Static, Buckling and Dynamic Behavior of Inflatable Beams

*† ‡ § A discussion regarding the relation of wrinkling criteria to the membrane collapse loads of inflatable cylindrical beams is presented together with an extension to multi-cell beams and supporting experimental evidence. A simple model is given to illustrate the effect of inflation pressure on the effective shear modulus, which may also be suitable for approximate shear deflection estimates for certain types of beam. Consideration is given to the effect of the difference between the zero bending strain axis (neutral fibre) and middiameter axis for a cylindrical beam. The nonlinear equation of motion for an inflatable beam is derived and basic observations made on the effect of wrinkling on the natural frequencies.