The application of reliability methods in the design of stiffened FRP composite panels for marine vessels

The use of composite laminate materials has increased rapidly in recent years due to their excellent strength to weight ratio and resistance to corrosion. In the construction of marine vessels, stiffened plates are the most commonly used structural elements, forming the deck, bottom hull, side shells and bulkheads. This paper presents the use of a stochastic approach to the design of stiffened marine composite panels as part of a current research programme into developing stochastic methods for composite ship structures, accounting for variations in material properties, geometric indices and processing techniques, from the component level to the full system level. An analytical model for the solution of a stiffened isotropic plate using a grillage analogy is extended by the use of equivalent elastic properties for composite modelling. This methodology is applied in a reliability analysis of an isotropic (steel) stiffened plate before the final application for a reliability analysis for a FRP composite stiffened plate.