Abstract
Large deployable space membrane structures are developing in recent years as Gossamer spacecraft for solar-sail, sun shield, and etc. To design the deployable membrane structures, the structural characteristics are significant to examine the deployment configuration, vibrational and dynamic properties of the membrane structures. However, the initial deformation on the membrane due to the folding line and wrinkle with plastic deformation is not negligible for evaluating the mechanical properties because it is very large with respect to the membrane thickness. This paper investigates the effects of relatively large initial deformation of membrane on the vibration properties numerically under the assumption that the initial deformations are random that has a band spectral of wavelength observed in the solar sail "IKAROS". Finally, it was revealed that the initial deformation on the membrane affected the vibration properties of the membrane drastically.
