Buckling Alleviation for Joined-Wing Aircraft

A novel mechanism is described that increases the critical buckling load of the rear wing of joined-wing aircraft in an effort to reduce structural weight. The benefits of the joined-wing configuration are briefly discussed, along with its current limitations. The behavior of the modified structure under lift is investigated by conducting a number of linear structural analyses for varying geometric arrangements. It is shown that the mechanism, called the buckling alleviation component, is effective in reducing structural weight for a significant proportion of aircraft geometries, even though there is a tradeoff between the rear wing buckling load and front wing root bending moment. A more detailed structural model is used to investigate the effect of geometric structural nonlinearities. The nonlinear analysis shows that the buckling alleviation component delays the onset of nonlinear behavior and that the critical buckling loads of the conventional configuration are drastically overestimated by the linear analysis, which means that the buckling alleviation component performs much more effectively than the initial linear analysis suggests.