Effects of specimen size and crack depth ratio on calibration curves for modified compact tension specimens

Abstract

The compact tension (CT) test is frequently used to determine fracture properties of metallic materials, such as fracture energy, fracture toughness, crack propagation rate and J-R curves. In the case of cement based composites, a modified compact tension (MCT) specimen can be advantageously used due to the negligible stress concentration arising around the pulling dowel pins during the test. In this work, finite element calculations are used to determine the calibrations curves for the stress intensity factor K, COD, CMOD and CMOD(4), needed for an accurate determination of the fracture parameters, as a function of the ratio a/W. Nominal diameters are selected according to the used core bits between 50 mm and 300 mm.