Finite element simulation of composite ship structures with fluid structure interaction

A finite element tool for structural analysis of a composite multi-hull structure is developed. Two-way fluid structure interaction (FSI) is implemented by coupling finite element analysis (FEA) and computational fluid dynamics (CFD). FEA models have been developed using sandwich construction having composite face sheets and foam core. Two types of analysis were performed; i) hydrodynamic and ii) blast load. In the hydrodynamic case, fluid domain is modeled and wave motion is simulated based on Sea State 5. FSI module is then used to connect FEA with CFD code, CFX. Dynamic response of the hull in time domain is generated. A critical area with high stress gradient is chosen and a sub model is developed with refined mesh. Force and displacement boundary conditions are transported from the global model. Interlaminar stresses and shear stress distribution at the core and girder are then determined. Materials failure criteria for composites and foam are applied on the sub model and structural integrity of each component is checked. In the blast analysis, a sphere is modeled in the fluid domain as a high pressure blast source. Pressure distribution in the hull and global dynamic response are extracted and simulated with respect to time.