for flat adherend and Fig. 5, Point A for
maximum of 30 min at the temperature of test to assure
contoured double-cantilever specimen.) Point A is the load at
equilibrium. The manufacturer of the adhesive may, however,
which the crack begins to grow rapidly. Then stop loading and
prescribe a definite period of conditioning under specific
follow crack growth curve on the chart. Wh
...