Steel or composite car deck structure – a comparison analysis of weight, strength and cost

Paper in proceeding, 2015

Stiffened panels play a significant role in marine industry because of their high strength-weight ratio, they account for a significant amount of a vessel’s weight. Hence, weight optimization of these struc-tures can reduce the material costs and to a great extent increase the cargo capacity of a vessel. The paper looks into the performance of car deck structures made of steel and composite materials for a Pure Car and Truck Carrier (PCTC): three steel car deck panels and two conceptual designs made of composite materials. The panels’ performance is compared against criteria such as weight and strength. In addition, the strength-weight ratio of the steel car deck panels was optimized by means of finite element analysis and parametric sensitivity analysis. The panels were modelled with linear elastic materials and a global strength analysis was made with a uniformly distributed load according to DNV rules. For the composite car deck structures, sys-tems engineering methods were used to develop concepts for the joining of and lashing in a predetermined composite car deck section. Conceptual designs were optimized and evaluated by means of finite element analyses with respect to stakeholder defined criteria, such as strength and the maximum allowed deflection during loading. The evaluation and analyses resulted in a composite car deck design composed of a glass fibre reinforced plastic sandwich with balsa core material. For lashing of cars, metal inserts in prefabricated holes were proposed. Finally, a weight and cost estimation performed for four car deck designs is presented.