The influence of coupling on the free vibration of anisotropic thin-walled closed-section beams

solution procedure for thin-walled laminated composite beams is presented. Two configurations are considered, producing extension-twist and bending-twist coupling, respectively. The influence of coupling on the characteristic equations for free vibration is isolated. It is shown that the characteristic determinant for extension-twist coupling can be expressed as the product of the two decoupled ones. For the ease of bending-twist coupling, a simple-quasi