Numerical Analysis of Crack Propagation in Silicon Nitride

Karaszewski, Waldemar

doi:10.4028/www.scientific.net/kem.490.216

Cited by 3 publications

(6 citation statements)

References 9 publications

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“…These new crack can be called as secondary surface cracks [7]. Detailed description and mechanism of crack propagation was described in other papers [6,11].…”

Section: Resultsmentioning

confidence: 99%

“…Typical ring cracks were produced by a 400 g impact load, dropped from 300 mm (crack P3), 500 mm (crack P4) and 750 mm (crack P5). Detailed information about test conditions was presented in author papers [6,8,9,10,11].…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Detailed information about calculation of K eff values, crack direction, crack increment extension and proposed way of comparison of experimental defined K effC (effective critical stress intensity factor) value to known value K IC of silicon nitride materials was presented in other papers [6,8,11].…”

Section: Stress Intensity Factors and Criterion Of Crack Growthmentioning

confidence: 99%

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Hertzian Crack Propagation in Ceramic Rolling Elements

Karaszewski

2014

KEM

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The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack front are analyzed using a three-dimensional boundary element model. The numerical analysis is verified by experimental studies.

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“…These new crack can be called as secondary surface cracks [7]. Detailed description and mechanism of crack propagation was described in other papers [6,11].…”

Section: Resultsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Stress Intensity Factors and Criterion Of Crack Growthmentioning

confidence: 99%

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Hertzian Crack Propagation in Ceramic Rolling Elements

Karaszewski

2014

KEM

Self Cite

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“…The crack front will propagate if the stress intensity factors on the crack front are higher then the threshold value. The threshold value of crack propagation (mode I) is from 2 to 4 MPa*m 1/2 for hot isostatically pressed silicon nitride material and the fracture toughness value is K IC = 6 MPa*m 1/2 [8,14].…”

Section: Analysis and Discussionmentioning

confidence: 99%

Analysis of Ceramic Elements with Ring-Crack Defects in Lubricated Rolling Contact

Karaszewski

2016

SSP

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The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. Surface ring cracks on lubricating rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three-dimensional model of the ring crack. The stress intensity factors along crack front are analyzed using a finite element analysis. The numerical analysis is verified by experimental studies.

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“…The curves in Figure 3 were calculated using the Forman equation [48] to account for the effects of the threshold on the crack growth rate, as given by the following relationship [49]:…”

Section: Fatigue Studiesmentioning

confidence: 99%

Increasing the fatigue resistance of epoxy nanocomposites by aligning graphene nanoplatelets

Bhasin

Ladani

et al. 2018

International Journal of Fatigue

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Graphene nanoplatelets (GNPs) offer great potential for enhancing the multifunctional properties of epoxy polymers, including the cyclic-fatigue crack growth resistance. In the present work we investigate the effectiveness of electric-field alignment of GNPs in increasing the fatigue resistance of such epoxy nanocomposites. The GNPs were aligned in an uncured (liquid) epoxy resin by applying an alternating-current electric field during the curing process, before gelation of the epoxy. The fatigue properties of the cured epoxy containing both random and aligned GNPs were measured using double cantilever beam (DCB) specimens tested in displacement control over a range of cyclic energy release rates from the threshold condition (i.e. below which no fatigue crack growth was observed) to fast fracture. The results show that aligning the GNPs using an electric field yields a greater improvement in the fatigue crack growth resistance than obtained using randomly-orientated GNPs, particularly in the near threshold region. The resistance of the epoxy nanocomposites to fatigue crack growth was increased as the weight fraction of the GNPs was increased up to a certain level, beyond which there was no further improvement in the fatigue resistance. These improvements have been attributed to several toughening mechanisms which retard the fatigue crack growth in the epoxy nanocomposites, including debonding of the GNPs, epoxy void growth, crack deflection and branching of the main fatigue crack caused by microcracking induced by the presence of the GNPs, pull-out and crack bridging by the GNPs, and crack shielding by GNP debris particles behind the advancing fatigue crack tip. These toughening mechanisms become more active when the GNPs are aligned normal to the direction of fatigue crack growth, which results in a higher fatigue resistance for the epoxy nanocomposites containing aligned GNPs than for those containing randomly-orientated GNPs.

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Numerical Analysis of Crack Propagation in Silicon Nitride

Cited by 3 publications

References 9 publications

Hertzian Crack Propagation in Ceramic Rolling Elements

Hertzian Crack Propagation in Ceramic Rolling Elements

Analysis of Ceramic Elements with Ring-Crack Defects in Lubricated Rolling Contact

Increasing the fatigue resistance of epoxy nanocomposites by aligning graphene nanoplatelets

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