Investigation of the nonlinear fracture behaviour of ordinary ceramic refractory materials

Harmuth, Harald; Rieder, Klaus‐Alexander; Krobath, M.; Tschegg, E. K.

doi:10.1016/0921-5093(96)10221-5

Cited by 108 publications

(63 citation statements)

References 7 publications

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“…The initial slope k init corresponds to the stiffness of a material and is proportional to an effective modulus of elasticity (Harmuth et al 1996). No significant differences were found between the RT and TR orientations for both species; k init was only slightly higher for yew RT than for yew TR, whereas it was distinctly higher for spruce TR than for spruce RT (Table 1).…”

Section: Characteristic Behaviour Prior To the Load Peakmentioning

confidence: 78%

Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test

Keunecke¹,

Stanzl-Tschegg²,

Niemz³

2007

Holzforschung

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Common yew (Taxus baccata L.) and Norway spruce (Picea abies wL.x Karst.) are gymnosperm species that differ in their microscopic structure and mechanical characteristics. Compared to spruce, the density of yew wood is high, but the modulus of elasticity is low when loaded parallel to the grain. Information about the transverse load direction is largely lacking. Therefore, the goal of this study was to assess the elastic and fracture mechanical behaviour of both wood species in the radialtangential plane (crack opening mode I). For this purpose, micro wedge splitting tests were performed. Characteristic elastic and fracture parameters (initial slope, critical load, specific fracture energy) were determined. After the tests, the fracture surfaces were evaluated using microscopic methods. The results reveal clear differences between the species regarding microscopic fracture phenomena and prove that yew wood was significantly stiffer than spruce wood. We suggest that the density and the cell geometry are predominantly responsible for both elasticity and failure behaviour in the transverse direction.

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Section: Characteristic Behaviour Prior To the Load Peakmentioning

confidence: 78%

Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test

Keunecke¹,

Stanzl-Tschegg²,

Niemz³

2007

Holzforschung

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“…The opposite may also occur, since the aggregates may be strongly bonded to the mortar, becoming fractured during the crack opening process 1,2,12 . To study the fracture behavior of the mortar and concretes, the wedge splitting method was used to produce stable crack propagation in the sample, which is a necessary situation for calculating fracture energy [17][18][19][20][21][22][23][24][25] . The wedge splitting method was patented in 1986 by Tschegg 26 and since then numerous studies have focused on improving this test, which is currently performed with well designed and accurate devices, as well as highly accurate testing machines.…”

Section: Introductionmentioning

confidence: 99%

Study of the fracture behavior of mortar and concretes with crushed rock or pebble aggregates

Ribeiro

Dias

et al. 2011

Mat. Res.

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The objective of this work was to compare the fracture energy of mortar and concretes produced with crushed rock and pebble aggregates using zero, 10, 20, 30 and 40% of aggregates mixed with standard mortar and applying the wedge splitting method to achieve stable crack propagation. The samples were cast in a special mold and cured for 28 days, after which they were subjected to crack propagation tests by the wedge splitting method to determine the fracture energies of the mortar and concrete. The concretes showed higher fracture energy than the mortar, and the concretes containing crushed rock showed higher resistance to crack propagation than all the compositions containing pebbles. The fracture energy varied from 38 to 55 J.m -2. A comparison of the number of aggregates that separated from the two concrete matrices with the highest fracture energies indicated that the concrete containing pebbles crumbled more easily and was therefore less resistant to crack propagation.

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“…em que d(U M +U S )/dc é a variação das energias elásticas armazenadas na máquina (U M ) e na amostra (U S ) por unidade de propagação de trinca (dc), sendo essa, portanto, a variação da energia potencial, e dW fs /dc é a variação da energia de superfície (dW fs ) por unidade de propagação de trinca [11,16,18], representando a variação da energia consumida durante o processo de propagação. Até pouco tempo atrás a energia de fratura de refratários era predominantemente determinada pelo método da barra prismática entalhada e flexionada em três pontos, conforme esquematizado na Fig.…”

Section: This Paper Discusses the Design And Installation Of Devices unclassified

“…F H e β são, respectivamente: força horizontal para a abertura da trinca e ângulo da cunha [10], (b) geometria da amostra, dimensões e secção transversal mostrando a região por onde a trinca propaga (medidas em mm) [11], (c) detalhes do entalhe, das ranhuras laterais e da secção de fratura após teste. 0,4 da altura, restando assim pequena área de fratura.…”

Section: And (B) Cross Section Showing the Region Where The Crack Prunclassified

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Projeto, adaptação, instalação e testes preliminares para um sistema de medida de energia de fratura de materiais cerâmicos pelo método da cunha

Ribeiro¹,

Exposito

Rodrigues

2008

Cerâmica

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Este trabalho discute o projeto e a instalação dos dispositivos para determinação da energia de fratura em materiais cerâmicos utilizando o método da cunha patenteado, além dos resultados preliminares de carga máxima e energia de fratura para duas argamassas. Para testar o sistema, e conseqüentemente implantar o método, foram preparadas argamassas com cimento Portland, areia e água, moldadas, curadas a 25 ºC por 7 dias e secas a 50 ºC por 48 h. Foram caracterizadas duas proporções de areia:cimento de 3:1 e 2:1. A partir dos testes preliminares foram estabelecidas as condições de propagação estável da trinca. A trinca percorre um plano imaginário definido por ranhuras laterais da amostra. O método está plenamente instalado e pronto para o desenvolvimento de trabalhos sistemáticos correlacionando energia de fratura e microestruturas de refratários e cerâmicas em geral, incluindo materiais para construção civil. Além do pleno funcionamento do método para temperatura ambiente, os resultados mostram que a técnica é sensível aos aspectos microestruturais do material caracterizado, distinguindo, neste trabalho, entre as duas composições de argamassas empregadas.

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Investigation of the nonlinear fracture behaviour of ordinary ceramic refractory materials

Cited by 108 publications

References 7 publications

Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test

Fracture characterisation of yew (Taxus baccata L.) and spruce (Picea abies [L.] Karst.) in the radial-tangential and tangential-radial crack propagation system by a micro wedge splitting test

Study of the fracture behavior of mortar and concretes with crushed rock or pebble aggregates

Projeto, adaptação, instalação e testes preliminares para um sistema de medida de energia de fratura de materiais cerâmicos pelo método da cunha

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