NUMERICAL AND EXPERIMENTAL ANALYSIS OF THE CHEVRON NOTCHED BRAZILIAN DISC

Resumo

The Linear Elastic Fracture Mechanics (LEFM) tries to describe the fracture and damage
phenomena in materials that obey Hooke ́s law. However some small scale plasticity can be bypassed.
The main studies in the fracture mechanics area come from the energy balance of Griffith, in 1920 and
some improvement with the energy release rate added by Irwin, in 1956. Rocks often features structural
defects, including flaws, cracks, cleavages and natural fractures. Fracture toughness represents the
capability of fragile materials, such as rocks and concretes, containing initial cracks to resist further
fracturing. A widely used test that provide this information to model fracture propagation is the Cracked
Chevron Notched Brazilian Disc (CCNBD). Nevertheless, there is some discussion about the precision
of this test. In this study, mortar specimens had their fracture toughness experimentally assessed by the
CCBND method. Numerical fracture analyses were carried out using the Extended Finite Element
Method (XFEM) trying to reproduce the CCNBD test comparing with the experimental results aiming
to better understand this test.Results indicate that the CCNBD test underestimatesthe fracture toughness
in about 13%.