The relationships between macro- and micro-mechanical parameters for modeling diamond rock cutting using DEM

Abstract

Micro-mechanical properties of particles are critical for DEM modeling. However these properties can not be measured in laboratory experiments as the particle model used in DEM is hypothetical. Therefore in practice, these micro-properties can only be obtained by numerical experiments (calibrations) using the DEM model. There are many parameters involved and all of them are important for the behaviors of the model. There is no prescribed way to derive these parameters and trials and errors is the most commonly used method in the calibration process. For a specimen of a given setup (i.e. particle size, specimen size), the micro-mechanical properties are changed systematically until the set of parameters used give the macro-mechanical properties that best match the actual properties of the rock. In these research, we try to establish the empirical relationships between micro-mechanical parameters, such as particle modulus, stiffness, friction coefficient and bond strength, and macro-mechanical properties of rocks, such as UCS, Young's modulus and Poisson's ratio for modeling rock cutting using diamond impregnated drill bits. The factors influencing these relations are also investigated, which include specimen size (scale), particle size and number of particles in the calibration model. The VLA of PFC3D is used for this research.