Nonlinear analysis and optimization of diamond cell morphing wings

In this work, a two-stage design optimization procedure is developed to explore the effect of optimal actuator placement and position on energy efficiency in morphing wings. Diamond-shaped cells similar to NextGen's Batwing concept are used to examine this procedure. The finite element model considers elastic skin, actuator, and aerodynamic loads. Force displacement and efficiency studies are conducted using one and two unit cells, respectively. The model is then expanded to include multiple unit cells and actuators. A two-stage optimization process using a Genetic Algorithm and gradient-based optimization is also developed. The two-stage optimization is used to optimize actuator position and placement for different constraints and load cases. Results show that placement and position optimization produce small gains in energy efficiency; morphing using a soft isotropic skin is more efficient than stiff isotropic or anisotropic skins. In addition, the GA did not use all of the available actuators to maximize energy efficiency. The total actuator mass is also considered and is dependent on the maximum applied force per actuator and the number of actuators in the mechanism.