Nonlinear Negative Stiffness Wingtip Spring Device for Gust Loads Alleviation

A recent consideration in aircraft design is the use of folding wingtips with the aim of enabling higher-aspect-ratio configurations with less induced drag while also meeting airport gate limitations. This study builds on previous work investigating the effect of exploiting the folding wingtips in flight as a device to reduce dynamic gust loads, but now with the introduction of a passive nonlinear negative stiffness hinge spring. A single-degree-of-freedom model and a representative civil jet aircraft aeroelastic model are used to investigate the dynamic gust responses for different hinge device designs. It is found that significant reductions in the dynamic loads are possible.