Griffith-based analysis of crack initiation location in a Brazilian test

Dual series solution for the standardized ISRM Brazilian disc test modelled as an advancing contact problem

“…Therefore, a failure criterion must be adopted for extrapolating the uniaxial tensile strength from a Brazilian disc test. Usually, the Griffith failure criterion is applied for brittle materials, 34 whereas the von Mises failure criterion is more suitable for ductile material. According to the Griffith failure criterion, 35 crack initiation in rocks occurs when the Griffith equivalent stress (4.4) is greater than or equal to the tensile strength σ T of the brittle material.…”

Accelerating fracture simulation with phase field methods based on Drucker-Prager criterion

“…According to Navidtehrani [5][6][7] Drucker-Prager fracture criterion applicable to brittle or quasi-brittle materials, such as rock or concrete, is shown as follows…”

“…To reproduce the fracture behaviors exhibiting asymmetric tension-compression characteristics, Zhou et al [3]and Wang et al [4] developed new driving force formulations, whereby Mohr-Coulomb criterion can be introduced to phase field fracture modeling. Navidtehrani et al [5][6][7] proposed a general framework for decomposing the strain energy density under multi-axial loading, which enables us to simulate compressive failure in rocks under Drucker-Prager criterion.…”

“…In this paper, we combine the work of Navidtehrani et al [5][6][7] and Lo et al [18,20] to accelerate the fracture phase field modeling of Drucker-Prager failure by using the degradation functions decoupling the phase field and physical length scales. The remainder of the paper is organized as follows.…”

Fracture of bio-cemented sands

“…The samples had a diameter of 70 mm and height of 150 mm, and the applied loading rate was 1.14 mm/min. The tensile strength was measured by means of the so-called Brazilian or indirect splitting test [26], using disk samples of diameter 70 mm and thickness 30 mm, in accordance with the standard ASTM D2936. The relationship between porosity p and CaCO 3 mass fraction was obtained from the bulk dry density ρ by using the usual relation:…”