Design and analysis of a morphing composite airfoil using unbalanced layup and unconventional ply angles

Abstract

Design of morphing wings is being considered as a potential way to improve aircraft performance. Composite materials are identified as suitable candidates to achieve some of the future morphing capabilities of aircraft wings. In this work, a morphing airfoil is designed and manufactured using a woven carbon fiber reinforced plastic (CFRP) composite material and a vacuum bagging technique. The layup arrangement and stacking sequence are chosen for maximum out-of-plane deflection under the applied actuation force using finite element analysis (FEA) and composite plate bending experiments. Additionally, manual actuation loads are applied simultaneously at various feasible locations on the airfoil top surface. The morphed airfoil new shape is studied using a JavaFoil airfoil analysis program to investigate its aerodynamic characteristics in terms of lift vs. angle of attack and lift-to-drag ratio vs. angle of attack. It is found that the numbers and locations of actuation forces depend on the flight envelope stage (e.g., take-off and cruising). In general, four factors are identified to have significant effects on the maximum deflection and consequently the ease of the airfoil to morph. These factors are the ply angles, the unbalanced stacking sequence, and the number of actuation forces and their location along the airfoil skin. © 2014 The Japan Society for Aeronautical and Space Sciences.