A theoretical model on coupled fluid-structure impact buckling (Q2366510)

A model simulating a coupled fluid-structure impact buckling phenomenon is constructed. Based on the experiment, the model is designed as an impact system in which a small imperfection elastoplastic column is attached by its upper end to a large mass and by its lower end to a flat plate; it then perpendicularly impacts a viscous water free surface from a certain drop height or in a certain falling velocity. A one-dimensional compressible inviscid air layer is assumed to exist between the plate and the water free surface. A coupled transversely flexural vibration is induced in the column when the hydrodynamic slamming between the plate and the water occurs during the impact. A mathematical description is given for the model with three sets of coupled dynamic equations; a nonlinear finite element and the Prandtl-Reuss plastic theory are applied to the structure, the one-dimensional continuity and momentum equations of a compressible inviscid fluid are applied to the air, and the two- dimensional Navier-Stokes equations of an incompressible viscous fluid are applied to the water. In numerical analysis, the three sets of coupled equations are first decomposed by a staggered iteration method and then solved by an extended Wilson-0 time integration scheme and a finite difference method.