The Brazilian test: a tool for measuring the toughness of a material and its brittle to ductile transition

Abstract

Due to their brittleness, assembling of ceramics pieces is generally achieved through brazing but thermal stresses during cooling frequently induce cracking of the material used for brazing. In order to check if such damage is avoidable, it is necessary to characterize the brittle to ductile transition (BDT) of the material. Simple compression is not suited for crack studies, because of mixed loading (mode II + compressive mode I cracking). Another type of test, the cylinder splitting test, known as the Brazilian test, can be carried out by applying compressive forces on two opposite generatrix of a cylinder: this causes a uniform tensile stress on the plane containing the axis of the cylinder and the generatrix, leading to mode I cracking. The advantage of this test is to avoid expensive and random machining of brittle samples. This study shows that the Brazilian test is well adapted for the measurement of toughness and the characterization of the BDT of materials whose room temperature behaviour is brittle (silicides, intermetallics etc.).

Fracture Propagation in Brazilian Discs with Multiple Pre-existing Notches by Using a Phase Field Method

“…Fig. 6b presents a schematic diagram of the experimental results from [21,22]. The crack pattern obtained by the phase field modeling is consistent with that of the experimental tests.…”

Relations between indirect tensile and flexural strengths for dry and plastic concretes

“…In the Brazilian test (diametral compression test or indirect tensile testing) the cylindrical sample, with extreme parallel plans, is subjected to a diametrical compression effort applied over a small width throughout its length, evenly, and this restricted load application area helps avoid the stresses concentration in addition to compensate small irregularities on the surface of the sample. Proveti and Michot [10] point out that this test allows a fracture test in mode I (pure stress) and that the stress field in the loading implementation plan is quite uniform, thus the test is fit for study of brittle materials fracture. Although it is not for everyday use in the concrete area, it is widely used on tensile strength measurement of asphalt concrete, aggregates and soils stabilized with hydraulic binders, and for analysis of rocks (especially its vertical strata).…”

Microcrack modelling of Brazilian tensile tests with the boundary element method

“…Several authors (e.g., [13,14]) have suggested performing Brazilian tests on samples with artificially drilled holes in different positions. This allows controlling the point at which the crack propagation starts and enhances the local opening stress.…”