Wrinkling prediction of cylindrical and conical inflated cantilever beams under torsion and bending

The combined load case of bending and torsion of a cantilever inflated beam is a load case that has not been studied extensively. When a series of inflated beams is placed parallel to each other as can be the case for an inflatable wing, each beam experiences a combination of torque and bending. A theoretical model already exist for such a load case but it is limited to membrane like materials. This paper deals with beams made of materials that need to be treated like a shell. It requires a modification for the wrinkling load due to solely bending and solely torsion. Semi-empirical expressions for both cases are presented for both cylindrical and conical shaped beams.