Reliability Engineering. Properties of Strength and Distribution for Ceramics Subjected to Contact Load.

Okabe, Nagatoshi; Abe, Yutaka; Ichikawa, Masahiro; Takamatsu, Tohru; Kan, Norio

doi:10.2472/jsms.47.1251

Cited by 4 publications

(5 citation statements)

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“…No failure of the ball occurred because the probability of a surface defect had decreased. 5 In a prior study by one of the co-authors on ball/plate contact conditions, 5 the m value of a ring crack initiation stress based on Hertzian stress was remarkably larger than m b . In contrast, it was damaged in the 70 • case.…”

Section: Ball/valve Indentation Testmentioning

confidence: 93%

“…Shape parameter m in this contact fracture was almost equivalent to m b (11) in the four-point bending strength test of the same material. 5 In a prior study by one of the co-authors on ball/plate contact conditions, 5 the m value of a ring crack initiation stress based on Hertzian stress was remarkably larger than m b . In contrast, scale parameter σ 0 was much larger than the bending strength and is almost twice as large as the ball/plate contact conditions.…”

Section: Ball/valve Indentation Testmentioning

confidence: 96%

“…Bending strength m b =11, Ref. (5) Probability of fracture P [%] The following stress analysis was discussed from fracture mechanics viewpoint about the position and the size of a defect that contributed to fracture. Because the stress was redistributed by crack extension, the crack path was not discussed in this study.…”

Section: Ball/valve Indentation Testmentioning

confidence: 99%

“…[5][6][7][8][9][10][11] The most important point to pay attention in designs using ceramics is rapidly changing stress fields. In particular, the specific strength of ceramics is extremely high compared with that of other high-strength materials.…”

Section: Introductionmentioning

confidence: 99%

“…The authors and their co-workers have been researching various strength tests and a special loading mode of the design criteria and reliability estimations of ceramics. [5][6][7][8][9][10][11] The most important point to pay attention in designs using ceramics is rapidly changing stress fields. This phenomenon can be seen in the stress distribution occurring near interfaces, such as joints and contacts.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Fracture analysis for ceramic ball in backflow valve

Takahashi¹,

Okabe²,

Abe³

et al. 2011

Fatigue Fract Eng Mat Struct

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Ceramic balls have been used as components of devices, such as those found in high‐pressure pumps for automobiles and industrial machines. In the backflow valve, for example, a ceramic ball is in contact with a conical surface. Fractures of ceramic balls are extremely rare. It is important to investigate the cause of these rare fractures to guarantee higher reliability in the backflow valve. In this paper, the fracture mechanism and strength are discussed for an equivalent normal stress σeq beneath the contact region and the maximum principal stress σp near the contact boundary using stress intensity from fracture mechanics. The fracture surface of the ceramic ball was formed perpendicular to load direction. We assumed that fracture origins (defect/crack) existed on lines through three high stresses that analysed by finite element method. Actual fracture of a ceramic ball was found to be caused by the equivalent normal stress beneath contact region and not to be caused by the Hertz principal stress. Stress intensity factor (SIF) was clarified to depend on pressure, taper angle, CrN‐coating thickness and the friction factor of the inside of the valve hole. A pre‐existing defect size involved in failure was estimated by the SIF using three‐dimensional elliptic defects and equivalent normal stress. Therefore, the actual fracture of a ceramic ball, which rarely occurs, could be evaluated by considering three‐dimensional elliptic defects and the Weibull distribution of defects.

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Section: Ball/valve Indentation Testmentioning

confidence: 93%

Section: Ball/valve Indentation Testmentioning

confidence: 96%

Section: Ball/valve Indentation Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fracture analysis for ceramic ball in backflow valve

Takahashi¹,

Okabe²,

Abe³

et al. 2011

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

Simple mechanics model and Hertzian ring crack initiation strength characteristics of silicon nitride ceramic ball subjected to thermal shock

Matsuda

Nakada

2018

Engineering Fracture Mechanics

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Initiation Strength Properties of Ring Crack Caused by Sphere Indentation in Damage-Tolerant Advanced Pore-Free SiC

Matsuda¹,

Takahashi²,

Matsushita³

et al. 2008

J. Soc. Mat. Sci., Japan

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Sphere indentation tests were performed to clarify damage properties on surface of Advanced Pore-Free SiC (APF-SiC) with excellent damage tolerance. The ring crack initiation strength properties were discussed from fracture mechanics viewpoint based on FEM analysis and detailed observations of growth behaviors of the ring crack and the cone crack. As compared to conventional SiC, the initiation strength was nearly equal to regardless of sphere sizes. However, its scatter was increased with increasing sphere sizes. Clusters are formed by uniting some in multi-micro cracks which occur near surface with increasing the contact load, one of that from which the ring crack occurs. Therefore, the strength and the scatter are controlled by the cluster size and its distribution, and the size depends on the generating crack density. It can be explained by the mechanics model which is expressed by the relationship between strength ratio and crack density based on the energy equilibrium theory.

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Reliability Engineering. Properties of Strength and Distribution for Ceramics Subjected to Contact Load.

Cited by 4 publications

References 0 publications

Fracture analysis for ceramic ball in backflow valve

Fracture analysis for ceramic ball in backflow valve

Simple mechanics model and Hertzian ring crack initiation strength characteristics of silicon nitride ceramic ball subjected to thermal shock

Initiation Strength Properties of Ring Crack Caused by Sphere Indentation in Damage-Tolerant Advanced Pore-Free SiC

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