On the Dynamics and Application of Sandwich Hydroelastic Foundation for Offshore Structures and Systems

Subsea systems and structures are constantly being redesigned, reshaped and reconstructed to enhance offshore exploration, production and exploitation activities. Their structural stability and integrity are strongly dependent on the ability of their foundation footings to dissipate vibration energy arising from external influences such as hydrodynamic forces and propagation of seismic waves through a moving seabed or ocean floor. In this paper, the dynamic behavior, suitability and application of sandwich hydroelastic foundation system for vibration control and enhancement of structural stability in subsea structures is investigated analytically. By employing mechanics of contact and laminated thin plate theory, a well posed boundary value partial differential equation is formulated for a fluid-structure-soil interaction model of slip damping mechanism. For this problem, the proposed sandwich foundation footing is assumed to be partially buried on a moving seabed and is idealized as two sandwich homogenous hydroelastic plate layers in a moving elastic subsoil layer. By assuming linear pressure profiles across the plate axes, the effects of varying pressure gradients and subsoil layer sliding velocities, across the foundation axes, on the energy dissipation mechanism are computed for design analysis and applications.