Calculation of Stress Intensity Factors for SENB Specimens by Boundary Collocation Procedure

Wakai, Fumihiro; Sakaguchi, Shuji; Matsuno, Yosoo

doi:10.2109/jcersj1950.93.1080_479

Cited by 25 publications

(10 citation statements)

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“…An equivalent crack length, i.e., the crack length in an infinite plate with the same SIF as the edge crack, is calculated assuming that the V-notch is an edge crack. The SIF of the edge-cracked specimen was calculated using the following estimation by Wakai et al 19)…”

Section: Dense Aluminamentioning

confidence: 99%

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

2006

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In order to improve the fracture toughness of inherently brittle ceramics, a new material design concept must be developed. One suitable concept involves the use of dislocation activities. Intra-type ceramic-based nanocomposites use dislocation activities to enhance strength and fracture toughness. The dislocations are generated by residual stresses induced during sintering process around the second-phase nanoparticles dispersed within the matrix grains. In this paper, first, we proposed an indirect technique for estimating a critical frontal process zone (CFPZ) size for ceramics and clarified the relation between the strength, fracture toughness, and CFPZ size. The fracture toughness of ceramics is closely related to the CFPZ size because ceramics with larger CFPZ size consume higher fracture energy during crack extension and consequently have higher fracture toughness. Second, we fabricated toughened alumina-nickel nanocomposites using a soaking method to construct an intra-type nanostructure, and found that the appropriate annealing conditions after sintering could achieve toughened nanocomposites. Finally, we discussed the relation between the experimentally obtained fracture toughness and the CFPZ size of monolithic alumina, as-sintered nanocomposites, and annealed nanocomposites. The results revealed that nanocomposites showed the largest CFPZ size and the highest fracture toughness after appropriate annealing: the sessile dislocations ahead of a crack tip in a nanocomposite are thought to serve as stress concentration, create many nanocracks in the CFPZ, and expand the CFPZ size.

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Section: Dense Aluminamentioning

confidence: 99%

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

2006

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“…To measure the fracture toughness, 4 © 2 © 18 mm bars were also cut as in the case of fracture strength measurement, a V-shaped notch with a depth of 0.5 mm, with a width of 100¯m and an end curvature radius of 10¯m was processed at the center of the specimen and a fracture toughness test was carried out with the span size set at 16 mm and the crosshead speed at 0.05 mm/min. The fracture toughness was calculated using the equation presented by Wakai et al 27) and the results obtained. The average fracture toughness was obtained from the measurements of 5 samples.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of textured Ti<sub>3</sub>SiC<sub>2</sub> ceramic by slip casting in a strong magnetic field and pressureless sintering

Sato

Mishra

Hirano

et al. 2014

J. Ceram. Soc. Japan

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Sinterable Ti 3 SiC 2 powder was synthesized from a powder mixture with a molar ratio of 1.0Ti:0.3Al:1.2Si:2.0TiC by heating at 1200°C in Ar flow. Almost single-phase peaks of Ti 3 SiC 2 were observed in X-ray diffraction patterns. The powder was dispersed in ethanol using polyethylenimine (PEI) as the polymer dispersant. Textured dense Ti 3 SiC 2 ceramics were successfully fabricated by slip casting in a strong magnetic field followed by pressureless sintering at 1400°C for 2 h. The relative density of these Ti 3 SiC 2 ceramics was 99.4%, and the bending strength, fracture toughness and electrical resistivity were 623 « 9 MPa, 5.9 « 0.1 MPa·m 1/2 and 0.31¯³·m, respectively. Compared with those of nontextured pressureless sintered samples of almost full density, the bending strength and fracture toughness of the textured Ti 3 SiC 2 ceramics were increased by factors of 1.6 and 1.4, respectively.

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“…The fracture toughness was calculated by the equation presented by Wakai et al, 9) using the results obtained. Thermal expansion was measured with the specimens in disk shape with thickness of 10 mm and diameter of 5 mm was used for the thermo mechanical analyzer (TMA-50H, Shimadzu Co.)(JIS R 1618).…”

Section: Characterizationmentioning

confidence: 99%

Relation between functional properties of alumina-based nanocomposites and locations of dispersed particles

Nishimura

Choi

Hashimoto

et al. 2009

J. Ceram. Soc. Japan

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We previously proposed the toughening and strengthening mechanisms of alumina-based nanocomposites on the basis of dislocation activities, assuming that nano-sized particles were embedded within the alumina grains. In this research, we fabricated both intragranular dominant and intergranular dominant nanocomposites of alumina/nickel(Ni) system. In order to fabricate intragranular dominant nanocomposites, γ-alumina powder with many nanopores was used as a starting material through a soaking method. Intergranular dominant nanocomposites were prepared using α-alumina powder as a starting material. Monolithic alumina samples were also sintered for comparison. Mechanical, thermal, and electrical properties were estimated for those specimens. The results showed that the intragranular nanocomposites had a higher mechanical strength and fracture toughness than the intergranular nanocomposites. The values of thermal expansion and thermal conductivity were slightly high in the intragranular nanocomposites compared to the intergranular one. The intergranular nanocomposites indicated a low dielectric breakdown voltage. Relations between the functional properties of the nanocomposites and the location of the dispersed Ni particles were discussed based on dislocation activities and the percolation model.

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Calculation of Stress Intensity Factors for SENB Specimens by Boundary Collocation Procedure

Cited by 25 publications

References 0 publications

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

Fabrication of textured Ti<sub>3</sub>SiC<sub>2</sub> ceramic by slip casting in a strong magnetic field and pressureless sintering

Relation between functional properties of alumina-based nanocomposites and locations of dispersed particles

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