Effect of Creases on the Stiffness of Spinning Circular Membrane

抄録

In this study, the effect of creases on the out-of-plane stiffness of a spinning circular membrane was investigated. A circular polyimide membrane, 600 mm in diameter and 25 µm in thickness, was used. Fanfold and flat-creased circular membranes with 12 fanfold creases in the radial direction, as well as a flat circular membrane without creases, were considered. First, forced vibration experiments on the spinning membranes were conducted in a vacuum chamber and the relationships between the rotation speed and first resonant frequencies were measured to examine the variations in stiffness due to creases. Subsequently, large deformation analyses of the membranes under gravity and eigenvalue analyses of the equilibrium states were conducted using a commercial nonlinear finite element software (i.e., Abaqus), and the fundamental modal frequencies were obtained and compared with the experimental results. The fundamental frequencies without gravity were also numerically analyzed. The author found that the fundamental frequency of the fanfold membrane was almost independent of gravity. Finally, the cause of variation in the fundamental frequencies of the membranes is discussed by estimating the stiffness due to the three-dimensional equilibrium shapes.