Foreign object damage in disks of gas-turbine-grade silicon nitrides by steel ball projectiles at ambient temperature

Choi, Sung R.; Pereira, J. Michael; Janosik, Lesley A.; Bhatt, Ramesh S.

doi:10.1023/b:jmsc.0000043584.35335.58

Cited by 30 publications

(15 citation statements)

References 21 publications

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“…The mean strength was 678±45MPa for AS800 and 426±60 MPa fo r SN282 . Weibull modulus (m= 18, 8 fo r AS800 and SN282, respectively) in biaxial configu rati on compares well with that (m=2 1, II fo r AS800 and SN282, respective ly, see Tabl e I) in uniaxial four-point configuration detennined previous ly [ 12]. The number of test specimens used in bi axia l strength testing was 10 and 21 , respectively, for AS800 and SN282.…”

Section: Post-impact Strengthsupporting

confidence: 78%

“…Although not presented here, a prediction of strength as a functio n of radi al crack size was made based on a semi-circular crack assum pti on and was fou nd in good agreement wi th the ex perimental data [21]. Thi impli es that the nece sity of detail ed knowledge on complex radial crack geo metry/configu ratio n (s uch as no n-symmetrical and significant elli ptical shapes) in vo lved in radi al cracking would be minimized or elimi nated.…”

Section: Fr Acture Surfaces/m Odesmentioning

confidence: 55%

“…Hence, the conecracking model , Eq. (4 or 5), would not be appropriate to describe adequately the post-impact biaxial strength behavior of AS8DD and SN282 silicon nitrides, as also observed previousl y from uniaxial flexure beam target specimens [11,12]. One of the reasons for this is ~hat the.…”

Section: Analytical Considerations Of Strength De Gradationmentioning

confidence: 96%

“…The velocity was then calculated based on the distance-time relationship. A relation ship between ve locity and pressure was determi ned in a range of pressure from 0 to 800 psi [12]. It was found that velocity increased with increasing pressure, rising sharply at lower pressure but moderately at higher pressure.…”

Section: Fore Ign Object Dam Age Testin Gmentioning

confidence: 99%

“…The reason for the occurrence of backs ide crack ing has been considered using an elastic foundation approach [21 ]. Al though the ta rget speci mens were rigidly supported, due to the significant impact force (es timated co nservatively by the quasi-static contact theory [ 1,4,5,8]), it was postulated that they might respond as though supported on an elastic foundation.…”

Section: Backside Cracking and I Ts Analytical Considerationmentioning

confidence: 99%

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

Choi

Pereira

Janosik

et al. 2003

Volume 1: Turbo Expo 2003

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A BSTRACTForeign object damage (FOD) behavior of two commercial gasturbine grade silicon nitrides, AS800 and SN282, wa determined at ambient temperature through post-impact st rength testing for thin disks impacted by steel-ball projectiles with a diameter of I.S9 mm in a velocity range from 115 to 440 m/s. AS800 silicon nitrid e ex hibited a greater FOD resistance than SN282, primarily due to its greater va lue of fracture toughness (Kid. The criti cal impact velocity in which th e correspo nd ing post-impact strength yielded the lowest va lue was V c ",,440 and 300 m/s fo r AS800 and SN282, respec ti ve ly. A unique lower-trength regime was typified fo r both silicon nitrides depending on impac t velocity, attributed to signi ficant radial cracking. The damages generated by projectile impact were typically in the fonns of ring, radial, and cone cracks with their severity and combinati on being dependent on impact velocity.U nl ike thick (3 mm) flexu re bar specimens used in the previous studies, th in (2 mm) disk target specimens exhibited a unique backside radial cracking occu rring on the reverse side just beneath the impact si tes a t and above impact veloci ty of 160 and 220 ml s fo r SN282 and AS800, respectively. INTRODUCTIONCerami cs, because of thei r brittle natu re, are susceptible to locali zed surface damage and/or cracking when subjected to impact by foreign objects. It is also true that cerami c components may fail structu rally even by soft particles when the kinetic energy of impacting objects exceeds certai n limi ts. The latter case has been often found in aerospace engi nes in which combus tion products, metallic parti cles or small fo reign objects cause severe damage to bl ade/vane components, resulting in serious s tructural problems. Therefore, foreign obj ec t damage (FOD) associated with particle impact needs to be considered when ceramic materials are designed fo r structu ral app licatio ns. In view of this importance, a considerable amou nt of work on impact damage of brittle materials by sharp particles as we ll as by "blunt" particles or by plates has been accumula ted both ex perimentally and

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Section: Post-impact Strengthsupporting

confidence: 78%

Section: Fr Acture Surfaces/m Odesmentioning

confidence: 55%

Section: Analytical Considerations Of Strength De Gradationmentioning

confidence: 96%

Section: Fore Ign Object Dam Age Testin Gmentioning

confidence: 99%

Section: Backside Cracking and I Ts Analytical Considerationmentioning

confidence: 99%

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