Amin Moosavian

Design and Motion Control of Fully Variable Morphing Wings

The ability to vary the geometry of a wing to adapt to different flight conditions can significantly improve the performance of an aircraft. However, the realization of any morphing concept will typically be accompanied by major challenges. Specifically, the geometrical constraints that are imposed by the shape of the wing and the magnitude of the aerodynamic and inertia loads make the usage of conventional mechanisms inefficient for morphing applications. This paper presents the design of a novel underactuated parallel mechanism, which addresses such concerns. This mechanism, which can be set up in a modular fashion, offers controlled motion in all six spatial degrees of freedom while providing multiple degrees of fault tolerance with only four actuators. The main feature of the design is the usage of active and passive linearly adjustable members to replace the structure of a conventional wing box. These members provide the necessary stiffness and load-bearing capabilities for the wing. With the excepti...

Optimal Configuration Design for the Variable Geometry Wing-Box

In wing morphing, it is desirable to have a system that acts both as a load-bearing structure and a morphing mechanism, without any distinction between the two. When dealing with a rather large design space, designing for this requirement would be less challenging because the constituting structural elements could be topologically placed in a fashion to enhance the static characteristics of the system, without sacrificing its kinematic abilities. However, in the case of an aircraft wing, where the design space is highly restrictive, conventional approaches typically yield inefficient designs from a static perspective. Such restrictions have served as inspirations for the proposed concept of a reconfigurable system, which is able to alter its kinematic and static characteristics to act both as a mechanism and a high-stiffness structure. The optimal configuration design of this system, referred to as the variable geometry wing-box is discussed in this paper. The optimal configuration design problem is posed...

A parametric study on a bio-inspired continuously morphing trailing edge

Inspired by the wave-like camber variation in the trailing edge feathers of large birds, the aerodynamic impact of similar variations in the geometry of morphing wings is investigated. The scope of this problem is reduced by exploring parametrically generated geometries derived from an existing morphing wing design, namely the Spanwise Morphing Trailing Edge (SMTE), which is actuated via conformally integrated Macro Fiber Composites (MFCs). Utilizing this design, the deformation of the trailing edge of the SMTE is parameterized as a function of the spanwise location using a sinusoidal relationship. The aerodynamic responses are then obtained using Computational Fluid Dynamics (CFD) simulations, while the efficacy of the proposed approach is explored using a Pareto-like frontier approach.

Design of a Sliding Morphing Skin with Segmented Rigid Panels

Presented in this paper are a sliding morphing skin and its design methodology. Instead of deforming a skin to morph with the underlying structure, a sliding skin is designed to morph using the relative sliding motion among the segmented panels. To realize this design, a design methodology is developed. It starts with discretizing the original wing skin along the airfoil to determine the number of segmented panels. Then, each segmented panel is designed as a telescopic sliding panel longitudinally, while interlayered laterally with the adjacent panels. To allow for the intended morphing motions, each panel pair is designed to connect to the inboard and outboard ribs via two separate passive linkages. To investigate the feasibility of a sliding skin, a kinematic model is provided to facilitate the establishment of the constraint equations (i.e., the conditions that these panels should meet during morphing). A search method is developed to solve the underlying problem. The proposed method is applied to simu...

Piezoelectrically strained bistable laminates with macro fiber composites

The bistability and snap through capability of an unsymmetric laminate consisting of only Macro Fiber Composites (MFC) are investigated. The non-linear analysis predicts two cylindrically stable configurations when strain anisotropy is piezoelectrically induced within a [0MFC/90MFC]T laminate. This is achieved by bonding two MFCs in their actuated states and releasing the voltage post cure to create in-plane residual stresses. The minimization of total potential energy with the Rayleigh-Ritz method are used to analytically model the resulting laminate. A finite element analysis is conducted in MSC Nastran using the piezoelectric-thermal analogy approach to verify the analytical results. The effects of adhesive properties, bonding cure cycles, MFC layup, and its geometry on the curvatures, displacements, and bifurcation voltages are characterized. Finally, the snap through and reverse snap through capabilities with piezoelectric actuation are demonstrated. This adaptive laminate functions as both the actuator and the primary structure and allows large deformations under a non-continuous energy input. Its snap through capability allows full configuration control necessary in morphing applications.

Effects of speed on coupled sweep and camber in morphing wings

Like birds, bats, and insects, a benefit of morphing aircraft is their ability to adapt to a variety of flight conditions by changing the geometry of their wings, unlike their traditional counterparts which remain designed and optimized typically for a single flight condition. Here we study the coupled effect of multi-scale morphing, namely sweep and camber, for varying velocities. Nine different wing configurations are considered consisting of combinations of three sweep angles and three airfoil profiles. The three sweep configurations include minimally, moderately, and highly swept planforms. The airfoil profiles considered include a NACA 0012 airfoil, a conventionally cambered airfoil, and a reflex cambered airfoil. The study is based on numerical simulations conducted using a Reynolds-averaged Navier-Stokes (RANS) turbulence model for low-Reynolds-number flow. The results for the simulations are presented and discussed with a particular focus on gliding behavior during steady level flight. From the numerical results, there is a clear indication that there are considerable benefits in the proposed multi-scale morphing, modifying the wing and the airfoil shapes at varying velocities.