The FishBAC is a morphing aerostructure that is currently both stiffer than desired in terms of actuation energy and softer than desired for aeroelastic effects. The research aims to remove those compromises by introducing a novel material that can actively change its stiffness. The novel approach is to fill aircraft wings with particles, which can be squeezed together under vacuum pressure to make a stiff aircraft wing. When the vacuum is turned off, the grains unlock, and the wing becomes soft enough to be deformed into a new shape. This allows the wing to immediately adapt its shape to changing operating conditions — reducing noise, drag and, therefore, fuel burned.
The following research includes a new detailed mechanical modelling for morphing structures that are able to switch stiffness using vacuum-packed particles. The model is based on Euler-Bernoulli and Mohr-Coulomb analysis to capture the stiffness response of the particles at different vacuum levels. This model is computationally fast and is able to predict the variation of the stiffness accurately. The experimental and the model results agree with a relative error of less than 5%.