STRUCTURAL DYNAMIC AND STABILITY ANALYSIS OF A STRIPPED SOLAR SAIL

Propelled by solar pressure, solar sail is thought as the most promising interstellar exploration technology. Two kinds of solar sail architecture have been proposed: boom-supporting solar sails and rotating solar sails, among them, stripped solar sail whose membrane is divided into separate narrow membrane strips is the ideal architecture for boom-supporting solar sails. How to precisely calculate structural dynamic characteristics of a stripped sails is worth studying. In this paper, the dynamic characteristics and stability of a stripped solar sail is studied. The whole solar sail structure is regarded as an assembly consisting of several sequentially connected boom-strip components, and one boom-strip component includes four boom segments and four membrane strips. In the stripped solar sail, the booms are under multiple-step axial loads and their vibrations are coupled with the vibrations of stripped membranes. Considering the coupling effects between booms and membrane strips, a closed form vibration model of the stripped solar sail is established by the distributed transfer function method. Based on this model, vibration characteristics and buckling loads of the stripped solar sail can be determined accurately and efficiently. Numerical results indicate that stripped solar sail architecture benefits to enhancing structural stiffness and stability, the more membrane strips will provide the higher stiffness and buckling loads, increasing membrane pre-stress will decrease base frequency of the stripped solar sail and worsen the structural stability, free vibration frequencies and buckling loads will increase with stiffness of the supporting booms. This presented analytical method is more efficiency and accurate than the numerical methods, which provides an efficient analysis tool for structure design and attitude control of stripped solar sails.