On a small size floating dock structural analysis in oblique design waves by 3D-FEM approach

Abstract

In this study we have enhanced the structural assessment analysis of a river-shipyard small size floating dock, with length overall of 60 m, for equivalent quasi-static oblique design wave conditions. The small size floating dock hull has two constructive layouts for the water ballast side tanks. The oblique design wave heading angle is in the range of 0 to 360 deg. The floating dock equilibrium in oblique equivalent design waves is achieved by own non-linear three parameters iterative program. The numerical analyses are done on full extended 3D-FEM structural models, from side to side and from stern to bow, of the small size floating dock, with specific boundary conditions for global and local strength computations. The modelling of the external oblique equivalent design wave pressure has requested to develop specialized user functions into FEM code. There are considered several loading scenarios of the small size floating dock, according to the shipbuilding classification societies. The structural assessment is based on three criteria: yielding stress, buckling and freeboard limit values. The numerical results of the structural assessment for the small size floating dock in oblique equivalent design waves made possible to establish the wave design height limits, according to the safety criteria restrictions.