Tensile and fatigue behavior of oxide/oxide ceramic matrix composite with simulated foreign object damage in combustion environment

2017 ◽  
Vol 15 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Abhendra Singh ◽  
Shankar Mall
Keyword(s):  
Matrix Composite ◽  
Fatigue Behavior ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Oxide Ceramic ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Combustion Environment

Fatigue behavior of double-edge notched oxide/oxide ceramic matrix composite in a combustion environment

2017 ◽  
Vol 51 (26) ◽  
pp. 3669-3683 ◽  
Author(s):  
Abhendra K Singh ◽  
Volodymyr Sabelkin ◽  
Shankar Mall
Keyword(s):  
Fatigue Limit ◽  
Matrix Composite ◽  
Fatigue Behavior ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Oxide Ceramic ◽  
Stiffness Reduction ◽  
Specimen Temperature ◽  
Double Edge ◽  
Combustion Environment

Tension–tension fatigue tests in a combustion environment were performed on double-edge notched oxide/oxide ceramic matrix composite specimens. The composite, designated as N720/A, constituted woven 0°/90° Nextel™720 fibers in alumina matrix. Monotonic tensile and cyclic loads at a frequency of 1 Hz and a stress ratio of 0.05 were applied on the specimens in a combustion environment. The maximum specimen temperature due to combustion flame impingement in the notch region was 1250 ± 50℃. A stiffness reduction of less than 10% evaluated for the run-out specimens showed the harsh combustion environment had a minimal effect on specimen degradation. The residual strength was evaluated to be ∼75%–85% the strength of non-fatigued (virgin) double-edge notch specimens in room temperature. The monotonic tensile strength and the fatigue limit for 90,000 cycles (run-out) were found to be ∼40 MPa less in the combustion environment when compared to published results for 1200℃ laboratory air environment. The damage mechanisms were also the same in the two environments. Finite element analyses showed that the reduction in strength and fatigue limit in the combustion environment (as compared to the laboratory air environment) was due to the presence of thermal gradient stresses because of non-uniform specimen temperature distribution.

Foreign Object Damage in an Oxide/Oxide Ceramic Matrix Composite (CMC) Under Prescribed Tensile Loading

2016 ◽  
Author(s):  
Nesredin Kedir ◽  
David Faucett ◽  
Luis Sanchez ◽  
Sung R. Choi
Keyword(s):  
Matrix Composite ◽  
Impact Damage ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Tensile Loading ◽  
Load Factor ◽  
Oxide Ceramic ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
The Impact

Foreign object damage (FOD) behavior of an N720/alumina oxide/oxide ceramic matrix composite (CMC) was characterized at ambient temperature by using spherical projectiles impacted at velocities ranging from 100 to 350 m/s. The CMC targets were subject to ballistic impact at a normal incidence angle while being loaded under different levels of tensile loading in order to simulate conditions of rotating aeroengine airfoils. The impact damage of frontal and back surfaces was assessed with respect to impact velocity and load factor. Subsequent post-impact residual strength was also estimated to determine quantitatively the severity of impact damage. Impact force was predicted based on the principles of energy conservation.

Foreign Object Damage in an Oxide/Oxide Ceramic Matrix Composite Under Prescribed Tensile Loading

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Nesredin Kedir ◽  
David Faucett ◽  
Luis Sanchez ◽  
Sung R. Choi
Keyword(s):  
Matrix Composite ◽  
Impact Damage ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Tensile Loading ◽  
Load Factor ◽  
Oxide Ceramic ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
The Impact

Foreign object damage (FOD) behavior of an N720/alumina oxide/oxide ceramic matrix composite (CMC) was characterized at ambient temperature by using spherical projectiles impacted at velocities ranging from 100 to 350 m/s. The CMC targets were subject to ballistic impact at a normal incidence angle while being loaded under different levels of tensile loading in order to simulate conditions of rotating aeroengine airfoils. The impact damage of frontal and back surfaces was assessed with respect to impact velocity and load factor. Subsequent postimpact residual strength was also estimated to determine quantitatively the severity of impact damage. Impact force was predicted based on the principles of energy conservation.

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