Abstract: “The corrosion of steel is the main problem in stiffened steel plated structures in bridge decks, ship structures and offshore oil platforms. Fiber reinforced polymer composite stiffened plates can be used as an alternative to steel plated structures due to its corrosion resistance, fatigue strength and high strength and stiffness to weight ratio. Large openings are provided in the plated structures for access and service, and the presence of opening influences the strength and failure mode of stiffened plated structures. The main objective of this study is to find the load deflection behaviour, failure mode and strength of stiffened composite plates under inplane and out-of-plane loading. Four glass fiber reinforced stiffened composite plates with and without large opening were fabricated by hand lay-up process using a special lay-up structure to integrate the stiffeners into the flange plate. Initial geometric imperfections in the plate and stiffeners of stiffened composite plates wer”

Keywords: Stiffened composite plates, inplane load, out-of- plane load, large opening, failure mode and ultimate strength.