Development of 3-D SPH-VCLM coupling method for simulating fluid-structure interaction

In this study, a coupled numerical framework integrating smoothed particle hydrodynamics (SPH) with the Voronoi-cell lattice model (VCLM) is developed and validated for three-dimensional (3-D) fluid–structure interaction (FSI) simulations. The original lattice elemental formulation is extended to achieve a general 3-D representation of geometrically nonlinear structural behavior. The FSI algorithm is further enhanced by introducing a cell-based interaction scheme, where the interactive forces and kinematic information are updated and exchanged between the SPH and Voronoi nodes at the level of individual cell units, ensuring numerical robustness even under the discontinuous displacement fields associated with material cracking and failure. Furthermore, the interaction scheme removes the need for geometric alignment between SPH and Voronoi nodes within the interaction zone, enabling independent generation of the fluid and structural meshes during the preprocessing stage. The applicability of the proposed SPH-VCLM method is demonstrated through five benchmark 3-D problems, involving geometrically nonlinear structural behavior, fluid loading histories, and free-surface flows interacting with structures undergoing small and large rotations, along with fracture. The numerical results confirm that the proposed method provides reliable and predictive capabilities across a broad spectrum of geometric and material nonlinearities using the VCLM interacting with SPH-based free-surface flows for 3-D FSI simulations.