Constructal Design of Flying Wing Aircraft: Curved and Swept Configurations

Abstract

Constructal law considers the design as a physics principle and uses energy flow configurations (e.g., the flow of stresses through the structure) to explain and predict the time arrow of change and evolutionary design in nature. Here, constructal law is used to explain why swept flying wings achieve higher flutter speed compared with curved wings. This investigation of the aeroelastic instability through the lens of constructal law is a new concept that envisions the evolutionary design of aircraft. Nonlinear Aeroelastic Trim And Stability of HALE Aircraft (NATASHA) performs the aeroelastic stability analyses. NATASHA benefits from geometrically exact, fully intrinsic, composite beam formulation of Hodges combined with Peters aerodynamic model. Variational Asymptotic Beam Sectional Analysis (VABS) conducts stress analysis. The results shed light on how changing the geometry would affect the flow of stresses and stability. The findings reveal an analogy between the instability and stress flow strangulation in the structure. Stress strangulation is observed in both configurations, whereas the curved configuration has lower flutter speed and stress strangulation with larger magnitude. The swept wing configuration provides easier access to the flow of stresses with less stress strangulation and leads to a more stable configuration.