Local Nonlinear Stores Induce Global Dynamical Effects in an Experimental Model Plane

Abstract

This work demonstrates that local nonlinear attachments (stores) can influence the global dynamics of a model airplane under broadband loading by means of nonlinear redistribution of vibrational energy in modal space. Each wing of the model airplane hosts a single store, which is constructed so that, when locked (by a specially designed mechanism), it contributes only mass to the dynamics; when unlocked, it induces nonlinear effects to the system. An experimental study is performed by considering three plane configurations: both stores locked, one store unlocked, and both stores unlocked. The experimental study reveals that, when unlocked, the local stores drastically affect the global dynamical response of the model plane by inducing low- to high-frequency energy transfers in the modal space. These energy transfers significantly enhance the overall dissipative capacity of the plane, without any additional damping. Accordingly, this work promotes a new concept for passively enhancing the inherent dissipative capacity of a complex structure through the addition of local nonlinear attachments. On the other hand, local nonlinearities often arise from the way that stores are attached to wings: for example, clearances. This study shows that such local nonlinearities can induce global effects in the entire aircraft: some of which could be undesired.