Characterization of Foreign Object Damage in an Oxide/Oxide Composite at Ambient Temperature

2009 ◽  
pp. 167-177 ◽  
Author(s):  
Sung R. Choi ◽  
Donald J. Alexander
Keyword(s):  
Ambient Temperature ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Oxide Composite

Foreign Object Damage in an Oxide/Oxide Composite at Ambient Temperature

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Sung R. Choi ◽  
Donald J. Alexander ◽  
Robert W. Kowalik
Keyword(s):  
Impact Strength ◽  
Ambient Temperature ◽  
Impact Damage ◽  
Ceramic Matrix Composite ◽  
High Energy ◽  
Strength Degradation ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Oxide Composite ◽  
Post Impact

Foreign object damage behavior of an oxide/oxide (N720/AS) ceramic matrix composite was determined at ambient temperature using impact velocities ranging from 100 m/s to 400 m/s by 1.59 mm diameter steel-ball projectiles. Two different support configurations of target specimens were used: fully supported and partially supported. The degree of post-impact strength degradation increased with increasing impact velocity and was greater in a partially supported configuration than in a fully supported one. For the fully supported configuration, frontal contact stress played a major role in generating composite damage, while for the partially supported case, both frontal contact and backside flexure stresses were the combined sources of damage generation. The oxide/oxide composite was able to survive high energy (∼1.3 J) impacts without complete structural failure. The degree of relative post-impact strength degradation of the oxide/oxide composite was similar to that of an advanced SiC/SiC composite observed from a previous study, regardless of the type of specimen support. Like the SiC/SiC composite, impact-damage tolerance was greater in the oxide/oxide than in monolithic silicon nitride ceramics for impact velocities >300 m/s.

Foreign Object Damage in an Oxide/Oxide Composite at Ambient Temperature

2008 ◽  
Author(s):  
Sung R. Choi ◽  
Donald J. Alexander ◽  
Robert W. Kowalik
Keyword(s):  
Impact Strength ◽  
Ambient Temperature ◽  
Impact Damage ◽  
Ceramic Matrix Composite ◽  
High Energy ◽  
Strength Degradation ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Oxide Composite ◽  
Post Impact

Foreign object damage (FOD) behavior of an oxide/oxide (N720/AS) ceramic matrix composite (CMC) was determined at ambient temperature using impact velocities ranging from 100 to 400 m/s by 1.59-mm diameter steel-ball projectiles. Two different support configurations of target specimens were used: fully supported and partially supported. The degree of post-impact strength degradation increased with increasing impact velocity, and was greater in a partially supported configuration than in a fully supported one. For the fully supported configuration, frontal contact stress played a major role in generating composite damage, while for the partially supported case both frontal contact and backside flexure stresses were the combined sources of damage generation. The oxide/oxide composite was able to survive high energy (∼1.3 J) impacts without complete structural failure. The degree of relative post-impact strength degradation of the oxide/oxide composite was similar to that of an advanced SiC/SiC composite observed from a previous study, regardless of the type of specimen support. Like the SiC/SiC composite, impact-damage tolerance was greater in the oxide/oxide than in monolithic silicon nitride ceramics for impact velocities >300 m/s.

scholarly journals Microstructural Characterization of Failed Aircraft Antenna

2018 ◽  
Vol 3 (4) ◽  
pp. 171-181
Author(s):  
Premkumar Manda ◽  
A Sambasiva Rao ◽  
Satyapal Singh ◽  
Ashok Kumar Singh
Keyword(s):  
Collision Avoidance ◽  
Traffic Control ◽  
Microstructural Characterization ◽  
Aircraft Engine ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
External Objects ◽  
Large Particles ◽  
Collision Avoidance System

This paper presents the failure analysis of aircraft antenna which is a sub-assembly of Traffic Collision Avoidance System (TCAS) used with Air Traffic Control (ATC) transponder. The base of the damaged antenna (metallic part) is made from Al-based alloy. The micrographs exhibit the typical solidification microstructure consisting of Al-rich matrix along with Si- and Mg-Si-Fe- rich phases. The antenna is coated with the paint consisting of three layers. First and third layers display the presence of Ti and C while second layer consists of Si, Cr and C elements. The small amount of oxygen is also present in all the three layers. The cracks are appeared in the central region of the fin due to impact of external objects (appears to be blankings and particles). Three types of foreign object damage particles are observed on the damaged / hit area. The antenna appears to be damaged during gale as a result of hitting of the large particles lying in aircraft parking area and aircraft engine blankings.

scholarly journals In situ characterization of foreign object damage (FOD) in environmental‐barrier‐coated silicon carbide (SiC) ceramic

2020 ◽  
Vol 103 (8) ◽  
pp. 4586-4601 ◽  
Author(s):  
Nesredin Kedir ◽  
Eugenio Garcia ◽  
Cody Kirk ◽  
Zherui Guo ◽  
Jinling Gao ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Foreign Object ◽  
In Situ Characterization ◽  
Foreign Object Damage ◽  
Environmental Barrier ◽  
Sic Ceramic

Crystallographic Characterization of Dislocation Loops in Irradiated Tungsten

1968 ◽  
Vol 26 ◽  
pp. 290-291
Author(s):  
Robert C. Rau
Keyword(s):  
Electron Microscope ◽  
Ambient Temperature ◽  
Dislocation Loops ◽  
Polycrystalline Specimen ◽  
Post Irradiation ◽  
Neutron Fluences

Previous work has shown that post-irradiation annealing, at temperatures near 1100°C, produces resolvable dislocation loops in tungsten irradiated to fast (E > 1 MeV) neutron fluences of about 4 x 1019 n/cm2 or greater. To crystallographically characterize these loops, tilting experiments were carried out in the electron microscope on a polycrystalline specimen which had been irradiated to 1.5 × 1021 n/cm2 at reactor ambient temperature (∼ 70°C), and subseouently annealed for 315 hours at 1100°C. This treatment produced large loops averaging 1000 Å in diameter, as shown in the micrographs of Fig. 1. The orientation of this grain was near (001), and tilting was carried out about axes near [100], [10] and [110].

Sign in / Sign up

Export Citation Format

Share Document