Study of Fluid-Structure Interaction in Elastic Structures Based on Improved SPH Method

An improved smoothed particle hydrodynamics (ISPH) solver is developed for free-surface flows interacting with elastic structures. The solver couples Riemann SPH and Hamiltonian SPH formulations. A conservation limiter is introduced into the fluid continuity equation to balance density-diffusion contributions, while a limiter in the structural momentum equation regulates numerical diffusion. The method is assessed through fluid and structural tests, three fluid–structure interaction benchmarks, and dam-break impact experiments at initial water depths of 0.20, 0.30, and 0.40 m. The results show that: (1) the modified fluid formulation balances the global density-diffusion contributions in the investigated benchmark, producing a smoother pressure field and closer agreement with the analytical pressure history; (2) the structural modification improves displacement predictions, with the total-energy deficit remaining below 1.5% in the cantilever-plate simulations. In the elastic-gate benchmark, horizontal and vertical displacement similarities increase from 91.2% and 89.4% to 93.5% and 90.9%, respectively; (3) the dam-break simulations reproduce the principal flow evolution and plate displacement responses. At an initial water depth of 0.30 m, the ISPH response spectral peaks at 2.76, 6.10, and 9.49 Hz agree more closely with experimental values than the original SPH predictions. The compared interface forces are equal in magnitude and opposite in direction, supporting the consistency of the coupling-force transfer. These findings support improved prediction of fluid pressure, structural displacement, and response frequency characteristics under the investigated conditions.