Optimal design of tendon-actuated morphing structures: Nonlinear analysis and parallel algorithm

The idea of a morphing aircraft wing has generated considerable interest in recent years. Such a structure has inherent advantages of possessing high maneuverability and efficiency under different flight conditions such as take off, cruise and loiter. The current focus is on achieving continuous wing shape change, as opposed to discrete, in order to help reduce drag. This research aims to achieve continuous wing morphing by employing a wing structure comprising of an optimized internal layout of cables and struts. Cables are employed as actuators while struts provide rigidity to the wing. In addition to achieving continuous morphing by changing cable length, this structure has the advantage of being light in weight. The focus of this paper is on obtaining an optimized cable and strut layout in the body of the wing. Non-linear Finite Element Analysis (FEA) has been performed to account for the large deflection requirements. An objective function that considers deflection under actuation and air loads has been incorporated. Results comparing linear and nonlinear FEA are presented for a particular wing design. The nonlinear finite element is found to be effective when using large actuation forces.