Abstract
A constrained optimization scheme is developed in order to analyze and design thin-walled, laminated composite, closed cross-section beams with mechanical couplings. Both elliptical and rectangular cross section shapes are considered in order to isolate the influence of the geometry on the coupled modes. The design variables are expressed in terms of material properties, stacking sequence, and number of layers. We focus on finding the optimal stacking sequence for a beam with extension-twist or bending twist coupling with no hygrothermal deformation, and with constraints on the natural frequencies.