The effect of bond thickness on the fracture toughness of adhesive joints was investigated from a microstructural perspective, using compact tension (CT) adhesive-joint specimens with different bond thicknesses. The adhesive material was a rubber-modified epoxy resin with 12.5 wt% carboxy-terminated butadiene acrylonitrile (CTBN) elastomer. The shapes of the rubber particles dispersed in adhesive layers of damaged and undamaged specimens were observed with an optical microscope. The damage was distributed along the interfaces between the adhesive layer and the two adherends. The results show that the primary causes of variations in the fracture toughness of an adhesive joint with the bond thickness are not only a damage zone around a crack tip but also the combination of a damage zone around a crack tip and additional damage zones along the interfaces.

Issue Section:
Technical Papers
Keywords:
fracture toughness, joining processes, adhesives, adhesion, rubber, polymer blends, curing, crack-edge stress field analysis, polymer structure
Topics:
Adhesive joints, Adhesives, Fracture (Materials), Fracture toughness, Rubber, Damage, Epoxy resins, Stress, Particulate matter
1.
Gardon
,
J. L.
,
1963
, “
Peel Adhesion. I. Some Phenomenological Aspects of the Test
,”
J. Appl. Polym. Sci.
,
7
, pp.
625
–
641
.
2.
Mostovoy
,
S.
, and
Ripling
,
E. J.
,
1971
, “
Effect of Joint Geometry on the Toughness of Epoxy Adhesives
,”
J. Appl. Polym. Sci.
,
15
, pp.
661
–
673
.
3.
Bascom
,
W. D.
,
Cottington
,
R. L.
,
Jones
,
R. L.
, and
Peyser
,
P.
,
1975
, “
The Fracture of Epoxy and Elastomer-Modified Epoxy Polymers in Bulk and as Adhesives
,”
J. Appl. Polym. Sci.
,
19
, pp.
2545
–
2562
.
4.
Bascom
,
W. D.
, and
Cottington
,
R. L.
,
1976
, “
Effect of Temperature on the Adhesive Fracture Behavior of an Elastomer-Epoxy Resin
,”
J. Adhes.
,
7
, pp.
333
–
346
.
5.
Kinloch
,
A. J.
, and
Shaw
,
S. J.
,
1981
, “
The Fracture Resistance of a Toughened Epoxy Adhesive
,”
J. Adhes.
,
12
, pp.
59
–
77
.
6.
Daghyani
,
H. R.
,
Ye
,
L.
, and
Mai
,
Y. W.
,
1995
, “
Mode I Fracture Behavior of Adhesive Joints. Part I. Relationship between Fracture Energy and Bond Thickness
,”
J. Adhes.
,
53
, pp.
149
–
162
.
7.
Daghyani
,
H. R.
,
Ye
,
L.
, and
Mai
,
Y. W.
,
1995
, “
Mode I Fracture Behavior of Adhesive Joints. Part II. Stress Analysis and Constraint Parameters
,”
J. Adhes.
,
53
, pp.
163
–
172
.
8.
Yan
,
C.
,
Mai
,
Y. W.
,
Yuan
,
Q.
,
Ye
,
L.
, and
Sun
,
J.
,
2001
, “
Effects of Substrate Materials on Fracture Toughness Measurement in Adhesive Joints
,”
Int. J. Mech. Sci.
,
43
, pp.
2091
–
2102
.
9.
Yan
,
C.
,
Yiao
,
K.
,
Ye
,
L.
, and
Mai
,
Y. W.
,
2002
, “
Numerical and Experimental Studies on the Fracture Behavior of Rubber-Toughened Epoxy in Bulk Specimen and Laminated Composites
,”
J. Mater. Sci.
,
37
, pp.
921
–
927
.
10.
Chai
,
H.
,
1984
, “
The Characterization of Mode I Delamination Failure in Non-Woven, Multidirectional Laminates
,”
Composites
,
15
(
4
), pp.
277
–
290
.
11.
Chai
,
H.
,
1986
, “
On the Correlation Between the Mode I Failure of Adhesive Joints and Laminated Composites
,”
Eng. Fract. Mech.
,
24
(
3
), pp.
413
–
431
.
12.
Chai
,
H.
,
1987
, “
A Note on Crack Trajectory in an Elastic Strip Bounded by Rigid Substrates
,”
Int. J. Fract.
,
32
, pp.
211
–
213
.
13.
Ikeda
,
T.
,
Yamashita
,
A.
,
Lee
,
D. B.
, and
Miyazaki
,
N.
,
2000
, “
Failure of a Ductile Adhesive Layer Constrained by Hard Adherends
,”
ASME J. Eng. Mater. Technol.
,
122
(
1
), pp.
80
–
85
.
14.
Varias
,
A. G.
,
Suo
,
Z.
, and
Shih
,
C. F.
,
1991
, “
Ductile Failure of a Constrained Metal Foil
,”
J. Mech. Phys. Solids
,
39
(
7
), pp.
963
–
986
.
15.
Hsia
,
K. J.
,
Suo
,
Z.
, and
Yang
,
W.
,
1994
, “
Cleavage due to Dislocation Confinement in Layered Materials
,”
J. Mech. Phys. Solids
,
42
(
6
), pp.
877
–
896
.
16.
Tvergaard
,
V.
, and
Hutchinson
,
J.
,
1996
, “
On the Toughness of Ductile Adhesive Joints
,”
J. Mech. Phys. Solids
,
44
(
5
), pp.
789
–
800
.
17.
Wegman, R. F., 1989, Surface Preparation Techniques for Adhesive Bonding, Noyes/William Andrew Publishing, ISBN 0-8155-1198-1, pp. 269.
18.
Holik, A. S., Kambour, R. P., Hobbs, S. Y., and Fink, D. G., 1979, “Grinding and Polishing Techniques for Thin Sectioning of Polymeric Materials for Transmission Light Microscopy,” Microstructural Science, Elsevier Publishing Company, New York, 7, pp. 357–367.
19.
Ikeda, T., Komohara Y., and Miyazaki, N., “Measurement of Mixed Mode Fracture Toughness of an Interface Crack in Electronic Devices,” Advanced Electronic Packaging, EEP-19-2, ASME, New York, pp. 1437.
20.
Ikeda
,
T.
, and
Sun
,
C. T.
,
2001
, “
Stress Intensity Factor Analysis for an Interface Crack between Dissimilar Isotropic Materials under Thermal Stress
,”
Int. J. Fract.
,
111
, pp.
229
–
249
.
21.
Lee
,
D. B.
,
Ikeda
,
T.
,
Miyazaki
,
N.
, and
Choi
,
N. S.
,
2002
, “
Damage Zone around Crack Tip and Fracture Toughness of Rubber-Modified Epoxy Resin under Mixed Mode Conditions
,”
Eng. Fract. Mech.
,
69
(
12
), pp.
1363
–
1375
.
22.
Lee
,
D. B.
,
Ikeda
,
T.
,
Miyazaki
,
N.
, and
Choi
,
N. S.
,
2002
, “
Damage Zone around Tip of an Interface Crack Between Rubber-Modified Epoxy Resin and Aluminum
,”
ASME J. Eng. Mater. Technol.
,
124
(
2
), pp.
206
–
214
.
Copyright © 2004
 by ASME
You do not currently have access to this content.