The authors have developed the optimization systems for hull construction of vessels via genetic algorithm in the initial design process. Since finite element analysis requires a lot of computational resources, it is impossible to evaluate strength for principal structural members of vessels in these optimization processes. In this paper, simplified evaluation methods of buckling strength and natural frequency for stiffened panel are investigated. Good agreements of solutions between these proposed methods and finite element analysis are observed in numerical examples. These proposed methods can estimate buckling strength and natural frequency for stiffened panel very easily and accurately. Hence, it becomes possible to take account of them in the optimization systems for hull construction of vessels via genetic algorithm.
The authors have developed the optimization systems for hull construction of vessels via genetic algorithm (Li and Furuno et al.,2000; Furuno and Kitamura,2001a), and have established simplified evaluation methods for hull structural strength in the initial design process, (Katoh and Li et al.,1998; Furuno and Katoh et al.,2001b; Furuno and Kitamura,2001c; Furuno and Katoh et al.,2002). In the structural optimization for hull construction, strength evaluations of principal structural members are needed because these structural members are required to satisfy constraint conditions for deformations, stresses, and so on. However, the strength evaluations by finite element analysis are impossible because the structural optimization with genetic algorithm needs a lot of design candidates resulting in tremendous computational resources. In this paper, simplified methods for evaluating the buckling strength under combined bi-axial thrust condition and natural frequency in corporating with added mass effects for the stiffened panel are investigated. Fujikubo and Yao (1999a and b) already developed the closed form formula for elastic buckling strength of stiffened panel considering interactions among panel, stiffener web, and flange.
