The ball on three balls test for strength testing of brittle discs: stress distribution in the disc

Influence of the Specimen Manufacturing Process on the Strength of Carbon‐Bonded Alumina (Al2O3–C)

“…The linear-elastic thin-plate theory [6,12,13] is applicable, in order to calculate an analytical approximation for the stress field in the B3B specimen. In case of a point load, the resulting solution would lead to a tensile stress singularity at the midpoint of the specimen on the bottom side.…”

“…Therefore, a centrically constant pressure load on a circular area with radius b is introduced. This finally results into a limited maximum tensile stress, which is independent on the number of supporting balls [6,14] :…”

“…[5,6] Miniaturized specimens are necessary to overcome the distinctive size dependency of the mechanical properties of the brittle bulk material. The advantage of the applied test set-up is that both specimen dimensions and loading are similar to the size of the filter struts and their mechanical loading during a casting process.…”

Effect of sintering time on the microstructure and mechanical properties of (Ti,Ta)(C,N)-based cermets

“…The flexural strength was measured under uniaxial stress using the ball on three balls test (B3B-test) [24][25][26][27][28], where a disc specimen is supported on three balls and loaded symmetrically by a fourth ball. In this loading situation, the three-point support guarantees three well-defined point contacts.…”

“…At the midpoint of the disc surface opposite of the loading ball, a biaxial tensile stress state exists, which is used for the biaxial strength testing. This test has been recognised to be tolerant for imperfect disc flatness, an imperfection in other small geometries or some misalignment [24,25].…”