Effect of Internal Gas on Modal Analysis of Space-Inflatable Structure

A study was conducted to investigate the follower pressure effect and fluid?structure coupling effect of enclosed air on the modal analysis of the inflated torus simultaneously using the nonlinear finite element method (FEM). It was demonstrated that the internal pressure always remains normal to the changed Surface when the surface of the torus changes during Vibration, and this follower pressure effect produced an important stiffness called follower pressure stiffness. The investigations also showed that the internal gas had important effects on modal analysis of space inflatable structures, and that the effects of the internal gas could not be neglected and needed to be considered.