Data-driven enhanced FDEM for simulating the rock mechanical behavior

Abstract

In this paper, a data-driven enhanced combined finite-discrete element method (DDFDEM) is proposed to simulate the rock mechanical behavior by directly assigning the rock experimental data into mechanical simulations, thus bypassing the empirical constitutive model of rock. To achieve this, a novel data-driven iterative solver with transient dynamic system equilibrium constraint is first proposed and embedded into the FDEM computing framework. Then, the bonding force update algorithm for crack elements is improved to mitigate the error accumulation during the iteration process. After that, a recommended formation for the proper size of the experimental data set is proposed to balance the computational accuracy and efficiency of DDFDEM, and an efficient nearest neighbor search algorithm is introduced to significantly improve the computational efficiency of DDFDEM. After the above improvements, the computational accuracy and efficiency of DDFDEM in simulating the rock deformation and complex failure process are validated by conducting several examples, including the thin plate tension test, uniaxial compression test, and Brazilian disk test. Finally, the advantage of DDFDEM over conventional FDEM in comprehensively presenting the information hidden behind the experimental data sets is validated by reproducing the nonlinear mechanical behaviors of rock samples based on a data set following the nonlinear elastic material law.