A 2D energy-conserving contact model for the combined finite-discrete element method (FDEM)

Abstract

The combined finite-discrete element method (FDEM) has been widely used to simulate the progressive fracturing of brittle materials from continua to discontinua. However, due to the relatively simple definition of contact potential, the contact interaction algorithm utilized in the original FDEM is element size-dependent. As a result, a non-smooth and fluctuating contact force direction can occur when a contact point moves from one area of an element to another, and the contact interaction algorithm may fail to accurately evaluate the tangential contact force. To circumvent these limitations, we adopt an energy-conserving model developed recently to calculate the contact force in 2D FDEM, in which the magnitude and direction of contact force can be directly determined by geometrical features. A suite of numerical benchmarks is conducted to validate the effectiveness and robustness of the proposed method for contact interaction processing between discrete bodies, and the advantages of the proposed method are also demonstrated. As an application, two typical examples are performed to systematically explore the potential of the proposed approach for evaluating the stability of rock mass and rock slope. The proposed contact model may help enhance the applicability and accuracy of FDEM for rock fracturing simulation.