Structural Dynamics Model of Multisegmented Folding Wings: Theory and Experiment

Morphing wing research has garnered much attention in the aerospace community over the last decade, and the folding wing is a promising concept that can improve aircraft performance over multiple types of missions. Several high-fidelity analyses of folding wing structural dynamics have been published, but most analyses are specific to certain wing planforms or a fixed number of wing segments. This paper presents a general structural dynamics model that predicts the natural frequencies of a folding wing with simplified geometry but with an arbitrary number of wing segments. The model is derived using beam theory and component modal analysis: the energy expressions and constraint equations are derived from kinematics, and the equations of motion are derived using Lagrange's equations with Lagrange multipliers. Three experimental models are constructed, and the natural frequencies are measured over a wide range of fold angles. The agreement between theory and experiment is within 10% for most data points. The results agree well with trends from existing work, and the model can be used to study the structural dynamics behavior of folding wings as well as similar multibody systems.