<i>J</i>‐Integral Measurements of the Fracture of 50% Alumina Refractories

Homeny, J.; Darroudi, Taghi; Bradt, R. C.

doi:10.1111/j.1151-2916.1980.tb10731.x

Cited by 25 publications

(20 citation statements)

References 10 publications

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“…The two methods require identification of the crack which is propagated. Alternatively, Bradt et al (58) proposed a method for refractory materials with marked non-linear behaviour. The method is based on the difference in areas between the load-displacement curve of an un-notched specimen of the material, where linear elastic behaviour is assumed, and the load-displacement curve of a notched specimen of the same material, which presents nonlinear behaviour (Fig.…”

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

“…[16]. For materials which present real or apparent ductility, the fracture toughness value, J IC , thus obtained is higher than the critical energy release rate (G IC ) (35,58) and corresponds to that of the component or structure of the same material whose integrity is analyzed if it is in the same deformation state as the beam tested.…”

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

“…There are different methods for calculating the critical Jintegral value, J IC , (58,(87)(88). The majority of them are based on the calculation of the energy absorbed by pre-cracked specimens, determined on the basis of the area under the load -crack opening displacement curves (87).…”

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

“…Fig. 10-Representation of the procedure followed to calculate the critical J-integral value, J IC , (58). The curve corresponds to a material of alumina+40vol.% aluminium titanate tested in three points bending.…”

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

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Comportamiento mecánico de materiales cerámicos estructurales

Bueno¹,

Baudı́n²

2007

Bol. Soc. Esp. Ceram. Vidr.

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The use of ceramic materials in structural applications is limited by the lack of reliability associated with brittle fracture behaviour. In order to extend the structural use of ceramics, the design of microstructures which exhibit flaw tolerance due to toughening mechanisms which produce an increase in crack growth resistance during crack propagation has been proposed. This work is a review of the mechanical behaviour of structural ceramic materials and its characterisation. Firstly, the basic brittle fracture parameters and the statistical criteria to determine the probability of exceeding the safety factors demanded for a particular application are analysed. Then, the toughening mechanisms which can be developed in the materials through microstructural design as well as the mechanical characterisation of toughened ceramics are discussed. The experimental values of linear elastic fracture toughness parameters (critical stress intensity factor, K IC , and critical energy release rate, G IC ) are not intrinsic properties for toughened materials and depend on crack length and the loading system. In this work, the different mechanical parameters proposed to characterise such materials are reviewed. The following fracture parameters are analysed: work of fracture (γ WOF ), critical J-integral value (J IC ) and R-curve. For the determination, stable fracture tests are proposed in order to ensure that the energy provided during the test is no more than the necessary one for crack propagation.Keywords: Microstructure, Strength, Weibull modulus, Fracture toughness, Toughening mechanisms. Comportamiento mecánico de materiales cerámicos estructuralesEl uso de los materiales cerámicos en aplicaciones estructurales está limitado por la falta de fiabilidad asociada a su comportamiento frágil durante la fractura. Para extender su aplicación se ha propuesto el diseño de microestructuras que presenten tolerancia a los defectos debido a la actuación de mecanismos de refuerzo. Este trabajo es una puesta al día sobre el estudio del comportamiento mecánico de los materiales cerámicos estructurales y su caracterización. En primer lugar, se revisan los parámetros de fractura utilizados para caracterizar materiales frágiles y los criterios de control estadístico que permiten determinar la probabilidad de que se sobrepasen los factores de seguridad exigidos en cada aplicación. A continuación, se discuten los mecanismos de refuerzo que se pueden desarrollar en los materiales cerámicos a través del diseño microestructural. En los materiales cerámicos en los que la actuación de mecanismos de refuerzo conduce a un comportamiento significativamente distinto del puramente frágil, los parámetros derivados del tratamiento lineal elástico (factor crítico de intensidad de tensiones, K IC , y tasa crítica de liberación de energía, G IC ), determinados experimentalmente, dejan de ser propiedades intrínsecas del material, independientes del tamaño de grieta y el sistema de carga. El presente trabajo revisa los parámetros mecánicos propuestos para...

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Section: Determination Of Fracture Parametersmentioning

confidence: 99%

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

See 2 more Smart Citations

Comportamiento mecánico de materiales cerámicos estructurales

Bueno¹,

Baudı́n²

2007

Bol. Soc. Esp. Ceram. Vidr.

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“…The strength measurements thus corroborate the acousto-ultrasonic evaluation that the crack growth in the refractory is quasi-static. Homeny and Bradt [8] studied the single quench thermal shock damage in high alumina castable refractories by measuring flexural strength and observed that the crack growth was quasi-static in all the refractories. AT ("C)…”

mentioning

confidence: 99%

Acousto-ultrasonic study of thermal shock damage in castable refractory

1991

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Thermal quenching of a brittle solid-like refractory leads to quasi-static or dynamic propagation of cracks resulting in decrease of strength [1,2]. Very little work seems to have been done to characterise and monitor thermal shock damage in refractories non-destructively [3][4][5]. Acousto-ultrasonics is a recently developed system for measuring the efficiency of stress wave energy transmission in a material [15]. Since flaws such as micro-cracks, voids, delamination, debonding etc. lead to decrease of stress wave energy transmission, acousto-ultrasonics has the potental to detect and measure the state of defect or damage in a material and thus predict its strength properties non-destructively [7]. In this letter the potential of acousto-ultrasonics in non-destructive evaluation of thermal shock damage in an aluminosilicate castable refractory has been investigated.The castable refractory chosen for the study was prepared using non-plastic fireclay grog and calcium aluminate cement. The fire-clay was calcined at 1450 °C with 5 h of soaking. The grog and cement contain 41. and 74% A1203 respectively. The mix composition was formulated using 82.5% grog and 17.5% cement. The different size fractions, viz.(-10 + 20), (-20 + 100) and -100 mesh ASTM, were used with a view to obtaining high packing density. The aggregate and the binder were mixed with 15% water and then cast into 50 mm cubes in steel moulds by hand poking and slopping technique. After 48 h the samples were dried at 110 °C and then fired at 1300 °C in a programme controlled electric furnace with 2 h of soaking. The apparent porosity and bulk density of the castable refractory were found to be in the range of 31 to 32% and 1.84 to 1.86 g crn -3 , respectively.Single quench thermal shock tests of the fired samples were done by quenching in water at room temperature (20 + 1)°C. The fired samples were heated in an electric furnace at 800, 1000, 1200 and 1300 °C and equilibrated for 30 min. The samples were then removed from the furnace and rapidly quenched in water. The quenched samples were again dried at 110 °C for 24 h.The fired as well as quenched refractory bodies were then evaluated by non-destructive acoustoultrasonic technique followed by measurement of compressive strength. Measurement of stress wave factor was carried out using the acousto-ultrasonic equipment (AET 206 AU, Acoustic Emission Technology Corporation, USA). The ultrasonic and 0261-8028/91 $03.00 +. 12 © 1991 Chapman and Hall Ltd. acoustic emission transducers were placed firmly on two smooth parallel surfaces of the cubic specimens with AET couplant SC6. The measurement was done in the pulse mode with a trigger rate of 500 p.p.s., gate width 250/zs, gain 60 riB, rate 1 s, threshold voltage 0.5 V and scale 100. The compressive strength was determined with a crosshead speed of 2 mm rain -1 using Instron Universal Tester 1185. The data presented in the paper are based on the average of at least six tests. The confidence limit shown is 95%.The effect of thermal quenching on the stress wav...

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Mathematical Software for Experimental Methods of Ceramics Investigations

Gogotsi¹,

Groushevsky²

1986

Computational Mechanics ’86

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J‐Integral Measurements of the Fracture of 50% Alumina Refractories

Cited by 25 publications

References 10 publications

Comportamiento mecánico de materiales cerámicos estructurales

Comportamiento mecánico de materiales cerámicos estructurales

Acousto-ultrasonic study of thermal shock damage in castable refractory

Mathematical Software for Experimental Methods of Ceramics Investigations

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