Structural Analysis and Sizing Optimization of a Composite Advanced Sail Design Concept.

Numerical design optimization coupled with finite-element analysis is applied to an advanced design concept for a submarine sail structure made of composite materials. Through a detailed design sensitivity analysis, the influence of stiffener and skin sizing on the weight and buckling characteristics of the sail structure is quantified. Furthermore, the sail is optimized for minimum weight under a severe loading condition based on two alternative discretization concepts for modeling the variations in skin thickness. The design constraints include the lower-bound limits on load factors corresponding to the lowest 10 buckling modes as well as the allowable normal and shear strains in each ply. The sizing optimization problem is solved using the modified exterior penalty function method. The results indicate that depending on the discretization concept, it is possible to reduce the structural weight by as much as 14% over the baseline model while meeting all the structural design criteria. As part of the postoptimization evaluation of the optimal design models, such response characteristics as the linear and nonlinear buckling were evaluated under a diverse set of loading conditions with the results showing a similar or superior performance as compared to the baseline model. [ABSTRACT FROM AUTHOR]