Abstract

Delamination is a common failure mode observed in ceramic matrix composites (CMCs) and occurs as a result of applied interlaminar tensile and shear stresses exceeding the interlaminar strength. As CMCs are further implemented into aero engines, the need to understand their interlaminar failure becomes increasingly important. While significant contributions have been made toward understanding the mode I fracture toughness of CMCs, limited work exists on mode II. Several test methods for measuring the mode II fracture toughness have been proposed in the literature, namely, the end-notched flexure (ENF) and the end-loaded split (ELS) tests. This work investigates the mode II fracture toughness of a melt-infiltrated SiC/SiC CMC at ambient temperature using the ENF and ELS test methods. Acoustic emission (AE), direct current potential drop (DCPD), and digital image correlation (DIC) are implemented as health monitoring techniques to monitor crack initiation and propagation. Results show reasonable correlation between the two test methods and that the ELS test method is better suited for characterizing R-curve behavior.

References

1.
Choi
,
S. R.
, and
Kowalik
,
R. W.
,
2008
, “
Interlaminar Crack Growth Resistances of Various Ceramic Matrix Composites in Mode I and Mode II Loading
,”
ASME J. Eng. Gas Turbines Power
,
130
(
3
), p.
031301
.10.1115/1.2800349
2.
Kumar
,
R. S.
, and
Welsh
,
G. S.
,
2012
, “
Delamination Failure in Ceramic Matrix Composites: Numerical Predictions and Experiments
,”
Acta Mater.
,
60
(
6–7
), pp.
2886
2900
.10.1016/j.actamat.2012.01.053
3.
Mansour
,
R.
,
Maillet
,
E.
, and
Morscher
,
G. N.
,
2015
, “
Monitoring Interlaminar Crack Growth in Ceramic Matrix Composites Using Electrical Resistance
,”
Scr. Mater.
,
98
, pp.
9
12
.10.1016/j.scriptamat.2014.10.034
4.
Mansour
,
R.
,
Maillet
,
E.
, and
Morscher
,
G. N.
,
2005
, “
Development of an Interlaminar Toughness Test for Ceramic Matrix Composites
,”
ASME
Paper No. GT2015-43490. 10.1115/GT2015-43490
5.
Kumar
,
R. S.
,
2017
, “
Crack-Growth Resistance Behavior of Mode-I Delamination in Ceramic Matrix Composites
,”
Acta Mater.
,
131
, pp.
511
522
.10.1016/j.actamat.2017.04.012
6.
Mansour
,
R.
,
Kannan
,
M.
,
Morscher
,
G. N.
,
Abdi
,
F.
,
Godines
,
C.
, and
DorMohammadi
,
S.
,
2017
, “
The Wedge-Loaded Double Cantilever Beam Test: A Friction Based Method for Measuring Interlaminar Fracture Properties in Ceramic Matrix Composites
.,”
Advances in High Temperature Ceramic Matrix Composites and Materials for Sustainable Development
,
Wiley
,
Hoboken, NJ
, pp.
273
282
.
7.
Mansour
,
R.
,
Singh
,
Y. P.
,
Kannan
,
M.
,
Morscher
,
G. N.
,
Abdi
,
F.
,
Ahmad
,
J.
,
Godines
,
C.
,
DorMohammadi
,
S.
, and
Choi
,
S. R.
,
2017
, “
Study of Interlaminar Fracture Properties of Ceramic Matrix Composites at Room and Elevated Temperatures
,”
ASME
Paper No.
GT2017-65168. 10.1115/GT2017-65168
8.
Abdi
,
F.
,
DorMohammadi
,
S.
,
Ahmad
,
J.
,
Godines
,
C.
,
Morscher
,
G. N.
,
Choi
,
S.
,
Mansour
,
R.
,
Gonczy
,
S.
, and
Ojard
,
G.
,
2017
, “
Crack Growth Resistance of CMC Attachment Element and Turbine Joint in Aircraft Engines
,”
ASME
Paper No.
GT2017-65089. 10.1115/GT2017-65089
9.
Abdi
,
F.
,
Ahmad
,
J.
,
DorMohammadi
,
S.
,
Godines
,
C.
,
Gonczy
,
S.
,
Mansour
,
R.
,
Morscher
,
G. N.
,
Choi
,
S.
,
Shi
,
J.
, and
Ojard
,
G.
,
2018
, “
Development of ASTM Test Standards for the Mode I Interlaminar Fracture Toughness (GIC—Crack Growth Resistance) of Ceramic Matrix Composites
,”
ASME
Paper No. GT2018-77147. 10.1115/GT2018-77147
10.
Mansour
,
R.
, and
Morscher
,
G. N.
,
2018
, “
Mode I Interlaminar Fracture Behavior of 2D Woven Ceramic Matrix Composites
,”
Int. J. Appl. Ceram. Technol.
,
16
(
2
), pp.
735
745
.10.1111/ijac.13117
11.
Carlsson
,
L. A.
,
Gillespie
,
J. W.
, and
Pipes
,
R. B.
,
1986
, “
On the Analysis and Design of the End Notched Flexure (ENF) Specimen for Mode II Testing
,”
J. Compos. Mater.
,
20
(
6
), pp.
594
604
.10.1177/002199838602000606
12.
Corleto
,
C.
, and
Bradley
,
W. L.
,
1989
, “
Mode II Delamination Fracture Toughness of Unidirectional Graphite/Epoxy Composites
,”
Composite Materials: Fatigue and Fracture, Second Volume
,
Paul A.
,
Lagace
, ed.,
American Society for Testing and Materials
,
Philadelphia
, pp.
201
221
.
13.
Wang
,
W.-X.
,
Nakata
,
M.
,
Takao
,
Y.
, and
Matsubara
,
T.
,
2009
, “
Experimental Investigation on Test Methods for Mode II Interlaminar Fracture Testing of Carbon Fiber Reinforced Composites
,”
Composites, Part A
,
40
(
9
), pp.
1447
1455
.10.1016/j.compositesa.2009.04.029
14.
ASTM
,
2014
, “
Standard Test Method for Determination of the Mode II Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Polymer Matrix Composites
,” ASTM International, West Conshohocken, PA, Standard No. D7905/D7905M-14.
15.
Wang
,
H.
, and
Vu-Khanh
,
T.
,
1996
, “
Use of End-Loaded-Split (ELS) Test to Study Stable Fracture Behavior of Composites Under Mode II Loading
,”
Compos. Struct.
,
36
(
1–2
), pp.
71
79
.10.1016/S0263-8223(96)00066-9
16.
Mansour
,
R.
,
2017
, “
Mode I Interlaminar Fracture Properties of Oxide and Non-Oxide Ceramic Matrix Composites
,” Ph.D. dissertation, The University of Akron, Akron, OH.
17.
Anderson
,
T. L.
,
2005
,
Fracture Mechanics: Fundamentals and Applications
,
Taylor & Francis
,
Boca Raton, FL
, pp.
34
41
.
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