Coupled SPH–FEM modeling of waterjet-assisted coal cutting: Numerical simulation and experimental validation

Coal remains a cornerstone of global energy supply, driving the need for more efficient and technologically advanced extraction methods. This study introduces a numerical framework that couples the Smoothed Particle Hydrodynamics (SPH) with the Finite Element Method (FEM) to model the dynamic response of coal under waterjet-assisted cutting—an emerging technique recognized for its applicability, minimal stress disturbance, and safe working conditions in underground mining. Implemented in LS-DYNA, the model captures two-phase fluid–solid interactions, including jet-induced fracture initiation, propagation, and material removal. A detailed parametric investigation evaluates the effects of jet velocity, nozzle diameter, impingement angle, and cutting duration on coal fragmentation behavior. Model predictions were rigorously validated through controlled laboratory experiments, achieving reliable correlation with empirical results—showing mean absolute errors of 7.2 % in Cutting Depth (CD) and 5.8 % in Cutting Volume (CV). To address the performance constraints of Pure Water Jet (PWJ) systems, extended simulations were conducted for Abrasive Water Jet (AWJ) and Ice Abrasive Water Jet (IAWJ) techniques. The AWJ configuration enhanced CD and CV by 51 % and 66 %, respectively, while IAWJ achieved up to 20 % improvement over PWJ. Stress field analysis further revealed that increased jet velocity is significantly more effective than nozzle enlargement in maximizing cutting efficiency. These findings not only validate the SPH–FEM model as a predictive tool but also offer actionable insights for optimizing next-generation waterjet systems in deep coal mining applications.