A particle-based framework for efficient FSI in compliant thin-walled arteries

Accurate simulation of blood flow in deformable vessels is critical in cardiovascular research for understanding disease progression and informing clinical decision-making. Meshfree Lagrangian particle methods, such as smoothed particle hydrodynamics (SPH), are attractive for patient-specific fluid–structure interaction (FSI) because they naturally accommodate complex geometries, moving interfaces, and strong coupling without repeated remeshing. However, modeling thin arterial walls as full-dimensional volumetric solids is computationally prohibitive, as resolving wall thickness requires very fine solid discretizations and consequently enforces redundant fluid refinement to maintain kernel support near the interface. Here we present an efficient SPH framework in arteries that combines blood flow with a reduced-dimensional deformable shell representation of the arterial wall. By representing the vessel wall with a single particle layer, the method decouples wall thickness from numerical resolution. We develop a robust pipeline that spans from particle generation to the implementation of physiologically realistic simulation processes. The approach is verified against analytical solutions and benchmark tests, and systematically compared with the conventional volumetric SPH wall model, demonstrating comparable accuracy at substantially coarser wall resolution and several-fold reductions in computational cost. Applications to patient-specific carotid and aortic geometries further demonstrate the robustness, efficiency and physiological fidelity of the method, and show that arterial compliance yields distinct pressure/flow waveforms, where rigid-wall simulations exhibit marked spurious oscillations, and alters the spatial distributions of key hemodynamic indices. The proposed particle-based FSI framework provides an efficient and physiologically accurate tool for personalized risk assessment and intervention planning in cardiovascular diseases. • A reduced-dimensional shell-based SPH framework is developed for fluid–structure interaction in thin compliant arteries. • The shell model is validated as an accurate hemodynamic wall boundary for blood flow simulations. • The shell representation achieves faster solid-mechanics convergence than the volumetric model at comparable FSI accuracy. • Patient-specific carotid and aortic arteries are simulated, demonstrating physiologically realistic effects of arterial compliance.