Optimal Design of Stiffened Panel Considering Post-Buckling Behavior

Abstract

In recent years, a feasibility study about ship structural design which allows panel buckling has been performed to bring out the advantage of using high-tensile strength steels. To optimize the structural components based on this design concept, a nonlinear buckling behavior has to be taken into account. This paper proposes a method of optimal design of stiffened panels allowing local panel buckling, subjected to deflection constraint and initial-yield constraint. The method consists of three parts: elastic large deflection analysis, sensitivity analysis and optimization. The first part is performed with analytical solutions assuming sinusoidal buckling deflections. Hence, any order of design sensitivities can be evaluated simply by direct differentiation. The Sequential Linear Programming (SLP) Technique is employed for structural optimization. The minimum weight design is performed for different panels of mild steel and high-tensile strength steel under inplane compression, taking thicknesses of plate and stiffener, stiffener height and the number of stiffeners as design variables. The empirical formula are used to evaluate the magnitude of initial deflection in panels. The advantages of buckling accepted design are discussed in terms of structural optimization.