Modelling the Brittle Rock Failure by the Quaternion-based Bonded-Particle Model in DEM

This research investigates brittle rock failure using a quaternion-based bonded-particle model within the discrete element method (DEM). Unit quaternions represent particle spatial rotations, enabling the computation of relative displacements and bonding forces. Validation is achieved through uniaxial compression tests, yielding good agreement with established experimental data. Findings reveal that stress oscillation, uniaxial compression strength, and failure patterns in solids are predominantly influenced by the loading strain rate. Increasing strain rates lead to intensified oscillations in the strain-stress curve due to force wave interactions and solid deformation inertia. A quasi-static loading condition with minimal stress oscillation is attainable only at very low loading strain rates. Brittle failure initiates with the nucleation of internal damage, forming interconnected failure planes that grow in area with increasing loading strain rates, ultimately transforming the failure pattern from localized damage to complete fragmentation.