Research on optimal design of curvilinearly stiffened panels

For the optimal design of innovative curvilinearly stiffened panels with several design variables, a parameter design approach is proposed to minimize the weight of stiffened panels subjected to constraints on buckling, Von Mises stress and crippling. MSC.PATRAN/NASTRAN are utilized to build panels' model parametrically and get structural responses, respectively. A non-dominated sorting genetic algorithm II (NSGA-II) is adopted to obtain the optimal design. In order to create the geometry of curvilinear stiffener reasonably and briefly, location and shape of stiffener's axis are defined in B spline based on the coordinates of start point, end point and control point. Placement and shape variables, as well as sizing variables including thicknesses and heights of stiffeners, and plate thickness, are optimized simultaneously in a single run using the one step strategy. Subjected to in-plane compress and shear loadings, quadrilateral simple supported panels stiffened with straight/curvilinear stiffeners are optimized to the minimum weight designs, respectively. The results show that in complex loading condition, panel stiffened with same number of curvilinear stiffeners, could improve its structural efficiency, and achieve structural weight reduction.