Experimental and numerical analysis of indirect and direct tensile strength using fracture mechanics concepts

Brazilian tests were conducted on an isotropic limestone with different length-to-diameter ratios and various bearing strip widths. The direct tensile strength of the rock specimens was also obtained using direct tension test apparatus and a servo-control testing machine. The Brazilian test was modeled using the computer program (Abaqus 6.7-1) and both smeared rotating crack and cohesive crack models were selected for the analysis of crack propagation. Comparison of the experimental and numerical analyses showed that the results from the smeared rotating crack model were closer to the experimental results than those from the cohesive crack model. Appropriate testing conditions for the Brazilian test are proposed, in order to achieve the results closest to the direct tension test.