ON THE PRESENCE OF BENDING STRESSES IN INFLATED THIN-WALLED STRUCTURES

It is proposed that, in appropriate circumstances, membrane structures can experience bending moments. On uniformly inflating a thin sheet s tructure, which has a shape consisting of multiple curvatures, the str ucture will deform in such a way that the final shape will have a sing le radius of curvature, assuming that failure does not occur. It is th e large change of shape from a multicurvature surface to a single curv ature surface that causes bending moments to exist within a membrane. The validity of the hypothesis has been demonstrated using four finite element models, including an elliptical cylinder, an ellipsoid, a 'do uble' cone and a trileaflet heart valve.