ABSTRACT

Materials used in ship industry usually change in parallel with technological advancements. Boats formed by connecting tree logs in ancient times were replaced by boats made of processed wood over time. Then, large and durable ships made of iron began to be produced when metals could be melt and formed. Composite is a structural material formed by the combination of two or more constituent materials. Polymer matrix composites are commonly used in shipbuilding industry. In these composites, polyester, epoxy or vinyl ester are used as resin whereas glass fiber, carbon fiber or aramid fiber are used as fiber. Composite boats are subjected to certain standards and rules while being produced. Scantling of a boat under 24 meters is determined within the framework of the rules set by the International Organization for Standardization (ISO). The standards allow for the calculation of the design loads that the plates and support elements must withstand. In this study, the bottom plate of a composite boat is optimized to reduce production costs. A top-hat stiffened composite plate which was studied in the literature is examined. The design loads are determined according to the International Organization for Standardization. The plate is modeled and analyzed by a commercial finite element analysis software. For the structural optimization, the most suitable orientation sequence is first identified. Then, by using the determined orientation sequence, plate width, stiffener height, and layer thickness parameters are optimized. As a result, it is shown that sufficient strength can be achieved with much less material by optimizing the angle and layer only on the plate without the need for additional reinforcement.