Fracture Toughness of Thin Plates by the Double-Torsion Test Method

Salem, Jonathan A.; Radović, Miladin; Nelson, George J.

doi:10.1002/9780470291313.ch6

Cited by 9 publications

(6 citation statements)

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“…The double‐torsion testing technique, 3–6 which has been critically reviewed by the authors, 6 was successfully applied to determine the fracture toughness and slow crack growth behavior of porous cordierite under ambient conditions. Recent work has demonstrated that the fracture toughness values calculated by the double‐torsion test technique are equivalent to those obtained byASTM‐standardized techniques for materials with a flat R ‐curve 7 . Other researchers have proposed techniques for determining the R ‐curve using double‐torsion testing geometry 8 .…”

Section: Introductionmentioning

confidence: 99%

“…Recent work has demonstrated that the fracture toughness values calculated by the double-torsion test technique are equivalent to those obtained byASTM-standardized techniques for materials with a flat R-curve. 7 Other researchers have proposed techniques for determining the R-curve using doubletorsion testing geometry. 8 The double-torsion methodology was selected for testing specimens fabricated from the walls of the filter for several reasons, namely (a) the rectangular specimen geometry of double-torsion specimens can be fabricated from the walls of the filter, (b) crack length measurement by optical techniques is difficult in porous cordierite because of the large number of pores, nonreflective nature of the surface, and small crack-opening displacements, and (c) specimen-gripping is difficult for fragile porous cordierite specimens and the doubletorsion loading geometry does not require gripping.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Characterization of Diesel Particulate Filter Substrates

Shyam

Watkins

Parten

2008

Journal of the American Ceramic Society

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Test procedures for the mechanical evaluation of diesel particulate filter (DPF) substrate materials have been developed and applied for the characterization of porous cordierite under ambient conditions. Specifically the double‐torsion test method was employed to characterize fracture toughness and slow crack behavior while resonant ultrasound spectroscopy (RUS) was used to determine the elastic properties of the substrate walls. A dry grinding procedure was developed to fabricate test specimens for these tests. The fracture behavior of porous cordierite was related to the pore structure inside the filter wall. Implications of the test results on the mechanical reliability of DPFs are discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical Characterization of Diesel Particulate Filter Substrates

Shyam

Watkins

Parten

2008

Journal of the American Ceramic Society

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“…The double-torsion test 30 was performed to determine the fracture toughness (K IC ) of the as-sintered and reduced samples at room temperature. Figure 2 provides a schematic view of the test setup and the loading configuration.…”

Section: Methodsmentioning

confidence: 99%

LaNbO₄–NiO–Y₂O₃ Stabilized ZrO₂ Anode‐Support Materials for Solid Oxide Fuel Cells

Chi

et al. 2015

J. Am. Ceram. Soc.

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As anode-support materials for solid oxide fuel cells, porous LaNbO 4 -NiO-Y 2 O 3 stabilized ZrO 2 (YSZ) composites (LNY), containing 0, 5, 10, 15, and 20 wt% of LaNbO 4 and designated as 0LNO, 5LNO, 10LNO, 15LNO, and 20LNO, respectively, are prepared by tape casting and sintering. They are investigated for their microstructure and mechanical, electrical and thermal expansion properties. The porosity of as-sintered LNY is around 30%, and that of reduced LNY cermets decreases from 47% for reduced 0LNO to 43% for reduced 20LNO. The fracture strength (r f ) of LNY is higher than that of the reduced form; however, both of them are not rather sensitive to the amount of LaNbO 4 , depending on crack-originating flaws in the specimens. The fracture toughness (K IC ) of LNY increases with LaNbO 4 content and is 1.87 MPaÁm 1/2 for 20LNO, which is more than 20% increase from that of 0LNO; however the K IC for reduced LNY is higher than that of LNY, and decreases with increasing LaNbO 4 content due to the decreased amount of ductile metallic Ni phase. The conductivity of reduced LNY depends on Ni content and is higher than 289 S/cm at temperatures below 900°C. The coefficient of thermal expansion (CTE) of both LNY and reduced LNY is in the range between 12.4 and 11.4 3 10 -6 K -1; which is closely matched with that of YSZ electrolyte.

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“…A summary of the properties relevant to this investigation is given in Table 1; density was obtained using the water displacement method in accordance with BS EN 993-1; Poisson's ratio and Young's Modulus were obtained from data sheets from the manufacturers [14][15][16]; and fracture toughness was obtained from literature for Sintox FA [17], Hexoloy SA [18], and B 4 C [19]. Ballistic performance and cost estimates were provided courtesy of Morgan Advanced Materials.…”

Section: Methodsmentioning

confidence: 99%

Understanding the ballistic event: methodology and initial observations

et al. 2016

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The purpose of the study is to accelerate the development of ceramic materials for armour applications by substantially increasing the information obtained from a high-energy projectile impact event. This has been achieved by modifying an existing test configuration to incorporate a block of ballistic gel, attached to the strike face of a ceramic armour system, to capture fragments generated during the ballistic event such that their final positions are maintained. Three different materials, representative of the major classes of ceramics for armour applications, alumina, silicon carbide, and boron carbide, have been tested using this system. Ring-on-ring biaxial disc testing has also been carried out on the same materials. Qualitative analysis of the fracture surfaces using scanning electron microscopy and surface roughness quantification, via stereo imaging, has shown that the fracture surfaces of biaxial fragments and ballistic fragments recovered from the edges of the tile are indistinguishable. Although the alumina and boron carbide fragments generated from areas closer to the point of impact were also similar, the silicon carbide fragments showed an increase in porosity with respect to the fragments from further away and from biaxial testing. This porosity was found to result from the loss of a boron-rich second phase, which was widespread elsewhere in the material, although the relevance of this to ballistic performance needs further investigation. The technique developed in this work will help facilitate such studies.

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Fracture Toughness of Thin Plates by the Double-Torsion Test Method

Cited by 9 publications

References 10 publications

Mechanical Characterization of Diesel Particulate Filter Substrates

Mechanical Characterization of Diesel Particulate Filter Substrates

LaNbO₄–NiO–Y₂O₃ Stabilized ZrO₂ Anode‐Support Materials for Solid Oxide Fuel Cells

Understanding the ballistic event: methodology and initial observations

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Fracture Toughness of Thin Plates by the Double-Torsion Test Method

Cited by 9 publications

References 10 publications

Mechanical Characterization of Diesel Particulate Filter Substrates

Mechanical Characterization of Diesel Particulate Filter Substrates

LaNbO4–NiO–Y2O3 Stabilized ZrO2 Anode‐Support Materials for Solid Oxide Fuel Cells

Understanding the ballistic event: methodology and initial observations

Contact Info

Product

Resources

About

LaNbO₄–NiO–Y₂O₃ Stabilized ZrO₂ Anode‐Support Materials for Solid Oxide Fuel Cells