Strength Evaluation Test of Hot-pressed Silicon Nitride at Room Temperature

MATSUSUE, Katsutoshi; TAKAHARA, Kitao; Hashimoto, Ryosaku

doi:10.2109/jcersj1950.90.1040_168

Cited by 13 publications

(4 citation statements)

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“…2e can produce, for one RVE, a cdf with two essential characteristics: (i) a power-law tail whose exponent m is Ϸ10-50, typical of Weibull moduli observed for various brittle materials, and (ii) a power-law tail reaching to P f ϭ 0.0001 to 0.01, which is a chain of 100-10,000 RVEs. For such sizes or larger, laboratory specimens of heterogeneous brittle materials follow the Weibull cdf (6,(20)(21)(22)(23)(24)(25)(26)(27)(28), whereas the behavior of the smallest possible test specimens of such materials can be described as Gaussian (29-33) (except for the far-left tail of histograms of strength tests that is normally undetectable).…”

Section: Structure As a Chain Of Rvesmentioning

confidence: 99%

Mechanics-based statistics of failure risk of quasibrittle structures and size effect on safety factors

Bažant

Pang

2006

Proc. Natl. Acad. Sci. U.S.A.

104

108

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In mechanical design as well as protection from various natural hazards, one must ensure an extremely low failure probability such as 10 ؊6 . How to achieve that goal is adequately understood only for the limiting cases of brittle or ductile structures. Here we present a theory to do that for the transitional class of quasibrittle structures, having brittle constituents and characterized by nonnegligible size of material inhomogeneities. We show that the probability distribution of strength of the representative volume element of material is governed by the Maxwell-Boltzmann distribution of atomic energies and the stress dependence of activation energy barriers; that it is statistically modeled by a hierarchy of series and parallel couplings; and that it consists of a broad Gaussian core having a grafted far-left power-law tail with zero threshold and amplitude depending on temperature and load duration. With increasing structure size, the Gaussian core shrinks and Weibull tail expands according to the weakest-link model for a finite chain of representative volume elements. The model captures experimentally observed deviations of the strength distribution from Weibull distribution and of the mean strength scaling law from a power law. These deviations can be exploited for verification and calibration. The proposed theory will increase the safety of concrete structures, composite parts of aircraft or ships, microelectronic components, microelectromechanical systems, prosthetic devices, etc. It also will improve protection against hazards such as landslides, avalanches, ice breaks, and rock or soil failures.cohesive fracture ͉ extreme value statistics ͉ activation energy ͉ Maxwell-Boltzmann ͉ scaling

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Section: Structure As a Chain Of Rvesmentioning

confidence: 99%

Mechanics-based statistics of failure risk of quasibrittle structures and size effect on safety factors

Bažant

Pang

2006

Proc. Natl. Acad. Sci. U.S.A.

104

108

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“…Tensile test [30][31][32][33][34], rotating disc test [31], ring compression test [3, 32,35] and ring expansion test [36][37][38] [36]. For comparison, the dashed straight lines as seen in Figs.…”

Section: Effects Of Specimen Geometry and Stress State On Strengthmentioning

confidence: 99%

“…The effect of specimen size on strength was investigated by bending test of various materials [4,6,26,31,32,37,39], ring expansion test of a reaction-bonded silicon nitride [36], and sphere compression test of a soda lime silica [40]. A typical result in 4-point bending test of an alumina is shown in Fig.…”

Section: Effects Of Specimen Geometry and Stress State On Strengthmentioning

confidence: 99%

Strength Characteristics of Structural Ceramics

Hoshide

1996

Journal of the Society of Materials Science, Japan

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In structural ceramics, a remarkable scatter of strength is observed due to brittle behavior in deformation and flaws unavoidably formed during material processing. Therefore, information on strength characteristics of ceramics is required for the mechanical design in their applications to high-performance components. In the present paper, the strength properties of typical ceramics are reviewed from statistical aspects, especially. As for the static strength, general features of ceramic strength are first outlined, and then several factors affecting strength, such as environments, specimen geometry, stress state and machining, are described. The fatigue strength is reviewed in two categories of the static and cyclic fatigue. As one of screening procedures to exclude components with a lower strength, the proof testing in ceramics is described and the problems in the testing are also mentioned.

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“…It has been reported that the shape and/or size of specimen and the loading mode affect strength characteristics in ceramic materials [1][2][3][4][5][6][7][8][9][10][11][12]. For successful applications of ceramics to engineering components, strength characteristics of notched components with an appropriate procedure to estimate them should be also investigated in the relation to the well-known size effect [13].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Bending Strength Affected by Specimen Geometry in Silicon Nitride

Hoshide

Sano

Honda

1997

Journal of the Society of Materials Science, Japan

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Four-point bending tests of a gas pressure sintered silicon nitride were conducted using notched specimens with different notch shapes as well as smooth specimens of distinct sizes, and the effect of the specimen geometry on the bending strength was experimentally clarified. The mean strength in smooth specimens could be almost correlated with the effective volume, though the mean strength in notched specimens shifted toward the lower strength side compared with the relation for smooth specimens. From observation of fracture surface, no unique correlation of the strength with the effective volume was suggested to be ascribed to a difference in flaw morphology between smooth and notched specimens. To discuss the efficiency of the effective volume, a Monte Carlo simulation was also carried out by assuming the same distribution characteristics of cracks in a material. The simulated result revealed that the effect of the specimen geometry on the strength was explained by using the effective volume. The effective volume, however, was found to be inefficient because of a failure of the primitive assumption in the Weibull theory when the flaw density was extremely low in a material.

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Strength Evaluation Test of Hot-pressed Silicon Nitride at Room Temperature

Cited by 13 publications

References 0 publications

Mechanics-based statistics of failure risk of quasibrittle structures and size effect on safety factors

Mechanics-based statistics of failure risk of quasibrittle structures and size effect on safety factors

Strength Characteristics of Structural Ceramics

Evaluation of Bending Strength Affected by Specimen Geometry in Silicon Nitride

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