Modelling and Experiments of Additively-Manufactured Fluid Actuated Morphing Unit Structures

Abstract

Fluid actuated morphing unit structures (FAMoUS) enable shape adaptability when implemented in larger sys-tems or vehicles, such as aircraft wings, in order to improve overall performance such as increased efficiency. FAMoUS units are composed of reinforced elastomeric chambers that tend to elongate when pressurized by air or liquid whilst preserving a relatively smooth outer surface, thereby combining the skin, substructure and actuation components into a tightly integrated compact package. A number of research challenges need to be first over-come and this paper presents numerical and experimental results of single FAMoUS units that have been pro-duced with additive manufacturing methods. With the specific composition of elastomeric and stiffening materi-als, the units exhibit actuator behaviour by generating force and stroke which can be used for carrying loads and changing shape. Approximating equations for force generation show that dependencies on pressure, material stiffness and incompressibility and geometry exist. Methods for fabrication include additive manufacturing though the associated material properties need to allow for sufficient strength for adequate force generation and stiffness. Specimens printed with real silicone elastomers and ongoing tests are hypothesized to show substantial-ly higher strength, working pressures and force than those with PolyJet® rapid prototyping materials.