The intrinsic cohesive zone model (ICZM) has been widely employed in the combined finite-discrete element method (FDEM) to model the fracturing of solids involving transitions from continuous elastic deformation to discontinuous contact interaction. As an improvement to ICZM, the extrinsic cohesive zone model (ECZM) has recently been incorporated into FDEM to overcome the “artificial compliance” problem, which, in the meantime, also enhances the computational efficiency. However, ECZM has the drawback of the “time discontinuity”, in which the non-smoothness of local nodal forces occurs upon the insertion of cohesive elements. To address this issue, we propose an algorithm that achieves time continuity of local nodal forces by equating nodal internal forces with cohesive tractions between adjacent finite element pairs, thereby providing a smooth transition of the progressive fracturing process of rock masses. We benchmark seven numerical cases to verify the accuracy of our method. These simulated results suggest that our method can accurately capture and reproduce failure patterns of rock masses, similar to those observed in experimental studies. This work demonstrates the advantages of our method in modeling rock fracturing, further extending the applicability of ECZM in FDEM. • A new 2D extrinsic cohesive zone model is implemented in FDEM • We propose an algorithm to overcome the ‘time discontinuity problem’ • The effectiveness of the proposed approach for rock fracturing simulation is verified • We eliminate the impediments to the application of ECZM in the FDEM community
Cai et al. (Sun,) studied this question.