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.

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 Behavior of a SiC Fibrous Ceramic Composite

2017 ◽  
Author(s):  
Nesredin Kedir ◽  
D. Calvin Faucett ◽  
Luis Sanchez ◽  
Sung R. Choi
Keyword(s):  
Ceramic Composite ◽  
Impact Force ◽  
Impact Damage ◽  
Incidence Angle ◽  
Fibrous Composite ◽  
Normal Incidence ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Post Impact ◽  
The Impact

The response of a SiC fibrous ceramic composite to foreign object damage was determined at ambient temperature and velocities ranging from 40 to 150 m/s. Target specimens were impacted, at a normal incidence angle and in a partially supported configuration, using 1.59 mm-diameter hardened steel ball projectiles. Qualitative analysis of the damage morphologies of targets and projectiles were made via scanning electron microscopy (SEM). In addition, the extent of impact damage was characterized by determining the post-impact strength of each target specimen as a function of impact velocity. Relative to the as-received strength, the fibrous composite showed limited strength degradation due to impact with the maximum reduction of 17 % occurring at 150 m/s. A quasi-static analysis of the impact force prediction was also made based on the principle of energy conservation and the results were verified via experimental data.

Target Size Effects on Foreign Object Damage in Gas-Turbine Grade Silicon Nitrides by Ceramic Ball Projectiles

2010 ◽  
Author(s):  
Sung R. Choi ◽  
Zsolt Ra´cz
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Impact Velocity ◽  
Impact Damage ◽  
Target Thickness ◽  
Foreign Object ◽  
Silicon Nitrides ◽  
Foreign Object Damage ◽  
Post Impact ◽  
Grade Silicon

Foreign object damage (FOD) phenomena of two gas-turbine grade silicon nitrides (AS800 and SN282) were determined at ambient temperature using impact velocities ranging from 25 to 150 m/s by 1.59-mm diameter silicon nitride ball projectiles. Targets in flexure bar configuration with two different thicknesses of 1 and 2 mm were impacted under a fully supported condition. The degree of impact damage as well as of post-impact strength degradation increased with increasing impact velocity, increased with decreasing target thickness, and was greater in SN282 than in AS800 silicon nitride regardless of target thickness. The critical impact velocity, in which targets fractured catastrophically, decreased monotonically with decreasing target thickness and was lower in SN282 than in AS800. Backside cracking was dominant in both AS800 and SN282 target specimens with a thickness of 1 mm, occurring from an impact velocity of 50 m/s. A backside cracking analysis based on the elastic foundation approach was made as a function of target thickness. Overall, FOD by ceramic projectiles was significantly greater than that by hardened metallic counterparts.

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.

scholarly journals Foreign Object Damage Behavior of a SiC/SiC Composite at Ambient and Elevated Temperatures

2004 ◽  
Author(s):  
Sung R. Choi ◽  
Ramakrishna T. Bhatt ◽  
J. Michael Pereira ◽  
John P. Gyekenyesi
Keyword(s):  
Elevated Temperatures ◽  
Ceramic Matrix Composite ◽  
Foreign Object ◽  
Structural Failure ◽  
Foreign Object Damage ◽  
Composite Damage ◽  
Sic Ceramic ◽  
Different Types ◽  
Bending Stresses ◽  
Post Impact

Foreign object damage (FOD) behavior of a gas-turbine grade SiC/SiC ceramic matrix composite (CMC) was determined at 25 and 1316°C, employing impact velocities from 115 to 440 m/s by 1.59-mm diameter steel-ball projectiles. Two different types of specimen support were used at each temperature: fully supported and partially supported. For a given temperature, 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. The elevated-temperature FOD resistance of the composite, particularly under partially supported loading at higher impact velocities ≥ 350 m/s, was significantly less than the ambient-temperature counterpart, attributed to a weakening effect of the composite. For fully supported loading, frontal contact stress played a major role in generating composite damage; whereas, for partially supported loading, both frontal contact and backside bending stresses were combined sources of damage generation. The SiC/SiC composite was able to survive higher energy impacts without complete structural failure but suffered more strength affecting damage from low energy impacts than AS800 and SN282 silicon nitrides.

Foreign Object Damage Behavior of a Silicon Carbide Fibrous Ceramic Composite

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Nesredin Kedir ◽  
D. Calvin Faucett ◽  
Luis Sanchez ◽  
Sung R. Choi
Keyword(s):  
Silicon Carbide ◽  
Ceramic Composite ◽  
Impact Damage ◽  
Incidence Angle ◽  
Fibrous Composite ◽  
Normal Incidence ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Post Impact ◽  
The Impact

The response of a silicon carbide (SiC) fibrous ceramic composite to foreign object damage (FOD) was determined at ambient temperature and velocities ranging from 40 to 150 m/s. Target specimens were impacted, at a normal incidence angle and in a partially supported configuration, using 1.59 mm diameter hardened steel ball projectiles. Qualitative analysis of the damage morphologies of targets and projectiles was made via scanning electron microscopy (SEM). In addition, the extent of impact damage was characterized by determining the post-impact strength of each target specimen as a function of impact velocity. Relative to the as-received (As-R) strength, the fibrous composite showed limited strength degradation due to impact with the maximum reduction of 17% occurring at 150 m/s. A quasi-static analysis of the impact force prediction was also made based on the principle of energy conservation and the results were verified via experimental data.

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.

Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk Configuration

2003 ◽  
Author(s):  
Sung R. Choi ◽  
J. Michael Pereira ◽  
Lesley A. Janosik ◽  
Ramakrishna T. Bhatt
Keyword(s):  
Impact Strength ◽  
Gas Turbine ◽  
Impact Velocity ◽  
Foreign Object ◽  
Silicon Nitrides ◽  
Foreign Object Damage ◽  
Post Impact ◽  
Grade Silicon ◽  
Thin Disks ◽  
The Impact

Foreign object damage (FOD) behavior of two commercial gas-turbine grade silicon nitrides, AS800 and SN282, was determined at ambient temperature through post-impact strength testing for thin disks impacted by steel-ball projectiles with a diameter of 1.59 mm in a velocity range from 115 to 440 m/s. AS800 silicon nitride exhibited a greater FOD resistance than SN282, primarily due to its greater value of fracture toughness (KIC). The critical impact velocity in which the corresponding post-impact strength yielded the lowest value was Vc ≈ 440 and 300 m/s for AS800 and SN282, respectively. A unique lower-strength regime was typified for both silicon nitrides depending on impact velocity, attributed to significant radial cracking. The damages generated by projectile impact were typically in the forms of ring, radial, and cone cracks with their severity and combination being dependent on impact velocity. Unlike thick (3 mm) flexure bar specimens used in the previous studies, thin (2 mm) disk target specimens exhibited a unique backside radial cracking occurring on the reverse side just beneath the impact sites at and above impact velocity of 160 and 220 m/s for SN282 and AS800, respectively.

Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

2005 ◽  
Author(s):  
Sung R. Choi ◽  
Zsolt Racz ◽  
Ramakrishna T. Bhatt ◽  
David N. Brewer ◽  
John P. Gyekenyesi
Keyword(s):  
Silicon Nitride ◽  
Impact Velocity ◽  
Impact Load ◽  
Impact Damage ◽  
Hardened Steel ◽  
Foreign Object ◽  
Foreign Object Damage ◽  
Post Impact ◽  
Critical Impact Velocity ◽  
Steel Balls

Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

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