Numerical Simulation of Aircraft Ditching using FPM Fluid-Structure Interaction Modeling Strategy

Abstract:
Numerical simulations are essential in the aircraft structures design process to assess safety margins and ensure structural integrity. Safe water landings ("ditching") impose extreme transient fluid-structure interaction (FSI) loads on aircraft. Traditionally, these interactions have been managed using simplified added-mass techniques, which often fail to capture nonlinear effects and free-surface topology changes. This paper showcases the modeling strategy of applying the mesh-free Finite Pointset Method (FPM) coupled two-way with the Virtual Performance Solution (VPS) explicit Finite Element Method structural solver to holistically model external ditching phases (impact, landing, and flotation). Guided high-speed panel tests at flight-representative velocities and legacy model-scale datasets are used to evaluate pressure timing, magnitude, and structural response. We examine gauge-pressure cut-off treatments for robustness during cavitation/ventilation regimes and explore rough-water effects using validated numerical wave generation. Results demonstrate strong correlation on rigid panels, credible multi-phase pressure histories, and highly stable aircraft-scale kinematics. Crucially, FPM's implicit time integration enables practical engineering runtimes where explicit Smoothed Particle Hydrodynamics (SPH) or meshed Arbitrary Lagrangian-Eulerian (ALE) frameworks would be computationally prohibitive.

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